RU2573328C2 - Reserve spillway of soil retaining structure (versions) - Google Patents

Abstract

FIELD: construction.SUBSTANCE: reserve spillway of a soil dam includes one (according to version 1) or several (according to version 2) soil eroded inserts in the form of sections 13, which represent a dam or a dike with a top elevation lower than in the retaining structure. The eroded insert is made in the form of a prism of trapezoidal cross section arranged in the water-conducting part of the reserve spillway. Along the perimeter of the trapezoidal cross section of one (according to version 1) or several (according to version 2) sections 13, as well as on upper and lower slopes there is a protective coating arranged from a polymer geomembrane, which is filled during construction with soil similar to dam body. To increase efficiency of evacuation of eroded inserts at several sections 13 of the spillway (according to version 2), the top elevation of eroded inserts 6 is set: for the first section - at the FPU elevation, for the second - at the elevation (FPU-0.5 m), for the third - at the elevation (FPU-1.0 m), etc., providing for serial connection of first the last section, then the last but one, and so on. The main spillway 14 is located in the soil dam body at the elevation of the normal retaining level (NRL).EFFECT: safe passing of rare-frequency flood and prevention of soil retaining structure damage.9 cl, 5 dwg

Description

The invention relates to hydraulic engineering construction and can be used as an auxiliary spillway in an underground retaining structure for passing floods of rare frequency in the presence of a main spillway in the hydraulic system.

Known spillway structure (SU 1209754, publ. 02/07/1986), including eroded soil insert, laid on a concrete flute between concrete abutments.

The disadvantage of this solution is that when the soil insert is eroded, the reservoir completely empties to the concrete flat bet, which is fraught with flooding of territories located downstream of the river bed. The absence of water flow energy absorbers in the downstream will be accompanied by erosion of the discharge channel. The presence of concrete elements in the design of the backup spillway increases the cost of building a culvert.

A known spillway of a retaining structure (Patent RU 2071527, publ. 10.01.1997), including a washable insert made in the form of a soil dam with a crest mark below the crest mark of a retaining structure and enclosed from the sides and bottom in clothing made of indissoluble material.

The disadvantage of this solution is that the spillway structural elements are made of concrete and steel sheet piles, which significantly increases the material consumption and the cost of construction of a spillway structure. Another disadvantage is that at the end of the flood, the tongue must be removed from the soil dam.

Known reserve spillway of an earth dam (Patent RU 2498007, publ. 04/13/2012), designed to pass emergency floods, made in the crest of the dam, with a protective film waterproof coating of the bottom slope.

The disadvantage of this solution is that the construction of a backup spillway may take longer than it is necessary to pass an unplanned emergency flood, as a result of which the construction device can only complicate the situation at the hydroelectric complex and lead to overflow of water through the crest of the soil dam. Another disadvantage of the backup spillway is that the use of this spillway design is possible only for small ponds and reservoirs with a relatively small discharge flow rate of up to 50 m ³ / s.

Known eroded soil dam spillway (Patent RU 2011736, publ. 04/30/1994), including the upper and lower prisms with slopes, combined anti-filter device containing inclined to the downstream insert from the material with a coefficient of friction different from the coefficient of friction of the soil of the lower prism .

The disadvantage of the above analogue is that the effectiveness of the backup spillway will depend on the creep of the bottom prism along an inclined insert made of sand or a synthetic film. However, the shift of the lower prism will occur under the influence of hydrostatic pressure and filtration forces within the lower prism. Since the movement of the filtration flow in the soil mass occurs very slowly, and the friction forces along the shear surface decrease slightly, the creep of the bottom prism will occur for a long period. As a result, the collapse of the dam crest will also be slowed down, which ultimately reduces the erosion efficiency of the soil dam of the spillway.

In addition, an anti-filter device in the form of a screen will prevent erosion of the soil dam of the backup spillway, as a result of which the throughput will decrease, which in turn will reduce the efficiency and, consequently, the safety of the structure.

The prototype of the proposed technical solution is a backup spillway of an underground retaining structure (SU 1532656, publ. 12/30/1989), which includes abutments and a concrete flute bet, an eroded soil insert located between them, made in the form of a dam with a height less than the height of the retaining structure.

