Anchoring structure of earth and rockfill dam core wall anti-seepage geomembrane adapting to bank slope shear deformation and construction method of anchoring structure

Abstract

The invention relates to an anchoring structure for an earth and rockfill dam core wall anti-seepage geomembrane to adapt to bank slope shear deformation and a construction method of the anchoring structure. The anchoring structure comprises a clay core wall, an inverted filter layer, bank slope concrete or rock mass, an anchoring component, an anchoring area geomembrane and a core wall geomembrane. The anchoring component is used for anchoring the anchoring area geomembrane on bank slope concrete or rock mass; the section, extending out of the anchoring component, of the anchoring area geomembrane is laid in an arch shape, polytetrafluoroethylene membranes are arranged on the two sides of the section, and a long pillow-shaped soft bag filled with flexible filler is placed on the concave face of the arch structure. The two sides of the geomembrane in the anchoring area are filled with high-plasticity clay; and the core wall geomembrane is laid between the clay core wall and the inverted filter layer and is spliced and fixedly connected with the anchoring area geomembrane. The anchoring structure can be smoothly completed through the corresponding construction method. According to the method, the shear deformation adapting capacity of the geomembrane in the bank slope anchoring area can be improved, and engineering leakage caused by shear tearing damage of the geomembrane in the extremely small range of the anchoring area of the bank slopes on the two banks due to shear deformation of the core wall in the slope direction is avoided.

Description

Technical Field

[0001] The invention relates to an anchoring structure of an anti-seepage geomembrane for an earth-rock dam core wall adapted to bank slope shear deformation and a construction method thereof, belonging to the technical field of anti-seepage geomembrane. Background Art

[0002] As an efficient and economical anti-seepage material, geomembrane has been widely used in many fields, including water conservancy, environmental protection, transportation, and construction. The anchorage of the geomembrane to the surrounding structure is often a key technical issue in geomembrane anti-seepage projects. This is because the anchorage between the geomembrane and the surrounding structure is usually subjected to concentrated stress, which can lead to geomembrane failure. For rockfill dams built on deep overburden foundations that use a combined clay core wall and geomembrane for anti-seepage projects, the anchorage between the geomembrane on the upstream side of the core wall and the concrete or rock mass on both sides of the bank will experience significant differential deformation between the core wall and the concrete or rock mass on both sides during the completion and water storage operation periods due to the different material properties of the core wall and the concrete or rock mass on the bank slope. This not only includes differential displacement deformation of the geomembrane slope perpendicular to the upstream side of the core wall, but more importantly, shear deformation of the core wall along the slope direction occurs at the connection anchorage between the geomembrane and the concrete on both sides of the bank slope, which causes the geomembrane to tear and fail within a very small area of ​​the anchorage area.

[0003] After searching, it was found that the invention patent with patent number 201410248046.5 and authorization announcement number CN104060580B is aimed at the "clamp effect" that is very likely to occur at the anchorage around the anti-seepage membrane on the upstream dam surface of a high-surface rockfill dam after the reservoir is filled with water, which leads to the damage of the anti-seepage membrane. The invention patent proposes a method to eliminate the clamp effect at the anchorage of the anti-seepage membrane of a high-surface rockfill dam based on the principle of compensation displacement. By setting the position of the geomembrane anchor line below the dam surface membrane laying line in the anti-seepage project of the high-surface rockfill dam, the geomembrane laid at the anchorage around the dam surface will return to the position of the anchorage line after the dam body settles and moves, thereby avoiding the tensile damage caused by the "clamp effect" at the anchorage.

[0004] The invention patent with patent number 202110096494.8 and authorization announcement number CN112900365B discloses a horizontal sliding anti-seepage connection structure of geomembrane and asphalt concrete panel. For the geomembrane anti-seepage project at the reservoir bottom, by setting a horizontal sliding plastic water-stopping material between the asphalt concrete panel and the reinforced concrete connecting plate, it can adapt to horizontal deformation of up to 50mm. At the same time, an overfill bulge is set at the contact position between the geomembrane and the concrete connecting plate, and the bulge is filled with fine-grained material or fine sand as a reserved settlement for reservoir foundation deformation, which can reduce the stress concentration caused by the "clamp effect" on the geomembrane and cause tensile failure.

