A reverse clay inclined core wall anti-seepage cofferdam structure and construction method

Abstract

The invention discloses a reverse clay oblique core wall anti-seepage cofferdam structure and a construction method, and relates to the technical field of water conservancy engineering. The structure comprises a gravel covering layer covering a bedrock layer, a diversion dike formed of gravel is constructed on the gravel covering layer, a block stone layer for protection and anti-seepage is laid on the water-facing side of the diversion dike, a diversion trough connected to the bedrock layer is excavated on the gravel covering layer on the backwater side of the diversion dike, the backwater side of the diversion dike is covered with a clay anti-seepage layer, the lower edge of the clay anti-seepage layer extends into the diversion trough and contacts the bedrock layer, and the side of the clay anti-seepage layer away from the diversion dike is covered with a backwater side gravel layer; the method controls the construction based on the cofferdam structure, and generally speaking, the implementation of the invention can overcome the problems of relatively long construction period and relatively high construction cost of the existing cofferdam structure and the inadaptability to anti-seepage in a gravel riverbed containing less fine particles.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy engineering, in particular to the technical field of earth-rock cofferdam construction, and specifically to a reverse clay inclined core wall anti-seepage cofferdam structure and a construction method. Background Art

[0002] When constructing water conservancy and hydropower projects in rivers, it is usually necessary to build water-retaining cofferdams before construction to form a construction pit, thereby ensuring dry land construction. Common cofferdams include earth-rock cofferdams, concrete cofferdams, steel sheet pile cofferdams, etc., and earth-rock cofferdams are the most widely used. They are filled with on-site materials. By using local materials and making full use of excavated waste materials as cofferdam fillings, they have the advantages of simple structure, convenient construction, easy dismantling and low engineering cost. However, the filling materials of the main earth-rock cofferdam basically have the problem of large permeability coefficient, especially for the gravel cover layer, that is, the study of the joint anti-seepage problem of cofferdam and foundation has become a key issue in the design of earth-rock cofferdams.

[0003] Since most earth-rock cofferdams need to be constructed underwater, the materials cannot be effectively compacted, especially the underwater anti-seepage materials cannot guarantee the anti-seepage quality of the cofferdam. In order to meet the anti-seepage requirements, the cross-section of the cofferdam cannot be too large. In addition, the construction period of the cofferdam is usually very tight and the cost should not be too high. The anti-seepage treatment methods commonly used in the construction of earth-rock cofferdams at home and abroad currently have the above-mentioned problems.

[0004] In the prior art, the Chinese utility model patent with application number 201320121707.9 discloses an earth-rock cofferdam structure, which aims to overcome the problems of long construction period and uneconomical construction. However, the earth-rock cofferdam structure still uses an anti-seepage body and a vertical anti-seepage wall to prevent seepage, which relatively speaking, also has the problems of long construction time and high cost. Moreover, for the gravel riverbed foundation with less fine particles, it is difficult to construct holes in the concrete anti-seepage wall, which is prone to hole collapse and poor troughing effect. In addition, the dike part is not fully utilized by the cofferdam, resulting in a large cross-section of the cofferdam structure, and the cofferdam filling volume is often large, which is not economical.

[0005] The Chinese utility model patent application number 201220172911.9 discloses an earth-rock cofferdam structure, which aims to overcome the problems of inconvenient construction period and low economy. However, the earth-rock cofferdam structure is more suitable for construction in reservoirs with still water or low flow rate, but not suitable for rivers with high flow rate and high riverbed permeability. The cofferdam structure also uses vertical anti-seepage walls for anti-seepage, but still has the disadvantages of high cost of the anti-seepage wall, long construction time, and difficulty in forming the foundation of the riverbed containing fine particles of sand, gravel, etc.

[0006] In summary, there is still a technical gap in designing a construction method and cofferdam structure for quickly building an earth-rock cofferdam under a gravel riverbed with less fine particles, while reducing the cross-section size as much as possible and meeting the anti-seepage requirements well under the cross-section that can meet the construction requirements. Summary of the invention

[0007] The purpose of the present invention is to overcome the problems of relatively long construction period, relatively high construction cost and unsuitability for anti-seepage of gravel riverbeds containing less fine particles in existing cofferdam structures, and to provide a reverse clay inclined core wall anti-seepage cofferdam structure and construction method.

