A dam is a structure used from antiquity to the present day. Great Soviet Encyclopedia - dam Constructions of soil dams

Diverse: rising water levels and increasing depths in the upper pool favor shipping, timber rafting, as well as water intake for irrigation and water supply; the concentration of pressure near the river creates the possibility of energy use of river flow; The presence of a reservoir makes it possible to regulate the flow, i.e. increase the flow of water in the river during low-water periods and reduce the maximum flow during floods, which can lead to destructive floods. The river and the reservoir significantly affect the river and adjacent territories: the river flow regime, water temperature, and the duration of freeze-up change; fish migration becomes more difficult; the banks of the river in the upper pool are flooded; The microclimate of coastal areas is changing. P. is usually the main structure of a waterworks. Dam construction arose as long ago as hydraulic engineering, in connection with the significant development of artificial irrigation of territories among the agricultural peoples of Egypt, India, China and other countries. The construction of P. was required for the construction of hydraulic power plants, and then the construction of hydroelectric power stations. The energy use of water resources was the main incentive for increasing the size and improving the design of waterways and the appearance of hydraulic structures on high-water rivers. On the territory of the USSR, water mills with water were built back in the days Kievan Rus. In the 17th-19th centuries. mining, metallurgy, textile, paper and other industries in the Urals, Altai, Karelia and central regions of Russia used mainly the mechanical energy of hydraulic power plants; their buildings were small in size and were constructed from local materials. Powerful hydroelectric power stations with large concrete and earthen pumps began to be built only under Soviet power, after the adoption of the GOELRO plan. In 1926, the first concrete spillway of the Volkhov hydroelectric power station was built. In 1932, a high concrete P. Dnieper hydroelectric power station was built (its maximum height is about 55 m). The spillway P. of the Nizhnesvirskaya HPP is the first P. built on weak clay soils. In the 50-70s. on high-water rivers were built: alluvial earthen P. on the Volga near Kuibyshev and Volgograd, concrete P. Bratsk hydroelectric power station on the Angara (height 128 m) and Krasnoyarsk hydroelectric power station on the Yenisei (124 m) (Fig. 1), a high 300-meter stone earthen P. Nurek hydroelectric power station on the river. Vakhsh, the arched Sayan hydroelectric power station on the Yenisei (height 242 m, crest length 1070 m; currently under construction, 1975), and many others. The design and construction of the Sayan hydroelectric power station in the USSR are distinguished by a high technical level, which allowed Soviet dam construction to take one of the leading places in the world. Of the P. built abroad, it should be noted: multi-arched P. Bartlett, height 87 m (USA, 1939), stone P. Paradela, height 112 m (Portugal, 1958), earthen P. Ser-Ponson, height 122 m ( France, 1960), stone-earth P. Miboro, height 131 m (Japan, 1961), gravity concrete P. Grand Dixence, height 284 m (Switzerland, 1961). The type and design of the P. are determined by its size, purpose, as well as natural conditions and the type of main building material . Based on their purpose, a distinction is made between reservoir reservoirs and water-lifting reservoirs (intended only for raising the level of the upper pool). Based on the magnitude of the pressure, pumps are conventionally divided into low-pressure (with a pressure of up to 10 m), medium-pressure (from 10 to 40 m), and high-pressure (more than 40 m). Depending on the role performed as part of a waterworks, the water supply can be: deaf, if it serves only as a barrier to the flow of water; drainage, when it is intended to discharge excess water flows and is equipped with surface drainage holes (open or with gates) or deep drainages; station, if it has water intake openings (with appropriate equipment) and water conduits feeding hydroelectric power station turbines. Based on the main material from which dams are built, a distinction is made between earthen dams, stone dams, concrete dams, and wooden dams. Earthen P. is constructed entirely or partially from low-permeability soil. Low-permeable soil laid along the upper slope of the P. forms a screen; when such soil is located inside the body of the P., a core is created. The presence of a screen or core makes it possible to construct the rest of the pavement from permeable soil or from stone materials (stone-earth pavement). At the bottom of the lower slope of the earthen P., drainage is installed to drain water filtered through the body and base of the P. The upper slope of P. is protected from the effects of waves by concrete slabs or rock riprap. When constructing an earthen embankment, soil is extracted from a quarry using excavators, transported to the construction site by dump trucks, placed in the body of the structure, leveled with bulldozers, and compacted layer by layer with rollers. The construction of alluvial soil involves the development of soil by dredgers or hydraulic monitors, transportation of the pulp through pipes and its distribution over the surface of the constructed soil, after which the water drains away and the settling soil compacts itself. To prepare the foundation and erect an earthen P. in the river bed, its foundation pit is fenced off with lintels, and the river is diverted through pre-laid temporary water conduits, which are closed after the construction of the P. In a stone (fill-fill) P. the screen or central waterproof element (diaphragm) is made of reinforced concrete, asphalt , wood, metal, polymer materials. The requirement of low water permeability also applies to the base of the P. If the base soil is permeable to a great depth, it is covered in front of the P. with a drooping layer (for example, made of clay), forming one whole with the screen. P. with a core is complemented by a device at the base of a steel sheet pile wall or an anti-filtration curtain. The stone in rockfill and rock-earth paving is poured in layers of great height. Concrete floors are usually classified according to their design, depending on the shear conditions; Accordingly, there are 3 main types of dams (Fig. 2) - gravity dams, arch dams, and buttress dams. Basic The material for modern concrete floors (mostly gravity-based) is hydraulic concrete. One of the most important issues when constructing concrete substructures is reducing water filtration at the base. For this purpose, an anti-filtration curtain is installed at the base of a high concrete floor near the top edge. In the remaining section, the base is drained to reduce water pressure on the base of the floor, which increases the stability of the structure. To avoid the formation of cracks due to temperature fluctuations, gravity and buttress panels are cut lengthwise into short sections, the seams between which are covered with waterproof seals (see Waterproofing). To prevent the appearance of cracks as a result of shrinkage of concrete during hardening and to reduce thermal stresses, the concrete block is concreted in separate blocks of limited sizes; artificial cooling of the components of the concrete mixture and the concrete laid in the blocks is used by circulating coolant (from the refrigeration unit) through a system of pipes laid in the body of the concrete block. Concrete pavement in the riverbed is usually constructed in 2 stages under the protection of lintels enclosing the pits. During the construction of the first stage of the river, the river flows along the free part of the channel; with the second - through the holes left in the P., which are closed after all construction work. If the river bed is narrow, the concrete waterway is built in one step, with the river temporarily diverted into coastal water conduits. A low-pressure concrete spillway dam, common in hydraulic engineering practice, is built on a non-rock foundation and is designed to pass high expenses water, has the design shown in Fig. 3. It is based on drainage spans formed by concrete flutbet and bulls and blocked by hydraulic gates. Behind the spillways, a massive fastening of the channel is installed - a water trench (sometimes buried in the form of a water well), followed by a lighter fastening - an apron. Drainage is installed under the reservoir. The spillway is connected to the shores or earthen P. by massive abutments. A low-pressure concrete spillway is usually built using reinforcement, often the entire structure (see Reinforced concrete dam). headwater level, and ships and rafts go through the lock. During high-water periods, gates and bridges are removed, buttress trusses are laid on the flatbet, opening the way for ships and rafts through the P. General trend modern dam construction - increasing the height of the dam. Technically achieved heights can be surpassed, however, from an economic point of view, the construction of two successive dams of lower height often turns out to be more rational than one high one. Improvement of types of construction made from soil materials is carried out while simultaneously reducing the cost and speeding up their construction by increasing the power of construction mechanisms and vehicles. Increasing the efficiency of concrete floors is achieved by reducing their volume, replacing gravitational floors with buttresses, and the wider use of arched floors. This trend is accompanied by an improvement and specialization of the properties of cement and concrete. It is very effective to combine a spillway dam and a hydroelectric power station building in one structure, which ensures a reduction in the concrete (most expensive) part of the pressure front of the hydroelectric complex. This hydraulic engineering work, M., 1970. A. Mozhevitinov.

