RU2539147C2 - Anti-filtration membrane of low-head dams and dykes from soil materials - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to the field of hydraulic engineering and may be used to eliminate filtration via a body of low-head dams of storage ponds, dams of river beds and canals. An anti-filtration membrane of low-head dams and dykes from soil materials includes a waterproof wall. The wall is assembled from boards of two types - A and B. Boards are made of polyolefine wastes. Boards have semi-cylindrical ledges and grooves. Boards of type A are equipped with a longitudinal cylindrical cavity and an inverse filter from geotextile. The inverse filter is arranged at sides of the membrane. It becomes possible to efficiently determine the position of a depression curve in the dam body.

EFFECT: increased operational reliability.

6 cl, 6 dwg

Description

The invention relates to the field of hydraulic engineering and can be used to eliminate filtering through the body of low-pressure dams of reservoirs, dams of riverbeds and channels up to 10 m high, made from soil materials.

Known antifiltration diaphragm of the dam from local materials (RU Patent No. 2265693, Е02В 3/16 dated December 10, 2005), which is made in the form of a wall along the longitudinal axis of the dam containing the inner and outer layers. The outer layer of the wall is formed by prefabricated blocks made of plastic asphalt concrete, placed vertically along the height of the diaphragm, and the inner layer of the wall is made of cast asphalt concrete, while the interblock seams of the outer layer of the wall are not monolithic.

The disadvantages of this design of the diaphragm are: the complexity of its implementation due to the fact that it consists of two layers and requires a phased arrangement of each layer, in addition, the layers are made of different physical and mechanical properties of asphalt concrete, as a result of which the outer layer is exposed to filtration water diaphragms made of blocks with non-monolithic seams can move and cause unwanted deformations in the body of the dam.

The reinforced concrete diaphragm of a soil dam is known (RU Patent No. 1801153, ЕВВ 3/16, ЕВВ 7/06 dated 03/07/1993), which is made of flat panels with double reinforcement in the longitudinal and transverse directions, separated by vertical and horizontal seams. A sealing metal sheet welded to the working fixture is installed around the entire perimeter of the panel.

The disadvantages of this diaphragm are the relatively high material consumption and the complexity of the implementation of this design, in addition, this design of the diaphragm can be performed only with simultaneous installation and dumping of the resistant prisms.

A soil dam with an antifiltration core is known (SU Author Certificate No. 1168653, ЕВВ 7/06 of 07/23/1985), including a water-permeable soil body and a central antifiltration core expanding downward, characterized in that the antifiltration core is made of soil filling the dam body, and is limited by two film diaphragms, each of which consists of separate vertical film sections connected by an overlap and shifted in height to the center of the anti-filtration core, while the upper section is about for both diaphragms.

The disadvantage of this device is that under the influence of a filtration stream passing through a water-permeable diaphragm, fine particles of soil of the lower slope of the dam can be removed, which can lead to the appearance of dangerous deformations in the first years of operation of the dam. In addition, the implementation of this design of the diaphragm is quite laborious due to the special arrangement of its film sections.

The closest is a device for protecting slopes of hydraulic structures (SU Author's certificate No. 1161626, ЕВВ 3/12), containing an airtight curtain made of elastic material, which is located in a trench on the slope of a hydraulic structure, characterized in that, in order to simplify the device and to increase reliability, the longitudinal trench is located in the middle of the slope, and the air curtain is placed in the longitudinal trench to a depth of (0.5-0.6) N, where N is the pressure of the groundwater on the slope of the hydraulic system weapons.

The disadvantages of this device are: the use of polyethylene as an elastic material, which is unreliable, since during the implementation of this device damage to this material is unavoidable, an increase in the filtration flow rate will be observed at the junctions of the polyethylene with the soil, which can lead to weakening of the base. In addition, the use of this device prevents the destruction of only the upper slope of the dam or dam of the structure, and the construction of the trench on the slope of the dam or dam is quite laborious.

When applying this technical solution during operation, soil may be removed by the filtration flow at the boundary of contact of the edges of the elastic material with the soil due to insufficient compaction of the soil in the trench.

The essence of the invention is to increase the operational reliability of low-pressure dams and dams of soil materials and to reduce the construction cost of the anti-filter diaphragm.

