Hydrodynamic structures. Hydraulic structures. General information about hydraulic engineering

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1. General Provisions

The branch of science and technology that, through the development of special complexes of structures, equipment and devices, deals with the use of water resources and combats their harmful effects is called hydraulic engineering.

In hydraulic engineering, the following main areas of its application have been identified:

the use of water energy, in which the energy of moving (falling) water is converted into mechanical and then electrical;

reclamation (improvement) of land by irrigating dry areas and draining wetlands, as well as by protecting them from the harmful effects of water (flooding, flooding, erosion, etc.);

water transport - improvement of navigable conditions of rivers and lakes, construction of ports, locks, canals, etc.;

water supply and sewerage for populated areas and industrial enterprises.

All of the listed branches of hydraulic engineering are not isolated, but are closely interconnected and intertwined in the complex solution of water management problems.

According to their purpose, hydraulic structures are divided into general and special. The first, used in all branches of hydraulic engineering, include: water-lifting structures that create pressure and maintain it - dams, dikes, etc.; culverts, serving for useful water intake or discharge of excess water; water supply - channels, trays, pipelines and tunnels; regulatory - for regulating channels, protecting banks from erosion, etc.; connecting, serving to connect pools and various hydraulic structures - drops, fast currents, abutments, separate bulls; ice and sludge disposal and sediment removal. Special hydraulic structures used only in certain conditions include: hydropower - machine buildings of hydroelectric power stations, diversion structures; water transport - locks, canals, port facilities; irrigation and drainage - water intakes, water pipelines, treatment facilities.

Hydraulic structures are usually erected in the form of a complex of structures, including water-lifting, culvert, drainage, transport, energy, etc. Such a complex of structures is called a hydraulic complex. Depending on the purpose, there may be energy, irrigation or shipping (transport) waterworks. However, in most cases, complex waterworks are built that simultaneously solve several water management problems.

Hydraulic engineering construction creates an intensive engineering impact on natural conditions, changing the position of the basis of erosion of the surrounding area in the reservoir area, causing changes in the conditions of supply and movement of groundwater, activating slope processes (landslides), changing the microclimate of the area, etc. In addition, the creation of reservoirs with a large supply of water can cause catastrophic flooding of the river valley below the structure in the event of an accident. All this requires a particularly careful study of the territory where hydroelectric power stations are located.

During the design process, based on the purpose of the structures and specific natural conditions, the selection of the most rational location of the main structures of the waterworks, its layout, the choice of the type and parameters of water-pressure structures, the depth of insertion and support on the base rocks, the interface with the rock mass adjacent to the sides of the valley is made. , as well as construction work schedules.

The history of dams shows that those whose destruction caused terrible disasters collapsed in 2/3 of cases not due to errors in calculations or in the choice of material, but due to deficiencies in the foundations - on poor soils, often water-saturated, which was a consequence of insufficient awareness about the geological and hydrogeological conditions of foundation soils. An example of this is the disaster at the Vajont reservoir in Italy.

In 1959, at the VI Congress on Large Dams, Italian hydraulic engineers L. Semenza, N. Biadene, M Pancini reported on the world's highest arch dam on the river. Vayont, 265.5 m high (70 km north of Venice). The report covered the design features of the dam in great detail. To discharge flood waters on the crest of the dam, a spillway with 10 holes, each 6.6 m long, two tunnel and one bottom spillway was provided. To strengthen the base of the dam, area cementation of the rock is provided, with a drilling volume of 37,000 m3. To prevent filtration under the dam and on the banks, a grouting curtain was installed with a drilling volume of 50,000 m3. The dam was calculated using 4 analytical methods (independent arches, test loads, etc.). In addition, the dam design was studied on two models at the institute in Bergamo (scale 1:35). Model tests made it possible to lighten the dam by slightly reducing its thickness. About the geological conditions, it was only said that the Vayont valley is composed of limestones and dolomites, characteristic of the eastern Alps, that the layers fall upstream of the river and this is favorable for supporting the dam (Fig. 1).

The dam was completed in 1960, and on October 9, 1963, one of the worst disasters in the history of hydraulic engineering occurred, resulting in the death of more than 2,600 people. The cause was a landslide that collapsed into the reservoir. The world's tallest thin arch dam survived; all the designers' calculations turned out to be correct. As the analysis of materials after the disaster showed, geologists did not take into account the fact that the limestone layers form a synclinal fold, the axis of which coincides with the direction of the valley. At the same time, the northern wing is cut by a fault. In 1960, a landslide with a volume of 1 million m3 formed on the left bank near the dam.

In 1960-1961 a 2-kilometer catastrophic spillway tunnel was breached if landslides resume. To monitor the development of landslide processes, a network of geodetic benchmarks was laid, but as it turned out, the benchmarks did not cut the main sliding surface. From 1961-1963 a continuous gravitational creep was observed. Late in the evening of October 9, 1963, 240 million m3 of soil shifted into the reservoir in 30 seconds, at a speed of 15-30 m/s. A huge wave 270 m high crossed the 2-kilometer reservoir reservoir in 10 seconds, overflowed the dam and, sweeping away everything in its path, crashed into the valley. Seismic tremors were recorded in Vienna and Brussels.

Rice. 1. Geological section of the river valley. Vajont (Italy): 1 - Upper Cretaceous; 2 - Lower Cretaceous; 3 - malm; 4 - dogger; 5 - leyas. Numbers in circles: 1 - main sliding surface; 2 - slid block; 3 - fault; 4 - bottom of the glacial valley; 5 - direction of ancient cracks; 6 - direction of young cracks; 7 - reservoir

2. Waterworks

The hydroelectric power station on the lowland river includes a hydroelectric power station. In order for the turbines of a hydroelectric power station to operate, not only a continuous flow of water is required, but also a pressure - the difference in levels between the upper and lower pools, i.e. sections of the river upstream and downstream of the hydroelectric power station. The pressure is concentrated in a convenient location as a result of the construction of a dam or other water-retaining structure and the filling of the reservoir. These two elements are important components of the waterworks. A reservoir is also necessary to regulate the uneven flow of the river, bringing it into line with water consumption, i.e. in this case with the graph of the electrical load of the hydroelectric power plant. Hydroelectric power stations on high-water plain rivers are located in their bed and are called either low-pressure run-of-river, or dam-based, if the pressure is high enough.

Since it is not economically feasible to accumulate rare high-water floods in the reservoir and since the consumption of electrical energy, i.e. the use of the water supply may be interrupted due to an accident; the hydroelectric complex must have a spillway to pass water from the upper pool to the lower pool, in addition to turbines, in order to avoid overflowing the reservoir and overflowing the water over the dam with the ensuing destructive consequences. In addition to the turbines, the passage of water into the lower pool in the event of a shutdown of hydroelectric power plant units may also be necessary when the reservoir is not filled, if without the supply of this water, water users located downstream - hydroelectric power plants, water transport, irrigation systems, etc. - will suffer damage. To solve this problem, culverts with deep holes - water outlets - are built as part of the hydraulic system.

The passage of water into the lower pool may also be necessary for the purpose of emptying the reservoir for inspection and repair of hydroelectric facilities. Then it should include drains with deep or bottom holes. To supply a large amount of water for its main purpose - to the turbines of a hydroelectric power station, clearing it of dangerous inclusions - ice, slush, sediment, litter, etc., special structures are needed - water intakes.

A hydroelectric power station may be located on a mountain river not near a dam, but downstream on the bank; water is supplied to it from the water intake by a special water conduit and is diverted from it into the river also by a special water conduit, which together are called diversion, and separately - inlet and outlet derivations. The purpose of the diversion device is the same as the construction of a dam, the concentration of pressure for its convenient use. In mountain rivers, water falls with a large surface slope, dissipating its potential energy. A canal laid along the shore with a minimal slope brings water to the hydroelectric power station with a surface level that differs little from the level of the upper pool.