Of all the dams, arch dams certainly make the greatest impression. It seems absolutely incredible how a thin curved concrete wall can hold billions of tons of water, and at the same time have a huge margin of safety. Well, in the end, arched dams are simply very beautiful.

Xiaowan is the highest arch dam in the world. Photo from here

The operating principle of arch dams is fundamentally different from all other types of dams. If gravity and buttress dams put pressure on the base, then arch dams transfer the load to the banks. An arched dam can even be specially cut off from the base using a special cut seam (this is sometimes done to relieve the stresses that arise in some types of dams).

Lumei Dam with a seam at the base

At the same time, the concrete in the arch dam works under compression, and in such a situation its strength is extremely high. Accordingly, an arch dam can be surprisingly thin - at a height of a hundred meters, its thickness can be only 2-3 m.

At the same time, such thin arched dams are not always built. Depending on specific conditions, it may be more effective to build a thicker or even an arch-gravity dam, the stability of which is ensured by both the emphasis on the banks and its own weight.

The main advantage of a concrete dam is significant savings in concrete, reaching 80% of the amount of concrete in a gravity dam. At the same time, arch dams place special demands on the banks - on the width of the valley, its shape and the quality of the rocks.

Inguri Dam. Photo from here

In wide valleys, the construction of arch dams is ineffective. There is a special coefficient that reflects the ratio of the length of the arched dam along the crest to its height (L/H). The most effective construction of arch dams is if this coefficient does not exceed 3.5, although there are known cases of construction of arch dams in relatively wide sections - for example, for the Sayano-Shushenskaya hydroelectric power station L/H = 4.56, for the Pieve di Cadore dam in Italy L/H=7.45.

Pieve di Cadore Dam. Photo from here

They do not like arched dams and asymmetrical valleys - the arch does not work normally in them. If necessary, they even resort to the construction of special tie-ins and retaining walls. And finally, the rocks into which the arch dam rests must be very strong. Accordingly, the ideal place for an arch dam is a mountain gorge, where they are mainly built.

Scheme of the Xiaowan hydroelectric dam.

The stability of arch dams is extremely high. In model experiments, they were destroyed only under loads 3-5 times higher than the calculated ones. There is a well-known example of a disaster at the Vayont dam (very high and very thin), when a landslide in the reservoir caused an overflow of water over the dam in a layer of at least 70 m - the dam stood and, moreover, was almost not damaged.

Vayont Dam. Photo from here

There are few arch dams in Russia - three purely arch dams (Chirkeyskaya, Miatlinskaya and Gunibskaya) and two arch-gravity dams (Sayano-Shushenskaya and Gergebilskaya). There is a project for the Agvalinskaya hydroelectric power station on the Andiiskoye Koysu River with an arch dam 210 m high.