[0008] The embodiment of the present invention is implemented as follows: a reverse clay inclined core wall anti-seepage cofferdam structure includes a gravel cover layer covering a bedrock layer, a diversion dike formed of gravel is constructed on the gravel cover layer, a block stone layer for protection and anti-seepage is laid on the water-facing side of the diversion dike, a diversion ditch connected to the bedrock layer is excavated on the gravel cover layer on the backwater side of the diversion dike, the diversion ditch is arranged along the edge of the foot of the diversion dike, the backwater side of the diversion dike is covered with a clay anti-seepage layer, the lower edge of the clay anti-seepage layer extends into the diversion ditch and contacts the bedrock layer, and the side of the clay anti-seepage layer away from the dike is covered with a backwater side gravel layer.

[0009] Furthermore, the side of the water-facing surface of the intercepting dike away from the bedrock layer is inclined toward the water-retaining surface of the intercepting dike, and the side of the water-retaining surface of the intercepting dike away from the bedrock layer is inclined toward the water-facing surface of the intercepting dike.

[0010] Furthermore, the slope ratio of the water-facing surface of the intercepting dike ranges from 1:1 to 2.5, and the slope ratio of the water-receiving surface of the intercepting dike ranges from 1:1 to 2.5.

[0011] Furthermore, the intercepting dike and the top of the clay anti-seepage layer are covered with a sand and gravel filling layer.

[0012] Furthermore, the gravel filling layer includes an upper gravel layer for covering the top of the diversion dike and a top gravel layer for covering the top of the clay impermeable layer. The upper surface of the top gravel layer is flush with the upper surface of the block stone layer, and the upper surface of the upper gravel layer is connected to the lower surface of the top gravel layer.

[0013] Furthermore, an anti-seepage retaining tip is formed on the clay anti-seepage layer near the upper surface of the interception dike, and the upper surface of the anti-seepage retaining tip is connected to the lower surface of the top gravel layer.

[0014] Furthermore, the side of the rock layer away from the bedrock layer is inclined toward the side of the gravel layer on the backwater side, and the slope ratio of the water-facing side of the rock layer ranges from 1:1 to 2.5.

[0015] Furthermore, the side of the gravel layer on the backwater side away from the bedrock layer is inclined toward the rock layer, and the slope ratio of the rock layer facing the water ranges from 1:1 to 2.5.

[0016] A construction method of a reverse clay inclined core wall anti-seepage cofferdam structure comprises the following steps: constructing an intercepting dike on a gravel cover layer of a riverbed, throwing and filling stones on the water-facing surface of the intercepting dike, excavating an intercepting trough at the place where the back surface of the intercepting dike and the gravel cover layer meet, the bottom of the intercepting trough is excavated until it contacts the bedrock layer of the riverbed, and timely backfilling the anti-seepage clay in the intercepting trough;

[0017] The backfilled impermeable clay is excavated according to a preset slope ratio to form an impermeable clay layer, which is backfilled to at least cover the backwater side of the interception dike, and gravel is covered on the backwater side of the impermeable clay layer to at least cover the backwater side of the impermeable clay layer.

[0018] Optionally, gravel is filled on the top of the intercepting dike and the anti-seepage clay layer to a specified elevation, and blocks are dumped on the water-facing side of the intercepting dike to a specified elevation.

[0019] The beneficial effects of the embodiments of the present invention are:

[0020] The anti-seepage cofferdam structure provided by the embodiment of the present invention can be used to quickly build a cofferdam structure for a riverbed with less fine particles. It is not necessary to use a built-in high-pressure spraying anti-seepage wall for anti-seepage, but a reverse clay inclined core wall is used to meet the needs of dry land construction of the riverbed foundation pit. It can not only avoid the use of high-pressure spraying anti-seepage walls as much as possible, but also greatly shorten the construction time of the anti-seepage system and reduce the construction difficulty. In addition, by excavating a water interception ditch on the riverbed gravel on the downstream side of the cofferdam body, i.e., the interception dike, and filling it with clay, the permeability of the cofferdam foundation can be greatly reduced, thereby improving the joint anti-seepage performance of the cofferdam body and the dike foundation. The cofferdam structure uses the interception dike constructed on site as a part of it, which can greatly reduce the cross-section and filling volume of the cofferdam structure, and the cost is more economical.