[0005] The invention patent with patent number 201910066713.0 and authorization publication number CN109537531B discloses a dam surface geomembrane anti-seepage rockfill dam, a construction method and a defect location method, including several independent dam sections arranged in sequence along the axis of the dam body; each independent dam section includes piers, a rockfill body, an anti-seepage body and a defect leakage monitoring system; the upstream face of each independent dam section is an arch inclined upstream, and the upstream dam slope ratio is 1:0.2; the anti-seepage body includes a geomat, a composite geomembrane and a cast-in-place concrete protective layer; the defect leakage monitoring system includes multiple drainage pipe groups and flow meters.

[0006] However, in the existing technology represented by the above-mentioned technical solutions, the technical means for the geomembrane anchoring structure are mainly aimed at the anchoring points of the anti-seepage geomembrane on the upstream dam surface of the rockfill dam, so as to solve the problem that the geomembrane at the anchoring point will be tensilely damaged in a very small range of the anchoring area due to the "clamp effect" caused by the settlement of the dam body after water storage. However, in the combined anti-seepage project of the clay core wall and geomembrane used for the rockfill dam built on the foundation of a deep covering layer, the geomembrane is laid on the upstream surface of the core wall and anchored on the concrete of the bank slopes on both sides. The geomembrane is inside the dam body rather than on the upstream dam surface. After water storage, the geomembrane will be sheared and torn at the connection and anchoring points between the core wall and the concrete or rock mass on both sides of the bank slope due to the shear deformation of the core wall along the dam slope direction. The shear deformation direction is along the slope of the upstream surface of the core wall, which is different from the stress deformation characteristics and failure mechanism of the "clamp effect" of the anti-seepage geomembrane on the upstream dam surface of the rockfill dam. There is currently no good solution to this problem. Therefore, in the combined anti-seepage engineering of clay core wall and geomembrane for rockfill dams built on deep overburden foundations, how to take certain engineering measures to enable the core wall anti-seepage geomembrane to adapt to the shear deformation of the core wall along the slope generated at the connection and anchoring parts between the core wall and the concrete or rock mass on both sides of the bank after the dam body is filled with water, and to avoid shear and tearing damage of the geomembrane, is a key technology in the combined anti-seepage engineering of core wall and geomembrane. Summary of the Invention

[0007] The main purpose of the present invention is to overcome the problems existing in the prior art and propose an anchoring structure and a construction method for the anti-seepage geomembrane of the core wall of an earth-rock dam that can adapt to the shear deformation of the bank slope. The structure can improve the ability of the geomembrane in the anchoring area of ​​the bank slope to adapt to the shear deformation, and avoid the shear tearing damage of the geomembrane in the extremely small range of the anchoring area of ​​the bank slopes on both sides due to the shear deformation of the core wall along the slope, resulting in engineering leakage.

[0008] The technical solution of the present invention to solve the technical problem is as follows:

[0009] An anchoring structure for an anti-seepage geomembrane of an earth-rock dam core wall adapted to bank slope shear deformation, comprising a clay core wall and an inverted filter layer, characterized in that it also comprises bank slope concrete or rock mass, an anchoring member, an anchoring zone geomembrane, and a core wall geomembrane; the bank slope concrete or rock mass is located at the junction of the bank slopes on both sides and the clay core wall; the anchoring member anchors the anchoring zone geomembrane to the bank slope concrete or rock mass; a section of the anchoring zone geomembrane extending from the anchoring member is laid in an arch shape in the direction opposite to the deformation of the dam body, and polytetrafluoroethylene membranes are provided on the upstream and downstream sides of the anchoring zone geomembrane, respectively. The convex surface of the structure faces upstream and the concave surface faces downstream. A long pillow-shaped soft bag extending from the bottom to the top of the clay core wall is vertically placed in the concave space formed by the concave surface of the arch structure, and the long pillow-shaped soft bag is filled with flexible filler; the upstream and downstream sides of the geomembrane in the anchoring area are filled with high plasticity clay respectively; the deformation modulus of the clay core wall>the deformation modulus of the high plasticity clay>the deformation modulus of the flexible filler; the core wall geomembrane is laid between the clay core wall and the filter layer along the upstream slope of the clay core wall; the core wall geomembrane is spliced ​​and fixedly connected to the geomembrane in the anchoring area.

[0010] This structure extends the geomembrane in the anchoring area out of the anchoring component and is laid in an arch shape in the opposite direction of the dam body deformation, and polytetrafluoroethylene membranes are arranged on both sides of the geomembrane in the anchoring area. This can increase the initial gauge length of the geomembrane in the anchoring area and reduce the friction resistance on both sides of the geomembrane in the anchoring area, thereby improving the ability of the geomembrane in the anchoring area to adapt to shear deformation and avoid shear deformation damage; at the same time, materials with different deformation moduli are filled on both sides of the upstream and downstream of the geomembrane in the anchoring area, and the material arrangement method with decreasing normal modulus pointing to the geomembrane is used to disperse the effect of normal pressure.

