RU2469147C1 - Dam of soil materials - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: dam comprises an antifiltration element in the form of a core from clayey soil, upper and lower side prisms from macrofragmental soils, a head of nonfrost-susceptible soil, an asphalted road surface of a dam crest traffic area and sorted stones. Sorted stones are orderly laid onto a dam slope illuminated with sunlight from its crest to the specified level, where they form open pores between each other. Open pores are partially filled with a soil material. At the same time the following conditions are met: ω_p>0.2D² _s and h_f ⁼(03-0.5)H_p, where ω_p - area of open pore clear space along its depth; D_s - mean average diameter of stones that form an open pore; h_f - height of open pore filling with soil material; H_p - open pore depth.

EFFECT: higher reliability of a dam due to prevention of permafrost formation in the upper part of its core.

5 cl, 2 dwg

Description

The invention relates to hydraulic engineering and can be used in the construction and operation of dams of soil materials in the northern climatic zone.

It is a well-known dam made of soil materials, which contains an anti-filtration element in the form of a core made of clay soil, upper and lower side prisms from coarse soil, a head made of non-porous soil (the same protective layer) and road surface of the carriageway of the dam crest [1].

The disadvantage of such a dam is its lack of reliability in the northern building and climatic zone. At negative average annual outdoor temperatures in the area, the upper part of the core can be frozen and permafrost, often layered, can develop in it. So, the upper parts of the core dams built in the northern climatic zone are already frozen up to 8 m or more, i.e. below the seasonal thawing boundary and well below the NHL. This occurs with the formation of a frozen “overlap” in the upper part of the core, supported by weakly deformed lateral prisms of the dam. All this leads to the formation of cracks and unconsolidated zones in this part of the dam core [2].

The main structural and technological features of well-known technical solutions (both implemented and unrealized), aimed at eliminating the indicated drawback of a well-known dam, are as follows [3]:

- the height of the tip (protective layer) H _og sufficient to prevent freezing of the core from above (economically justified at an average annual outdoor temperature of at least minus 2-3 ° C);

- the core above the NPU is made of weakly grained frozen soil;

- the tip of the dam contains a rigid and / or flexible impervious diaphragm;

- the upper part of the core is equipped with a horizontally stacked film that prevents the migration of water from below into the freezing tip;

- the upper part of the core is heated by water or electric current;

- the upper part of the core contains a trench filled with loose or clogging material;

- the core above the NPU is created by filling in a trench with cohesive soil made in the tip;

- the upper part of the core contains a trench filled with a refractory gel-like material - a cryophylactic with a low freezing temperature [4];

- in the head above the core, a repair and inspection heated gallery was made [5].

Common disadvantages of these well-known technical solutions (tools) are as follows:

- their implementation on a dam in operation is associated with complex and costly reconstruction of the dam head;

- at an average annual outdoor temperature below minus 7 ° С, the operability of a dam with a reconstructed head may be insufficient (except for the last most expensive head [5]);

- the possibility of a combination of two or more of these technical solutions in one dam is not visible.

Moreover, the use of modern heat-insulating materials in a dam, known from a number of technical solutions, can only slow down the formation of permafrost in the upper part of the core, but cannot completely prevent this process.

The problem to which the invention is directed, is to increase the reliability of the dam and save money on its construction and operation in the northern climatic zone. The technical result is to simplify and reduce the cost of work aimed at preventing the formation of permafrost in the upper part of the core, as well as the ability of the proposed technical solution to work in conjunction with known other similar technical solutions.

The problem is solved, and the technical result is achieved by the fact that a dam of soil materials contains an anti-filter element in the form of a core of clay soil, upper and lower side prisms from coarse soil, a head made of non-porous soil, asphalt road surface of the carriageway of the dam crest and sorted stones. These sorted stones are orderedly laid on the slope of the dam illuminated by the sun from its crest to a predetermined level, where they form open pores between themselves, while the open pores are partially filled with soil material. At the same time, the conditions are satisfied:

and

where ω _p - the lumen area of the open pore in its depth;

D _to - the arithmetic mean diameter of the stones forming an open pore;

_sn h - the height of filling the open pores of soil material;

H _p - the depth of the open pore.

Additionally:

- the condition is satisfied

- the dam contains a thin layer coating, which is located on the surface of the impassable part of the dam crest, sorted stone and filling the open pores of the soil material, and which has a dark color and increases the absorption of solar radiation by the impassable part, sorted stone and soil material filling the open pores;

- a thin layer coating is made of bitumen or paint or polymer material of a dark color;

- a thin layer coating increases the absorption coefficient of solar radiation of the impassable part, sorted stone and soil material filling open pores, to a value of not less than 0.7.

It is the performance of a pavement made of asphalt or asphalt concrete and laying on a slope of a dam of sorted stone according to the indicated rules that significantly increases the ability of the upper part of the dam to absorb solar radiation, especially in the case of additional execution of a thin layer of dark color. This circumstance, with the corresponding economically feasible height of the tip H _og , due to the increased heat reserve from solar radiation and the heating effect of filtering water through the dam, can prevent freezing of the upper part of the core in the cold season at an average annual outdoor temperature in the area of about minus 6-7 ° C.