As a result, the station uses greater pressure, the fall of a larger section of the river, not only due to the support of the dam, but also due to the difference in slopes of the river and the canal. The role of abductive derivation is similar; the water level in it differs little from the water level in the river at the end of the diversion, so that at the beginning of the outflow diversion at the hydroelectric power station the level is lower than nearby in a parallel flowing river. Thus, the station gains even greater pressure, using the fall of an additional section of the river. Diversion hydrosystems have a large extent, so they include a head assembly with a dam, a spillway and a water intake, a station assembly with a pressure basin that completes the supply diversion, pipelines supplying water to the turbines, and a hydroelectric power station building and the previously mentioned diversion elements.

Rice. 2. Run-of-river low-pressure hydroelectric complex with a hydroelectric power station and a shipping lock

In Fig. Figure 3 shows a hydroelectric power station with a short diversion canal on a mountain river. The head unit includes a concrete spillway dam, a water intake with a sedimentation tank. The station unit includes a pressure basin and an idle spillway. In Fig. 9 shows, partially in section, an underground hydroelectric power station with tunnel diversion. A high spillway dam, a deep water intake, as well as a surge tank at the end of the pressure inlet part of the diversion are visible.

Rice. 3. Hydroelectric power station with a diversion canal

If there is a dam, the hydroelectric complex must include spillways, as well as water outlets necessary for navigation. Both of these functions are often combined in one building. As a result of the construction of the dam, a drop (level difference) arises between the pools, to overcome which ships both going upstream and going downstream need navigation facilities (locks, ship lifts. Often, a port is built next to the waterworks with a water area protected from storm waves, berths, and a backwater for wintering ships.

The approach channels to the navigation facility, upstream and downstream, form a kind of diversion along which ships move, but little water flows, only for filling and emptying the lock chamber during the process of locking ships. Sometimes these canals acquire a considerable length if it is necessary to bypass a section of the river that is inconvenient for navigation - to straighten a sharp bend, to bypass rapids. Long canals with many locks connect different rivers with each other.

The use of water resources for irrigating agricultural lands and watering arid areas requires the construction of its own complexes of hydraulic structures and imposes its own requirements for regulating river flow. The area of ​​irrigated land is usually very large, and the hydraulic structures located on it are so numerous that their complex cannot be called a hydraulic system; they are called an irrigation system. Part of the structures, compactly located on the used river, as part of a dam that forms a reservoir to regulate the flow of the river, a spillway to pass the flood, a water intake and a sedimentation tank for sedimentation from water taken for irrigation, is called the head unit of the irrigation system.

From the head node to the irrigated lands, water is supplied by a main water pipeline, most often a canal. Its length is measured in tens and hundreds of kilometers; along the way, distributors branch off from it, and sprinklers branch off from them. Unused residual water from the fields is collected by collectors and discharged into the watercourse. If part of the irrigated land is located above the water level in the main canal, water for these lands is supplied by pumping stations. On the irrigation network itself there are regulators, differentials, discharge structures, etc.

Drainage systems in areas of excessive soil moisture and widespread swamps naturally do not require the construction of dams. The complex of structures of these systems includes drainages, small and large canals, various structures on the drainage network; Corrective work is carried out on watercourses (straightening, clearing, deepening, coastal dams). The drainage system can be gravity-fed, however, if the terrain is too flat, pumping stations may be required on the network and to pump water into the watercourse.

Integrated water supply and sewerage systems are very complex and varied. The variety depends mainly on the type of water consumer - municipal or industrial water supply. Many industries require a continuous supply of large volumes of water, these include, for example, pulp and paper, metallurgical, chemical, thermal (and nuclear) power plants (for cooling condensers). Before the remaining part of this water, changed in its quality (wastewater), is discharged into a watercourse or returned to production (recycled water supply), it must be purified, disinfected, cooled, etc. As part of an integrated water supply and wastewater system, in addition to the head unit of structures on the river and the network of water pipelines at the consumer, there are pumping stations and a system for purifying water taken from the watercourse, as well as a more complex system for purifying water removed from the consumer.

3. Reservoirs

A reservoir is an artificial reservoir of significant capacity, usually formed in a river valley by water-retaining structures to regulate its flow and further use in the national economy. In table 1 shows the largest reservoirs in the world.

Table 1. Largest reservoirs in the world

The following main elements and zones are distinguished in the reservoir (Fig. 4).

Rice. 4. Main elements and zones of the reservoir. Main elements of the regime: 1 - low water level up to backwater; 2 - flood level up to backwater; 3 - normal retaining level; 4 - high water level under backwater conditions

The throughput capacity of a waterworks complex (its turbines, spillway spans, bottom holes, sluices) is limited for economic and, less often, technical reasons. Therefore, when a reservoir flows at a very rare frequency (once every hundred, thousand, or even ten thousand years), the hydraulic system is not able to pass the entire mass of water flowing along the river. In these cases, the water levels throughout the reservoir and at the dam rise, sometimes increasing its volume by a significant amount; At the same time, the capacity of the waterworks increases. Such a rise in the level above the FSL during the period of high floods of rare frequency is called forcing the reservoir level, and the level itself is called forced retaining water (FRU). On reservoirs used for water transport or timber rafting, the level drawdown during the navigation period is limited to the level at which the river fleet, due to the state of the depths, can continue normal operation. This level, located between the NPU and the UMO, is called the navigation response level (NS). Water levels, especially during NPU and FPU, at the dam and in the middle and upper zones of the reservoir are not the same. If the level of the dam corresponds to the NSL mark, then as it moves away from it it increases, first by centimeters, and then by tens of centimeters. This phenomenon is called the backwater curve.

In addition to the great and undoubted benefits that reservoirs bring, after they are filled there are associated, often negative, consequences. These include the following. The greatest damage to the national economy is caused by constant flooding of territories with settlements, industrial enterprises, agricultural land, forests, mineral resources, railways and roads, communication and power lines, archaeological and historical monuments and other objects located on them. By permanently flooded we mean areas located below the normal retaining level. Temporary flooding of areas located on the banks of reservoirs ranging from normal to forced backwater levels also causes damage, but occurs rarely (once every 100 - 10,000 years).

An increase in the groundwater level in the area adjacent to the reservoir leads to its flooding - swamping, flooding of underground structures and communications, which is also unprofitable.

Reshaping (reworking) of the banks of reservoirs by waves and currents can lead to the destruction of large areas of useful, developed territory. Landslide processes occur or become more active along the banks of reservoirs. The conditions for navigation and timber rafting on the river change radically, the river turns into a lake, depths increase, speeds decrease. The underbridge dimensions required for water transport are reduced.

The winter regime of the river changes greatly, the ice cover on the reservoir lengthens, and the sludge disappears, if there was any. Turbidity decreases as sediment settles into the reservoir.

Among the measures to compensate for damage caused by flooding and flooding of lands, cities, workers' settlements, collective farm estates, as well as industrial enterprises are relocated and restored to new non-flooded places. Individual sections of roads are moved, their surface is expanded, embankment slopes are strengthened, etc. They move or protect historical and cultural monuments, and if this is not possible, they study and describe them. They raise bridge spans and rebuild bridge crossings. River boats are being replaced by lake fleets, and mole rafting is being replaced by towing rafts. They carry out deforestation and forest clearing of the reservoir area. They complete the development of mineral resources (for example, coal, ore, building materials, etc.) or ensure the possibility of their subsequent development in the presence of a reservoir. Sometimes it turns out to be economically feasible, instead of removing economic facilities and settlements from the flood zone of a reservoir, to implement measures for their engineering protection.

The complex of hydraulic engineering and reclamation measures, united under the name engineering protection, includes diking or fencing of objects and valuable lands, draining flooded or embanked areas using drainage and pumping out water, strengthening the banks in certain sections of the reservoir, etc.

4. Dams

A dam is a structure that blocks a watercourse, which backs up water to a level higher than the domestic level and thus concentrates in one place a convenient pressure for use, i.e., the difference in water levels in front and behind the dam. The dam occupies an important place in any pressure hydraulic system.