[0011] The technical solutions further improved by the present invention are as follows:

[0012] Preferably, the deformation modulus of the clay core is in the range of 10 to 100 MPa; and the deformation modulus of the high plasticity clay is in the range of 1 to 10 MPa.

[0013] Preferably, the difference between the arch length and the arch width of the geomembrane arch structure in the anchoring area is greater than 15 cm; the thickness of the geomembrane in the anchoring area and the thickness of the core wall geomembrane are not less than 1.5 mm respectively; the thickness of the polytetrafluoroethylene membrane is 0.1 to 0.2 mm; and the high plasticity clay is filled in the range of 0.5 to 1 m on the upstream and downstream sides of the geomembrane in the anchoring area.

[0014] More preferably, the liquid limit of the high plasticity clay is greater than 50%, and the plasticity index is greater than 25.

[0015] Preferably, the upstream and downstream sides of the geomembrane in the anchoring area are provided with smooth polytetrafluoroethylene membrane and geotextile respectively from the inside to the outside, forming a five-layer material structure, and the adjacent materials are separable; the upstream and downstream sides of the core wall geomembrane are provided with geotextile respectively, forming a two-cloth and one-membrane structure, and the core wall geomembrane and the geotextile are separable.

[0016] Preferably, the anchoring member comprises: a galvanized bolt, a nut, a steel washer, a galvanized angle steel, and an elastic washer.

[0017] More preferably, the specific structure of the anchoring component anchoring the geomembrane in the anchoring area is: one end of the galvanized bolt is pre-buried or driven into the slope concrete or rock mass, and the other end thereof extends out of the anchoring base surface of the slope concrete or rock mass, and the first elastic gasket, the geomembrane in the anchoring area, the second elastic gasket, the galvanized angle steel, the steel gasket, and the nut are sequentially sleeved on the galvanized bolt from the anchoring base surface, and the anchoring is completed by tightening the nut.

[0018] More preferably, sealant is applied between the anchoring base surface and the first elastic gasket, between the first elastic gasket and the geomembrane in the anchoring area, and between the geomembrane in the anchoring area and the second elastic gasket; and sealant is injected into the gaps between the first elastic gasket, the geomembrane in the anchoring area, the second elastic gasket and the galvanized bolts.

[0019] By adopting the above preferred solutions, specific technical details can be further optimized to achieve better technical effects.

[0020] The present invention also provides:

[0021] A construction method for the aforementioned earth-rockfill dam core wall anti-seepage geomembrane anchoring structure adapted to bank slope shear deformation is characterized by comprising the following steps:

[0022] The first step is to plan the filling area of ​​the clay core wall and the filter layer, and reserve space for anchoring material filling in the predetermined area near the geomembrane in the anchoring area;

[0023] The second step is to excavate and / or clean the bedrock of the bank slopes on both sides section by section, and then pour the concrete cushion layer according to the predetermined plan to form the bank slope concrete or rock mass as the anchor base;

[0024] Step 3: The anchoring components include: galvanized bolts, nuts, steel washers, galvanized angle steels, and elastic washers; pre-embed the galvanized bolts on the bank slope concrete or rock mass;

[0025] Step 4: Anchor the geomembrane in the anchoring area on the anchoring base surface of the slope concrete or rock mass;

[0026] Step 5: Fill the reserved anchoring material filling space in the order from downstream to upstream. First, fill the downstream side of the geomembrane in the anchoring area with high plasticity clay, then lay long pillow-shaped soft bags filled with flexible fillers, lay the anchored geomembrane in an arch shape against the deformation direction of the dam body, then fill the upstream side of the geomembrane in the anchoring area with high plasticity clay, and finally fill the filter layer. During this process, lay the core wall geomembrane between the clay core wall and the filter layer along the upstream slope of the clay core wall.

[0027] Step 6: Splice the geomembrane in the anchoring area with the geomembrane in the core wall; the construction is completed.

[0028] This construction method can successfully complete the anchoring structure of the anti-seepage geomembrane of the core wall of the earth-rock dam to adapt to the shear deformation of the bank slope.