[0021] The construction method of the anti-seepage cofferdam structure provided by the embodiment of the present invention can achieve rapid filling of the construction cofferdam structure through effective control of the construction sequence, and timely ensure dry land construction of the riverbed foundation pit, especially for the construction of riverbeds with less fine particles of gravel, which greatly shortens the construction period and makes the cost more economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 A schematic diagram of a three-dimensional expression of an anti-seepage cofferdam structure provided in an embodiment of the present invention;

[0024] Figure 2 for Figure 1 The schematic cross-sectional view of the anti-seepage cofferdam structure shown;

[0025] Figure 3 A schematic diagram of the construction of the first step of the anti-seepage cofferdam structure provided by an embodiment of the present invention;

[0026] Figure 4 A schematic diagram of the construction of the second step of the anti-seepage cofferdam structure provided by an embodiment of the present invention;

[0027] Figure 5 A schematic diagram of the construction of the third step of the anti-seepage cofferdam structure provided by an embodiment of the present invention;

[0028] Figure 6 A schematic diagram of the construction of the fourth step of the anti-seepage cofferdam structure provided in an embodiment of the present invention.

[0029] Icons: 1-bedrock layer; 2-gravel covering layer; 3-riverbed ground line; 4-gravel layer on the backwater side; 4a-gravel on the backwater side; 5-stone layer; 6-upper gravel layer; 7-top gravel layer; 8-clay anti-seepage layer; 8a-clay; 8b-clay layer; 8c-anti-seepage retaining tip; 9-intercepting ditch; 10-intercepting dike; 11-gravel platform; 11a-gravel filling platform. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0033] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0034] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] Example

[0036] Please refer to Figure 1 and Figure 2 The reverse clay inclined core wall anti-seepage cofferdam structure provided in this embodiment includes a gravel cover layer 2 covering the bedrock layer 1, and the riverbed surface line 3 passes through the gravel cover layer 2, which means that the cofferdam structure can be applied to the gravel riverbed with less fine particles, so that the cofferdam body can be successfully constructed and a better anti-seepage effect can be achieved. Of course, this anti-seepage cofferdam structure includes but is not limited to the gravel riverbed. The application of this application to the gravel riverbed is to overcome the current technical difficulties or break through the bottleneck of technology, and provide a cofferdam structure and construction method that can be constructed on the gravel riverbed. Specifically, a dike 10 formed of gravel is constructed on the gravel cover layer 2. As a part of the cofferdam body, the dike 10 can play a preliminary waterproof and anti-seepage role, and the construction method using local materials has a great saving effect on construction costs and material costs.

[0037] In order to further improve the anti-seepage effect, a block stone layer 5 for protection and anti-seepage is laid on the water-facing side of the intercepting dike 10. A water intercepting ditch 9 connected to the bedrock layer 1 is excavated on the gravel cover layer 2 on the backwater side of the intercepting dike 10, which means that the water intercepting ditch 9 is located on the backwater side of the intercepting dike 10, and the bottom of the water intercepting ditch 9 is in contact with the surface of the bedrock layer 1, that is, the water intercepting ditch 9 is excavated to the surface of the bedrock layer 1. The opening direction of the water intercepting ditch 9 is arranged along the edge of the foot of the intercepting dike 10, which means that the entire direction of the water intercepting ditch 9 is consistent with the direction of the intercepting dike 10, and is arranged along the edge of the foot of the intercepting dike 10, reaching a state of close connection. The backwater side of the intercepting dike 10 is covered with a clay anti-seepage layer 8, the lower edge of which extends into the intercepting groove 9 and contacts the bedrock layer 1, which means that the entire clay anti-seepage layer 8 covers the backwater side of the intercepting dike 10, and the lower edge of the clay anti-seepage layer 8 extends into the intercepting groove 9 and can contact the surface of the bedrock layer 1. In addition, the backwater side gravel layer 4 is covered on the side of the clay anti-seepage layer 8 away from the intercepting dike 10. The method of constructing gravel on the backwater side of the block stone layer 5 is replaced by a method of intercalating clay in the middle, that is, clay is used to fill the intercepting groove 9 and the back side of the intercepting dike 10, which can greatly reduce the permeability of the entire weir foundation (the lower part of the intercepting dike 10) and even the weir body (the upper part of the intercepting dike 10), ensuring better anti-seepage performance.

