Overall anti-seepage structure of cemented sand gravel dam on deep covering layer and construction method
By setting up a flexible connection between the dam-based suspended high-pressure rotary spray pile wall and the external anti-seepage protection layer on the deep cover layer, combining the flexible layer and the water-stop structure, the anti-seepage problem of cemented sand and gravel dam is solved, and the overall anti-seepage effect is improved and adapted to complex geological conditions.
Patent Information
- Application Number
- CN202510500316.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-21
- Publication Date
- 2025-08-01
AI Technical Summary
When building cemented sand and gravel dams on deep cover layers, the existing technology is difficult to effectively solve the problem of anti-seepage between the dam body and the dam foundation, especially the cemented sand and gravel materials have low permeability, poor durability, and uneven settlement leads to the disconnection of the anti-seepage body from the dam body, resulting in anti-seepage failure.
The dam-based suspended high-pressure rotary spray pile wall is combined with the outer anti-seepage protective layer of the dam body, and a flexible layer and a water stop structure are set up, including high-pressure rotary spray piles, concrete cast-in-place blocks, flexible layer, multi-layer water stop structure and cushion layer combinations of different materials to form an overall anti-seepage structure.
It improves the anti-seepage reliability of cemented sand and gravel dams, adapts to the deformation of the dam body and cover layer, enhances the anti-seepage effect, and is suitable for complex geological conditions, especially in strata containing lonely stones, pebbles and other strata.
Smart Images
Figure CN120401417A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of water conservancy and hydropower engineering, and in particular to an integral anti-seepage structure of a cemented gravel dam on a thick overburden layer and a construction method thereof. Background Art
[0002] As my country's water conservancy and hydropower projects expand into geologically complex regions, dam construction technology in deep overburden conditions faces new challenges. Cemented gravel dams, a new dam type intermediate between face rockfill dams and roller-compacted concrete gravity dams, offer significant economic advantages due to their high gravel utilization rate and low cement consumption. They have been widely used in recent years. Cemented gravel dams have a low elastic modulus, a relatively large dam cross-section, and low stress levels. Compared to concrete dams, they can effectively adapt to the uneven settlement characteristics of deep overburden. However, there are currently few examples of cemented gravel dams constructed on deep overburden. Dam construction on deep overburden presents the challenge of preventing seepage from reaching both the dam body and foundation. Cemented gravel inherently has low impermeability and durability, making it unsuitable as a direct anti-seepage barrier. Furthermore, when building a dam on deep overburden, the foundation anti-seepage barrier cannot fall to the bedrock, resulting in uneven settlement between the foundation and the dam body, potentially leading to complete separation and failure of the anti-seepage barrier. In order to effectively improve the overall anti-seepage capacity of cemented gravel dam, this paper proposes an overall anti-seepage structure and construction method of cemented gravel dam on thick overburden. Summary of the Invention
[0003] In response to the shortcomings of the prior art, the first object of the present invention is to provide an integrated anti-seepage structure for a cemented gravel dam on a deep overburden layer. The present invention can effectively improve the reliability of the anti-seepage structure of the cemented gravel dam and ensure the overall anti-seepage effect of the dam body and dam foundation.
[0004] In the first aspect, an embodiment of the present invention provides an overall anti-seepage structure of a cemented gravel dam on a deep covering layer, comprising a cemented gravel dam located on the deep covering layer and a dam base suspended high-pressure rotary jet pile wall with its bottom penetrating into the deep covering layer; the cemented gravel dam comprises a cemented gravel dam body and an external anti-seepage protective layer of the dam body, and the external anti-seepage protective layer of the dam body wraps the cemented gravel dam body; the dam base suspended high-pressure rotary jet pile wall is connected to the external anti-seepage protective layer of the dam body at the top, and a flexible layer is provided at the connection between the dam base suspended high-pressure rotary jet pile wall and the external anti-seepage protective layer of the dam body.
[0005] In one embodiment, the dam foundation suspended high-pressure rotary jet grouting pile wall is composed of a number of high-pressure rotary jet grouting piles that are continuously arranged along the axis of the cemented gravel dam body and are interconnected. The top of each high-pressure rotary jet grouting pile is connected to a cast-in-place concrete block, and the pile body of the high-pressure rotary jet grouting pile extends vertically into a thick covering layer.