[0029] The technical solutions further improved by the present invention are as follows:

[0030] Preferably, in the second step, anchor bars are arranged in the concrete cushion layer, and grouting is performed at the contact surface between the concrete cushion layer and the bank rock mass;

[0031] In the third step, during the pre-buried installation, first drill holes at the predetermined bolt positions, with the hole diameter being 1 to 2 mm smaller than the bolt diameter. Then, after embedding the galvanized bolts, use an anchoring agent to seal the gaps around the galvanized bolts.

[0032] In the fourth step, before anchoring, the anchoring base surface of the geomembrane anchoring area is leveled by grinding the protruding parts or filling the concave parts with mortar. The specific process of anchoring is as follows: first, sealant is applied to the anchoring base surface, and then, starting from the anchoring base surface, the first elastic gasket, the geomembrane in the anchoring area, the second elastic gasket, the galvanized angle steel, the steel gasket, and the nut are sequentially installed on the galvanized bolt, and the anchoring is completed by tightening the nut to anchor the geomembrane in the anchoring area to the anchoring base surface; wherein, sealant is applied between the first elastic gasket and the geomembrane in the anchoring area, and between the geomembrane in the anchoring area and the second elastic gasket respectively; and sealant is injected into the gaps between the first elastic gasket, the geomembrane in the anchoring area, the second elastic gasket and the galvanized bolt respectively;

[0033] In the fifth step, the specific process of filling is: first fill high plasticity clay within 0.5 to 1m on the downstream side of the geomembrane in the anchoring area, then lay long pillow-shaped soft bags filled with flexible fillers and make the geomembrane in the anchoring area fit with them, and naturally stretch the anchoring area geomembrane along the edge of the anchoring base surface to a predetermined length in the direction opposite to the deformation of the dam body, and then change the direction and lay it in an arch shape; then fill high plasticity clay within 0.5 to 1m on the upstream side of the geomembrane in the anchoring area, and finally fill the filter layer.

[0034] By adopting the above preferred solutions, the specific technical details of the construction method can be further optimized to achieve better technical effects.

[0035] Compared with the prior art, the present invention lays a section of the geomembrane in the anchoring area extending from the anchoring member in an arch shape in the direction opposite to the deformation of the dam body, thereby increasing the initial gauge length of the geomembrane in the anchoring area. This allows the geomembrane in the anchoring area to use the geometric displacement of a portion of the material to replace the deformation of the material itself when shear deformation occurs, thereby improving its ability to adapt to shear deformation. By arranging a polytetrafluoroethylene membrane, the friction coefficient between the geomembrane in the anchoring area and the materials on both sides is reduced, thereby reducing the frictional resistance on both sides of the geomembrane in the anchoring area to improve its ability to adapt to shear deformation. By arranging materials with decreasing normal modulus, the normal pressure is dispersed, thereby reducing the normal pressure of the geomembrane in the anchoring area. The present invention can improve the ability of the geomembrane in the anchoring area of ​​the bank slope to adapt to shear deformation, and avoid shear tearing damage of the geomembrane in the extremely small range of the anchoring area of ​​the bank slopes due to the shear deformation of the core wall along the slope, resulting in engineering leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the anchoring structure of the anti-seepage geomembrane of the core wall of Example 1 of the present invention.

[0037] Figure 2 for Figure 1 Enlarged schematic diagram of the anchoring member at the circle.

[0038] Figure 3 Schematic diagram of the shear deformation process of the arch structure in Example 1 of the present invention.

[0039] In the figure: 1-bank slope concrete or rock mass; 2-clay core wall; 3-filter layer; 4-high plasticity clay; 5-anchoring area geomembrane; 6-core wall geomembrane; 7-anchoring member; 8-long pillow-shaped soft bag; 9-flexible filler; 10-geomembrane; 11-geotextile; 12-polytetrafluoroethylene membrane; 13-galvanized bolt; 14-nut; 15-steel gasket; 16-galvanized angle steel; 17-elastic gasket; 18-sealant; 19-anchoring base. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to the embodiments. However, the present invention is not limited to the examples given. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] This embodiment is a specific implementation of an anchoring structure and construction method for the anti-seepage geomembrane of the core wall of an earth-rock dam that adapts to shear deformation of the slope, and is mainly applicable to the core wall geomembrane combined anti-seepage project of a high rockfill dam on a deep overburden in water conservancy and hydropower projects.

[0043] like Figures 1 to 3As shown, the earth-rock dam core wall anti-seepage geomembrane anchoring structure of this embodiment includes slope concrete or rock mass 1, clay core wall 2, filter layer 3, anchoring member 7, anchoring area geomembrane 5 and core wall geomembrane 6.

