Pile foundation structure for preventing and treating erosion of hot karst lake and construction method of pile foundation structure

Abstract

The invention relates to a pile foundation structure for preventing and controlling erosion of a hot karst lake, which comprises a pile foundation sequentially penetrating through a movable layer and a permafrost layer, and is characterized in that a water collecting and draining device is tightly attached to the ground surface and surrounds the pile foundation, and a power supply system and a control panel with a protective cover are arranged on one side of the top end of the pile foundation; a capillary water conveying layer is attached to the surface of the pile foundation located on the movable layer, one end of the capillary water conveying layer is arranged in the water collecting and draining device, and the other end of the capillary water conveying layer penetrates through the movable layer and is fixed through a hoop; a plurality of drainage holes are annularly distributed in the upper end surface of the water collecting and draining device; and the control panel is electrically connected with the power supply system. Meanwhile, the invention further discloses a construction method of the pile foundation structure. The device is simple in structure and high in practicability, water is prevented from making direct contact with the pile foundation, transfer of the water in the movable layer is achieved, therefore, prevention and treatment are combined, and the effect of treating both symptoms and root causes is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of prevention and control of diseases of pile foundations eroded by thermokarst lakes, and particularly relates to a pile foundation structure for preventing and controlling thermokarst lake erosion and a construction method thereof. Background Art

[0002] Under the influence of external disturbance factors, the thickness of the active layer increases in permafrost, and local melting occurs in the underground ice or ice-rich permafrost layer. The surface soil layer subsides accordingly, and the lake ponds formed after water accumulation are called thermokarst lakes. Thermokarst lakes are widely developed in the circum-Arctic region and high mountains in low latitudes. Under the background of global warming, with the accelerating degradation of permafrost, the number of thermokarst lakes increases and the area expands. The latest research data shows that there are more than 161,300 thermokarst lakes developed in the Qinghai-Tibet Plateau region, with an area exceeding 2,830 km 2 . In this scenario, the infrastructure built in permafrost areas is inevitably affected by thermokarst lakes. Especially for the pile foundation structures of highway or railway bridges, directly affected by the lateral expansion of thermokarst lakes, the pile body is eroded by the lake water for a long time, which will cause damage to the pile foundation and a decrease in bearing capacity, seriously affecting the operation safety of highways or railways. Therefore, it is of great practical significance to carry out research on the prevention and control technology of diseases of pile foundations eroded by thermokarst lakes.

[0003] The lateral expansion of thermokarst lakes will cause the underlying permafrost to melt, resulting in thaw settlement of the pile foundation. At the same time, the erosion of the lake water causes corrosion of the pile foundation structure. At present, for the prevention and control of diseases of pile foundations eroded by thermokarst lakes, it mainly relies on adding cofferdams around the pile foundation to prevent the lake water from contacting the pile body. However, the cofferdams set around the pile body can only prevent the surface lake water from directly contacting the pile foundation and cannot effectively isolate the moisture that penetrates to the periphery of the pile foundation through the active layer.

[0004] In actual engineering, there are still problems such as damage to the pile body caused by lake water erosion and induced decrease in the bearing capacity of the pile foundation. Therefore, there is an urgent need for a pile foundation structure for preventing and controlling thermokarst lake erosion, which can efficiently achieve the drainage of lake water, prevent the pile foundation structure from being eroded by lake water, and ensure the safety of the superstructure of the pile foundation. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a pile foundation structure for preventing and controlling thermokarst lake erosion with a simple structure and strong practicability.

[0006] Another technical problem to be solved by the present invention is to provide a construction method for the pile foundation structure for preventing and controlling thermokarst lake erosion.

[0007] To solve the above problems, a pile foundation structure for preventing and controlling the erosion of thermokarst lakes according to the present invention includes a pile foundation that sequentially penetrates through the active layer and the permafrost layer, and is characterized in that a drainage device is provided close to the ground surface and surrounding the pile foundation, and a power supply system and a control panel with a protective cover are provided on one side of the top end of the pile foundation; a capillary water conveyance layer is attached to the surface of the pile foundation in the active layer, one end of the capillary water conveyance layer is arranged inside the drainage device, and the other end passes through the active layer and is fixed by a clamp; a plurality of drainage holes are annularly arranged on the upper end surface of the drainage device; the control panel is electrically connected to the power supply system.