The disadvantage of the above invention is that it takes a sufficiently long time to build a backup spillway due to the arrangement of the main elements - abutments and a concrete flute bet and the complexity of the soil insert, which increases the cost of building a backup spillway.

The purpose of the invention is to pass the flood of rare frequency due to eroded soil insert in the body of the soil retaining structure and reducing the cost of the backup spillway.

The essence of the invention is the creation of a backup spillway for the passage of flood waters of rare frequency and increasing its efficiency.

EFFECT: safe passage of a flood of rare repeatability and prevention of destruction of an underground retaining structure.

The technical result according to the first embodiment is achieved by means of a backup spillway device in the body of an underground retaining structure (for example, a dam or dam) in the form of a trapezoidal prism from an easily destructible soil insert, protected from the upstream side by a geomembrane spillway located between the protective soil layer from the side uphill slope and an insert located in a bed of waterproof polymeric material - a geomembrane, which is mounted on the uphill slope and the edges of the slopes of the gap on using reinforced concrete slabs.

EFFECT: safe passage of a flood of rare repeatability and prevention of destruction of an underground retaining structure.

The technical result according to the second embodiment is achieved due to the arrangement of several soil washable inserts in the form of sections and representing a dam or dam with a top mark less than that of the retaining structure, characterized in that each washable insert is made in the form of a trapezoidal prism located in the water supply parts of the reserve spillway, where, along the entire perimeter of the bed, as well as on the upper and lower slopes, a protective coating of polymer geomembrane is arranged, which is filled in the period from construction with soil similar to the body of the dam, while to increase the efficiency of erosion of eroded inserts for several sections of the spillway, the top mark of eroded inserts is set: for the first section - at the FPU mark, for the second - at the mark (FPU - 0.5 m), for the third - at the mark (FPU - 1.0 m) and so on, ensuring the sequential inclusion of the last section, then the penultimate, and so on.

The reserve spillway is designed to prevent dam destruction in the event of the passage of flood waters of infrequent frequency, with most of the flood passing through the main spillway (for example, coastal).

The invention is illustrated by the figures: FIG. 1 is a diagram of the backup spillway of an underground retaining structure, top view; FIG. 2 - transverse section of the soil retaining structure in the presence of one section of the backup spillway, section AA; FIG. 3 - a longitudinal section of the soil retaining structure in the presence of one section of the backup spillway, section BB; FIG. 4 is a diagram of a soil retaining structure in the presence of one section of the backup spillway at the mark of the top of the eroded insert at the mark of the forced retaining level (FPU); FIG. 5 is a diagram of a soil retaining structure in the presence of several sections of a backup spillway at different elevations of the top of eroded inserts.

The numbers in the drawings indicate: 1 - threshold of the soil dam under the eroded insert; 2 - fastening with reinforced concrete slabs of a protective coating; 3 - a protective coating of polymer geomembrane; 4 - spillway screen from the geomembrane; 5 - strongly filtering element of two or three layers of geotextiles; 6 - eroded soil insert; 7 - water supply part (path) of the backup spillway; 8 - crest of an underground retaining structure; 9 - erosion area on the bottom edge of the eroded insert; 10 - perforated part of the protective coating of the geomembrane; 11 - geotextile ("Dornit") in two or three layers according to the type of inverse filter; 12 - a bucket with a stone outline; 13 - section of the backup spillway; 14 - main spillway (coastal).

The reserve spillway consists of a threshold of a soil dam 1 with a height of N _prg . Above the threshold there is a soil insert 6 made of local materials with a height of _Hvt , which is located in the bed of the protective coating in the form of a polymer geomembrane 3. The coating is fastened with reinforced concrete slabs 2 from the upper pool side of the reservoir and on the edge of the slopes of the water supply path 7. From the side of the upper slope to the eroded the soil insert is placed on the spillway from the geomembrane 4 at an angle of 75 ° -80 ° in the direction of the upper pool of the reservoir relative to the crest of the soil retaining structure 8, which is attached with arch panels to a previously laid in a bed of trapezoid prisms. A strongly filtering element of two or three layers of geotextiles (for example, Dornita with a filtration coefficient of 50-100 cm / s) is placed on the spill screen from the geomembrane. From the bottom of the slope on the threshold of the soil dam, a perforated part from the geomembrane 10 is arranged in the fast flow, which is attached to the protective coating and serves to divert the filtration stream. Under the perforated part, geotextiles are laid in two or three layers according to the type of inverse filter 11. In the downstream downstream slope of the threshold, the perforated part of the protective coating is fastened with reinforced concrete slabs on the edge of the rapid flow. The end part of the protective coating is fastened to the previous part by welding, reinforced concrete slabs are placed on the edge on top of the geomembrane, and at the beginning of the discharge channel, with a stone outline in the bucket 12.