[0038] In this embodiment, the water-facing side of the intercepting dike 10 is away from the bedrock layer 1, that is, the upper side, and is inclined toward the water-retaining side of the intercepting dike 10. The water-retaining side of the intercepting dike 10 is away from the bedrock layer 1, that is, the upper side, and is inclined toward the water-facing side of the intercepting dike 10, which means that the cross-sectional shape of the entire intercepting dike 10 is wide at the bottom and narrow at the top, especially in the shape of a trapezoid, which can better highlight the appearance and high anti-seepage performance of the intercepting dike 10 (it is thicker below the liquid level and has a better anti-seepage effect). Among them, the slope ratio of the water-facing side of the intercepting dike 10 is in the range of 1:1 to 2.5, and is preferably 1:1.175 in this embodiment, and the slope ratio of the water-retaining side of the intercepting dike 10 is in the range of 1:1 to 2.5, and is preferably 1:1.175 in this embodiment. The anti-seepage cofferdam structure provided in this embodiment adopts a reverse clay inclined core wall as the core of the anti-seepage system. Compared with the existing high-pressure spray anti-seepage wall form, from the perspective of construction, it greatly shortens the construction time, reduces the construction difficulty, and also saves construction costs. In addition, by digging a water interception ditch 9 on the backwater side of the interception dike 10 and filling it with clay, the clay anti-seepage layer 8 covers the entire backwater side of the interception dike 10 from the bedrock layer 1 and extends to the top of the backwater side of the interception dike 10, which greatly improves the joint anti-seepage performance of the weir body, the weir foundation, and even the bedrock. At the same time, the interception dike 10 constructed with local materials is used as a part of the entire cofferdam structure, which not only saves construction costs, but also greatly reduces the cross-section of the cofferdam and the amount of earth and stone filling, and the cost is more economical.

[0039] In order to further enhance the anti-seepage performance of the top of the entire cofferdam structure, the intercepting dike 10 and the top of the clay anti-seepage layer 8 are covered with a gravel filling layer as an external protective layer for further anti-seepage and protection. Specifically, the gravel filling layer includes an upper gravel layer 6 for covering the top of the intercepting dike 10 and a top gravel layer 7 for covering the top of the clay anti-seepage layer 8, which means that the upper gravel layer 6 and the top gravel layer 7 are used to protect and prevent the intercepting dike 10 and the clay anti-seepage layer 8, respectively. In this embodiment, the upper surface of the top gravel layer 7 is flush with the upper surface of the block stone layer 5, which can ensure that the top of the entire cofferdam structure is flat and beautiful, and the anti-seepage effect is better; the upper surface of the upper gravel layer 6 is connected to the lower surface of the top gravel layer, which means that the upper gravel layer 6 is located between the top gravel layer 7 and the top of the intercepting dike 10, and mainly plays a filling and compacting role and an inner layer protection and anti-seepage role. In order to further enhance the cut-off and anti-seepage effect of the clay inclined core wall, the clay anti-seepage layer 8 is formed with an anti-seepage retaining tip 8c near the upper surface of the cutoff dike 10. The upper surface of the anti-seepage retaining tip 8c is connected to the lower surface of the top gravel layer 7, which means that the anti-seepage retaining tip 8c extends upward from the top of the clay anti-seepage layer 8 and contacts the lower surface of the top gravel layer 7, which can play a better anti-seepage effect on the weir body and weir base below the top gravel layer 7.

[0040] In order to make the cofferdam structure of this embodiment more beautiful in appearance and to ensure high anti-seepage performance under the premise of suitable material cost, the side of the block stone layer 5 away from the bedrock layer 1, that is, the upper side, is inclined toward the side of the backwater side gravel layer 4, and the slope ratio of the water-facing surface of the block stone layer 5 is in the range of 1:1 to 2.5, and the preferred embodiment is 1:1.175. Similarly, the side of the backwater side gravel layer 4 away from the bedrock layer 1, that is, the upper side, is inclined toward the block stone layer 5, and the slope ratio of the water-facing surface of the block stone layer 5 is in the range of 1:1 to 2.5, and the preferred embodiment is 1:1.175. The block stone layer 5 and the backwater side gravel layer 4 can be inclined at the same time, or one of them can be inclined separately. This external form of expression can not only conform to the appearance shape currently recognized by the cofferdam structure industry, but also can save a certain amount of material cost. Under the premise of ensuring that the lower the water level, the thicker the cofferdam structure, the better the anti-seepage effect and support strength.