[0008] The inner diameter of the drainage device is equal to the body diameter of the pile foundation.

[0009] The drainage device is of an annular structure and includes a U-shaped frame and an inclined surface connected together; one end of the inclined surface is connected to the side wall of the pile foundation, and the other end is connected to the top end I of the U-shaped frame; a plurality of the drainage holes are annularly arranged on the inclined surface; the control panel is provided on the pile foundation at the top of the inclined surface; the top end II of the U-shaped frame is connected to the outer edge of the top of the capillary layer in the capillary water conveyance layer; a fogging pool is arranged in the inner cavity of the U-shaped frame, and a floating atomizer is arranged in the fogging pool; one end of the floating atomizer is connected with a swing arm, and the swing arm is connected to a swing arm bracket fixed inside the fogging pool through a rotating shaft; a blower is arranged in the outer cavity of the fogging pool, and the blower and the floating atomizer are respectively connected to the control panel through power supply wires.

[0010] The drainage holes are arranged on the inclined surface close to the top end I, and the diameter of the drainage holes is 5 to 8 cm.

[0011] The power supply system is arranged at a position 1 to 2 meters below the top of the pile foundation and is composed of a solar or wind power generation device.

[0012] The capillary water conveyance layer is composed of a waterproof layer and a capillary layer in a Γ shape; the waterproof layer is composed of an inclined surface body and a vertical body connected together; the top of the inclined surface body is hermetically connected to the inner surface of the inclined surface in the drainage device; the inner side of the vertical body is attached to the surface of the pile foundation, and the capillary layer is arranged on the outer side; the bottom of the vertical body and the capillary layer are fixed by a clamp in a ┛ shape; the top of the capillary layer extends along the side wall of the fogging pool to the fogging pool in the drainage device.

[0013] The clamp is arranged at the junction of the active layer and the permafrost layer, and its inner diameter is equal to the outer diameter of the pile foundation.

[0014] A construction method for the pile foundation structure for preventing and controlling the erosion of thermokarst lakes as described above includes the following steps: ⑴ After leveling the construction site, determine the design position of the pile foundation in the site, excavate the pile hole to the design elevation, and determine the thickness of the active layer based on the survey data and the geological conditions during the pile hole excavation; (2) Carry out steel cage binding operation, lay capillary water transmission layer in the section where steel cage passes through the active layer, fix one end of the capillary water transmission layer with clamps at the same depth of the active layer and steel cage, embed the power supply system bracket 1~2 meters below the top of the pile foundation, embed the components of the fixed drainage device 0.5~0.8 meters above the junction of the steel cage and the ground, and hoist the bound steel cage into the pile hole; ⑶ After the steel cage hoisting operation is completed, concrete pouring is carried out, and the capillary water transport layer is ensured to be in a taut state during pouring; (4) According to the size of the pile foundation, the drainage device is prefabricated and assembled in the component factory, and then the assembled drainage device is hoisted and nested with the pile foundation and fixed, the outer edge of the capillary layer is placed in the atomization pool through the drainage hole, and the waterproof layer is sealed and connected with the inclined inner wall of the drainage device; ⑸Fix the power supply system on the pre-buried bracket and connect the power supply system to the control panel using the power supply line; ⑹After all components are installed, debug the entire system to ensure that the capillary layer and atomizer are working normally before completing the construction.

[0015] Compared with the prior art, the present invention has the following advantages: 1. The present invention isolates the moisture on the pile side in the active layer from direct contact with the pile body by means of a waterproof layer attached to the side wall of the pile foundation. At the same time, the moisture on the pile side is transferred to the drainage device by means of a capillary layer, and then the liquid water is atomized by a floating atomizer and discharged into the atmosphere, thereby effectively preventing the erosion of the pile foundation by the penetration of moisture from the thermal karst lake.

[0016] The overall size of the drainage device in the present invention is larger than the pile base body, and when the pile foundation melts and sinks and moves downward, it can withstand shear force and play a certain role in preventing melting and sinking.