[0044] The bank slope concrete or rock mass 1 is located at the junction of the two bank slopes and the clay core wall 2. Anchor members 7 anchor the anchoring zone geomembrane 5 to the bank slope concrete or rock mass 1. The deformation modulus of the clay core wall 2 is typically in the range of 10 to 100 MPa. The filter layer 3 is 2 meters wide.

[0045] The section of geomembrane 5 in the anchoring area that extends out of the anchoring member 7 is laid in an arch shape in the direction opposite to the deformation of the dam body. The convex surface of the arch structure faces upstream and the concave surface faces downstream. A long pillow-shaped soft bag 8 extending from the bottom to the top of the clay core wall 2 is vertically placed in the concave space formed by the concave surface of the arch structure, which is filled with flexible filler 9. The characteristics of the arch structure are used to offset part of the shear deformation of the geomembrane in the slope direction of the core wall: laying with an arch structure can increase the initial gauge length of the geomembrane 5 in the anchoring area, so that when shear deformation occurs, the geomembrane 5 in the anchoring area uses a part of the material's geometric displacement to replace the deformation of the material itself, thereby improving its ability to adapt to shear deformation (such as Figure 3 As shown). The difference between the arch length and the arch width of the geomembrane 5 arch structure in the anchoring area exceeds 15 cm. In this embodiment, the arch width is 20 cm, the arch height is 15 cm, and the arch length is about 42.6 cm.

[0046] The upstream and downstream sides of the geomembrane 5 in the anchoring area are respectively provided with a smooth polytetrafluoroethylene membrane 12 and a geotextile 11 from the inside to the outside, forming a five-layer material structure, and the five layers of material are separable. The thickness of the geomembrane 5 in the anchoring area is generally not less than 1.5 mm, usually a PVC membrane with a thickness of 1.5 to 3.5 mm. This embodiment uses a 3.0 mm thick PVC membrane, and the thickness of the polytetrafluoroethylene membrane is 0.1 to 0.2 mm. Among them, the smooth polytetrafluoroethylene membrane can reduce the friction coefficient between the geomembrane 5 in the anchoring area and the materials on both sides, thereby reducing the friction resistance on both sides of the geomembrane 5 in the anchoring area to improve its ability to adapt to shear deformation.

[0047] High-plasticity clay 4 is filled within a range of 0.5 to 1 m on the upstream and downstream sides of the geomembrane 5 in the anchoring zone. The main component of the high-plasticity clay 4 is hydrophilic minerals, with a liquid limit greater than 50% and a plasticity index greater than 25. The deformation modulus of the high-plasticity clay 4 is smaller than that of the clay core wall, and is generally between 1 and 10 MPa. It has significant water absorption and water loss shrinkage properties, which serves to disperse the normal pressure, and the normal pressure is perpendicular to the geomembrane 5 in the anchoring zone. At the same time, the deformation modulus of the flexible filler 9 filled in the long pillow-shaped soft bag 8 is smaller than that of the high-plasticity clay 4. Therefore, the arrangement of materials with decreasing normal modulus can disperse the normal pressure, thereby reducing the normal pressure on the geomembrane in the anchoring zone.

[0048] The core geomembrane 6 is laid along the upstream slope of the clay core 2, between the clay core 2 and the filter layer 3. Geotextiles 11 are placed on the upstream and downstream sides of the core geomembrane 6, forming a two-fabric, one-membrane structure. The core geomembrane 6 is typically no less than 1.5 mm thick, typically a 1.5-3.5 mm thick PVC membrane. This embodiment uses a 3.0 mm thick PVC membrane. The core geomembrane 6 is spliced ​​and securely connected to the anchoring zone geomembrane 5.

[0049] The anchoring member 7 includes an M25 galvanized bolt 13 (bolt diameter 25 mm), a nut 14, a steel washer 15, a galvanized angle steel 16 (using Q235 with a specification of 125×80×8), and an elastic washer 17 (using a 3 mm thick EPDM rubber washer). The specific structure of the anchoring member 7 for anchoring the geomembrane 5 in the anchoring area is as follows: one end of the galvanized bolt 13 is embedded or driven into the bank slope concrete or rock mass 1, and the other end extends out of the anchoring base 19 of the bank slope concrete or rock mass 1. Starting from the anchoring base 19, the first elastic washer 17, the geomembrane 5 in the anchoring area, the second elastic washer 17, the galvanized angle steel 16, the steel washer 15, and the nut 14 are sequentially installed on the galvanized bolt 13. The anchoring is completed by tightening the nut 14. Sealant 18 is applied between the anchoring base 19 and the first elastic gasket 17, between the first elastic gasket 17 and the anchoring geomembrane 5, and between the anchoring geomembrane 5 and the second elastic gasket 17. Sealant 18 is also injected into the gaps between the first elastic gasket 17, the anchoring geomembrane 5, the second elastic gasket 17, and the galvanized bolts 13 to prevent water seepage between the anchors. Note: Sealant 18 is made of liquid SR glue and solid SR filler.