Chirkey hydroelectric power station. Photo from here

The highest arch dam in the world is the dam of the Chinese Xiaowan hydroelectric power station on the Mekong River with a height of 292 m, commissioned in 2010. Before that, for a long time the leadership was held by the Inguri hydroelectric power station dam in Georgia, its height is 271.5 m. Many high-rise arch dams are being built in China - for example, the Xiluodu hydroelectric power station dam is 278 m high (by the way, the power of the hydroelectric power station is also impressive - 13,860 MW!). The highest arch dam in the world, Zhinpin-1, 305 m high, is also being built there. However, this is not the limit - there is beautiful project Abu Sheneila Dam in Sudan with a height of 335 m!

Classification. In SNiP II-54-77; Concrete and reinforced concrete dams are divided into the following main types according to their design.

Gravitational (Fig. 7.1, a-6): massive (Fig. 7.1, a); with extended seams (Fig. 7.1,6); with a longitudinal cavity at the base (Fig. 7.1, c); with a screen on the pressure face (Fig. 7.1, d); with anchors in the base (Fig. 7.1,6).

A gravity dam is a massive structure whose stability is ensured mainly by the mass of the structure.

Buttress (Fig. 7.1, f-h) with massive heads (massive-buttress, Fig. 7.1, f); with an arched ceiling (multi-arched, Fig. 7.1, g); with a flat ceiling (Fig. 7.1, h).

These dams are a series of buttresses 5 (walls) located at some distance from each other with pressure ceilings in the form of massive caps 6, or arches 7, or flat slabs 8, etc. (domes, flexible ceilings).

Arched - at (Fig.7.1, m; b - width of the dam at the base, h - height of the dam); with pinched heels (Fig. 7.1,i); with a perimeter seam (Fig. 7.1, /c); from three-hinged belts (Fig. 7.1, l); with gravity abutments (Fig. 7.1, m).

Typically, arch-gravity dams are considered a type of arch dam (which is also accepted below in Chapter 7.4).

An arched dam is a spatial water-retaining structure in the form of a vault that transfers the loads acting on it mainly to the rocky shores of the gorge.

Often, so-called cellular dams are distinguished separately, having cavities usually filled with soil (Fig. 7.2, 7.3). They can be either gravitational (Fig. 7.2, a, b) or buttress (Fig. 7.2, c, 7.3), and in some cases they can be attributed to each of these types (Fig. 7.2, c).

Concrete and reinforced concrete dams, which differ in design from massive gravity dams (Fig. 7.1,a) and have a smaller volume of concrete than the latter, are often called lightweight (Fig. 7.1,6-m, 7.2, 7.3).

By technological purpose dams can be blind (Fig. 7.1, a-e, g, h) and spillway: with surface (overflow) holes (Fig. 7.1,6, f, 7.2, 7.3), with deep holes (Fig. 7.23,6) and two-tier (Fig. 4.1, f).

General characteristics of the main types of dams. The dams under consideration are erected on various foundations - rocky, semi-rocky and non-rocky, while arched dams are built only on rocky ones. Concrete dams are usually built for rocky foundations, and reinforced concrete dams for non-rocky foundations. For non-rocky foundations, they are usually arranged as spillways; blind dams here usually turn out to be uneconomical, and the blind part of the pressure front of the hydroelectric complex is blocked by an earth dam.

Properly designed concrete and reinforced concrete dams of all types are seismic resistant, even at high seismicity (but in the absence of differential foundation movements). Concrete dams are successfully used in harsh climatic conditions and on high-water rivers; with sufficiently wide openings, they make it possible to do without tunnels while skipping construction costs; they are used at various pressures (heights), including large ones; volumes of concrete can reach several million cubic meters.

The disadvantage of dams in this group is the cost of their construction of concrete and metal, which are usually not local materials (require significant transportation costs) and can be scarce and relatively expensive under certain conditions.

For reliable design and construction of the dams under consideration, it is extremely important to know and correctly assess the geological conditions at the site of construction of the hydroelectric complex; obtain reliable geotechnical characteristics of soils (especially shear and deformation characteristics, including for fillers of cracks in rocks).

Great advances in the development of soil mechanics (including rock mechanics) and methods for improving foundations in recent years have contributed to the improvement and reliable use of concrete and reinforced concrete dams, including at high pressures and on non-rocky foundations. The largest and most outstanding dams in terms of engineering on non-rock foundations were built in the USSR (on the rivers Svir, Volga, etc.)

There are two ways to reduce the cost of concrete dams.

1. Simplification of the structure (refusing to install various water conduits and holes in it or reducing them to a minimum; using a simple massive gravitational structure that reduces the amount of formwork, etc.). This makes it possible to build them using high-performance methods, widely using mechanization (layer-by-layer laying of low long blocks of concrete using the Toktogul method, the use of conveyors, etc.); do not monolith construction seams (or not monolith all seams); use low-cement rollable concrete mixtures,

During the construction of the Willow Creek gravity dam (USA, 1982, A = 66.5 m, volume of concrete 306 thousand m3) from a compacted concrete mixture, the cement consumption at the top edge was 104 kg per 1 m3 of concrete, and in the inner zone 47 kg /m3 with the addition of fly ash 19 kg/m3.

Rolling was carried out using vibrating rollers in layers 25...30 m thick in four passes of the roller; the cost of rolled concrete was 3.4 times less than the cost of conventional massive concrete. The time and cost of construction were significantly reduced compared to the option of a waterworks with a rock-earth dam. 2. Lightening the structure - reducing the volume of concrete through the use of buttresses and cellular structures, taking into account spatial considerations!” work of the structure (arch dams, gravity dams with embedded intersectional joints, etc.), anchoring (involvement of the base in the work), etc.