[0006] In one embodiment, the flexible layer covers the outer surface of the cast-in-situ concrete block, and the external anti-seepage protection layer of the dam body covers the outside of the flexible layer.
[0007] In one embodiment, reinforcing bars are connected between multiple high-pressure jet grouting piles and the cast-in-situ concrete block.
[0008] In one embodiment, a first water-stop structure is arranged between the suspended high-pressure jet grouting pile wall of the dam foundation and the external anti-seepage protection layer of the dam body, and a second water-stop structure is arranged inside the external anti-seepage protection layer of the dam body, and the first water-stop structure and the second water-stop structure are connected.
[0009] In one embodiment, the external anti-seepage protection layer of the dam body includes an upstream slurry-rich cemented gravel layer, a downstream slurry-rich cemented gravel layer, a slurry-rich cemented gravel cushion layer and a normal concrete cushion layer; the slurry-rich cemented gravel cushion layer and the normal concrete cushion layer are arranged at the bottom of the cemented gravel dam body, and the slurry-rich cemented gravel cushion layers are laid on both the upstream side and the downstream side of the normal concrete cushion layer; the upstream slurry-rich cemented gravel layer is arranged on the upstream-facing side of the cemented gravel dam body and is connected to the upstream-side slurry-rich cemented gravel cushion layer at the bottom; the downstream slurry-rich cemented gravel layer is laid on the downstream-facing side of the cemented gravel dam body and is connected to the downstream-side slurry-rich cemented gravel cushion layer at the bottom.
[0010] In one embodiment, a first horizontal copper sheet water-stop and a second horizontal copper sheet water-stop are respectively arranged at the construction joints between the normal concrete cushion layer and the upstream-side slurry-rich cemented gravel cushion layer and the downstream-side slurry-rich cemented gravel cushion layer; a first circumferential copper sheet water-stop is arranged on the upstream side of the axis of the suspended high-pressure jet grouting pile wall of the dam foundation at the joint of the cemented gravel dam body in the normal concrete cushion layer, and a second circumferential copper sheet water-stop is arranged on the downstream side of the axis of the suspended high-pressure jet grouting pile wall of the dam foundation at the joint of the cemented gravel dam body, and the first circumferential copper sheet water-stop and the second circumferential copper sheet water-stop respectively extend upward into the upstream slurry-rich cemented gravel layer and the downstream slurry-rich cemented gravel layer; the first horizontal copper sheet water-stop is connected to the first circumferential copper sheet water-stop, and the second horizontal copper sheet water-stop is connected to the second circumferential copper sheet water-stop.
[0011] In one embodiment, at least two first circumferential copper sheet water-stops are arranged and are spaced apart along the thickness direction of the upstream slurry-rich cemented gravel layer.
[0012] In one embodiment, a gravel replacement layer is arranged below the external anti-seepage protection layer of the dam body on the deep overburden layer.
[0013] In a second aspect, the second object of the present invention is also to provide a construction method for the overall anti-seepage structure of a cemented gravel dam on a deep overburden layer, which is characterized in that it includes the overall anti-seepage structure of a cemented gravel dam on a deep overburden layer as described in any one of the above, and the construction method includes the following steps:
[0014] S1. Arrange the construction platform according to the axis of the suspended high-pressure jet grouting pile wall of the dam foundation, construct high-pressure jet grouting piles for the deep overburden layer, and socket adjacent high-pressure jet grouting piles.
[0015] S2. Chip the top of the high-pressure jet grouting pile poured to the design elevation and set trapezoidal key grooves. After embedding inserted steel bars in the key grooves, cast-in-place concrete blocks are cast. The inserted steel bars are anchored into the cast-in-place concrete blocks. The outer surface of the cast-in-place concrete blocks is coated with a flexible layer, and a first water-stop structure is arranged between the cast-in-place concrete blocks and the upper normal concrete cushion layer.
