CN202830882U - Geomembrane impervious structure on concrete dam upstream surface - Google Patents

Abstract

The utility model relates to a geomembrane impervious structure on a concrete dam upstream surface. The geomembrane impervious structure on the concrete dam upstream surface is saving in investment, convenient to construct and capable of solving the dam impervious problem. The technical scheme is that the geomembrane impervious structure on the concrete dam upstream surface is characterized in that the concrete dam upstream surface is sequentially provided with a draining geonet and a polyvinyl chloride (PVC) composite geo-membrane in a paving mode. The PVC composite geo-membrane is fixed on a dam surface in an anchoring mode through an anchoring mechanism and a peripheral anchoring waterstop mechanism, a draining system is formed by the draining geonet 4 and gaps which are positioned between the PVC composite geo-membrane and the dam surface and are generated by the anchoring mechanism, the bottom of the draining system is connected with a draining pipe. The geomembrane impervious structure on the concrete dam upstream surface is suitable for imperiously treating of the dam upstream surface under the condition that a reservoir of a dam which is built already is not discharged completely, solves the leakage problem of the dam, and is mainly suitable for concrete dam impermeable reinforcing processing.

Description

A geomembrane anti-seepage structure on the upstream face of a concrete dam

technical field

The utility model relates to a geomembrane anti-seepage structure, in particular to a geomembrane anti-seepage structure on the upstream surface of a concrete dam. It is suitable for anti-seepage treatment on the upstream surface of the dam without emptying the reservoir to solve the problem of dam leakage. It is mainly suitable for anti-seepage reinforcement treatment of concrete dams. the

Background technique

Many concrete dams have been built in my country since the 1950s and 1960s. However, due to the technical level of dam construction at that time, the quality of concrete was poor and there were pores inside. With the increase of the service time of the dam, it is inevitable that there will be various leakages, which will cause corrosion, cracks, freezing and thawing, and the rise of the dam body's uplift pressure, which will seriously affect the strength, stability and durability of the dam. Engineering efficiency and safety have serious consequences. Therefore, the leakage treatment of the concrete dam body and the leakage treatment of the horizontal joints between layers may be an unavoidable problem, and it is necessary to strengthen the anti-seepage of the dam body in this regard. PVC composite geomembrane has the advantages of convenient construction, low cost, short construction period, not affected by rainy season and winter in the anti-seepage and reinforcement treatment of dam body, saving engineering amount, good anti-seepage performance, adaptable to dam body deformation, and corrosion resistance.

Contents of the invention

The technical problem to be solved by the utility model is to provide a geomembrane anti-seepage structure on the upstream surface of a concrete dam with low investment and convenient construction to solve the problem of dam leakage. the

The technical solution adopted by the utility model is: a geomembrane anti-seepage structure on the upstream surface of a concrete dam, which is characterized in that: the upstream surface of the concrete dam is sequentially laid with a drainage geonet and a PVC composite geomembrane, and the PVC composite geomembrane is anchored The mechanism and the peripheral anchoring and water-stopping mechanism are anchored on the dam surface. The drainage geonet 4 and the gap between the PVC composite geomembrane and the dam surface formed by the anchoring mechanism form a drainage system, and the bottom of the drainage system is connected to a drainage pipe.

The anchoring mechanism is divided into an above-water anchoring mechanism and an underwater anchoring mechanism with the normal storage water level of the dam as the boundary;

The above-water anchoring mechanism includes a U-shaped inner shell member and an Ω-shaped outer shell member, wherein the U-shaped mouth of the inner shell member faces outwards and is covered with the PVC composite geomembrane, and the outer shell member is covered on the PVC composite geomembrane, and is connected with The inner shell components are anchored on the dam surface through anchor bolts, and the surface of the outer shell components is covered with smooth geomembrane;

The underwater anchoring mechanism is that two adjacent PVC composite geomembranes are connected by mechanical anchoring. The underwater anchoring mechanism has a groove-shaped shell, the notch of the shell is inward and is fixed on the dam surface, and the surface of the groove-shaped shell is laminated and covered. Adjacent to the PVC composite geomembrane, a stainless steel washer is pressed on the layer of the PVC composite geomembrane, and the stainless steel washer is fixed with the grooved shell by bolts and nuts.

The peripheral anchoring water-stop mechanism is composed of stainless steel bead, sealing gasket, joint plate and anchor rod, wherein the stainless steel bead is pressed on the surface edge of the PVC composite geomembrane, and the sealing gasket and joint plate are placed between the PVC composite geomembrane and the dam surface. During the period, the three are anchored to the dam surface through bolts. the

The beneficial effects of the utility model are: the utility model adopts different anchoring structures for the geomembrane for different environments up and down the water level, so as to ensure the stability of the geomembrane and the smoothness of the geomembrane; The anti-seepage treatment on the dam surface has good feasibility and reliability, low investment and convenient construction, which effectively solves the problem of dam leakage and has remarkable benefits in all aspects. the

Description of drawings

Fig. 1 is the structural representation of the utility model.