In each specific case, it is necessary to analyze which of these directions is the most rational. At the same time, a combination of these directions is promising and may be appropriate - reasonable lightweighting of the structure (not leading to significant production complications) and its construction using high-performance industrial methods developed or modified in relation to this design. For example, the design of the lightweight (massive buttress) Kirov dam (L = 83 m) was adopted in such a way (sufficiently thick buttresses, etc.) that it could be successfully erected by layer-by-layer concrete laying.

With a rock foundation, lightweight gravity dams (Fig. 7.1,6-d) compared to massive gravity dams (Fig. 7.1, a) have a volume of concrete less by about 8...15% (rarely more than 15%). Anchored dams at low heights (up to 20 or 30 m) can also provide greater savings in concrete (Ault na Lairridge dam, h = 22.2 m - 50%). The use of massive buttress dams allows for concrete savings of up to 25...40% (Fig. 7.1,e), dams with flat pressure ceilings - 25...45% (Fig. 7.1,6), multi-arch dams -30... 60% or more (Fig. 7.1g). In favorable geological and topographic conditions with relatively narrow sections, the volume of concrete of arch dams (Fig. 7.1, and m) is reduced by 50...80% or more compared to the volume of concrete of a massive gravity dam under similar conditions. For arch-gravity dams this reduction is significantly less (about 20...30%).

In cost, the percentage of savings is less (by 5...10%, sometimes more) due to complications in the work, a slight increase in concrete grades and an increase in formwork work for lightweight dams, etc. It depends on many local conditions - the method of passing and the values ​​of construction expenses, cost labor force and materials, etc.

With a non-rock foundation, significant savings in concrete (up to 20... 45%) compared to a massive structure (see Fig. 7.25) can usually be obtained only when loading cavities with ballast, that is, when using various cellular structures with filled cavities (Fig. 7.2 , 7.3). This is due to the fact that with a solid foundation slab (Fig. 7.2,6), which is usually required for a lightweight dam with a non-rock foundation (except for the design of A. M. Senkov, Fig. 7.2, a), the filtration pressure does not decrease compared to a massive gravity dam (with lightweight dams on the rock, shown in Fig. 7.1,6c, and buttress dams, it decreases), and a significant flattening of the pressure face of the buttress dam, necessary from the condition of ensuring the stability of the dam for shear in the absence of soil loading of the cavities between the buttresses, is almost always leads to an insufficiently constructive solution.

Massive gravity dams on rock foundations (Fig. 7.1, a) have become widespread due to their simplicity. Dams with expanded seams (Fig. 7.1,6) were successfully used in a number of cases, but were not widely used; dams with a longitudinal cavity (Fig. 7.1, a) have found application only in isolated cases. This can be explained by the fact that the savings in concrete with these types of lightweight dams are not very large, but the work on their construction becomes somewhat more complicated. Dams with a screen on the pressure face are still rarely built, but recently attention has been paid to them, and a number of interesting studies and studies have been carried out in relation to the Kurpsai dam (a version of this dam without a screen has been adopted). In such a design, with reliable operation of the screen, it is possible to allow tensile stresses on the top edge (which gives a more compressed profile) and lower the requirements for the grade of concrete (remove the requirement for water resistance, allow the formation of cracks at the top edge). Their use is constrained by very high requirements for the quality of the screen (from stainless steel or polymeric materials) and doubts about the possibility of reliably meeting these requirements, as well as the complexity repair work in case of damage to the integrity of the screen.

Anchored dams (Fig. 7.1, c?) are used in a number of cases, and they are made as gravity and as buttress dams at heights usually not exceeding 55...60 m (at higher heights, difficulties arise in creating the pre-tensioning required to obtain the proper effect anchors), on good rock foundations, which allowed for reliable anchoring.

Anchoring was also used in the superstructure of dams. Such dams have not become widespread, mainly due to some complexity in the implementation of this design, difficulties in placing various culverts in the dam in the presence of anchors, and rather high requirements for the foundation and the quality of the anchoring.

From various types buttress dams, especially over the last 30...40 years, the most widespread are massive buttress dams (Fig. 7.1, e), which have fairly thick elements and small reinforcement (5...15 kg of steel per 1 m3 of concrete or less), which makes it possible to build them using industrial methods and use them in harsh climatic conditions. Multi-arch dams are used much less frequently, which is explained by the complexity of their construction and large reinforcement (30... 50 kg of steel or more per 1 m3 of concrete). Dams with flat pressure ceilings are now very rarely built. Of the relatively new dams of this type, only the Mada dam in Malaysia, built in 1970, and the Cordova dam in the USA can be mentioned (h = 27.4 m, spans between the axes of the buttresses 12.5 m). This is due to the fact that the structures of such dams are relatively thin-walled (which is not always acceptable under the conditions modern production works), and covering significant spans with slabs is usually impractical. In addition, quite significant reinforcement of the structure is required (20...40 kg of steel per 1 m3 of concrete or more). The relative thinness of the elements can sometimes be undesirable for durability reasons.

The significantly greater prevalence of massive buttress dams compared to similar gravity dams with expanded seams is quite natural, since they provide greater savings in concrete (see above) without significant additional complication of the design. Buttress dams, in addition, make it possible to obtain large (in modulus) vertical compressive stresses a" at the base at the pressure face (Fig. 7.4, a, b) and thereby prevent the opening of the contact seam at the base in the area of ​​the grouting curtain. With buttress dams, if necessary, it is possible to obtain a fairly uniform stress diagram in the foundation, which is one of their advantages and has been implemented in a number of dams, especially on relatively low-modulus foundations. This can be achieved by constructing a flatter bottom edge in the lower part of the buttress (tide A in Fig. 7.4, c), and if additional stress reduction is necessary, by constructing a full or partial foundation slab (Andijan dam - see Fig. 7.44, Ben Metir).