[0016] S3. After the foundation of the cemented gravel dam is excavated to the design elevation, the gravel replacement layer is paved and compacted in sequence, the normal concrete cushion layer is poured, and the rich-slurry cemented gravel cushion layer is paved and compacted. Among them, the normal concrete cushion layer is arranged on the top of the suspended high-pressure jet grouting pile wall of the dam foundation. The rich-slurry cemented gravel cushion layer is laid on both the upstream side and the downstream side of the normal concrete cushion layer, and the first circumferential copper sheet water stop, the second circumferential copper sheet water stop, the first horizontal copper sheet water stop, and the second horizontal copper sheet water stop are arranged.
[0017] S4. Pave and compact the cemented gravel of the dam body to form the main body of the dam.
[0018] S5. On the upstream and downstream sides of the dam body, the upstream rich-slurry cemented gravel layer and the downstream rich-slurry cemented gravel layer are respectively paved, vibrated and compacted, and surface scarifying treatment is carried out. Extended first circumferential copper sheet water stops and second circumferential copper sheet water stops for anti-seepage are respectively arranged at the joints of the cemented gravel dams of the upstream rich-slurry cemented gravel layer and the downstream rich-slurry cemented gravel layer.
[0019] The beneficial effects of an integral anti-seepage structure and construction method of a cemented gravel dam on a deep overburden layer provided by the embodiment of the present invention are as follows:
[0020] 1. The measures such as arranging the external anti-seepage protection layer of the dam body outside the cemented gravel dam, using flexible connection between the suspended high-pressure jet grouting pile wall and the external anti-seepage protection layer of the dam body, and setting water stops between structural joints in the present invention can effectively improve the reliability of the anti-seepage structure of the cemented gravel dam and ensure the overall anti-seepage effect of the dam body and the dam foundation.
[0021] 2. A flexible layer is arranged between the suspended high-pressure jet grouting anti-seepage pile wall and the cemented gravel dam body in the present invention, which can effectively adapt to the deformation and uneven settlement of the upper cemented gravel dam body and the deep overburden foundation. Moreover, the high-pressure jet grouting pile wall has stronger adaptability to the overburden foundation, is applicable to sand layers, silty soils, clay soils, gravel layers and some soft rock strata, and performs well especially in complex strata (such as strata containing boulders and pebble layers).
[0022] 3. In the present invention, the construction joint between the normal concrete cushion layer and the slurry-rich cemented gravel cushion layer, two different cushion materials, is likely to become a weak link in leakage. Arranging copper sheet water stops between the two can effectively prevent seepage, thereby improving the overall anti-seepage capacity of the cemented gravel dam. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following-described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0024] Figure 1 It is a typical sectional view of the overall anti-seepage structure of the cemented gravel dam provided by the embodiment of the present invention;
[0025] Figure 2 It is a typical sectional view of the top structure of the suspended high-pressure jet grouting pile wall provided by the embodiment of the present invention.
[0026] Reference numerals: 1 - suspended high-pressure jet grouting pile wall; 2 - gravel replacement layer; 3 - cemented gravel dam body; 4 - upstream slurry-rich cemented gravel layer; 5 - downstream slurry-rich cemented gravel layer; 6 - first circumferential copper sheet water stop; 7 - slurry-rich cemented gravel cushion layer; 8 - normal concrete cushion layer; 9 - cast-in-place concrete block; 10 - inserted reinforcement; 11 - flexible layer; 12 - second circumferential copper sheet water stop; 13 - first water stop structure; 14 - first horizontal copper sheet water stop; 15 - second horizontal copper sheet water stop; 16 - deep overburden layer. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0027] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following describes the preferred implementation schemes of the present invention in combination with specific embodiments. However, it should be understood that the drawings are only for illustrative purposes and cannot be construed as a limitation to the present invention; for better illustration of this embodiment, some components in the drawings will be omitted, enlarged or reduced, and do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationships described in the drawings are only for illustrative purposes and cannot be construed as a limitation to the present invention.
[0028] The following further illustrates the present invention in combination with the drawings and embodiments, but it is not used as a basis for limiting the present invention.