Reserve spillway includes one or more eroded soil inserts, presented in the form of sections 13.

The main spillway (for example, coastal) 14 is located in the body of the soil dam at the level of the normal retaining level (NPU).

Reserve spillway is as follows (Fig. 1-5).

First, the threshold of the soil dam 1 from the soil is performed similarly to the body of the dam, then the water supply part 7 of one or more sections of the backup spillway 13 is arranged. A prefabricated protective coating is laid out around the trapezoidal section of the water supply path of one or more sections 3. The protective coating is made of a polymer geomembrane ( for example, produced according to TU 5774-002-39504194-97 "Geomembrane waterproofing polymer roll", developed by LLC "Gidrokor", and TU 2246-001-56910145-2004 (sheet olimerny TYPE 1), developed by "Tehpolimer"). The geomembrane is laid manually, connecting the individual parts with each other by welding (for example, with the PST-2 extruder) and securing it from the upstream side, on the edge of one or several sections and in the downstream side with reinforced concrete slabs, and at the beginning of the discharge channel, they are mounted in the form of a stone outline (rubble stone) 12. On the protective coating within the water supply part, a washable soil insert 6 from the soil is made similar to the body of the dam, in which a spillway screen from the geomembrane 4 is attached to the protective coating by welding. A strongly filtering element 5 is attached to the spillway screen, for example, of two or three layers of geotextiles (Dornite with a density of 300-450 g / m ² ) using water-repellent glue (Ferozit 111 - adhesive for the reinforcing mesh, gray (fiber-reinforced, frost-resistant water-repellent). From the side of the uphill slope, the spillway screen rests on the soil insert at an angle of 75 ° -80 ° relative to the soil dam. On the downhill slope, a quick run along the perimeter is carried out, which the perforated part of the protective coating from the geomembrane 10 is laid for and seepage under the perforated bottom portion of the container -. coating stacked two or three layers of geotextile (e.g., "Dornita") as the inverse filter 11 type.

Most of the flood is passed through the main spillway (for example, a coastal one) 14 located at the level of the NPU, and the remaining part through the reserve spillway 13 with the top mark less than that of the retaining structure. At the same time, the top mark of several sections of soil washable inserts is set: for the first section - at the FPU mark, for the second - at the mark (FPU-0.5 m), for the third - at the mark (FPU-1.0 m) and so on, ensuring the sequential inclusion of the last section, then the penultimate, and so on.

To quench the energy of the waste stream in the downstream, a bucket from a stone draft 12 is provided.

If there is a carriageway on the dam after the completion of the backup spillway device, it is planned to erect a collapsible metal bridge laid and fixed to the plates located on the edge of the channel of the water supply path.

The spillway screen, high filter element and protective coating are reused when restoring the washable insert.

The height of the eroded insert is determined by hydraulic calculation based on the formula for the throughput of the culvert part of the backup spillway after erosion of the soil insert operating according to the overflow threshold scheme using the following equation for the Nth number of spillway sections:

where Q _rez.v is the estimated discharge flow through the reserve spillway equal to the difference between the maximum flood discharge of rare occurrence (Q _{p <0.5 ... 1.0%} ) and the estimated discharge of the main spillway (Q _main.v ):

Q _rez.v = Q _{p <0,5 ... 1,0%} ^_ Q _ocн.в , m ³ / s;

where m is the flow coefficient for a spillway with a wide threshold;

b - width along the bottom of the culvert part of the backup spillway, m;

H _adt - the pressure threshold in the culvert, after the dirt erosion insert, taken equal height erodible inserts, m;

m ₀ - the coefficient of laying slopes of the trapezoidal section of the culvert;

N is the number of spillway sections, N = 1;

g - acceleration of gravity, m / s ² .