In the body of buttress dams, stresses are distributed more evenly than in massive gravity dams.

This disadvantage of massive gravity dams (small ohm in the contact seam) can be eliminated or reduced by using anchoring (Fig. 7.1, e, 7.4, d), constructing a longitudinal cavity (Fig. 7.1, c), using appropriate cutting of the dam, temporary, grouted before filling reservoirs using a seam (Fig. 7.4, e), as well as using an “active seam” with flat jacks (Fig. 7.4, f). The last effective measure has been applied in practice only for buttress dams; it involves the base in the work and allows you to reduce the volume of concrete with a favorable distribution of stresses in the base. Active joints with flat jacks are simple and have proven themselves in practice.

A fundamentally different solution, taking into account the possibility of opening a contact seam in a gravity dam in the case of small calculated values ​​of oh, which in reality may turn out to be tensile (especially with a compressed profile), is the construction of a short depression with a grouting curtain under it, somewhat placed in the VB beyond the zone of possible the occurrence of tensile stresses (see Fig. 7.1, d). With this solution, the seals in the seam between the short depression (or the mass above the curtain) and the body of the dam are very important, the repair of which is difficult. This solution may be considered necessary when tensile stresses are allowed on the upstream face of the dam. It is permitted by SNiP II-54-77 only if the top edge is waterproofed (see Fig. 7.1, d). It should be considered with an unfavorable base of different moduli, when under the lower part of the dam it has a lower deformation modulus than under the upper part.

Arch dams have become widespread in mountainous areas in many countries around the world and

have proven themselves well in operation. They are usually economical, fit well into the surrounding landscape, are beautiful, and work reliably in conditions of high seismicity and overloads. Thus, the Pacoima dam with a height of 116 m (California, USA) withstood a very strong earthquake with a maximum horizontal acceleration of 1.25 g and a vertical acceleration of up to 0.75 g without damage, and the Italian thin Vajont dam with a height of 266 m and a thickness at the bottom of 23 m survived, receiving very slight damage when a wave about 70 m high overflowed through it in 1963, caused by a huge landslide in the reservoir, into which about 300 million m3 of rock fell in 5...7 minutes.

The most common are arched dams with pinched heels (Fig. 7.1, i), as well as with a perimeter (contour) seam (Fig. 7.1, c); dams with abutments are also often built (Fig. 7.1, l). Dams that are more complex in construction, divided by seams into separate arches (including those from three-hinged belts - Fig. 7.1, l), working mainly as flat systems, are erected only in isolated cases at low heights.

Recently, arched dams of the dome type have become widespread, that is, with significantly curved vertical sections (the so-called consoles). In such dams it is usually possible to obtain the most favorable stress distribution.

Arch-gravity dams are currently used mainly at high pressures, in fairly wide sections and when culverts - spillways, hydraulic station pipelines (Sayano-Shushenskaya, Glen Canyon dams) are located in the dam body.

Concrete and reinforced concrete dams are usually built from cast-in-place concrete. Only in isolated cases and at relatively low heights were such dams made entirely from prefabricated elements (the multi-arch Mefrush dam in Algeria with a height of 25 m, the experimental cellular dam on the Stepnoy Zay River in the USSR and some others). This is mainly due to the fact that such dams are not mass standard structures and prefabricated non-standard structures are in most cases ineffective even for small and moderate heights of structures.

At low pressures (5...7 m), in a number of cases prefabricated monolithic cellular structures were used, consisting of blocks in the form of paired reinforced concrete slabs, monolithic with concrete (Fig. 7.2,6). Four dams of this type were built according to Giproselelectro projects (Krasnoyarsk on the Medveditsa River, Perevozskaya, Lykovskaya and Shilskaya). A similar type of dam was built in Iraq (Soyuzgiprovodkhoz project).

Separate prefabricated elements that facilitate the work (grooved structures, parapets, slabs of reinforced concrete permanent formwork for buttress dams, permanent reinforced concrete formwork for viewing galleries, etc.) are used in the construction of concrete and reinforced concrete dams.

Gravity, buttress and arch dams can be made not only from concrete, but also from masonry with mortar. Currently, masonry dams have practically been replaced by concrete ones, which have significant production advantages (the possibility of extensive mechanization, high rates of work, etc.). Only in India are gravity dams still sometimes built from masonry. In 1969, the construction of the 124.7 m high Nagarjanasagar rock dam, the tallest dam of its type in the world, was completed there.

Explanatory dictionary of the Russian language. D.N. Ushakov

dam

dams, railway

A dam, a structure made of earth, stone, iron, concrete, etc., built across a river to raise the water level or across a ravine to form an artificial pond. The miller's dam was leaked by water. Krylov. Wooden dam. Concrete dam.

trans. An obstacle, an obstacle to something. Create a dam against military danger.

Explanatory dictionary of the Russian language. S.I.Ozhegov, N.Yu.Shvedova.

dam

Y, f. A structure that blocks a river or current to raise the water level. Concrete village Zemlyanaya, wooden village Vodosbrosnaya village

adj. dam, -aya, -oe.

New explanatory dictionary of the Russian language, T. F. Efremova.

dam

A structure installed across a river or other body of water that blocks the flow and usually serves to raise the level of water in front of it.

trans. Something that interferes, prevents the development, manifestation of something.