[0017] 3. The present invention has a simple structure and strong practicability, and realizes the transfer of moisture in the active layer, thereby realizing the combination of prevention and treatment, and achieving the effect of treating both the symptoms and the root causes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0019] Figure 1 This is a cross-sectional view of a pile foundation structure for preventing and controlling erosion of a thermal karst lake according to the present invention.

[0020] Figure 2 It is a schematic diagram of the drainage device in the present invention.

[0021] Figure 3Schematic diagram of the connection relationship between the atomization pond and the floating atomizer in the present invention.

[0022] Figure 4 Axonometric view of the pile foundation structure for preventing and controlling the erosion of thermokarst lakes in the present invention.

[0023] In the figure: 1 - active layer, 2 - permafrost layer, 3 - pile foundation, 4 - drainage and water collection device, 5 - power supply system, 6 - capillary water conveyance layer, 7 - waterproof layer, 8 - capillary layer, 9 - clamp, 10 - drainage hole, 11 - power supply line, 12 - atomization pond, 13 - floating atomizer, 14 - fan, 15 - control panel, 16 - swing arm, 17 - rotating shaft, 18 - swing arm support. Detailed implementation manners

[0024] As Figures 1 to 4 shown, a pile foundation structure for preventing and controlling the erosion of thermokarst lakes includes a pile foundation 3 that sequentially penetrates through the active layer 1 and the permafrost layer 2. A drainage and water collection device 4 is closely arranged on the ground surface and surrounds the pile foundation 3. One side of the top end of the pile foundation 3 is provided with a power supply system 5 and a control panel 15 with a protective cover; a capillary water conveyance layer 6 is attached to the surface of the pile foundation 3 in the active layer 1. One end of the capillary water conveyance layer 6 is arranged inside the drainage and water collection device 4, and the other end passes through the active layer 1 and is fixed by a clamp 9; several drainage holes 10 are annularly arranged on the upper end surface of the drainage and water collection device 4; the control panel 15 is electrically connected to the power supply system 5.

[0025] Among them: the inner diameter of the drainage and water collection device 4 is equal to the body diameter of the pile foundation 3.

[0026] The drainage and water collection device 4 is of an annular structure and includes a U-shaped frame and an inclined surface connected together; one end of the inclined surface is connected to the side wall of the pile foundation 3, and the other end is connected to the top end Ⅰ of the U-shaped frame; several drainage holes 10 are annularly arranged on the inclined surface; a control panel 15 is arranged on the pile foundation 3 at the top of the inclined surface; the top end Ⅱ of the U-shaped frame is connected to the outer edge of the top of the capillary layer 8 in the capillary water conveyance layer 6; an atomization pond 12 is arranged in the inner cavity of the U-shaped frame, and a floating atomizer 13 is arranged in the atomization pond 12; one end of the floating atomizer 13 is connected to a swing arm 16, and the swing arm 16 is connected to a swing arm support 18 fixed inside the atomization pond 12 through a rotating shaft 17; a fan 14 is arranged in the outer cavity of the atomization pond 12, and the fan 14 and the floating atomizer 13 are respectively connected to the control panel 15 through a power supply line 11.

[0027] The drainage holes 10 are arranged on the inclined surface near the top end Ⅰ, and the diameter of the drainage holes 10 is 5 - 8 cm, aiming to facilitate the installation of the waterproof layer 7 and the capillary layer 8 through the drainage holes 10.

[0028] The power supply system 5 is arranged at a position 1 - 2 m downward from the top of the pile foundation 3, and it is composed of a solar or wind power generation device.

[0029] The capillary water transport layer 6 is composed of a waterproof layer 7 and a capillary layer 8 in a Г shape; the waterproof layer 7 is composed of an inclined body and a vertical body connected as one; the top of the inclined body is sealed with the inner surface of the inclined surface in the drainage device 4; the inner side of the vertical body is in contact with the surface of the pile foundation 3, and a capillary layer 8 is provided on the outer side; the bottom of the vertical body and the capillary layer 8 are fixed by a ┛-shaped clamp 9; the top of the capillary layer 8 extends along the side wall of the atomization pool 12 to the atomization pool 12 of the drainage device 4.