Dams are built in different climatic and natural conditions - in northern latitudes and in permafrost areas, as well as in the south, in tropical and subtropical zones, with high positive temperatures. Their location includes high-water plain rivers flowing in channels composed of non-rocky soils - sand, sandy loam, loam and clay, as well as mountain rivers flowing in deep rocky gorges, where strong earthquakes often occur. The variety of natural conditions, purposes for creating dams, the scale and technical equipment of construction has led to a variety of types and designs. Like other structures, dams can be classified according to many criteria, for example, by height, the material from which they are built, the ability to pass water, the nature of their work as retaining structures, etc.

Hydraulic water-retaining structures, which include dams, perceive forces of different origin, nature and duration, the total impact of which is much greater and more complex than the impact of forces on buildings and structures of industrial and civil type.

To understand the operating conditions of water-retaining structures, consider the diagram of a concrete dam with the main loads acting on it. Like all extended concrete structures, the dam is cut into sections with seams that allow the sections to freely deform under temperature influences, shrinkage and precipitation, which prevents the formation of cracks. The following forces act on each section of the dam with length L, height H and base width B.

The weight of the dam section G is determined by its geometric dimensions and the specific gravity of the concrete g=rґg (as is known, the specific gravity of a substance is equal to the product of its density and the acceleration of gravity).

Rice. 5. Transverse profiles of modern dams in comparison with the silhouettes of other structures (dimensions in meters): 1 - Dnieper; 2 - Bukhtarminskaya; 3 - Krasnoyarsk; 4 - Bratskaya; 5 - Charvakskaya; 6 - pyramid of Cheops; 7 - Toktogul; 8 - Chirkeyskaya; 9 - Sayano-Shushenskaya; 10 - Usoi dam; 11 - Nurek; 12 - Moscow State University; 13- Ingurskaya

The pressure of filtered water on the base of the dam arises due to the underground flow of water flowing under pressure through the pores and cracks in the soil of the dam base from the upper tail to the lower one. The approximate value of this force, called back pressure, is equal to:

U=ґgBL,

where H1, H2 are the water depths in the pools; g is the specific gravity of water; a is a reduction factor that takes into account the influence of anti-seepage devices and drainage at the base of the dam.

The hydrostatic water pressure from the upper and lower pools is determined by the formulas:

W1=gH12L/2; W2 =gH22L/2.

The forces listed above belong to the category of the most important and constantly operating. In addition to them, in necessary cases, special formulas take into account the dynamic pressure of waves, the pressure of ice, sediment deposited in the reservoir, as well as seismic forces. Uneven temperature fluctuations have an additional effect on the strength of a concrete dam. Cooling of the dam surfaces causes tensile stresses in them, and cracks can form in concrete that weakly resists them. Under the conditions of the listed forces and water pressure, the dam must be strong, shear-resistant and waterproof (this requirement also applies to its foundation). In addition, the dam must be economical, i.e. Of all the options that satisfy the mentioned requirements, the option characterized by a minimum cost should be selected.

A special place in hydraulic engineering is occupied by issues related to the filtration of water from the upstream to the downstream. This phenomenon is inevitable, and the task of hydraulic engineering is to predict and organize it, and to prevent dangerous or unprofitable consequences with the help of engineering measures. The paths of filtration currents can be: the body of the structure, even if it is built of concrete; the foundation of a structure, especially when it is non-rocky or fractured rock; banks in places where pressure structures adjoin them. The harmful consequences of filtration are unproductive losses of water from reservoirs, which is therefore not used for national economic purposes, backpressure, which reduces the degree of stability of the pressure structure, and filtration disturbances or deformations of the body of the soil dam or non-rock foundation, in particular, in the form of suffusion or uplift.

Suffusion is usually called the removal of small particles by filtration flow through the pores between larger particles; it occurs in non-cohesive (loose) soils - heterogeneous sandy, sandy-gravel. With chemical suffusion, salts located in rocks are dissolved. An outflow is the removal by an underground flow, filtering from under a pressure structure into the downstream, of significant volumes of foundation soil consisting of cohesive rocks, such as loams, clays, etc.

To ensure normal operation of the structure and eliminate hazardous phenomena, a rational underground circuit is provided when designing the structure (Fig. 6). This is achieved by increasing the filtration path under the structure, creating a waterproof coating in the upper pool (downstream) and a powerful water reservoir in the lower pool, laying sheet piles or other curtains, teeth or other measures.

Rice. 6. Diagram of a dam on a filter base (according to S.N. Maksimov, 1974): 1 - dam body, 2 - water body, 3 - apron, 4 - down, 5 - flow lines, 6 - sheet piles

Dams made of soil materials.

An ancient type of pressure hydraulic structures are dams made of soil materials. Depending on the soils used, dams can be homogeneous or heterogeneous; in the transverse profile, the body of the latter consists of several types of soils. To build a homogeneous soil dam, various low-permeable soils are used - sand, moraine, loess, sandy loam, loam, etc. In terms of the design of the dam and its connection with the foundation, this is the simplest type of pressure structure.

Heterogeneous soil dams, in turn, are divided into dams with a screen of low-permeability soil, laid on the side of the upstream slope of the dam, and dams with a core, in which low-permeability soil is located in the middle of the dam profile. Instead of a soil core, non-soil diaphragms made of asphalt concrete, reinforced concrete, steel, polymers, etc. can be used. Screens can also be made from the specified non-soil materials.

Depending on the method of carrying out the work, soil dams can be either bulk dams, with mechanical compaction of the poured soil, or alluvial dams, built using hydromechanization means; the latter method of constructing earth dams, subject to appropriate conditions (supply of water, energy and equipment, the presence of a suitable soil composition, etc.), is characterized by high productivity, reaching up to 200 thousand m3/day.

Rock-and-earth dams are built in the main part of the volume from rock fill; their waterproofness is achieved by constructing a screen or core, laid from low-permeability soils (loams, etc.). Between the stone and the fine-grained soil, reverse filters are installed - transitional layers of sand and gravel with increasing coarseness towards the stone to prevent suffusion of the soil of the anti-filtration devices.

Such dams are widely used in high-pressure hydraulic structures on mountain rivers. Thus, the height of the Nurek hydroelectric power station dam on the river. Vakhshe is 300 m.

Their advantage, compared to other types of dams, is the use of stone and soil available at the construction site, the possibility of extensive mechanization of the main types of work (stone casting and soil filling), as well as sufficient seismic resistance. Compared to other types of earth dams, rock-earth dams are distinguished by greater slope steepness, i.e. less amount of materials.

The small width of the low-permeability contact between the rock-earth dam and the foundation complicates the design of their waterproof interface. In non-rocky soils, it is necessary to drive a sheet piling row or lay a concrete spur, and in rocky soils, a cement curtain is installed by injecting cement mortar through drilled wells into rock cracks. Such connections prevent dangerous filtration phenomena at the base of pressure structures.

Rockfill dams are erected by throwing or pouring stone, and their water resistance is ensured by a screen on the upstream slope or a diaphragm in the middle of the profile, constructed from non-soil materials (reinforced concrete, wood, asphalt concrete, steel, plastics, etc.). Stone dams are built from dry stone masonry, which also requires the installation of screens, or from stone masonry with mortar. These dams are rarely built nowadays.

Dams made of artificial materials.

Wooden dams are one of the oldest types of pressure structures, dating back many hundreds of years. In these dams, the main loads are carried by wooden elements, and their stability against shearing and floating is ensured by securing wooden structures in the base (for example, driving piles) or loading them with ballast from stone or soil (in row structures). Wooden dams are built for low heads, from 2 to 20 m.

Fabric dams began to be built relatively recently due to the advent of durable, waterproof synthetic materials. The main structural elements of fabric dams are the shell itself, filled with water or air and acting as a gate (weir), anchor devices for attaching the shell to the concrete flute, a piping system and pumping or fan equipment for filling and emptying the shell. The scope of application of fabric dams rarely goes beyond the head limit of 5 m.