Encyclopedic Dictionary, 1998

dam

a hydraulic structure that blocks a river (or other drainage) to raise the water level in it, concentrate pressure at the location of the structure or create a reservoir. A dam can be a dead dam, which only blocks the flow of water, or a spillway, designed to discharge excess water. Based on the main material, dams can be divided into earthen, stone, concrete, reinforced concrete, wooden and other dams.

Dam

a hydraulic structure that blocks a river (or other watercourse) to raise the water level in front of it, concentrate pressure at the location of the structure and create a reservoir. The water-economic importance of the river is manifold: the rise in water level and the increase in depths in the upper pool favor shipping, timber rafting, and water intake for irrigation and water supply needs; the concentration of pressure near the river creates the possibility of using the river flow as an energy source; the presence of a reservoir makes it possible to regulate the flow, i.e., increase the water flow in the river during low-water periods and reduce the maximum flow during a flood, which can lead to destructive floods. The river and the reservoir significantly affect the river and adjacent territories: the river flow regime, water temperature, and the duration of freeze-up change; fish migration becomes difficult; the banks of the river in the upper pool are flooded; The microclimate of coastal areas is changing. P. is usually the main structure of a waterworks.

Dam construction arose as long ago as hydraulic engineering, in connection with the significant development of artificial irrigation of territories among the agricultural peoples of Egypt, India, China and other countries. The construction of P. was required for the construction of hydraulic power plants, and then the construction of hydroelectric power stations. The energy use of water resources was the main incentive for increasing the size and improving the design of waterways and the appearance of hydraulic structures on high-water rivers.

On the territory of the USSR, water mills with water were built back in the days of Kievan Rus. In the 17th-19th centuries. mining, metallurgy, textile, paper and other industries in the Urals, Altai, Karelia and central regions of Russia used mainly the mechanical energy of hydraulic power plants; their buildings were small in size and were constructed from local materials. Powerful hydroelectric power stations with large concrete and earthen pumps began to be built only under Soviet power, after the adoption of the GOELRO plan. In 1926, the first concrete spillway of the Volkhov hydroelectric power station was built. In 1932, a high concrete P. Dnieper hydroelectric power station was built (its maximum height is about 55 m). The spillway reservoir of the Nizhnesvirskaya hydroelectric power station is the first reservoir built on weak clay soils. In the 50s-70s. on high-water rivers were built: alluvial earthen P. on the Volga near Kuibyshev and Volgograd, concrete P. Bratsk hydroelectric power station on the Angara (height 128 m) and Krasnoyarsk hydroelectric power station on the Yenisei (124 m) ( rice. 1), a high 300-meter stone-earth P. Nurek hydroelectric power station on the river. Vakhsh, the arched P. Sayan hydroelectric power station on the Yenisei (height 242 m, length along the crest 1070 m; currently under construction, 1975), and many others. The design and construction of P. in the USSR are distinguished by a high technical level, which allowed Soviet dam construction to take one of the leading places in the world.

Of the P. built abroad, it should be noted: multi-arched P. Bartlett, height 87 m (USA, 1939), stone P. Paradela, height 112 m (Portugal, 1958), earthen P. Ser-Ponson, height 122 m ( France, 1960), stone-earth P. Miboro, height 131 m (Japan, 1961), gravity concrete P. Grand Dixence, height 284 m (Switzerland, 1961).

The type and design of a building are determined by its size, purpose, as well as natural conditions and the type of main building material. Based on their purpose, a distinction is made between reservoir reservoirs and water-lifting reservoirs (intended only for raising the level of the upper pool). Based on the magnitude of the pressure, pumps are conventionally divided into low-pressure (with a pressure of up to 10 m), medium-pressure (from 10 to 40 m), and high-pressure (more than 40 m).

Depending on the role performed as part of a waterworks, the water supply can be: deaf, if it serves only as a barrier to the flow of water; drainage, when it is intended to discharge excess water flows and is equipped with surface drainage holes (open or with gates) or deep drainages; station, if it has water intake openings (with appropriate equipment) and water conduits feeding hydroelectric power station turbines. Based on the main material from which dams are built, a distinction is made between earthen dams, stone dams, concrete dams, and wooden dams.

Earthen P. is constructed entirely or partially from low-permeability soil. Low-permeable soil laid along the upper slope of the P. forms a screen; When such soil is located inside the body of the soil, a core is created. The presence of a screen or core makes it possible to construct the rest of the pavilion from permeable soil or from stone materials (stone-earth pavilion). At the bottom of the lower slope of the earthen P., drainage is installed to drain water that has filtered through the body and base of the P. The upper slope of P. is protected from the effects of waves by concrete slabs or rock riprap. When constructing an earthen embankment, soil is extracted from a quarry using excavators, transported to the construction site by dump trucks, placed in the body of the structure, leveled with bulldozers, and compacted layer by layer with rollers. The construction of alluvial soil involves the development of soil by dredgers or hydraulic monitors, transportation of the pulp through pipes and its distribution over the surface of the constructed soil, after which the water drains away and the settling soil compacts itself. To prepare the foundation and construct an earthen pipeline in the river bed, its foundation pit is fenced off with lintels, and the river is diverted through pre-laid temporary conduits, which are closed after the construction of the pipeline.

In stone (fill-fill) paving, the screen or central waterproof element (diaphragm) is made of reinforced concrete, asphalt, wood, metal, and polymer materials. The requirement of low water permeability also applies to the base of the P. If the base soil is permeable to a great depth, it is covered in front of the P. with a drooping layer (for example, made of clay), forming one whole with the screen. P. with a core is complemented by a device at the base of a steel sheet pile wall or an anti-filtration curtain. The stone in rockfill and rock-earth paving is poured in layers of great height.