The anti-filtration diaphragm consists of two types of plates A and B, made of polyolefin waste, equipped with internal and external semi-cylindrical protrusions and channels that are tightly in contact with each other, preventing them from shifting during operation and the penetration of filtration water into the downstream. Connected by means of semi-cylindrical protrusions and channel channels, the plates are placed in a trench on the crest of a dam or dam to a depth necessary to cut off the filtration flow, while longitudinal cylindrical cavities are provided in the plates, equipped with filtration holes made from the upstream side and designed to determine the water level in the body dams or dams. To prevent the removal of soil by the filtration stream along the contour of the anti-filtration diaphragm, a reverse filter of non-woven geotextiles is performed.

The technical result is achieved by the use of an anti-filtration diaphragm made of plates made of polyolefin waste, equipped with a longitudinal cylindrical cavity designed to determine the water level and arranged in the crest of a low-pressure dam or dam from soil materials.

The proposed device provides increased reliability of low-pressure dams and dams of soil materials up to 10 m high by ensuring the waterproofing of the anti-filtration device and the availability of monitoring groundwater levels in the dam body, the use of the proposed anti-filtration diaphragm helps to reduce construction costs and material consumption while recycling polyolefin waste.

Improving the operational reliability of low-pressure dams and dams of soil materials up to 10 m high is achieved as follows.

When identifying foci of filtrational deformations on the lower slope of a low-pressure dam or dam in the form of griffins and keys, the exit position of the depression curve of the filtration flow is determined. Then, an anti-filtration diaphragm is arranged in a trench on the crest of the dam or dam to a depth equal to S = h + a, where h is the vertical distance from the mark of the crest of the dam to the place of manifestation of the focus of filtering deformation on the lower slope, and a is the depth of the aperture taken from 1.0 to 1.5 m depending on the height of the structure. A trench under the diaphragm is performed to a depth S, with a width of 0.2-0.3 m, work is carried out using an excavator that provides the necessary depth of soil development.

и уменьшить выходные градиенты фильтрационного потока до безопасного значения, исключающего образование фильтрационных деформаций (суффозии, грифонов и ключей). Устройство противофильтрационной диафрагмы на глубину более S=h+а нецелесообразно, так как при этом устройство траншеи для противофильтрационной диафрагмы усложняется, а эффект защиты низового откоса не увеличивается.The device impervious diaphragm to a depth of S = h + a will significantly reduce the height of the output of the depression curve to the bottom slope from the value of h ₁ to $$h_{\mathrm{one}}^{\text{'}\text{'}}$$

and reduce the output gradients of the filtration flow to a safe value, excluding the formation of filtration deformations (suffusion, griffins and keys). The device of the impervious diaphragm to a depth of more than S = h + a is impractical, since in this case the device of the trench for the impervious diaphragm is complicated, and the effect of protecting the bottom slope does not increase.

Plates made in the factory from waste polyolefins have the following parameters: thickness - 0.1 m, width - 1.5 m, length - 8.0 m, equipped with semi-cylindrical protrusions and channels. Type A plates are equipped with external semi-cylindrical protrusions having a rounded shape, and also have a longitudinal cylindrical cavity with a diameter of 0.08 m, the center of which is located at a distance of 0.5 m from the edge of the plate, while the longitudinal cylindrical cavity has openings with a diameter of 0 on one of the walls , 03 m, located with a distance between the centers of 0.5 m. To prevent getting into the longitudinal cylindrical cavity of the soil, the holes are closed by a filter of non-woven geotextile with a density of 200 g / m ² . Type B plates are provided with internal semi-cylindrical channels.

Next, the plates are cut into sections of length S, from the obtained sections form an anti-filtration diaphragm by connecting the internal and external connectors. The length of the impervious diaphragm is determined by the formula L _P.D. = L _T -1.0, where L _T is the length of the trench, 1.0 m is the reserve.

Then the geotextile is cut into panels with a size of: 0.6 m wide and a length equal to the depth of the trench S, the resulting panels are attached to the lateral faces of the diaphragm with an overlap of 0.1 m by heating the surface of the plate.

Next, the impervious diaphragm is manually or using a truck crane lowered into a trench located on the crest of the dam, while the holes in the plates of type A are directed towards the uphill slope. Trench filling is done manually.