The invention is illustrated by drawings, which schematically depict:

figure 1 - the upper part of the dam, a cross section;

figure 2 - open pore formed on the slope by sorted stones, while the slope has a southern exposure, the angle of inclination to the horizon α = 30 °, and the sunbeam for example is also inclined to the horizon at an angle of 30 °.

The dam from soil materials contains a core 1 made of clay soil, side prisms top 2 and bottom 3 made of stone, transition layers - top 4 and 5 and bottom 6 and 7, head 8 made of gravel sand, and road surface 9 of the roadway of crest 10 of the dam . The road surface 9 is made of asphalt concrete, which has a solar radiation absorption coefficient of at least 0.9. Sorted stones (hereinafter referred to as stones) 13 (figure 2) are laid on an illuminated by the sun, for example, bottom slope 11 in order to form open pores 12. These stones 13 are stacked from the crest 10 of the dam to a predetermined level of 14, for example, to point A — the level at the height of the suction of the depression curve 15 at the water downstream.

Each open pore 12 has its depth H _p and partly to a height h _cp filled with soil material 16. The stones 13 are selected and laid in compliance with the conditions:

and

where ω _p - the lumen area of the open pore in its depth;

D _to - the arithmetic mean diameter of the stones (balls) forming an open pore.

Each stone 13 has its own shape and dimensions, while for its diameter D _to accepted, as is done in hydraulic engineering, the diameter of the ball is equally volume to him D _W.

When tightly placed on the plane of the balls, the lumen area per one ball is 0.215D _w ² , when staggered cubes with an edge of length α, the lumen area per one cube is 0.5a ² . Based on this, condition (1) can be refined to the form:

and taking into account the desire to increase the size of open pores, as “traps” of the sun's rays 16, condition (1) can be refined and have the form (3), i.e.

On the surface of the roadsides 17 (the impassable part of the dam crest), sorted stone 13 and filling the open pores 12 of the soil material 18, it is advisable to arrange a thin layer coating 19 (shown in dotted lines in the drawings), which can be made, for example, of bitumen or paint or polymer material of a dark color . This coating 19 increases the absorption coefficient of solar radiation of the coated material, at least to a value of not less than 0.7.

The essence of the thermotechnical calculations of the dam for specific climatic conditions, its location and orientation relative to the cardinal points is that first they predict the boundary 20 freezing of the upper part in the prototype dam, and then the freezing border 21 in the proposed dam. Then evaluate the efficiency of the last dam.

In case of insufficient such efficiency, the possibility of supplementing the dam with the previously indicated known technical solution, structurally compatible with the proposed dam, is considered.

In the example shown in the drawings, the bottom slope 11 has a southern exposure, and its angle of inclination to the horizon is α = 30 °, while the sunbeam 16 is also inclined to the horizon at an angle of 30 ° for clarity.

From the drawing (figure 2) for the above example, the following clearly follows.

1. The sun's ray 16, which fell on the illuminated surface of the stone 13 above the boundary of the effective level 22 corresponding to this surface, will immediately be reflected and return to space only once attenuated (in Fig. 2, the rays going out into space are shown by a dotted line). The sun's ray 16, which fell on the surface of the stone 13 below this level 22, will be reflected many times within the open pore 12 from the stones 13 and from the soil material 18 and will return to space many times weakened, scattering almost all its thermal energy in such a “trap” on downhill slope 11. This circumstance increases the absorption coefficient of solar radiation by downhill slope 11 against such a coefficient of rocks, of which the slope is composed.

2. The maximum high position of the boundary of the effective level 22, therefore, the greatest absorption of solar heat by the lower slope 11 will be with the perpendicular direction of the sun beam 16 to the lower slope 11, i.e. when the tilt of the sun's ray 16 to the horizon at an angle of 60 °.

The peculiarity of the dam construction is as follows:

1. When laying each stone 13 on a slope, the bottom 11 and / or top 23 is produced with the surface of the stone 13 facing South, the greatest inclination, in comparison with the inclination of its surfaces facing in other directions. At the same time, the design of the open pore 12 and its dimensions, and, if necessary, the number and places of contact of the stone 13 with adjacent stones forming this pore 13 are provided by the design.

2. When creating a thin-layer coating 19, it is advisable to apply the material to the surface of the shoulder 17 and the slope 11 and / or 23 with a spray gun, the nozzle of which should be directed from the South to the North, i.e. in the prevailing direction of sunlight 16.

The peculiarity of the operation of this dam in specific climatic conditions is as follows.

1. The abundant absorption of solar radiation heat by the upper part of the dam and its accumulation mainly during the warm season ensures the freezing of the upper part of core 1, therefore, the formation of permafrost in it during the cold season at an average annual outdoor temperature of about minus 6-7 S.Eto ° about 3-4 ° C lower than usual dam prototype, in which the height H _og tip 8, which protects the core from freezing 1 is adopted in accordance with the heat engineering and economic calculation rationale.