Concrete floors are usually classified according to their design, depending on the shear conditions; Accordingly, there are 3 main types of P. ( rice. 2) ≈ gravity dams, arch dams, buttress dams. Basic The material for modern concrete floors (mostly gravity-based) is hydraulic concrete. One of the most important issues in the construction of concrete substructures is the reduction of water filtration in the base. For this purpose, an anti-filtration curtain is installed at the base of a high concrete floor near the top edge. In the remaining section, the base is drained to reduce water pressure on the base of the floor, which increases the stability of the structure. To avoid the formation of cracks due to temperature fluctuations, gravity and buttress panels are cut lengthwise into short sections, the seams between which are covered with waterproof seals (see Waterproofing). To prevent the appearance of cracks as a result of shrinkage of concrete during hardening and to reduce thermal stresses, the concrete block is concreted in separate blocks of limited sizes; artificial cooling of the components of the concrete mixture and the concrete laid in the blocks is used by circulating coolant (from the refrigeration unit) through a system of pipes laid in the body of the concrete block. Concrete pavement in the riverbed is usually constructed in 2 stages under the protection of lintels enclosing the pits. During the construction of the first stage of the river, the river flows along the free part of the riverbed; in the second case, through the holes (holes) left in the P., which are closed upon completion of all construction work. If the river bed is narrow, a concrete waterway is built in one step, with the river temporarily diverted into coastal waterways. A low-pressure concrete spillway dam, common in the practice of hydraulic engineering, built on a non-rock foundation and designed to pass large flows of water, has the design shown in rice. 3. Its basis is made up of drainage spans formed by concrete flutbet and bulls and blocked by hydraulic gates. Behind the spillways, a massive channel support is installed - a water trough (sometimes buried in the form of a water well), followed by a lighter fastening - an apron. Drainage is installed under the reservoir. The spillway is connected to the shores or earthen P. by massive abutments. A low-pressure concrete spillway is usually built using reinforcement, often the entire structure (see Reinforced concrete dam). In order to save material, flutbet and bulls of this kind are sometimes made of a lightweight cellular structure, with the cells filled with soil.

In forest areas, low-pressure wooden pumps of pile and cord construction are often built (usually they are equipped with spillways).

A special type of water-retaining structure is a collapsible navigable bridge. To erect it during summer low water, buttresses made of steel trusses are installed on a flat surface, bridges are laid across them, on which gates of the simplest design rest. The port supports the level of the upper pool, and ships and rafts go through the lock. During high-water periods, gates and bridges are removed, buttress trusses are laid on the flatbet, opening the way for ships and rafts through the P.

The general trend of modern dam construction is to increase the height of the dam. Technically achieved heights can be exceeded, but from an economic point of view, the construction of two successive dams of lower height often turns out to be more rational than one high one. Improvement of types of construction made from soil materials is carried out while simultaneously reducing the cost and speeding up their construction by increasing the power of construction mechanisms and vehicles. Increasing the efficiency of concrete floors is achieved by reducing their volume, replacing gravitational floors with buttresses, and the wider use of arched floors. This trend is accompanied by an improvement and specialization of the properties of cement and concrete. It is very effective to combine a spillway dam and a hydroelectric power station building in one structure, which ensures a reduction in the concrete (most expensive) part of the pressure front of the hydroelectric complex. This problem is solved both by placing hydraulic units in a high-pressure cavity and by using an underwater array of a low-pressure hydroelectric power station to install spillway openings in it.

Lit.: Grishin M. M., Hydraulic structures, M., 1968; Nichiporovich A. A., Dams from local materials, M., 1973; Moiseev S.N., Rock-earth and rock-fill dams, M., 1970; Grishin M. M., Rozanov N. P., Concrete dams, M., 1975; Production of hydraulic engineering works, M., 1970.

A. L. Mozhevitinov.

Wikipedia

Dam

Dam- a hydraulic structure that blocks a watercourse to raise the water level, also serves to concentrate pressure at the location of the structure and create a reservoir.

Dam (Karelia)

Dam- a rural settlement in the Loukhsky district of the Republic of Karelia, the administrative center of the Plotinskoye rural settlement.

Dam (Yaroslavl region)

Dam- a village in the Gavrilov-Yamsky district of the Yaroslavl region. It is part of the Velikoselsky rural settlement, being the center of the Plotinsky rural district and the Kolos collective farm.

Located near the Yaroslavl - Ivanovo highway. It borders the village of Shalava. Adjacent to Sidelnitsy and Vostritsevo. It has a store that serves the residents of the above villages, and an asphalt road.

Dam (disambiguation)

Dam:

• Dam- a hydraulic structure that blocks a watercourse or reservoir to raise the water level.
• Dam- natural limestone formation of karst caves.
• Dam- names of a number of settlements:
  • Dam - village in Karelia
  • Dam - a village in the Kostroma region
  • Dam - a village in the Perm region
  • Dam - a village in the Rostov region
  • Dam - a village in the Sverdlovsk region
  • Dam - a village in the Tyumen region
  • Dam - a village in the Yaroslavl region
  • Dam - a village in the Lugansk region of Ukraine
• Pompeia Plotina (d. 121/122) - wife of the Roman emperor Trajan.

Dam (Lugansk region)

Dam- village, belongs to the Stanichno-Lugansk district of the Lugansk region of Ukraine.

The population according to the 2001 census was 764 people. Postal code - 93643. Telephone code - 6472. Covers an area of ​​3.71 km².