[0050] The specific construction method of this embodiment is as follows:

[0051] S1. When planning the filling of the clay core wall 2 and the filter layer 3, a space for filling the anchoring material is reserved in a predetermined area near the geomembrane 5 in the anchoring area.

[0052] S2. Excavate and / or clean the bedrock on both sides of the bank section by section. Then, pour bank concrete as a cushion layer according to the predetermined plan, forming a bank concrete or rock mass 1 that serves as the anchor base. Furthermore, anchor bars are installed to enhance its anti-sliding stability, and grouting is performed at the interface between the concrete cushion layer and the bank rock mass to meet contact anti-seepage requirements.

[0053] S3. Pre-buried installation of M25 type galvanized bolts 13, with a bolt spacing of 30 cm and a burial depth of 20 cm; during pre-buried installation, first drill holes at the predetermined bolt positions with a hole diameter of 23 to 24 mm (the hole diameter should be 1 to 2 mm smaller than the bolt diameter). After burying the galvanized bolts 13, use an anchoring agent (such as epoxy resin) to seal the gaps around the galvanized bolts 13.

[0054] S4. Before anchoring, for construction joints or structural joints, grind the protruding parts on the surface and fill the concave parts with mortar to ensure that the anchoring base surface 19 of the geomembrane 5 anchoring area is flat.

[0055] S5. Mechanically anchor the geomembrane 5 in the anchoring area and anchor it on the slope concrete or rock mass 1. The specific process is: first apply sealant 18 on the anchoring base surface 19, and then, starting from the anchoring base surface 19, sequentially install the first elastic gasket 17, the geomembrane 5 in the anchoring area, the second elastic gasket 17, the galvanized angle steel 16, the steel gasket 15, and the nut 14 on the galvanized bolt 13, and complete the anchoring by tightening the nut 14, and anchor the geomembrane 5 in the anchoring area on the anchoring base surface 19; wherein, sealant 18 is applied between the first elastic gasket 17 and the geomembrane 5 in the anchoring area, and between the geomembrane 5 in the anchoring area and the second elastic gasket 17 respectively; sealant 18 is injected into the gaps between the first elastic gasket 17, the geomembrane 5 in the anchoring area, the second elastic gasket 17 and the galvanized bolt 13 respectively to prevent water seepage in the gaps between the anchors.

[0056] S6. Fill the reserved anchoring material filling space in the order from downstream to upstream. First, fill the highly plastic clay 4 within 0.5 to 1 m downstream of the anchoring geomembrane 5. Then, lay the long pillow-shaped soft bag 8 filled with flexible filler 9, and make the anchoring geomembrane 5 fit with it. The anchored anchoring geomembrane 5 is naturally stretched 25 cm along the edge of the anchoring base surface 19 in the direction opposite to the dam body deformation (in the direction perpendicular to the upstream dam surface of the clay core wall 2). Then, turn 90 degrees and lay it in an arch shape with an arch width of 20 cm, an arch height of 15 cm, and an arch length of approximately 42.6 cm. Then, fill the highly plastic clay 4 within 0.5 to 1 m upstream of the anchoring geomembrane 5. Finally, fill the 2 m wide filter layer 3. During this process, the core wall geomembrane 6 is laid along the upstream slope of the clay core wall 2 between the clay core wall 2 and the filter layer 3.

[0057] S7. Finally, the anchoring area geomembrane 5 is spliced ​​with the core wall geomembrane 6. The construction is completed.

[0058] In combination with the above embodiments, the technical solution of the present invention has the following advantages:

[0059] (1) The present invention lays a section of the geomembrane extending out of the anchoring member in an arch shape in the opposite direction of the dam body deformation. The arched laying method can increase the initial gauge length of the geomembrane, so that when shear deformation occurs, the geometric displacement of a part of the material replaces the deformation of the material itself, which can improve its ability to adapt to shear deformation.