Concrete dams are widely used in hydraulic engineering. They are built in various natural conditions and allow the overflow of water through special spans on their crest (spillover dams), which is impossible or irrational in dams made of soil materials. Their structural forms are very different, which depends on many factors. The highest height of the concrete gravity-type dam Grand Dixance (Switzerland) is 284 m. In Russia, the Sayano-Shushenskaya dam of the arch-gravity type was erected on the Yenisei with a height of 240 m. The dam has a rocky foundation. The spillway dams of the Svirsky and Volzhsky cascades were built on a non-rock foundation in difficult geological conditions. Lightweight concrete dams appeared later than massive ones and have a relatively small distribution in Russia. By design, concrete dams are divided into three types: gravity, arch and buttress. The most famous type of these dams are buttress dams. Their advantage over massive ones is the smaller volume of concrete work. At the same time, they require more durable concrete and reinforcement with reinforcement.

Gravity dams, when subjected to the main forces of hydrostatic pressure, provide sufficient shear resistance, mainly due to their large dead weight. In order to combat water filtration, cementation curtains are installed at the base of the dam (in rocky foundations), and sheet pile rows are driven in (in non-rocky foundations). To increase the stability of the dam, drainage is organized, cavities are installed that reduce back pressure, and other measures are taken.

Arch dams are curved in plan with a convexity towards the upper pool; they resist the action of hydrostatic pressure and other horizontal shear loads mainly due to their emphasis on the banks of the gorge (or abutments). When constructing arch dams, a mandatory requirement is the presence of sufficiently strong and low-yield rocks in the coastal areas. These dams, like gravity dams, do not require a significant weight of concrete masonry; they are more economical than gravity dams. The radii of curvature of their arched elements increase from bottom to top.

Buttress dams consist of a number of buttresses, the shape of which in the side façade is close to a trapezoid, located at a certain distance from each other; the buttresses support the pressure ceilings, which absorb the loads acting from the upstream side. The bridge spans rest on the buttresses on top. In turn, the buttresses transfer the load to the base. The most well-known types of buttress dams are: massive buttress dams, with flat ceilings, and multi-arch dams. Buttress dams can be either blind or spillway. They are built on rocky and non-rocky soils; in the latter case, they have an additional structural element in the form of a foundation slab, the purpose of which is to reduce stress in the foundation soil. To give greater seismic resistance to buttresses under transverse seismic conditions (across the river), they are sometimes connected to each other by massive beams.

A feature of buttress dams is the increased width at the base and the slope of the top face, which leads to the fact that a significant vertical component of water pressure is transferred to the latter, pressing the dam to the base and providing it with stability against shear, despite the reduced weight. The back pressure in such dams is less than in massive gravity dams.

Buttress dams require smaller volumes of concrete than gravity dams, however, the costs of improving the quality of concrete, reinforcement and complicating the work make them quite close to each other in terms of economic indicators. The highest buttress (multi-arch) dam, Daniel-Johnson, 215 m high, was built in Canada.

5. Spillways

In addition to the blind dam, spillways are of great importance in the structure of a hydroelectric complex, i.e. devices for discharging excess flood waters or passing flows for other purposes. There are several different solutions for the location of spillways in a waterworks.

Spillway spans can be constructed at the crest of a concrete dam in the riverbed or on a river floodplain; then the structure will take the form of a spillway dam. A spillway can be constructed independently of the dam in the form of a special structure located on the coastal slope and therefore called a coastal spillway.

Both in the dam body and on the bank slope, spillway openings can be placed close to the dam crest mark or deep below the headwater level. The first are called surface, the second - deep or bottom spillways.

Surface spans of spillway dams can be open (without gates), but usually they have gates that regulate the upstream water level. To prevent the reservoir from overflowing, the gates are opened partially or completely, preventing the water level from rising above the normal retaining level (NLV). To improve the conditions for the passage of water through the dam, its crest is given a smooth, rounded outline, which then turns into a steeply falling surface, ending near the tailwater level with another reverse rounding, directing the flow into the river bed. The entire length of the spillway front is divided into a number of spans using bulls. Bulls, in addition, perceive water pressure from the gates, and also serve as supports for bridges intended to service lifting mechanisms and gates and transport connections between the banks.

The water released through the dam has a large supply of potential energy, which turns into kinetic energy. The fight against the destructive energy of the flow discharged through the dam is carried out in various ways. Behind the spillway dam, energy absorbers are installed on a massive concrete slab in the form of separate concrete masses - checkers, piers or reinforced concrete beams. Sometimes, in the downstream of a spillway dam, a surface regime is organized by installing a ledge and toe in the lower part of the spillway, breaking off from which at a higher speed, the flow concentrates at the surface, and a roller with moderate reverse velocities at the bottom is formed under it.

Behind spillway dams, which have non-rock foundations, an apron is made behind the water holes - a reinforced permeable section of the river bed.

Typically, on the shore, spillways are located in waterworks with dams made of soil materials that do not allow water flows to pass through their crest, as well as in waterworks with concrete dams in narrow gorges, where the channel is occupied by a hydroelectric power station building near the dam. Their types are very diverse. The most commonly used are surface spillways, in which the discharge flows along the surface of the bank in an open excavation. They are located on one or two banks, often next to the dam, and have the following components: an inlet canal, the spillway itself with spillway spans, bulls and gates (or automatic action without gates), an outlet canal in the form of a high-flow or stepped drop (used rarely). The coastal spillways are completed with water trenching devices, similar to those installed in the downstream of spillway dams - a water trench well.

If local conditions prevent the routing of the outlet channel, then it can be replaced with an outlet tunnel; This will result in a tunnel-type coastal spillway. Tunnel coastal spillways have the following components: an inlet channel located at high elevations of the coastal slope in the upper pool, the spillway itself with gates, and an outlet tunnel ending with a section of the canal and a water dispenser.

Deep and bottom spillways are located at elevations close to the bottom of the watercourse on which the hydraulic system is being built. They are arranged for the following purposes: to pass river flow during the construction of a dam in the riverbed (construction spillways), and in some cases to pass all or part of the discharge flow. Their main varieties are tunnel and tubular spillways. Spillway tunnels are located in rocky coastal massifs, bypassing the dam, their length is several hundred meters, the cross-sectional dimensions are determined by the flow rate. The cross-sectional shape of construction spillways is usually horseshoe-shaped. The remaining tunnels, operating under high pressure, have a circular cross-section.

Tubular spillways are located in the hydroelectric complex depending on the type of dam. If the dam is concrete (gravity, buttress or arch), then the spillways are pipes that cut through its body from the upstream to the downstream and are equipped with gates. If the dam is ground, then tubular drains are installed under the dam, deepening them into the base. They are a tower from which steel or reinforced concrete pipes of round or rectangular cross-section originate, depending on the pressure. They can be single or assembled into a kind of “batteries”, depending on consumption. Gates and control mechanisms are placed in the inlet and outlet parts of the pipes.

Gates and lifts. The main gates serve to regulate discharge flows and water levels in the upper pool, as well as to allow, in some cases, the passage of forest, ice, litter, and sediment. They can completely or partially cover culverts. The design of the gates depends on their location; gates of surface holes, often large, perceive relatively low hydrostatic pressure; valves of deep holes, which have significantly smaller dimensions, experience high hydrostatic pressure. Gates are most often made of steel, for small pressures and spans of blocked holes - from wood, in low-pressure non-critical structures with large spans - from fabric materials (fabric dams). The most widespread in hydraulic structures are flat valves, which are a metal structure in the form of a shield that moves in the vertical grooves of bulls and abutments. The components of a flat gate are: a waterproof lining that absorbs the pressure of the upstream water, then a system of beams, trusses and support structures that roll or slide along special rails embedded in grooves. The mass of the moving part of the gates is quite significant; at large heights and spans it exceeds 100 tons, which requires powerful lifting mechanisms. To reduce the lifting force of the mechanisms, segmental valves are used, which, when raising and lowering them, rotate around hinges embedded in the bulls and abutments. Such valves are also widely used, but their cost exceeds the cost of flat valves.

6. Water intakes

waterworks dam plain reservoir

Purpose of the water intake. Water intakes are parts of water intake structures, the main purpose of which is to collect water from a watercourse (river, canal) or reservoir (lake, reservoir); the action for which they are intended can be called water intake.