[0029] As Figure 1As shown in the figure, an integral anti-seepage structure for a cemented gravel dam on a deep overburden layer includes a cemented gravel dam located on the deep overburden layer 16 and a suspended high-pressure jet grouting pile wall 1 at the dam foundation that penetrates deep into the deep overburden layer 16. The cemented gravel dam includes a cemented gravel dam body 3 and an anti-seepage protection layer outside the dam body. The anti-seepage protection layer outside the dam body completely wraps the cemented gravel dam body 3 to solve the anti-seepage and durability problems of the dam itself. The suspended high-pressure jet grouting pile wall 1 at the dam foundation is connected to the anti-seepage protection layer outside the dam body at the top. A flexible layer 11 is provided at the connection between the suspended high-pressure jet grouting pile wall 1 at the dam foundation and the anti-seepage protection layer outside the dam body. In this embodiment, the material used for the flexible layer 11 is asphalt mastic.
[0030] In this embodiment, the cemented gravel dam body 3 mainly undertakes the functions of the dam structure stress and overall stability, and its strength grade needs to meet the design requirements. According to engineering experience, the cemented gravel dam body can adopt cemented gravel with a strength grade of C8.
[0031] The suspended high-pressure jet grouting pile wall 1 at the dam foundation is composed of a number of high-pressure jet grouting piles arranged continuously along the axis direction of the cemented gravel dam body, and the tops of the high-pressure jet grouting piles are connected to the cast-in-place concrete block 9. The pile body of the high-pressure jet grouting pile extends vertically into the deep overburden layer 16.
[0032] The flexible layer 11 is coated on the outer surface of the cast-in-place concrete block 9, and the anti-seepage protection layer outside the dam body covers the outside of the flexible layer 11.
[0033] Reinforcing bars 10 are connected between multiple high-pressure jet grouting piles and the cast-in-place concrete block 9. In this embodiment, the height of the cast-in-place concrete block 9 is 0.5 m, the width is 1 m, and it is a C30 concrete block.
[0034] A first water-stop structure 13 is provided between the suspended high-pressure jet grouting pile wall 1 at the dam foundation and the anti-seepage protection layer outside the dam body. A second water-stop structure is provided inside the anti-seepage protection layer outside the dam body, and the first water-stop structure 13 and the second water-stop structure are connected. The second water-stop structure includes a first circumferential copper sheet water-stop 6, a second circumferential copper sheet water-stop 12, a first horizontal copper sheet water-stop 14, and a second horizontal copper sheet water-stop 15. The specific layout forms of the first circumferential copper sheet water-stop 6, the second circumferential copper sheet water-stop 12, the first horizontal copper sheet water-stop 14, and the second horizontal copper sheet water-stop 15 are as Figure 2 shown. In this embodiment, the first water-stop structure 13 is set as two vertically arranged copper sheet water-stops, and the copper sheet water-stop is connected to the first circumferential copper sheet water-stop 6.
[0035] The external anti-seepage protective layer of the dam body includes an upstream slurry-rich cemented gravel layer 4, a downstream slurry-rich cemented gravel layer 5, a slurry-rich cemented gravel cushion layer 7 and a normal concrete cushion layer 8; the slurry-rich cemented gravel cushion layer 7 and the normal concrete cushion layer 8 are arranged at the bottom of the cemented gravel dam body 3, and the slurry-rich cemented gravel cushion layer 7 is laid on the upstream and downstream sides of the normal concrete cushion layer 8; the upstream slurry-rich cemented gravel layer 4 is arranged on the side of the cemented gravel dam body 3 facing upstream, and is connected to the slurry-rich cemented gravel cushion layer 7 on the upstream side at the bottom; the downstream slurry-rich cemented gravel layer 5 is laid on the side of the cemented gravel dam body 3 facing downstream, and is connected to the slurry-rich cemented gravel cushion layer 7 on the downstream side at the bottom.
[0036] In this embodiment, the strength grade of the upstream slurry-rich cemented gravel layer 4, the downstream slurry-rich cemented gravel layer 5 and the slurry-rich cemented gravel cushion layer 7 are set to C20 and the anti-seepage grade is W6. The thickness of the upstream slurry-rich cemented gravel layer 4 is 2m, the thickness of the downstream slurry-rich cemented gravel layer 5 is 1m, and the thickness of the slurry-rich cemented gravel cushion layer 7 is 2m.