[0030] The waterproof layer 7 is a PVC waterproof coil with good ductility. The capillary layer 8 is a fiber cotton cloth with good water absorption capacity. The floating atomizer 13 is composed of a piezoelectric ceramic sheet embedded in an annular plastic cavity, which is made by using the principle that the piezoelectric ceramic sheet, the core component of a conventional humidifier, can atomize liquid water.

[0031] The clamp 9 is made of an annular stainless steel material and is disposed at the junction of the active layer 1 and the permafrost layer 2 . The inner diameter of the clamp 9 is equal to the outer diameter of the pile foundation 3 .

[0032] Working principle of the present invention: The waterproof layer 7 arranged on the pile side isolates the moisture from direct contact with the pile foundation 3, and the capillary layer 8 realizes the transfer of moisture in the active layer 1, thereby realizing the combination of "prevention" and "treatment" and achieving the effect of treating both the symptoms and the root causes. The specific working principle is: when the hot karst lake located near the pile foundation 3 gradually expands, the lake water penetrates through the active layer 1 and contacts the capillary water transport layer 6, the moisture in the active layer 1 migrates upward through the capillary layer 8 to reach the atomization pool 12; the floating atomizer 13 is always in contact with the water level in the atomization pool 12, the control panel 15 issues a command, and the power supply system 5 provides power for the floating atomizer 13, vaporizes the liquid water in the atomization pool 12, and discharges the water vapor with the help of the fan 14.

[0033] A construction method of a pile foundation structure for preventing and controlling erosion of a thermal karst lake comprises the following steps: (1) After leveling the construction site, determine the design position of the pile foundation 3 in the site, excavate the pile hole to the design elevation, and determine the thickness of the active layer 1 based on the survey data and the geological conditions during the pile hole excavation; (2) Carry out steel cage binding operation, lay capillary water transport layer 6 in the section where the steel cage passes through the active layer 1, fix one end of the capillary water transport layer 6 with clamp 9 at the same depth as the active layer 1 and the steel cage, pre-embed the power supply system 5 bracket 1~2 meters below the top of the pile foundation 3, pre-embed the components of the fixed drainage device 4 0.5~0.8 meters above the junction of the steel cage and the ground surface, and hoist the tied steel cage into the pile hole; ⑶ After the steel cage hoisting operation is completed, concrete pouring is carried out, and during pouring, the capillary water transport layer 6 is ensured to be in a taut state; ⑷ According to the size of the pile foundation 3, prefabricate and assemble the drainage device 4 in the component factory, then hoist the assembled drainage device 4 and nest it with the pile foundation 3 and fix it. Place the outer edge of the capillary layer 8 in the atomization pool 12 through the drainage hole 10, and seal and connect the waterproof layer 7 with the inclined inner wall of the drainage device 4; ⑸ Fix and install the power supply system 5 on the embedded bracket, and connect the power supply system 5 with the control panel 15 using the power supply wire 11; ⑹ After all components are installed, debug the entire system. After ensuring that the capillary layer 8 and the atomizer 13 work properly, the construction is completed.

Claims

1. A pile foundation structure for preventing and controlling the erosion of thermokarst lakes, comprising a pile foundation (3) sequentially passing through an active layer (1) and a permafrost layer (2), characterized in that: A drainage device (4) is provided closely adjacent to the ground surface and surrounding the pile foundation (3). On one side of the top end of the pile foundation (3), a power supply system (5) and a control panel (15) with a protective cover are provided; on the surface of the pile foundation (3) in the active layer (1), a capillary water conveyance layer (6) is attached. One end of the capillary water conveyance layer (6) is arranged inside the drainage device (4), and the other end passes through the active layer (1) and is fixed by a clamp (9); on the upper end surface of the drainage device (4), several drainage holes (10) are annularly arranged; the control panel (15) is electrically connected to the power supply system (5).

2. The pile foundation structure for preventing and controlling the erosion of thermokarst lakes according to claim 1, characterized in that: The inner diameter of the drainage device (4) is equal to the body diameter of the pile foundation (3).