Fig. 2 is a structural schematic diagram of the above-water anchoring mechanism in the utility model.

Fig. 3 is a structural schematic diagram of the underwater anchoring mechanism in the utility model.

Detailed ways

As shown in Figure 1, a continuous anti-seepage PVC composite geomembrane 3 is set on the upstream dam surface of the concrete dam 1 from the dam crest to the heel in the present embodiment, the geomembrane is connected with the dam foundation, and the PVC composite geomembrane 3 inside is attached There is a layer of drainage geonet 4. In this example, the PVC composite geomembrane 3 is anchored to the concrete dam surface through an anchoring mechanism, which is divided into an above-water anchoring mechanism and an underwater anchoring mechanism based on the normal storage water level of the dam.

Above the water level, adjacent PVC composite geomembranes 3 are combined by vertical thermal welding. In this example, above the water level, the PVC composite geomembrane 3 is fixed on the dam surface by pad fusion welding and anchored by the water anchor mechanism. As shown in Figure 2, the water anchoring mechanism includes a "U"-shaped inner shell member 5 and an "Ω"-shaped outer shell member 6. The PVC composite geomembrane 3 is deployed into the U-shaped groove, and the Ω-shaped outer shell member 6 is Placed on the PVC composite geomembrane and fastened to the inner shell member 5, the inner shell member 5 is anchored on the dam surface through the anchor bolt 7, and the outer shell member is used to fasten the PVC composite geomembrane 3 to achieve anchoring and tension composite The purpose of geomembrane. The shell member 6 is directly installed on the original exposed surface with a center-to-center distance of 3-4m. The PVC composite geomembrane 3 is perforated according to the distance and diameter of the anchor bolts 7, and is fastened on the U-shaped inner shell member with an Ω-shaped outer shell member. The inner shell member 5 and the outer shell member 6 are covered with a smooth geomembrane 8 with a thickness of 2.5mm, and the smooth geomembrane 8 is welded to the PVC composite geomembrane 3 by heat welding to prevent seepage. All the welding of PVC composite geomembrane 3 and smooth geomembrane 8 is carried out by "hot air method" using manual monorail heat welding gun.

Below the water level, since the vertical thermal welding method cannot be carried out in water, the underwater installation of geomembranes must rely on mechanical anchoring. Adjacent geomembranes are directly connected by mechanical anchoring to seal the overlap between geomembranes. As shown in Figure 3, in this embodiment, the PVC composite geomembrane 3 is anchored and connected by using an underwater anchoring mechanism. The underwater anchoring mechanism has a grooved shell 9, the groove of which is inward and fixed on the dam surface, and the surface of the grooved shell 9 is laminated to cover two adjacent pieces of PVC composite geomembrane 3, where the PVC composite geomembrane 3 is laminated. Pressed with EPDM gasket 12 and stainless steel washer 10, the stainless steel washer is fixed with the grooved shell 9 through bolts, nuts and spring washers. In this example, rubber gaskets are placed between the grooved shell and the geomembrane, between the geomembrane and the geomembrane, and between the geomembrane and the EPDM gasket 12 .

A peripheral anchoring water-stop mechanism is set around the PVC composite geomembrane 3 to prevent water from penetrating into the PVC composite geomembrane 3 . The peripheral anchoring water-stop mechanism is composed of stainless steel bead 2, sealing gasket, joint plate and anchor rod. Between the stainless steel bead 2 and the joint plate, PVC composite geomembrane and sealing gasket are pressed together, and the anchor rod is used to anchor into the concrete. In the structure: if the concrete support layer is stabilized, use short anchors; if the dam surface is damaged, use longer anchors in the concrete dam body. The type and spacing of anchor rods should be determined according to the tensile test on the existing support layer. Generally, the anchor rod spacing is 15cm, the diameter is 12mm, and the length is greater than 10cm. The anchors can be either mechanical expansion anchors or chemical anchors (extruded epoxy).

According to the installation environment (above water and underwater), the types of anchor rods, sealing gaskets and stainless steel bead 2 will vary. Generally, when the water head is low or higher than 50m, the surrounding anchorage water-stop mechanism adopts (width×thickness=60×6mm) or (width×thickness=80×8mm) stainless steel bead; the peripheral seal of the dam crest is determined by the specification (width×thickness) =30×3mm) flat stainless steel layering, only need to resist the infiltration of rainwater and wind and waves.

When the anchor rod penetrates the PVC composite geomembrane 3, it is necessary to prevent seepage water. The anchor head can be covered with glued pavement, synthetic resin, etc., or a strip or patch of synthetic material like a geomembrane can be used to cover the anchor system and then heat welded to the geomembrane.