Dam (Sverdlovsk region)

Dam- a village located in the Nevyansky urban district of the Sverdlovsk region (Russia) north of Yekaterinburg, south of Nizhny Tagil and 28 km south of the regional center of the city of Nevyansk near the dam on the Ayat River, propping up Lake Ayat. The nearest settlements are Shaidurikha, Pyankovo, Kunara.

According to historical data, the Dam does not appear in the lists of settlements of the late 19th century.

Examples of the use of the word dam in literature.

Now he pulled this rope, and a howling pack of hounds burst out and mingled with the maddened bulls and sheep, among which eight excisemen were panickingly trying to make their way back to dam.

By dam a man was walking quickly - Alexandrinsky and Lidochka, busy in conversation, saw him when he came very close.

In the hive of the Great White Brotherhood, Hermes Trismegistus was formed, whose influence on the Italian Renaissance was irrefutable, as well as on the Gnosticism of Princeton, Homer, the Gallic Druids, Solomon, Solon, Pythagoras, Plotinus, Joseph of Arimathea, Alcuin, King Dagobert, Saint Thomas, Bacon, Shakespeare, Spinoza, Jacob Boehme, Debussy, Einstein.

From Amina, Salavat learned why everyone listened to him so much and stood up for him before the foreman: he learned that the workers he dispersed never returned to the site of the destroyed construction site and did not begin to dams.

And here are the arches of the railway bridge across the Volkhov, the stormy white foamy waters of which, pouring over dam, rushing under the bridge.

When all the wells were filled with water, the beaver team immediately dismantled dam so that no one understands where the water came from.

Shortly after noon the river became narrow and shallow, and then the path was blocked by a giant dam beavers, the air was filled with the menacing slip of beaver tails and the gloomy hum of the turuins.

In 1898, in Transbaikalia, on the Bodaibo River, in the area of ​​​​the rich Zakharyevsky mine, bottom ice that surfaced and clogged the entire channel formed dam, around which a large ice then appeared.

But, raising the countercurrent, Her to dam The wave carried her out, And there she remained by the shore, Where Flanders competed with Brabant at the bowling pins.

There was a feeling of unprecedented lightness and freedom, dam collapsed, it turned out that any gurgling and quacking can be pasted into the music.

On dam The barge haulers mixed into a solid mass, through which it was necessary to make one’s way with great effort, and Osip Ivanovich again turned to the help of the most selective curses, the choice of which he had a remarkably varied choice and amazed even the barge haulers.

Remained powerful in my memory dam hydroelectric power stations with waterfalls overflowing the shields, we were just driving in a small truck along the lower pool, and it seemed that the water was bubbling and collapsing on us, and the wind was blowing splashes and foam onto the road.

He was by nature an excellent horseman and marksman with a bow, crossbow and gun; he often went hunting alone to the distant ridge of foothills, where the water of Bris rushed madly in a white stream through dams and tailwaters of the ancient canal system.

But what was the amazement of the engineer and his companions when they saw that the shipyard was destroyed, the trench was partially filled up, the drainage was blocked by sand dam and that, therefore, it is in no way possible to let water into Melrir before thorough corrections are made in this point!

Atlantic Wall, began restoration work on dams Mene and Eder.

In publications on the topic of hydraulic engineering and hydropower, there are often a lot of terms that are completely understandable to specialists, but not so clear to everyone else. In this regard, we are starting a series of publications devoted to the basics of hydraulic engineering and hydropower. In them we will talk about what types of dams and turbines there are, why hydroelectric power plant gates and SF6 switches are needed - and much more. Today I will talk about what types of dams there are; In the future, we will dwell on each type in more detail.

Roosevelt Arch Dam

All dams can be roughly divided into two groups: soil and concrete (we can ignore various exotics, such as metal, fabric or wooden dams, as they are practically not used in modern hydropower engineering).

Earth dams

As their name suggests, earth dams are built from ground materials - sand, loam, stone. They are all gravitational, i.e. their stability is ensured by their weight. The advantages of earth dams are the simplicity and manufacturability of their creation, the use of readily available local materials, and high seismic resistance. The disadvantages are the need for special measures to combat filtration, more complex and expensive spillway structures, and instability when water flows over the crest.
Soil dams are divided depending on the material used in their creation - into earthen, stone and stone-earth. Earth dams are most widely used, especially at lowland hydroelectric facilities, where they are part of the pressure front in 99% of cases.

Scheme of the Nurek hydroelectric power station dam

Concrete dams

Concrete dams are divided into three large groups - gravity, buttress and arch.

Gravity dams maintain stability due to their weight. They are simple, reliable, technologically advanced, and can be easily combined with water discharge structures and hydroelectric power station buildings, and therefore have become very widespread. From low-head spillway dams in run-of-river hydroelectric projects to high-rise dams in the mountains, this type of dam can be seen everywhere. The main disadvantage is that such a dam requires a lot of concrete.

Gravity concrete dam of the Krasnoyarsk hydroelectric power station

Buttress dams work mainly not due to weight, but by transferring forces to the foundation with the help of special retaining walls - buttresses. This dam design requires significantly less concrete, but is significantly more difficult to construct.

Types of buttress dams.

Arch dams transfer water pressure to the banks. The concrete in them works under compression, and in this case its strength is very high. Therefore, arch dams can be very thin and economical. The disadvantages of arch dams are the impossibility of their construction in wide sections, as well as the presence special requirements to the quality and configuration of the slopes.

Arch dam of the Inguri hydroelectric power station