2. The amount of solar radiation depends on the height of the sun, which determines the distance that a sunbeam must travel before it reaches the surface of the earth, season, transparency of the atmosphere (dust, water vapor, ozone, atmospheric pressure, etc.). Solar radiation is usually measured by its thermal effect and is expressed in calories per surface unit per unit time. Solar radiation is not blocked by clouds and it is strong near the poles during the polar days when the sun is even above mid-horizon at midnight. At the equator, and at high levels and in middle latitudes, there is practically no significant difference between winter and summer, and solar radiation acts year-round with almost the same intensity.

3. The intensity of absorption by the upper part of the dam of heat of solar radiation depends on the intensity of the sun's beam 16 on the ground, the angle of its incidence on the outer surface of the dam and the absorption coefficient of solar radiation by the material of this surface. In this case, the absorption coefficient of solar radiation depends on the color of the surface and varies from 0.25 of a white glossy surface (enamel) to 0.9 or more of a black surface (asphalt concrete). Moreover, the most common rock formations have an absorption coefficient of about 0.6 or less, namely light gray sandstone 0.62, granite 0.55, dark limestone 0.5 and light limestone 0.35.

4. Soil material 18 under condition (2) fills the open pore 12 with 30-50 percent of the pore height N _p. This is sufficient to fix the position of the stone 13 on the slope of the dam and to efficiently transfer heat from the heated stone 13 to the soil material in the warm season downstream slope 11 and / or upstream 23. There is no decrease in the absorption of solar radiation by these slopes of the dam, because the surface of the soil material 18 does not exceed the boundary of the effective level 22.

5. Open pores 12 reduce the loss of heat from the upper part of the dam by creating stagnant zones in these pores when blowing the slope with atmospheric air during the warm season and by increasing the retention of snow on the slope during the cold season.

A thin layer coating 19, if necessary, can be performed during the period of operation of the dam from a dark-colored liquid material made in place. This material can be obtained from substandard graphite and / or coal mixed after grinding with a liquid binder. Such a layer will provide an increase in the absorption coefficient of solar radiation by the outer surface of the dam to about 0.8 or more.

The proposed invention improves the reliability of the dam and, if necessary, can be implemented at any time during the operation of the dam, regardless of other technical solutions already implemented or being implemented for this purpose and without creating interference with them.

Designations:

1 - core

2 - riding side prism

3 - bottom side prism

4 and 5 - upper transitional layers

6 and 7 - lower transitional layers

8 - tip

9 - road surface

10 - crest (dam)

11 - downhill slope

12 - open time

13 - sorted stone (hereinafter - stones)

14 - level of point A

15 - depression curve

16 - sunbeam

17 - roadside (impassable part)

18 - soil material

19 - thin coating

20 - freezing boundary in the dam-prototype

21 - freezing boundary in the proposed dam

22 - effective level boundary

23 - riding slope

H _og - head height

N _p - the depth of the open pore

ω _p - the smallest parallel to the slope open pore area along its depth

_sn h - the height of filling the open pores of soil material

m - laying downstream slope.

Information sources

1. SNIP 2.06.05-84 * Dams from soil materials, paragraphs 2.1 *, 2.14,2.15.

2. Yagin V.P. Dams of soil materials erected in the northern climatic zone. // Hydrotechnical construction, 1997, No. 3.

3. Yagin V.P. The head of the soil dam being erected in the northern climatic zone. // Hydrotechnical construction, 2002, No. 4.

4. Pat. Of the Russian Federation No. 2418132, publ. 05/10/2011.

5. Pat. Of the Russian Federation No. 2207428, publ. 06/27/2003.

Claims (5)

1. A dam made of soil materials contains an antifiltration element in the form of a core of clay soil, upper and lower side prisms from coarse soil, a head made of non-porous soil, an asphalted road surface of the carriageway of the dam crest, and sorted stones that are arranged in an orderly manner on the dam slope from the sun from its crest to a predetermined level, where they form open pores between themselves, while the open pores are partially filled with soil material and the conditions are satisfied
ω _p > 0.2

and
h _sn = (0.3-0.5) N _p
where ω _p - the lumen area of the open pore in its depth;
D _to - the arithmetic mean diameter of the stones forming an open
time to go;
_sn h - the height of filling the open pores of soil material;
N _p - the depth of the open pore. 2. The dam according to claim 1, characterized in that the condition ω _p > 0.3 is satisfied

. 3. The dam according to claim 1, characterized in that it contains a thin layer coating, which is located on the surface of the impassable part of the dam crest, sorted stone and filling the open pores of the soil material, and which has a dark color and increases the absorption of solar radiation by the impassable part, sorted stone and soil material filling open pores. 4. The dam according to claim 3, characterized in that the thin-layer coating is made of bitumen or paint or polymer material of a dark color. 5. The dam according to claim 3, characterized in that the thin-layer coating increases the absorption coefficient of solar radiation of the impassable part, sorted stone and soil material filling open pores, to a value of not less than 0.7.

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