In this embodiment, the drainage geonet 4 and the gap between the PVC composite geomembrane 3 and the dam surface formed by the anchoring mechanism form a continuous drainage system, and the bottom of the drainage system is connected to the drainage pipe 11 . The vertical concrete dam surface is conducive to the flow of seepage water, and the water flows freely in the drainage system, and gathers to the bottom drain pipe 11 under the action of gravity and is discharged through the drain pipe. The drainage pipe 11 is installed in the borehole from the corridor to the upstream face, and a stainless steel plate will be installed in front of each drainage pipe to prevent the composite geomembrane from blocking the pipeline under the relevant water source. Drainage is piped into an inspection gallery, into a sump equipped with a pump, or directly downstream.

In this example, the PVC composite geomembrane 3 material is selected: the dam height h<40 m, the PVC composite geomembrane 3 is a 2mm thick geomembrane thermally bonded to the 200g/ ^mm2 geotextile; the dam height h>40m, the PVC composite geomembrane The geomembrane 3 is a 2.5mm thick geomembrane thermally bonded to a 500g/ ^mm2 geotextile.

In this embodiment, all inner shell members 5, outer shell members 6, anchor bolts 7, grooved outer shells 9, bolts, nuts, anchor rods, etc. must have corrosion resistance, and can resist soluble chemicals in dam concrete or other cement products , and other corrosion in the reservoir can be made of stainless steel.

The concrete construction method of present embodiment enters as follows:

a. According to the grade of the project, taking into account factors such as dam height, water storage depth, geological conditions, permeability coefficient, friction coefficient between materials, project exhaust and project cost, the PVC composite geomembrane 3 material is selected and installed in the factory Or in an open space, weld the standard specification 2.10m wide PVC composite geomembrane 3 to 6m wide.

b. Transport the 6m wide PVC composite geomembrane to the crest of the dam that needs to be reinforced; install a platform operated by a hoist, start from the crest, and lower the coiled material along the crest. The PVC composite geomembrane is welded by pad fusion welding on the working platform that can be lifted.

c. Lift the prefabricated 6m wide PVC composite geomembrane with a construction pontoon, then fix the geomembrane on the top of the dam with stainless steel bead 2, and then lower it into the water. The geomembrane is correctly positioned and fastened by divers underwater. Underwater dam surface.

d. Put the preset drilling template in place. After the holes of the anchoring mechanism and the surrounding sealing water-stop mechanism are drilled, the drilling template can be removed. At this time, the PVC composite geomembrane is placed in the correct position and installed Anchor the mechanism and tension the PVC composite geomembrane. Finally, anchor rods, sealing gaskets and stainless steel bead 2 are used for peripheral sealing. the

Claims (3)

1. A geomembrane anti-seepage structure on the upstream face of a concrete dam, characterized in that: the upstream face of the concrete dam (1) is successively laid with a drainage geonet (4) and a PVC composite geomembrane (3), and the PVC composite geomembrane ( 3) Anchored on the dam surface through the anchoring mechanism and the peripheral anchoring and water-stopping mechanism, the drainage geonet (4) and the gap between the PVC composite geomembrane (3) and the dam surface formed by the anchoring mechanism form a drainage system , the drain pipe (11) is connected to the bottom of the drainage system. 2. The geomembrane anti-seepage structure on the upstream face of a concrete dam according to claim 1, wherein the anchor mechanism is divided into an above-water anchor mechanism and an underwater anchor mechanism with the normal water storage level of the dam as a boundary; The above-water anchoring mechanism includes a U-shaped inner shell member (5) and an Ω-shaped outer shell member (6), wherein the U-shaped opening of the inner shell member (5) faces outwards, and the PVC composite geomembrane (3) is covered on it, and the The outer shell member (6) is covered on the PVC composite geomembrane (3), and together with the inner shell member (5) is anchored on the dam surface through anchor bolts (7), the surface of the outer shell member (6) is covered with smooth geomembrane (8 ); The underwater anchoring mechanism is two adjacent PVC composite geomembranes (3) connected by mechanical anchoring. The underwater anchoring mechanism has a groove-shaped casing (9), the groove of the casing is inward and fixed on the dam surface, and the groove-shaped casing (9) The surface is laminated to cover the adjacent PVC composite geomembrane (3), and the PVC composite geomembrane (3) is laminated with a stainless steel washer (10), which is fixed to the grooved shell (9) by bolts and nuts . 3. The geomembrane anti-seepage structure on the upstream face of a concrete dam according to claim 1 or 2, characterized in that: the peripheral anchoring water-stopping mechanism consists of stainless steel bead (2), sealing gasket, joint plate and anchor rod Composition, in which the stainless steel layer (2) is pressed on the surface edge of the PVC composite geomembrane (3), the sealing gasket and the joint plate are placed between the PVC composite geomembrane (3) and the dam surface, and the three are anchored to the dam surface through anchor rods superior.

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