[0037] like Figure 2 As shown, the construction joints between the normal concrete cushion layer 8 and the upstream side rich slurry cemented gravel cushion layer 7 and the downstream side rich slurry cemented gravel cushion layer 7 are respectively provided with a first horizontal copper sheet waterstop 14 and a second horizontal copper sheet waterstop 15; the normal concrete cushion layer 8 is provided with a first annular copper sheet waterstop 6 at the joint of the cemented gravel dam and on the upstream side of the axis of the dam foundation suspended high-pressure rotary jet pile wall 1, and a second annular copper sheet waterstop 12 is provided at the joint of the cemented gravel dam and on the downstream side of the axis of the dam foundation suspended high-pressure rotary jet pile wall. The first annular copper sheet waterstop 6 and the second annular copper sheet waterstop 12 extend upward to the upstream rich slurry cemented gravel layer 4 and the downstream rich slurry cemented gravel layer 5 respectively; the first horizontal copper sheet waterstop 14 is connected to the first annular copper sheet waterstop 6, and the second horizontal copper sheet waterstop 15 is connected to the second annular copper sheet waterstop 12.
[0038] In this embodiment, the second annular copper sheet waterstop 12 arranged in the downstream rich slurry bonded gravel layer 5 is 0.5m away from the dam surface, and the top of the second annular copper sheet waterstop 12 is 1m higher than the downstream highest water level; the second annular copper sheet waterstop 12 is 1.6m away from the dam foundation in the downstream side rich slurry bonded gravel cushion layer 7 and the normal concrete cushion layer 8.
[0039] At least two first annular copper sheet waterstops 6 are provided, spaced apart along the thickness of the upstream slurry-rich cemented gravel layer 4. In this embodiment, the two first annular copper sheet waterstops 6 are located 0.5m and 1m from the dam surface, respectively, within the upstream slurry-rich cemented gravel layer 4. Their tops are 1m above the upstream maximum water level. The two first annular copper sheet waterstops 6 are located 1.1m and 1.6m from the dam foundation, respectively, within the normal concrete cushion layer 8.
[0040] A gravel replacement layer 2 is arranged below the external anti-seepage protection layer of the dam body on the deep overburden layer 16. In this embodiment, the thickness of the gravel replacement layer 2 is 20 cm.
[0041] The present invention also provides a construction method for the integral anti-seepage structure of a cemented gravel dam on a deep overburden layer. The construction method includes the following steps:
[0042] S1. Construct a construction platform according to the axis of the suspended high-pressure jet grouting pile wall 1 of the dam foundation, and construct high-pressure jet grouting piles on the deep overburden layer 16. The adjacent high-pressure jet grouting piles are socketed. The high-pressure jet grouting piles adopt triple tubes, the pile forming diameter is not less than 0.8 m, the pile spacing is 0.6 m, and the verticality deviation is less than 1%. The construction control parameters are determined according to the test pile conditions.
[0043] S2. Chip the top of the high-pressure jet grouting pile poured to the design elevation and set a trapezoidal key groove. The depth of the key groove is 15 cm and the bottom width is 10 cm. After embedding the inserted steel bars 10 in the key groove, cast-in-place concrete blocks 9 are cast. Among them, the size of the inserted steel bars 10 is Φ20 and the length is 1 m. The spacing of multiple inserted steel bars 10 is 0.6 m. The inserted steel bars 10 are anchored into the cast-in-place concrete blocks 9 by 0.5 m. The outer surface of the cast-in-place concrete blocks 9 is coated with a flexible layer 11, and a first water stop structure 13 is arranged between the cast-in-place concrete blocks 9 and the upper normal concrete cushion 8;
[0044] S3. After the foundation of the cemented gravel dam is excavated to the design elevation, sequentially pave and roll the gravel replacement layer 2, pour the normal concrete cushion 8, and pave and roll the slurry-rich cemented gravel cushion 7; among them, the normal concrete cushion 8 is arranged on the top of the suspended high-pressure jet grouting pile wall 1 of the dam foundation, and the width is 2 m and the thickness is 2 m. The slurry-rich cemented gravel cushions 7 are laid on both the upstream side and the downstream side of the normal concrete cushion 8, and the first circumferential copper sheet water stop 6, the second circumferential copper sheet water stop 12, the first horizontal copper sheet water stop 14, and the second horizontal copper sheet water stop 15 are arranged.