3. A pile foundation structure for preventing and controlling the erosion of thermokarst lakes according to claim 2, characterized in that: The drainage device (4) is of an annular structure, including a U-shaped frame and an inclined surface connected together; one end of the inclined surface is connected to the side wall of the pile foundation (3), and the other end is connected to the top end I of the U-shaped frame; several drainage holes (10) are annularly arranged on the inclined surface; on the pile foundation (3) at the top of the inclined surface, the control panel (15) is provided; the top end II of the U-shaped frame is connected to the outer edge of the top of the capillary layer (8) in the capillary water conveyance layer (6); an atomization pool (12) is arranged in the inner cavity of the U-shaped frame, and a floating atomizer (13) is arranged in the atomization pool (12); one end of the floating atomizer (13) is connected with a swing arm (16), and the swing arm (16) is connected to a swing arm bracket (18) fixed inside the atomization pool (12) through a rotating shaft (17); a blower (14) is arranged in the outer cavity of the atomization pool (12), and the blower (14) and the floating atomizer (13) are respectively connected to the control panel (15) through a power supply wire (11).

4. A pile foundation structure for preventing and controlling the erosion of thermokarst lakes according to claim 3, characterized in that: The drainage holes (10) are arranged on the inclined surface near the top end I, and the diameter of the drainage holes (10) is 5 to 8 cm.

5. A pile foundation structure for preventing and controlling the erosion of thermokarst lakes according to claim 1, characterized in that: The power supply system (5) is arranged at a position 1 to 2 meters below the top of the pile foundation (3), and it is composed of a solar or wind power generation device.

6. The pile foundation structure for preventing and controlling the erosion of thermokarst lakes according to claim 1, characterized in that: The capillary water conveyance layer (6) is composed of a waterproof layer (7) and a Г-shaped capillary layer (8); the waterproof layer (7) is composed of an inclined body and a vertical body connected together; the top of the inclined body is hermetically connected to the inner surface of the inclined surface in the drainage device (4); the inner side of the vertical body is attached to the surface of the pile foundation (3), and the capillary layer (8) is arranged on the outer side; the bottom of the vertical body and the capillary layer (8) are fixed by a ┛-shaped clamp (9); the top of the capillary layer (8) extends along the side wall of the atomization pool (12) into the atomization pool (12) of the drainage device (4).

7. A pile foundation structure for preventing and controlling the erosion of thermokarst lakes according to claim 1, characterized in that: The clamp (9) is arranged at the junction of the active layer (1) and the permafrost layer (2), and its inner diameter is equal to the outer diameter of the pile foundation (3).

8. The construction method of a pile foundation structure for preventing the erosion of thermokarst lakes according to claim 1, comprising the following steps: ⑴ After leveling the construction site, determine the designed position of the pile foundation (3) in the site, excavate the pile hole to the designed elevation, and determine the thickness of the active layer (1) based on the exploration data and the geological conditions during the pile hole excavation. (2) Carry out steel cage binding operation, lay a capillary water transport layer (6) in the section where the steel cage passes through the active layer (1), fix one end of the capillary water transport layer (6) by using a clamp (9) at a position where the active layer (1) and the steel cage are at the same depth, pre-embed a power supply system (5) bracket 1 to 2 meters below the top of the pile foundation (3), pre-embed a component of a fixed drainage device (4) 0.5 to 0.8 meters above the junction of the steel cage and the ground surface, and hoist the bound steel cage into the pile hole; (3) After the steel cage is hoisted, concrete is poured, and during the pouring, the capillary water transport layer (6) is ensured to be in a taut state; (4) Prefabricate and assemble the drainage device (4) in a component factory according to the size of the pile foundation (3), then hoist the assembled drainage device (4) to be nested with the pile foundation (3) and fixed, place the outer edge of the capillary layer (8) in the atomization pool (12) through the drainage hole (10), and seal the waterproof layer (7) to the inclined inner wall of the drainage device (4); (5) The power supply system (5) is fixedly mounted on the pre-buried bracket, and the power supply system (5) is connected to the control panel (15) using the power supply line (11); (6) After all components are installed, the entire system is debugged to ensure that the capillary layer (8) and the atomizer (13) are working properly, and then the construction is completed.

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