The consumer usually regulates the water flow. Water intake must be ensured at any retaining level - from normal (NLV) to the lowest - dead volume level (LVL).

The functions of the water intake structure include purifying water from impurities and foreign bodies.

Water intake structures. The design and equipment of the water intake largely depend on the type of hydraulic unit and the type of water pipeline - pressure or non-pressure. Therefore, a description of the designs and equipment of water intakes and their operation is only possible separately for each type. The dimensions of the water intake are characterized by the dimensions of its inlet section, where debris-retaining gratings are located (often called debris-retaining grates). To facilitate cleaning of the screens and reduce pressure losses on the screens, the flow velocity at the inlet is taken to be no more than 1.0 m/s. The inlet area of ​​large turbines is measured in hundreds of square meters.

A water intake of this type, individual for each turbine, is a rectangular hole in the dam mass, gradually narrowing and turning into a circular section of the turbine conduit.

The upper part of the entrance is closed by a reinforced concrete wall - a visor, lowered below the ULV. The visor absorbs ice pressure and traps floating objects. In front of the entrance to the water intake, a grid 1 of strip steel rods is installed to retain debris suspended in the water that could damage the turbine. During operation, the debris that accumulates at the water inlet and on the grate is removed with a mechanical rake or grab, since if the grate becomes clogged, its resistance to water flow will increase significantly.

Behind the grate, grooves are made in the bulls to install the gate 3 and stop the water supply to the turbine conduit. In order to be able to maintain and repair the high-speed shutter, grooves 2 are arranged in front of it for the repair shutter. You can get to the valve for inspection and repair through inspection hatch 6. The repair valve is simpler, it is not required to operate quickly, it is lowered not into the stream, but into calm water. An air duct 7 is installed behind the valve - a pipe for supplying air to the turbine water duct, replacing the water leaving through the turbine in the event of the water intake being closed by an emergency repair valve. For ease of operation, a building equipped with an overhead assembly crane is erected above the water intake. In favorable climatic conditions, the building is not built and a portal-type assembly crane is used.

The main valve regulates water flow in accordance with the water consumption schedule. The movement of the shutter is carried out using a hydraulic drive.

In case of small fluctuations in the level of the upper pool, the water intake structure is located at high elevations of the coast; this is the so-called surface coastal water intake. With a wide range of operational levels of the reservoir, it is necessary to install a deep coastal water intake, located slightly below the ULV.

7. Water pipelines

Purpose of water pipelines. Water that enters the water intake and is cleared of impurities must be left to the consumer in accordance with the consumption schedule. One of the main requirements for water pipelines (pressure and non-pressure) is the waterproofness of their walls. Water should not be lost along the way, and this loss should not make the surrounding area swampy. For a hydroelectric power station, it is also necessary that the potential energy of the flow be lost as little as possible along the path, and that the slope of its free or piezometric surface be small. To do this, the walls of the conduit must be smooth and characterized by low resistance to flow. Smooth walls are needed by water pipelines and irrigation systems and water supply systems - the higher the water is supplied, the easier it is to ensure its gravity supply to consumers, the less energy is spent on operating pumping stations. Only for shipping canals the roughness of the walls does not matter, since the velocities in them are small or equal to zero.

The walls of conduits should not be eroded by current speeds and waves (waves arise, for example, when ships move along canals).

The dimensions of the cross-section of the water pipeline are determined on the basis of technical and economic calculations. The type and design of the water pipeline are also determined on the basis of technical and economic comparisons. Depending on the purpose of the water pipeline, its size, natural conditions and conditions of construction and operation, channels, trays, pipelines, and tunnels can be used as a water pipeline. The first two types are non-pressure, the third is pressure; the tunnel can be either pressure or non-pressure (if it is not filled to the top with water). Often the optimal solution is achieved by sequentially combining different types of water pipeline sections.

The simplest and cheapest type of conduit is usually a canal. Channels are common in all areas of hydraulic engineering. It is advisable to lay the canal route on the plan so that the water in it is in the recess and the height of the dams is small. The cross-sectional shape is trapezoidal (sometimes of a more complex shape), the steepness of the slopes is determined by their stability; the soil should not slide.

In rocky soil, the cross-section of the channel approaches rectangular. The cross-sectional width of the channel is greater than its depth in order to reduce water losses due to filtration from the channel, increase the flow speed and reduce flow resistance, i.e. The slope of the surface, the bottom and slopes of the canal are covered with lining, most often concrete or reinforced concrete. A layer of coarse soil (gravel) is placed under the cladding as drainage.

A tunnel is the most expensive type of conduit per unit of length. If the tunnel is laid in weak, non-rocky soils, then its cost especially increases. In this regard, it can be preferred to surface types of diversion only if it is significantly shorter, allows the route to be straightened, or if the coastal slope along which the route can be laid is unsuitable for surface diversion - very rugged terrain, high steepness, landslides, avalanches .

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Hydraulic structures (HTC) include pressure front structures and natural dams (dams, locks, dams, irrigation systems, dams, dams, canals, storm drains, etc.), creating a difference in water levels before and after them, intended for the use of water resources , as well as to combat the harmful effects of water.

A dam is an artificial water-retaining structure or a natural (natural) obstacle in the path of a watercourse, creating a difference in levels in its upper and lower reaches along the river bed; is an important type of general hydraulic structure with culverts and other devices created with it.

Artificial dams are created by man for his own needs; These are dams of hydroelectric power stations, water intakes in irrigation systems, dams, dams, and dams that create a reservoir in their upstream. Natural dams are the result of natural forces: landslides, mudflows, avalanches, landslides, earthquakes.

Pool - a section of a river between two adjacent dams on a river or a section of a canal between two locks.

The upstream of a dam is the part of the river above the retaining structure (dam, sluice).

Tailwater is the part of the river below the retaining structure.

An apron is a reinforced section of a river bed in the downstream of a spillway hydraulic structure that protects the bed from erosion and equalizes the flow speed.

Reservoirs can be long-term or short-term. A long-term artificial reservoir is, for example, the reservoir of the upper pool of the Iriklinskaya State District Power Plant. A long-term natural reservoir is formed due to the blocking of rivers by a collapse of solid rocks (Tian Shan, Pamir mountains, etc.).

Short-term artificial dams are built to temporarily change the direction of the river bed during the construction of hydroelectric power stations or other hydraulic structures. They arise as a result of blocking the river with loose soil, snow or ice (jams, constipation).

As a rule, artificial and natural dams have drains: for artificial dams - directed, for natural - randomly formed (spontaneous). There are several classifications of hydraulic structures. Based on the location of the GTS, they are divided into:

• on land (pond, river, lake, sea);
• underground pipelines, tunnels.

Based on the nature and purpose of use, the following types of hydraulic structures are distinguished:

• water and energy;
• for water supply;
• reclamation;
• sewer;
• water transport;
• decorative;
• timber smelting;
• sports;
• fisheries.

According to their functional purpose, hydraulic structures are classified as follows:

• water-retaining structures that create pressure or a difference in water levels in front of and behind the structure (dams, dikes);
• water supply structures (water conduits) used to transfer water to specified points (canals, tunnels, flumes, pipelines, sluices, aqueducts);
• regulatory (correction) structures designed to improve the conditions for the flow of watercourses and protect river beds and banks (shields, dams, half-dams, bank protection, ice guide structures);
• spillway structures used to pass excess water from reservoirs, canals, pressure basins, which allow partial or complete emptying of reservoirs.

Special hydraulic structures are included in a special group:

• GTS for the use of water energy - hydroelectric power station buildings and pressure pools;
• GTS for water transport - shipping locks, log chutes;
• reclamation hydraulic structures - main and distribution canals, gateways, regulators;
• fishery hydraulic structures - fish passages, fish ponds;
• complex hydraulic structures (waterworks) - hydraulic structures united by a common network of dams, canals, locks, power plants, etc.

Hydraulic structures(GTS) - a type of engineering structures designed to provide different types of water use (water use) and/or to combat the harmful effects of water by influencing the regime and properties of natural water bodies and the water contained in them.