[0045] S4. Pave and roll the dam body cemented gravel C8 to form the main body of the dam body. The layer thickness is about 70 cm, and the construction parameters can be determined according to the production test.
[0046] S5. Respectively pave the upstream slurry-rich cemented gravel layer 4 and the downstream slurry-rich cemented gravel layer 5 on the upstream and downstream sides of the dam body, vibrate and compact them, and perform surface chipping treatment; respectively arrange the extended first circumferential copper sheet water stop 6 and the second circumferential copper sheet water stop 12 for anti-seepage at the cemented gravel dam joints of the upstream slurry-rich cemented gravel layer 4 and the downstream slurry-rich cemented gravel layer 5.
[0047] Before paving the cemented gravel material and concrete, temporary protection shall be set on both sides of the corresponding water stop structure to ensure the integrity of the water stop structure. And it shall be ensured that the cemented gravel or normal concrete around the water stop structure is compacted to prevent leakage along the water stop structure.
[0048] Based on the description and drawings of the present invention, those skilled in the art can easily manufacture or use the integral anti-seepage structure and construction method of the cemented gravel dam on the deep overburden layer of the present invention, and can produce the positive effects recorded in the present invention.
[0049] Unless otherwise specified, in the present invention, if there are terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicating the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the orientation or positional relationship in the present invention are only used for exemplary illustration and cannot be understood as a limitation to the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood by combining the drawings and according to specific circumstances.
[0050] Unless otherwise clearly specified and defined, in the present invention, if there are terms such as "set", "connected" and "connected", they shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0051] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Any simple modification and equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.
Claims
1. An overall anti-seepage structure for a cemented gravel dam on a deep overburden layer, characterized in that: It includes a cemented gravel dam located on a deep overburden layer and a suspended high-pressure jet grouting pile wall at the dam foundation that penetrates deep into the overburden layer; the cemented gravel dam includes a cemented gravel dam body and an external anti-seepage protection layer for the dam body, and the external anti-seepage protection layer for the dam body wraps the cemented gravel dam body; the suspended high-pressure jet grouting pile wall at the dam foundation is connected to the external anti-seepage protection layer of the dam body at the top, and a flexible layer is provided at the connection between the suspended high-pressure jet grouting pile wall at the dam foundation and the external anti-seepage protection layer of the dam body.
2. The integral anti-seepage structure of the cemented gravel dam on the deep overburden layer according to claim 1, characterized in that: The suspended high-pressure jet grouting pile wall at the dam foundation is composed of a number of high-pressure jet grouting piles arranged continuously along the axis direction of the cemented gravel dam body and sleeved with each other. The top of each high-pressure jet grouting pile is connected to a cast-in-place concrete block, and the pile body of the high-pressure jet grouting pile vertically extends into the deep overburden layer.
3. The integral anti-seepage structure of the cemented gravel dam on the deep overburden layer according to claim 2, characterized in that: The flexible layer covers the outer surface of the cast-in-place concrete block, and the external anti-seepage protection layer of the dam body covers the outside of the flexible layer.
4. The integral anti-seepage structure of the cemented gravel dam on the deep overburden layer according to claim 2, characterized in that: There are dowels connecting multiple high-pressure jet grouting piles and the cast-in-place concrete block.
5. The integral anti-seepage structure of the cemented gravel dam on the deep overburden layer according to claim 1, characterized in that: A first water-stop structure is provided between the suspended high-pressure jet grouting pile wall at the dam foundation and the external anti-seepage protection layer of the dam body, and a second water-stop structure is arranged inside the external anti-seepage protection layer of the dam body, and the first water-stop structure and the second water-stop structure are connected.