From the above flow formula we find the equation for determining the calculation of the height of the eroded insert:

which is solved by the selection method in several approximations, where the width of each section is equal to b = 10 ... 15 m and the number of sections N.

The height of the reserve spillway threshold is calculated as

N _prg = N _pl -N _vst -d,

where N _PL - the height of the soil retaining structure (dam, dam) to the crest, m;

N _stand - the height of the eroded insert, m;

d is the excess of the dam crest above the top of the eroded insert or the calculated water level (FPU), m

Reserve spillway to allow an emergency flood through several sections of the spillway with a different mark of the top of the eroded insert, where the height of each section is determined by the equation:

9

- расчетный расход, пропускаемый через все секции резервного водосброса, м³/с;Where $$Q_{Res.\mathrm{at}}^{\mathrm{about}bu}$$

- estimated flow through all sections of the backup spillway, m ³ / s;

H _in.i - insert height of the i-th section of the spillway, m;

m _i - flow coefficient of the i-th section for a spillway with a wide threshold;

b _i - width along the bottom of the i-th section of the backup spillway, m

m ₀ - the coefficient of laying slopes of the trapezoidal section of the culvert;

N is the number of spillway sections;

g - acceleration of gravity, m / s ² .

On the other hand, the height of the reserve spillway threshold is determined by calculating, based on the required minimum volume of water in the reservoir, necessary for water users for the period of restoration of the eroded insert, according to the equation:

where from:

- площадь водохранилища, м²;Where

- reservoir area, m ² ;

- минимальный объем воды в водохранилище, определяемый по формуле:

- the minimum amount of water in the reservoir, determined by the formula:

where W _VP - the volume of water in the reservoir, necessary for water users for the period of restoration of the eroded insert, m ³ ;

W _mo - the dead volume of the reservoir, m ³ ;

The final value of the spillway threshold is the highest value obtained by hydraulic calculation and taking into account the requirements of water users. If necessary, increase the number of sections and recalculate the height of the insert by hydraulic calculation in order to get H _prg close to each other.

Reserve spillway of a soil dam works as follows.

When the water level rises in the upper pool of the reservoir and the forced retaining water level is reached (Fig. 1-5), the flow overflows through the top of the spillway screen from the geomembrane 4 and eroded soil insert 6, at the same time, arriving through a strongly filtering element from two or three layers of geotextile (“Dornita”) 5 in the lower part of the soil insert to increase the erosion efficiency of the entire prism of the trapezoidal section of the water supply path 7. After erosion of the insert from local soil, the drainage screen 4 under the action of the driving forces of the flow dyval on the protective coating of the polymer in the bed 3 geomembrane water conducting portions 7, completely freeing the entire cross section of the prism dirt. The filtration stream is diverted through the perforated portion of the protective coating from the geomembrane 10 into the outlet channel. Most of the flood is passed through the main spillway (for example, a coastal one) 14, located at the level of the NPU, and the rest through the reserve spillway 13 with a top mark less than that of the retaining structure. At the same time, the top mark of several sections of soil washable inserts is set: for the first section - at the FPU mark, for the second - at the mark (FPU-0.5 m), for the third - at the mark (FPU-1.0 m) and so on, ensuring the sequential inclusion of the last section, then the penultimate, and so on.

Using this technical solution will simplify the design of the backup spillway and increase the efficiency of the erosion insert, as well as reduce the cost of the structure and reduce the time it takes to create it.