[0060] (2) For a section of geomembrane extending out of the anchoring structure and laid in an arch shape in the opposite direction of the dam body deformation, a layer of smooth polytetrafluoroethylene membrane is set tightly on both sides of the geomembrane. The advantage is that it can reduce the friction coefficient between the geomembrane and the materials on both sides, thereby reducing the friction resistance on both sides of the geomembrane to improve its ability to adapt to shear deformation.

[0061] (3) For a section of geomembrane extending out of the anchoring member and laid in an arch shape in the direction opposite to the deformation of the dam body, high plasticity clay is filled on the upstream and downstream sides of the geomembrane, and long pillow-shaped soft bags are placed under the arch of the arched section and along the clay core wall from the top to the bottom of the core wall. The long pillow-shaped soft bags are filled with flexible fillers. Since the deformation modulus of the clay core wall is the largest, followed by the high plasticity clay, and the smallest is the flexible filler filled in the long pillow-shaped soft bags, the normal pressure can be dispersed by arranging materials with decreasing normal modulus, thereby reducing the normal pressure of the geomembrane in the anchoring area.

[0062] In addition to the above embodiments, the present invention may also have other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. An earth-rock dam core wall anti-seepage geomembrane anchoring structure adapted to bank slope shear deformation, comprising a clay core wall and a filter layer, characterized in that: It also includes bank slope concrete or rock mass, anchoring components, anchoring zone geomembrane, and core wall geomembrane; the bank slope concrete or rock mass is located at the junction of the bank slopes and the clay core wall on both sides; the anchoring components anchor the anchoring zone geomembrane to the bank slope concrete or rock mass; a section of the anchoring zone geomembrane extending from the anchoring components is laid in an arch shape in the direction opposite to the deformation of the dam body, and polytetrafluoroethylene membranes are respectively provided on the upstream and downstream sides of the anchoring zone geomembrane, with the convex surface of the arch structure facing upstream and the concave surface facing downstream. A long pillow-shaped soft bag extending from the bottom to the top of the clay core wall is vertically placed in the concave space formed by the concave surface, and the long pillow-shaped soft bag is filled with flexible filler; the upstream and downstream sides of the geomembrane in the anchoring area are respectively filled with high plasticity clay; the deformation modulus of the clay core wall>the deformation modulus of the high plasticity clay>the deformation modulus of the flexible filler; the core wall geomembrane is laid between the clay core wall and the filter layer along the upstream slope of the clay core wall; the core wall geomembrane is spliced ​​and fixedly connected to the geomembrane in the anchoring area.

2. The anchoring structure of the earth-rock dam core wall anti-seepage geomembrane adapted to bank slope shear deformation according to claim 1, characterized in that: The deformation modulus of the clay core wall is in the range of 10 to 100 MPa; the deformation modulus of the high plasticity clay is in the range of 1 to 10 MPa.

3. The anchoring structure of the earth-rock dam core wall anti-seepage geomembrane adapted to bank slope shear deformation according to claim 1, characterized in that: The difference between the arch length and the arch width of the geomembrane arch structure in the anchoring area is greater than 15 cm; the thickness of the geomembrane in the anchoring area and the thickness of the core wall geomembrane are not less than 1.5 mm respectively; the thickness of the polytetrafluoroethylene membrane is 0.1 to 0.2 mm; the high plasticity clay is filled in the range of 0.5 to 1 m on the upstream and downstream sides of the geomembrane in the anchoring area.

4. The anchoring structure of the earth-rock dam core wall anti-seepage geomembrane adapted to bank slope shear deformation according to claim 1, characterized in that: The liquid limit of the high plasticity clay is greater than 50%, and the plasticity index is greater than 25.

5. The anchoring structure of the earth-rock dam core wall anti-seepage geomembrane adapted to bank slope shear deformation according to claim 1, characterized in that: The upstream and downstream sides of the anchoring zone geomembrane are respectively provided with smooth polytetrafluoroethylene membrane and geotextile from the inside to the outside, forming a five-layer material structure, and the adjacent materials are separable; the upstream and downstream sides of the core wall geomembrane are respectively provided with geotextile, forming a two-cloth and one-membrane structure, and the core wall geomembrane and the geotextile are separable.

6. The anchoring structure of the earth-rock dam core wall anti-seepage geomembrane adapted to bank slope shear deformation according to claim 1, characterized in that: The anchoring components include: galvanized bolts, nuts, steel washers, galvanized angle steels, and elastic washers.