The first hydraulic structures

The construction of the first hydraulic structures dates back to the era of the 4th and 3rd millennia BC. e., to the era of the Sumerian civilization. Having settled in Mesopotamia, they gradually mastered irrigation, navigation and navigation along rivers and canals. The Iturungal and I-nina-gena, Arakhtu, Apkallatu and Me-Enlila canals, and the Zubi canal were built. The appearance of the first irrigation systems relatively early formed the economic basis for the emergence of an extensive system of economic relations in Mesopotamia. The construction of the canals also resulted in the construction of new cities on their banks, which became the economic, political and cultural centers of the Sumerians. There is a legend that the destruction of Babylon in the 7th century. BC e. by the Assyrian king Sennacherib was carried out using a specially created and then released (by destroying the dam) reservoir on the Euphrates.

In Europe, the first reservoirs, as far as can be judged from available data, appeared before our era. So, in Spain, presumably in the 2nd century. BC e. on the river Albarregas, the Carnalbo Dam was built with a reservoir of 10 million m3 (still exists). Probably, during this era, reservoirs were created in Greece, Italy, Southern France and other Mediterranean countries, but we have no specific information about them. This can be indirectly judged, for example, by the surviving remains of hydraulic structures in the area of ​​Rome. Retaining structures were also erected in the 1st millennium AD. e. in connection with the construction of mills and for irrigation. In Gaul, the first mills appeared in the 3rd–4th centuries; Thus, near the city of Arles, the remains of a complex of 16 mills have been preserved. The construction of mill dams became widespread in the 8th–9th centuries and especially in the 12th–13th centuries. The reservoirs formed by mill dams had, of course, a small volume and, according to the modern classification of artificial reservoirs, they can mostly be classified as ponds. Larger reservoirs in Europe appeared later, with the development of ore mining, metal processing, sawmilling, etc.

Significant hydraulic structures were built by the Aztecs, Mayans and Incas in pre-Columbian America. Several reservoirs for collecting melt water existed at the foot of the Andes, such as the reservoir in the Nepeña Valley, 1.2 km long and 0.8 km wide. Many dams for water abstraction were built by the Maya people; The reservoir near the ancient city of Tikal is well known. To supply water to cities, the Mayans built numerous open reservoirs with an impervious bottom coating; some of them survived until the 19th century. The Aztecs built hydraulic structures that were grandiose for those times, for example, the 16 km long Netzoualcoyotl dam, which divided the lake. Texcoco and formed the Mexico City reservoir. The Spanish conquistadors destroyed most of the ancient hydraulic structures of the Aztecs, Incas, and Mayans. Similar structures created by the Spaniards were often inferior in complexity and size to the previous ones. Still, during this period, some large reservoirs were built: Zhururia with a volume of 220 million m 3 and a surface area of ​​96 km 2 (still in use) and Chalviri with a volume of 3 million m 3 to supply water to the silver mines in Potosi.

Russia is rich in water, so in ancient times there was no need for hydraulic structures. At the same time, from the X–XI centuries. Water supply and sewerage systems were built in cities. And since rivers were used as means of communication, canals were often installed to straighten bends - called prosts. Such canals, which have acquired a completely natural appearance over the centuries, still exist in different places to this day. The oldest hydraulic engineering project on the Volga was the expansion and deepening of the channel in the area of ​​Lake Sterzh (the Volga is a small stream here) to ensure the passage of ships into the river. Paul and further to Novgorod.

Since ancient times, hydraulic power plants - water mills - have become widespread. They often powered not only flour-grinding mechanisms, but also sawmills, metallurgical and other industries, still retaining the name of mills (“saw mills”, etc.). The construction of the mills involved the construction of a dam blocking the river, which was prohibited on navigable rivers (according to the Council Code of 1649 - “so that the navigation on those rivers would not be taken over”), however, the abundance of small rivers, not suitable for use as communication routes, opened up ample opportunities to use their water energy. There were water mills in the 18th–19th centuries. a lot, they were such a familiar attribute of life and landscapes that statisticians and geographers simply did not notice them in their descriptions. In the second half of the 19th century. The shallowing of the Volga began to threaten Russia with the loss of its main route of communication, the “artery of the Russian land.” And the reason for the shallowing was definitely called not only the clearing of forests and plowing of lands in its basin, but also the destruction of tens of thousands of mill ponds after the reforms of 1861. Despite this, at the beginning of the twentieth century. in the Volga basin there were 13,326 hydropower plants, and in terms of their total capacity, Russia, according to GOELRO, ranked third in the world after the USA and Canada.

Large-scale hydraulic engineering construction began under Peter I - the Vyshnevolotsk shipping system was built to supply St. Petersburg with bread from the Volga. It included canals, dams, and shipping locks. From the beginning of the 19th century. right up to the railway “boom” of the 1860s–1880s. The construction of navigable hydraulic systems was extremely active. Then the Volga, in addition to the Vyshnevolotsk shipping system, received two more connections with St. Petersburg: the Tikhvin (1811) and Mariinsk (1810) systems (the latter acquired dominant importance from the mid-19th century). A canal named after Duke Alexander of Württemberg (now the North Dvina Canal) was built, connecting the Volga with the Northern Dvina (1825–1829); the North Ekaterininskaya system was completed (connection of the Kama with the Northern Dvina via the Vychegda River); construction was resumed, begun and abandoned by Peter I in 1711 due to the loss of the Azov Ivanovo Canal (connection of the Oka and Don); a connection between the Volga and Moscow was built along the Sestra and Istra rivers and the canal between them; connections of the Dnieper with the Western Dvina (Berezinskaya system), Neman (Oginskaya system) and Vistula (Dnieper-Bug system) were built. The connections of the Kama with the Irtysh, the Volga with the Don in the Tsaritsyn area, etc. were designed.

Since both in cargo transportation and in the concerns of the government, the Mariinsky system (the current Volga-Baltic Canal) has been used since the middle of the 19th century. dominated, over a century of its repairs and reconstructions, several generations of engineers developed the optimal types of wooden hydraulic structures - dams and locks of the “Russian” or “Mariinsky” type.

In the XVIII–XIX centuries. In Russia, trade and military ports developed on the Baltic, Black and White Seas. In connection with this, large fencing and mooring structures were built.

Classification of hydraulic structures

According to modern classification, hydraulic structures can be divided into the following types and types:

IN depending on the water body on which the hydraulic structures are located, they can be river, lake, sea.

By location relative to the earth's surface distinguish between above-ground and underground hydraulic structures.

IN in accordance with the types of water use provided Hydraulic structures are divided into drainage (drainage, water supply, irrigation), water transport, hydropower, fisheries, for water supply and drainage, for the use of water resources, sports purposes, etc.

By the nature of interaction with a water body There are water-retaining, water-supplying, regulatory, water-intake and water-discharge hydraulic structures.

Water-retaining structures, supporting a watercourse, create a pressure or difference in water levels in the watercourse in front of and behind the structure and perceive the water pressure that arises as a result of the pressure. These are, first of all, dams - structures that block river channels (and often the upstream parts of river valleys) in order to increase the water level (for example, for shipping needs) or create a reserve volume of water in a reservoir (pond, reservoir). Retaining dams can be protective dams that fence off the coastal area and prevent its flooding during floods, tides, surges and storms on the seas and lakes. Retaining structures are also river-bed buildings of hydroelectric power stations, shipping locks, and some water intake structures.

Water supply structures (water conduits) serve to transfer water (its supply or discharge) from one point to another. These are channels, tunnels (hydraulic), flumes, pipelines.

are designed for targeted influence on the flow conditions of watercourses, protection of their beds and river banks from erosion, sediment deposition, ice exposure, etc. When regulating rivers, flow control structures (dams, half-dams, etc.), bottom and bank protection structures (“garments” are used) ), structures that regulate the movement of ice and floating bodies (pans, ice walls, ice cutters, etc.).

Water intake (water intake) structures are arranged to collect water from a water source and direct it into a water pipeline. They are usually equipped with devices that protect water supply structures from the ingress of ice, slush, sediment, floating bodies, etc.