Claims (9)

1. The backup spillway of an underground retaining structure, including a ground erosion insert, which is a dam or dam with a top mark less than that of a retaining structure, characterized in that the erosion insert is made in the form of a trapezoidal section prism located in the water supply part of the backup spillway, where along the entire perimeter of the bed, as well as on the upper and lower slopes, a protective coating of polymer geomembrane is arranged, which is filled during the construction period with soil, similar the body of the dam. 2. The backup spillway according to claim 1, characterized in that on the uphill slope of the prism of the washable insert, a spillway screen made of geomembrane is arranged, which is attached to the protective coating laid on the threshold of the water supply part. 3. The backup spillway according to claim 1, characterized in that to increase the reliability of the work, a protective coating of polymer material is fixed on the side of the upstream side and on the edge of the slopes of the water supply part, and on the lower slope of the retaining structure - along the width of the artificial aperture. 4. The backup spillway according to claim 2, characterized in that in order to increase the efficiency of erosion (erosion) of the soil insert, a strongly filtering element in the form of a geotextile of 2-3 layers of Dornit geotextile is attached to the spill screen. 5. The backup spillway according to claim 1, characterized in that for the passage of large water consumption during floods of rare frequency, a washable insert is used, the top of which is set at the mark of the forced retaining level (FPU). 6. The backup spillway according to claim 1, characterized in that for the emergency flood to pass through it through the top of the spillway erosion insert, the height of the erosion insert is determined by hydraulic calculation based on the flow capacity equation of the water supply part after erosion of the soil insert operating according to the overflow threshold scheme, which is solved by the selection method in several approximations:

where Q _{res. c} - the estimated discharge flowing through the reserve spillway equal to the difference between the maximum flood discharge of rare occurrence (Q _{p <0.5 ... 1.0%} ) and the estimated discharge of the main spillway (Q _{main c} ):
Q _{res. in} = Q _{p <0.5 ... 1.0%} ^_ Q _{main. in} , m ³ / s
where m is the flow coefficient for a spillway with a wide threshold;
b - width along the bottom of the culvert part of the backup spillway, m;
H _stand - the pressure at the threshold of the culvert after erosion of the soil insert, taken equal to the height of the eroded insert, m;
m ₀ - the coefficient of laying slopes of the trapezoidal section of the culvert;
N is the number of spillway sections, N = 1;
g - acceleration of gravity, m / s ² . 7. The backup spillway according to claim 1, characterized in that for retaining part of the volume of water in the reservoir, the culvert is arranged on the threshold of the backup spillway, the height of which is determined from two conditions: passing through the reserve spillway of a flood of rare frequency:
H _prg = H _pl -H _vst -d,
where N _PL - the height of the soil retaining structure (dam, dam) to the crest, m;
N _vst - the height of the eroded insert, m;
d is the excess of the dam crest above the top of the eroded insert or the calculated water level (FPU), m;
and detention in the reservoir of the required volume of water for water users for the period of restoration of the eroded insert:

Where

- reservoir area, m ² ;

- the minimum amount of water in the reservoir, determined by the formula:

where W _VP - the volume of water in the reservoir, necessary for water users for the period of restoration of the eroded insert, m ³ ;
W _mo - the dead volume of the reservoir, m ³ ;
and is final as the highest value obtained by the two above formulas. 8. The spillway of the soil retaining structure, including several eroded soil inserts in the form of sections and representing a dam or dam with a top mark less than that of the retaining structure, characterized in that each eroded insert is made in the form of a trapezoidal section prism located in the water supply parts of the reserve spillway, where along the entire perimeter of the bed, as well as on the upper and lower slopes, a protective coating of polymer geomembrane is arranged, which is filled during the construction soil, similar to the body of the dam, while to improve the efficiency of erosion of eroded inserts for several sections of the spillway, the top mark of eroded inserts is set: for the first section - at the FPU mark, for the second - at the mark (FPU - 0.5 m), for the third - at the mark (FPU - 1.0 m) and so on, ensuring the sequential inclusion of the last section, then the penultimate, and so on. 9. The backup spillway according to claim 8, characterized in that for the emergency flood to pass through several sections of the spillway with a different mark of the top of the eroded insert, the height of each section is determined by the equation:

Where

- estimated flow through all sections of the backup spillway, m ³ / s;
H _{stand i} is the insertion height of the i-th spillway section, m;
m _i - flow coefficient of the i-th section for a spillway with a wide threshold;
b _i - width along the bottom of the i-th section of the backup spillway, m;
m ₀ - the coefficient of laying slopes of the trapezoidal section of the culvert;
N is the number of spillway sections;
g - acceleration of gravity, m / s ² .

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