7. The anchoring structure of the earth-rock dam core wall anti-seepage geomembrane adapted to bank slope shear deformation according to claim 6, characterized in that: The specific structure of the anchoring component anchoring the geomembrane in the anchoring area is as follows: one end of the galvanized bolt is pre-buried or driven into the bank slope concrete or rock mass, and the other end thereof extends out of the anchoring base surface of the bank slope concrete or rock mass, and the first elastic gasket, the anchoring area geomembrane, the second elastic gasket, the galvanized angle steel, the steel gasket, and the nut are sequentially sleeved on the galvanized bolt from the anchoring base surface, and the anchoring is completed by tightening the nut.

8. The anchoring structure of the earth-rock dam core wall anti-seepage geomembrane adapted to bank slope shear deformation according to claim 7, characterized in that: Sealant is applied between the anchoring base surface and the first elastic gasket, between the first elastic gasket and the geomembrane in the anchoring area, and between the geomembrane in the anchoring area and the second elastic gasket; sealant is injected into the gaps between the first elastic gasket, the geomembrane in the anchoring area, the second elastic gasket and the galvanized bolts.

9. A construction method for an anchoring structure of an earth-rockfill dam core wall anti-seepage geomembrane adapted to bank slope shear deformation according to any one of claims 1 to 8, characterized in that: The following steps are involved: The first step is to plan the filling area of ​​the clay core wall and the filter layer, and reserve space for anchoring material filling in the predetermined area near the geomembrane in the anchoring area; The second step is to excavate and / or clean the bedrock of the bank slopes on both sides section by section, and then pour the concrete cushion layer according to the predetermined plan to form the bank slope concrete or rock mass as the anchor base; Step 3: The anchoring components include: galvanized bolts, nuts, steel washers, galvanized angle steels, and elastic washers; pre-embed the galvanized bolts on the bank slope concrete or rock mass; Step 4: Anchor the geomembrane in the anchoring area on the anchoring base surface of the slope concrete or rock mass; Step 5: Fill the reserved anchoring material filling space in the order from downstream to upstream. First, fill the downstream side of the geomembrane in the anchoring area with high plasticity clay, then lay long pillow-shaped soft bags filled with flexible fillers, lay the anchored geomembrane in an arch shape against the deformation direction of the dam body, then fill the upstream side of the geomembrane in the anchoring area with high plasticity clay, and finally fill the filter layer. During this process, lay the core wall geomembrane between the clay core wall and the filter layer along the upstream slope of the clay core wall. Step 6: Splice the geomembrane in the anchoring area with the geomembrane in the core wall; the construction is completed.

10. The construction method according to claim 9, characterized in that: In the second step, anchor bars are set in the concrete cushion layer and grouting is performed at the interface between the concrete cushion layer and the bank rock mass; In the third step, during the pre-buried installation, first drill holes at the predetermined bolt positions, with the hole diameter being 1 to 2 mm smaller than the bolt diameter. Then, after embedding the galvanized bolts, use an anchoring agent to seal the gaps around the galvanized bolts. In the fourth step, before anchoring, the anchoring base surface of the geomembrane anchoring area is leveled by grinding the protruding parts or filling the concave parts with mortar. The specific process of anchoring is as follows: first, sealant is applied to the anchoring base surface, and then, starting from the anchoring base surface, the first elastic gasket, the geomembrane in the anchoring area, the second elastic gasket, the galvanized angle steel, the steel gasket, and the nut are sequentially installed on the galvanized bolt, and the anchoring is completed by tightening the nut to anchor the geomembrane in the anchoring area to the anchoring base surface; wherein, sealant is applied between the first elastic gasket and the geomembrane in the anchoring area, and between the geomembrane in the anchoring area and the second elastic gasket respectively; and sealant is injected into the gaps between the first elastic gasket, the geomembrane in the anchoring area, the second elastic gasket and the galvanized bolt respectively; In the fifth step, the specific process of filling is: first fill high plasticity clay within 0.5 to 1m on the downstream side of the geomembrane in the anchoring area, then lay long pillow-shaped soft bags filled with flexible fillers and make the geomembrane in the anchoring area fit with them, and naturally stretch the anchoring area geomembrane along the edge of the anchoring base surface to a predetermined length in the direction opposite to the deformation of the dam body, and then change the direction and lay it in an arch shape; then fill high plasticity clay within 0.5 to 1m on the upstream side of the geomembrane in the anchoring area, and finally fill the filter layer.

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