[0041] In general, the cofferdam structure provided by this embodiment can use the interception dike 10 constructed on site as the base part under the same or even better anti-seepage effect, which can greatly reduce the cross-section and earth-rock filling volume of the cofferdam structure, and the cost is more economical. In addition, there is no need to construct a concrete anti-seepage wall inside, and a clay anti-seepage layer is used as the oblique core wall to play an anti-seepage role. Under the same construction conditions, it can ensure a shorter construction period, less construction cost, and the construction difficulty is also reduced.

[0042] Through effective control of the construction sequence, it is also possible to quickly fill the construction cofferdam and ensure the dry land construction of the riverbed foundation pit in time. To achieve this purpose, the present embodiment also provides a construction method of a reverse clay inclined core wall anti-seepage cofferdam structure, which mainly includes the following steps: constructing an intercepting dike 10 on the gravel cover layer 2 of the riverbed, and throwing stones on the water-facing surface of the intercepting dike 10 to form a stone layer 5; excavating a diversion ditch 9 at the place where the backwater surface of the intercepting dike 10 is connected to the gravel cover layer 2, and the bottom of the diversion ditch 9 is dug until it contacts the bedrock layer 1 of the riverbed, and the diversion ditch 9 is backfilled with anti-seepage clay in time; the backfilled anti-seepage clay is dug according to a preset slope ratio to form an anti-seepage clay layer 8, and the anti-seepage clay layer 8 is backfilled to at least cover the backwater surface of the intercepting dike 10, and gravel is covered on the backwater side of the anti-seepage clay layer 8 to at least cover the backwater side of the anti-seepage clay layer 8, that is, the backwater side gravel layer 4 is thrown and covered. When the main part of the cofferdam structure is completed, the top of the intercepting dike 10 and the anti-seepage clay layer 8 is filled with sand and gravel to the specified elevation, and then the block stones on the water-facing surface of the intercepting dike 10 are thrown to the specified elevation to complete the construction. The above construction method can achieve the construction of the cofferdam structure in an orderly and rapid manner. Compared with the existing cofferdam construction method, the construction period can be controlled to be shorter, especially the construction can be completed within one flood season.

[0043] See also Figure 3 to Figure 6 Specifically, the anti-seepage cofferdam structure of this embodiment is constructed, such as Figure 3 As shown, first, a dike 10 is built on the gravel cover layer 2 of the riverbed, and large stones are thrown on the water-facing surface of the dike 10 to form a protective anti-seepage layer on the water-facing surface. At this time, a gravel platform 11 is built on the back side of the dike 10, and the platform is filled to a certain height to meet the requirements of later construction. Figure 4 As shown, a water intercepting ditch 9 is excavated on the gravel platform 11, and the water intercepting ditch 9 is excavated to the bedrock layer 1 that contacts the riverbed, and clay 8a is backfilled in the water intercepting ditch 9 in time, and the clay 8a is backfilled to the elevation of the gravel platform 11. At this time, the original gravel platform 11 becomes a gravel filling platform 11a only on the back side of the water intercepting ditch 9, which is covered with clay 8a and serves as a post-positioning protection. Figure 5 As shown, the clay 8a below the height of the gravel platform 11 is excavated according to the preset slope ratio, and backfilled to the height of the gravel platform 11 after meeting the required body requirements. At this time, the clay 8a is excavated to cover the backwater side of the interception dike 10 and has a clay layer 8b with a certain slope ratio on the backwater side. The remaining space in the interception trough 9 is filled with backwater gravel 4a to the height of the gravel platform 11. Figure 6As shown, a designated elevation is preset, and the clay layer 8b is continuously filled to the designated elevation to form a clay anti-seepage layer 8 with an anti-seepage retaining tip, and then the backwater side gravel 4a is continuously filled to the designated high level to form a backwater side gravel layer 4. The clay anti-seepage layer 8 and the backwater side gravel layer 4 can be constructed simultaneously or separately. After the clay anti-seepage layer 8 and the backwater side gravel layer 4 are reduced in size and compacted, a gravel filling layer is constructed on the top and finally reaches the designated elevation, and then the large block stones on the water-facing surface are thrown and filled to the designated elevation to form a block stone layer 5 to complete the construction.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. It should be noted that the structures or components illustrated in the accompanying drawings are not necessarily drawn to scale, and the present invention omits the description of known components and processing technologies and processes to avoid unnecessary limitations on the present invention.