Spillways (spillways) are used to release (“discharge”) excess water from reservoirs, canals, pressure basins, etc. They can be channel and coastal, surface and deep, allowing partial or complete emptying of reservoirs. To regulate the amount of released (discharged) water, spillway structures are often equipped with hydraulic gates.

By purpose a distinction is made between general hydraulic structures that provide all types (or several types) of water use, and special ones, built for any one type of water use.

General purpose hydraulic structures include all water retaining and drainage structures and, in part, water supply, regulation and water intake structures - unless they are parts of special purpose structures.

Special (industry) hydraulic structures include the following:

In some cases, general and special hydraulic structures can be combined: for example, a spillway is placed in the building of a hydroelectric power station, a hydroelectric power station is placed in the body of a spillway dam (“combined hydroelectric power station”), a shipping lock can serve as a spillway, etc.

When carrying out complex water management activities, hydraulic structures, united functionally and located in one place, form complexes called hydraulic structure units, or hydraulic units.

Currently (since January 1, 2014) there is a classification of hydraulic structures according to their degree of danger. In accordance with it, all hydraulic structures are divided into four classes: low, medium, high and extremely high danger.

Depending on the class, the degree of reliability of hydraulic structures is assigned, i.e. reserves of their strength and stability, the estimated maximum water consumption, quality of construction materials, etc. are established.

Hydraulic structures differ from all civil and industrial buildings in the presence of influences on them from water flow, ice, sediment and other factors. These effects can be mechanical (static and hydrodynamic loads, removal of soil particles by filtration flow (suffusion), etc.), physical and chemical (abrasion of surfaces, corrosion of metals, concrete), biological (rotting of wooden structures, wear of wood by living organisms, etc. ).

In addition, unlike civil and industrial buildings, the conditions for the construction of hydraulic structures are complicated by the need to pass through the river bed and unfinished structures during their construction (usually several years) the so-called construction costs of the river, as well as ice, rafted timber, ships, etc. .

A peculiarity of the maintenance and operation of hydraulic structures in the Russian Federation is their fragmentation according to departmental, sectoral affiliation and forms of ownership. Thus, according to the total book value, agriculture owns 29% of all hydraulic structures, industry - 27%, housing and communal services - 20%, hydropower - about 15%, water transport - about 6%, fisheries - 2%, on the balance sheet of the structures of the Federal Water Agency resources – less than 2%. In addition, out of 29.4 thousand pressure hydraulic structures, 1931 objects (7%) are federal property, 7675 objects (26%) are regional property, 16087 objects (54%) are municipal property, about 4 thousand objects (13%) are ownerless.

Yu.V. Bogatyreva, A.A. Belyakov

GOVERNMENT OF THE RUSSIAN FEDERATION

RESOLUTION

On the classification of hydraulic structures

In accordance with Article 4 of the Federal Law "On the Safety of Hydraulic Structures" the Government of the Russian Federation

decides:

1. Establish that hydraulic structures are divided into the following classes:

Class I - hydraulic structures of extremely high danger;

Class II - hydraulic structures of high danger;

III class - hydraulic structures of medium danger;

Class IV - low-hazard hydraulic structures.

2. Approve the attached criteria for the classification of hydraulic structures.

3. Establish that if a hydraulic structure, in accordance with the criteria approved by this resolution, can be classified into different classes, such a hydraulic structure belongs to the highest of them.

Chairman of the Government
Russian Federation
D.Medvedev

Criteria for the classification of hydraulic structures

APPROVED
Government resolution
Russian Federation
dated November 2, 2013 N 986

1. Classes of hydraulic structures depending on their height and type of foundation soil:

Notes: 1. Soils are divided into: A - rocky; B - sandy, coarse-grained and clayey in solid and semi-solid state; B - clayey, water-saturated in a plastic state.

2. The height of the hydraulic structure and the assessment of its foundation are determined according to the design documentation.

3. In positions 4 and 7, instead of the height of the hydraulic structure, the depth of the base of the hydraulic structure is taken.

2. Classes of hydraulic structures depending on their purpose and operating conditions:

Notes: 1. The class of hydraulic structures of hydraulic and thermal power plants with an installed capacity of less than 1000 MW, specified in position 2, increases by one if the power plants are isolated from energy systems.

2. The class of hydraulic structures specified in position 6 is increased by one for canals transporting water to arid regions in difficult mountainous terrain.

3. The class of hydraulic structures of the canal section from the head water intake to the first regulating reservoir, as well as canal sections between regulating reservoirs, provided for in position 6, is reduced by one if the water supply to the main water consumer during the period of liquidation of the consequences of an accident on the canal can be ensured due to the regulating capacity of reservoirs or other sources.

4. The class of hydraulic structures of river ports specified in position 10 is increased by one if damage to hydraulic structures of river ports can lead to emergencies of a federal, interregional and regional nature.

5. The class of hydraulic structures specified in positions 13 and 14 is increased by one depending on the complexity of the ships being built or repaired.

6. The class of hydraulic structures specified in position 16 is increased by one if damage to such hydraulic structures could lead to an emergency.

7. The class of hydraulic structures specified in position 17 is increased by one if damage to bank protection hydraulic structures can lead to emergencies of a federal, interregional and regional nature.

3. Classes of protective hydraulic structures depending on the maximum pressure on the water-retaining structure:

4. Classes of hydraulic structures depending on the consequences of possible hydrodynamic accidents:

Electronic document text
prepared by Kodeks JSC and verified against:
Collection of legislation
Russian Federation,
N 45, 11.11.2013, art. 5820

The use of water resources has always been one of the basic conditions for maintaining human life. The need for them is determined not only by drinking needs, but also by economic, and nowadays, increasingly, industrial tasks. Regulation of the use of water sources is ensured by hydraulic structures, which have different shapes and functional contents.

General information about hydraulic engineering

In a general sense, a hydraulic facility can be represented as any functional structure or structure that interacts with water in one way or another. These can be not only man-made engineering systems, but also natural regulators, initially created by nature, but later exploited by people. What tasks are performed by modern hydraulic structures? The main ones can be presented as follows:

• Structures intended for the use of water resources. As a rule, these are objects with water supply communications and equipment.
• Water protection structures. Complexes in the infrastructure of which several tasks can be performed. The most common restrictions for such objects are restrictions on use and influence on the hydrological environment in order to prevent harmful effects on it.
• Industrial buildings. Engineering systems in which water circulation can be used as a source of energy.

Of course, this is only part of the functions that hydraulic engineering performs. It rarely happens that such structures are assigned one or two tasks. Typically, large complexes support several work processes at once, including environmental, protective, regulatory, etc.

Main and secondary hydraulic engineering structures

To begin with, it is worth defining the basic classification, in which there are permanent types of hydraulic structures and temporary ones. According to the standards, the first group includes primary and secondary objects. As for the main structures, they mean technical infrastructure, the destruction or damage of which can lead to the cessation of the normal functioning of the economy served by hydro resources. This could include stopping the water supply to the irrigation system, stopping the operation of power plants, reducing shipping, etc. It is important to consider that the energy of hydrological turbines can serve entire enterprises (marine, ship repair, heating). Accordingly, stopping the water supply will disrupt the functionality of such facilities.

The category of secondary structures includes hydraulic engineering, the destruction or damage of which will not entail the above consequences. For example, if the main hydraulic structures supply enterprises with production resources, then the secondary ones can participate in the regulation of this process without significantly influencing the result.

It is also worth mentioning the features of temporary structures that are used during periods of repair activities. If depressurization occurs at the same main water supply facility, for example, then the maintenance team with the designer will have to create technical conditions to eliminate the problem. The solution to this problem can be the organization of a temporary waterworks.