During operation of a water-supporting structure, periodic observations of the level of groundwater in the body of the structure are possible, while the level of groundwater is measured in longitudinal cylindrical cavities by a borehole level gauge, for example, USP-L-50. Observation data will predict the change in the reliability indicators of the structure.

The invention is illustrated by drawings: FIG. 1 - an anti-filtration diaphragm in a body of a water-supporting structure (general view), FIG. 2 - anti-filtration diaphragm in a body of a water-supporting structure (top view), FIG. 3 - anti-filtration diaphragm in a body of a water-supporting structure (section A-A) , Fig. 4 - plate type A, Fig. 5 - plate type A (section BB), Fig. 6 - plate type B.

The anti-filtration diaphragm of dams and dams of soil materials is performed as follows: (Figs. 1, 2, 3) in the body of the water support structure 1 (low-pressure dam or dam up to 10 m high) form a trench 2 (Figs. 4, 5, 6), from type A plates and type B plates collect the anti-filtration diaphragm 3 by connecting the outer semi-cylindrical protrusions 4 and the internal semi-cylindrical channels 5, nonwoven geotextile webs that act as a reverse filter 6 are attached to the anti-filtration diaphragm, then the diaphragm is lowered into a trans 2 it orienting openings 7 protected geotextile filter 8, toward the upstream. Then, trench 2 is backfilled. During operation, specialists of the operating organization can monitor the position of the groundwater level in the body of the water-supporting structure by measuring the water level in a longitudinal cylindrical cavity 9.

When a low-pressure dam or dam appears on the lower slope of the center of filtration deformations 10, an anti-filter diaphragm 3 is made in its body. The anti-filter diaphragm works as follows. The filtration flow, encountering an anti-filtration diaphragm 3 on its way, extinguishes a significant part of the filtration head, resulting in a significant decrease in the depression curve 11 to position 12, as a result of which the output gradients of the filtration flow decrease to safe values, eliminating the further occurrence of filtration deformations.

The proposed antifiltration diaphragm of dams and dams made of soil materials will eliminate filtering through the body of the water support structure, the implementation of the antifiltration diaphragm of plates made of polyolefin waste, reduces the cost of the design and the recycling of polymer waste, the presence of a reverse filter from geotextiles eliminates the possibility of soil removal along the contour of the antifiltration diaphragm . The presence of longitudinal cylindrical cavities in the slabs will make it possible to monitor the level of groundwater in the body of the water-supporting structure, which will make it possible to timely determine and predict changes in its technical condition. In addition, the manufacture of plates with a length of 8.0 m and the possibility of cutting them into sections of the required length make the proposed device universal.

Claims (6)

1. The impervious diaphragm of low-pressure dams and dams of soil materials, including a waterproof wall, characterized in that the antifiltration diaphragm is assembled from two types of plates - A and B, manufactured in the factory from waste polyolefins having respectively semi-cylindrical protrusions and channels, and plates of the type And equipped with a longitudinal cylindrical cavity to determine the water level in the body of a hydraulic structure during its operation, as well as a reverse filter from geotextiles, arranged along the lateral edges of the diaphragm and preventing the removal of soil. 2. The antifiltration diaphragm according to claim 1, characterized in that it is arranged to a depth S = h + a , where h is the vertical distance from the mark of the dam crest to the point of manifestation of the focus of filtering deformations on the lower slope, and a is the depth of the diaphragm taken from 1.0 to 1.5 m, depending on the height of the structure, and is placed in a trench formed on the crest of the water-supporting structure. 3. The impervious diaphragm according to claim 1, characterized in that the semi-cylindrical protrusions and channels of plates A and B are tightly in contact with each other, preventing them from shifting during operation and penetration of filtration water into the downstream. 4. The antifiltration diaphragm according to claim 1, characterized in that the longitudinal cylindrical cavity has holes on the wall with a diameter of 0.03 m located at a distance between the centers of 0.5 m 5. The antifiltration diaphragm according to claim 1, characterized in that the longitudinal cylindrical cavity is protected from the ingress of soil particles using a geotextile filter. 6. The impervious diaphragm according to claim 1, characterized in that the waterproof wall is made by cutting plates into sections of different lengths.

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