6. The integral anti-seepage structure of the cemented gravel dam on the deep overburden layer according to claim 1, characterized in that: The external anti-seepage protection layer of the dam body includes an upstream slurry-rich cemented gravel layer, a downstream slurry-rich cemented gravel layer, a slurry-rich cemented gravel cushion layer and a normal concrete cushion layer; the slurry-rich cemented gravel cushion layer and the normal concrete cushion layer are arranged at the bottom of the cemented gravel dam body, and the slurry-rich cemented gravel cushion layer is laid on both the upstream side and the downstream side of the normal concrete cushion layer; the upstream slurry-rich cemented gravel layer is arranged on the upstream side surface of the cemented gravel dam body and is connected to the upstream-side slurry-rich cemented gravel cushion layer at the bottom; the downstream slurry-rich cemented gravel layer is laid on the downstream side surface of the cemented gravel dam body and is connected to the downstream-side slurry-rich cemented gravel cushion layer at the bottom.
7. The integral anti-seepage structure of the cemented gravel dam on the deep overburden layer according to claim 6, characterized in that: First horizontal copper sheet water stops and second horizontal copper sheet water stops are respectively arranged at the construction joints between the normal concrete cushion layer and the upstream-side slurry-rich cemented gravel cushion layer and the downstream-side slurry-rich cemented gravel cushion layer; a first circumferential copper sheet water stop is arranged on the upstream side of the axis of the suspended high-pressure jet grouting pile wall at the dam foundation at the dam joint of the cemented gravel dam body inside the normal concrete cushion layer, and a second circumferential copper sheet water stop is arranged on the downstream side of the axis of the suspended high-pressure jet grouting pile wall at the dam foundation at the dam joint of the cemented gravel dam body. The first circumferential copper sheet water stop and the second circumferential copper sheet water stop respectively extend upward into the upstream slurry-rich cemented gravel layer and the downstream slurry-rich cemented gravel layer; the first horizontal copper sheet water stop is connected to the first circumferential copper sheet water stop, and the second horizontal copper sheet water stop is connected to the second circumferential copper sheet water stop.
8. The integral anti-seepage structure of the cemented gravel dam on the deep overburden layer according to claim 7, characterized in that: At least two first circumferential copper sheet water stops are provided and arranged at intervals along the thickness direction of the upstream slurry-rich cemented gravel layer.
9. The integral anti-seepage structure of the cemented gravel dam on the deep overburden layer according to claim 1, characterized in that: A gravel replacement layer is arranged below the external anti-seepage protection layer of the dam body on the deep overburden layer.
10. A construction method for the overall anti-seepage structure of a cemented gravel dam on a deep overburden layer, characterized in that, It includes the overall anti-seepage structure of the cemented gravel dam on the deep overburden layer as described in any one of claims 1-9, and the construction method includes the following steps: S1. Arrange a construction platform according to the axis of the suspended high-pressure jet grouting pile wall at the dam foundation, and construct high-pressure jet grouting piles for the deep overburden layer, and adjacent high-pressure jet grouting piles are sleeved. S2. Rough the top of the high-pressure jet grouting pile poured to the design elevation and set trapezoidal key grooves. After embedding inserted steel bars in the key grooves, cast-in-place concrete blocks are cast. The inserted steel bars are anchored into the cast-in-place concrete blocks. The outer surface of the cast-in-place concrete blocks is coated with a flexible layer, and a first water-stop structure is arranged between the cast-in-place concrete blocks and the upper normal concrete cushion layer; S3. After the foundation of the cemented gravel dam is excavated to the design elevation, sequentially pave and roll the gravel replacement layer, pour the normal concrete cushion layer, and pave and roll the rich-slurry cemented gravel cushion layer. Among them, the normal concrete cushion layer is arranged on the top of the suspended high-pressure jet grouting pile wall of the dam foundation. Rich-slurry cemented gravel cushion layers are laid on both the upstream side and the downstream side of the normal concrete cushion layer, and a first circumferential copper sheet water stop, a second circumferential copper sheet water stop, a first horizontal copper sheet water stop, and a second horizontal copper sheet water stop are arranged; S4. Pave and roll the dam body cemented gravel to form the main body of the dam; S5. Respectively pave the upstream rich-slurry cemented gravel layer and the downstream rich-slurry cemented gravel layer on the upstream and downstream sides of the dam body, vibrate and compact them and perform surface scarifying treatment. Extended first circumferential copper sheet water stops and second circumferential copper sheet water stops for anti-seepage are respectively arranged at the joints of the cemented gravel dam in the upstream rich-slurry cemented gravel layer and the downstream rich-slurry cemented gravel layer.