Classification by method of interaction with the resource

The same task can be performed in different ways. As already noted, one complex is capable of supporting several functional processes, but what fundamentally differs is the conditions of interaction with a reservoir or drain and, accordingly, the nature of the performance of a particular function. Based on these characteristics, the following structures are distinguished:

• Water-retained. Designed to block a watercourse, fencing a reservoir or pond by absorbing water pressure. When assessing a watercourse, the level above the water-retaining station (upstream) and below the downstream are noted. The difference between these levels is called the head at the hydrological structure.
• Multifunctional reclamation stations. These can be water outlets, sluices, dams and water separators. Within this group, a classification of hydraulic structures is also provided, according to which a distinction is made between interfacing and blocking complexes.
• Water-conducting. Typically a network infrastructure formed by channels, tunnels, pipelines, and trays for carrying water. Their task is simple - delivering the resource from the collection point to the storage tank or final place of water use.
• Water intakes. The resource is collected from the same drives for transportation to consumers.
• Spillways. Unlike intake structures, such stations only remove excess water. These objects include deep spillways, drainage channels, spillways, etc.
• Regulatory. They control the interaction of the flow with the channel, preventing water from escaping beyond the boundaries of the fence, erosion and sedimentation.

Dangerous hydraulic structures

This group of structures may include representatives of all hydraulic facilities, regardless of purpose. A station can be dangerous due to a high risk of an accident, an abandoned state, being in a risk zone due to the influence of third-party factors, etc. Lists of hazardous objects are compiled by specialists from the Ministry of Emergency Situations and employees of Rosprirodnadzor. For each region, a comprehensive audit is carried out to identify objects that pose a threat. Hydraulic structures are recognized as dangerous after performing the following procedures:

• The morphometric characteristics of the object are identified and clarified.
• The technical condition of the structure and the degree of its safety are determined.
• The potential amount of harm that may occur in the event of an accident (for example, after the destruction of the dam body) is determined.
• The area around the facility is zoned with an area that will depend on the degree of risk and threat from a particular structure.

After an object is recognized as dangerous, its surveillance is organized, and a schedule is drawn up for maintenance, repair and restoration work aimed at eliminating or minimizing the threat.

General and special hydraulic facilities

General structures mean the majority of hydraulic engineering facilities related to regulation, water supply, water intake and wastewater stations. They are united by a single principle of performing their functions, which can be technologically applied to different operating conditions.

In turn, special hydraulic engineering objects are designed for use in narrow areas where it is necessary to take into account the specific use of the equipment. This applies to design nuances, construction requirements, as well as the direct operation of hydraulic structures. Examples of this kind of objects are well demonstrated by the water transport infrastructure:

• Shipping locks.
• Facilities for servicing marine equipment.
• Rafting ships and piers.
• Forest descents.
• Boat lifts.
• Boathouses.
• Docks.
• Breakwaters, etc.

In fisheries, fish ponds, fish lifts and fish ladders are used. In social and entertainment infrastructure, this could be water parks with swimming pools and aquariums. In each case, maintenance activities will have their own specifics, which are taken into account at the project development stage. However, the terms of reference for the construction of hydraulic engineering should be considered separately.

Design of hydraulic facilities

The design documentation includes technical calculations of structures, characteristics of the equipment used, as well as the results of field observations of the operating conditions of the future structure for the timely detection of unfavorable processes and the appearance of possible defects. The surrounding situation must be comprehensively and comprehensively assessed in order to initially anticipate and possibly prevent the threat of accidents.

In particular, the design for a hydraulic structure includes the following data:

• List of diagnostic and controllable indicators of the object and its basis, including safety criteria.
• List of controlled impacts and loads on structures from the environment.
• Composition of visual and instrumental observations.
• Results and operating conditions of control and measuring equipment.
• Technical and structural solutions and a structural diagram of the state of the object’s elements, as well as information predicting the behavior of the structure when interacting with man-made and natural factors.

Special attention is paid to safety criteria, on the basis of which decisions are also made on the use of equipment with certain characteristics. In addition, the main types of hydraulic structures for permanent operation are supplemented by emergency action projects. This documentation, in particular, describes measures aimed at preventing emergency situations.

Security Requirements

From the moment of design development and throughout the entire period of operation, the safety of a hydraulic engineering facility is ensured on the basis of the requirements of the relevant declaration. This is the main document that identifies the risks, threats and operational nuances that must be taken into account by maintenance personnel. The main safety requirements for hydraulic structures include the following:

• Maintaining an acceptable level of accident risks.
• Regular diagnostics of structures and equipment with subsequent adjustments to the safety declaration.
• Ensuring continuity of facility operation.
• Maintaining measures to organize protective equipment and technical control of structures.
• Monitoring potential threats to the facility.

Construction of hydraulic structures

First of all, the means of construction work are determined. The question of the degree of mechanization of the process is fundamental, since in most cases the implementation of hydraulic power station projects occurs with the support of special equipment. At the very first stages of construction, excavation work is carried out with bulldozers, dump trucks, loaders and excavators, which allow you to quickly equip trenches, holes, wells and simply clear the work site.

In some cases, soil compaction is carried out. For example, when creating reservoirs with a soil bowl. Such operations are carried out layer by layer on cleared ground using special rollers. For smaller sites, diesel or gasoline rammers can be used. However, experts still recommend abandoning hand tools in favor of mechanics. The recommendation is related not so much to accelerating the pace of the work process, but to the quality of the result. And this is especially true for the construction of hydraulic structures at the main stage of construction. Concrete work requires high-quality reinforcement with strapping, the use of instructional materials and the addition of waterproof plasticizers.

At the final stage, the engineering arrangement of the structure is carried out. Functional units, technical devices are installed and communications are laid. If we are talking about an autonomous station, then non-volatile generators are used, which will also require appropriate maintenance conditions in the infrastructure of the complex.

Operation of hydraulic engineering

The main activities of maintenance personnel are related to maintaining the optimal level of technical condition of the structure, as well as monitoring its basic functions. As for the first operational part, it comes down to the tasks of updating consumables, diagnosing equipment, communications, etc. In particular, operators check the technical condition of energy supply networks, units and the integrity of structural materials. In case of detection of serious problems or damage, the rules for the operation of hydraulic structures require the preparation of a separate project for repair and restoration measures, taking into account the available material reserves.

The second part of the operational tasks is focused on control functions. Using automation, communications and telemechanics, another team of operators regulates the operation of the structure and its functional units, relying on control operations according to standard parameters with permissible loads.

Reconstruction of hydraulic structures

The processes of obsolescence of structures and increasing requirements for the functional and power potential of an object inevitably lead to the need for modernization. As a rule, the main working modules and units undergo reconstruction without stopping their operation. However, this will depend on the nature of the planned changes. In each case, hydraulic structures are inspected for opportunities for reconstruction. The ultimate goals may be to increase the reliability of the facility’s foundation, increase throughput, increase the capacity of pumping equipment, etc. After this, specific operations related to changes in the technical and operational properties of the structure are implemented. The objectives are achieved by strengthening the soil, replacing building materials and adding new structural elements.

Hydraulic engineering and environmental protection

Even at the design stage, together with a safety declaration, a report is drawn up on measures that during operation should lead to an improvement in the surrounding environmental situation. Initially, the situation in the natural environment is assessed, and later the developers make a comprehensive adjustment to maintain the protection of natural objects after the project has been implemented. In particular, biotechnical measures are being developed aimed at protecting the population from accidents at hydraulic structures and creating conditions to neutralize negative operational factors.

Particular attention is paid to the impact of building structures and equipment on hydrological resources. For example, in reservoirs special beds are prepared for storing or discharging liquid waste. Each facility also contains technical means to eliminate sources of hazardous chemicals or simply dirty substances. To continuously monitor the environmental background, the infrastructure of hydraulic structures is supplemented with measuring instruments that record biological and chemical indicators of the water and air environments. The main characteristics of this kind include color, oxygen saturation, concentration of certain elements, sanitary indicators, etc.

Conclusion

The high responsibility of hydrological objects is determined by the breadth of their areas of application and the significance of the problems that they solve. As a rule, hydraulic structures act only as a link in the work chain of large production and economic cycles. But the ultimate goals that are achieved through the support of such objects can be extremely important. For example, energy, land reclamation, transport, water supply are only some of the areas in which water resources are used.