Claims

1. A reverse clay inclined core wall anti-seepage cofferdam structure, characterized in that: It comprises a gravel cover layer covering the bedrock layer, a dike formed of gravel is constructed on the gravel cover layer, a block stone layer for protection and anti-seepage is laid on the water-facing side of the dike, a dike connected to the bedrock layer is excavated on the gravel cover layer on the backwater side of the dike, the dike is opened along the edge of the foot of the dike, the backwater side of the dike is covered with a clay anti-seepage layer, the lower edge of the clay anti-seepage layer extends into the dike and contacts the bedrock layer, and the side of the clay anti-seepage layer away from the dike is covered with a backwater side gravel layer; The side of the water-facing surface of the intercepting dike away from the bedrock layer is inclined toward the side of the water-retaining surface of the intercepting dike, and the side of the water-retaining surface of the intercepting dike away from the bedrock layer is inclined toward the side of the water-facing surface of the intercepting dike; The intercepting dike and the top of the clay anti-seepage layer are covered with a sand and gravel filling layer.

2. The reverse clay inclined core wall anti-seepage cofferdam structure according to claim 1, characterized in that: The slope ratio of the water-facing surface of the intercepting dike is in the range of 1:1 to 2.5, and the slope ratio of the water-receiving surface of the intercepting dike is in the range of 1:1 to 2.

5.

3. The reverse clay inclined core wall anti-seepage cofferdam structure according to claim 1, characterized in that: The gravel filling layer includes an upper gravel layer for covering the top of the dike and a top gravel layer for covering the top of the clay impermeable layer. The upper surface of the top gravel layer is flush with the upper surface of the block stone layer, and the upper surface of the upper gravel layer is connected to the lower surface of the top gravel layer.

4. The reverse clay inclined core wall anti-seepage cofferdam structure according to claim 3 is characterized in that: The clay anti-seepage layer is formed with an anti-seepage retaining tip near the upper surface of the intercepting dike, and the upper surface of the anti-seepage retaining tip is connected to the lower surface of the top gravel layer.

5. The reverse clay inclined core wall anti-seepage cofferdam structure according to claim 1, characterized in that: The side of the block rock layer away from the bedrock layer is inclined toward the side of the backwater gravel layer, and the slope ratio of the water-facing surface of the block rock layer is in the range of 1:1 to 2.

5.

6. The reverse clay inclined core wall anti-seepage cofferdam structure according to claim 1 or 5, characterized in that: The side of the backwater gravel layer away from the bedrock layer is inclined toward the block rock layer, and the slope ratio of the water-facing surface of the block rock layer is in the range of 1:1 to 2.

5.

7. A construction method for a reverse clay inclined core wall anti-seepage cofferdam structure, characterized in that: The following steps are involved: A dike is constructed on the gravel cover layer of the riverbed, blocks of stone are dumped on the water-facing surface of the dike, and a diversion ditch is excavated at the place where the backwater surface of the dike meets the gravel cover layer. The bottom of the diversion ditch is excavated until it contacts the bedrock layer of the riverbed, and the diversion ditch is backfilled with anti-seepage clay in time; the backfilled anti-seepage clay is excavated according to a preset slope ratio to form an anti-seepage clay layer, and the anti-seepage clay layer is backfilled to at least cover the backwater surface of the dike, and gravel is covered on the backwater side of the anti-seepage clay layer to at least cover the backwater side of the anti-seepage clay layer.

8. The construction method according to claim 7, characterized in that: Gravel is filled on the top of the intercepting dike and the anti-seepage clay layer to a specified elevation, and rocks are thrown on the water-facing surface of the intercepting dike to the specified elevation.

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