A recyclable drainage structure and construction method in soft foundation soil

Abstract

The present invention aims to provide a drainage structure and construction method that can be recovered in soft foundation soil, which can reduce construction costs, avoid long-term post-construction settlement caused by retaining drainage structures, and reduce environmental pollution. The present invention includes a structural main body, a cap, and a first geotextile. The structural main body is buried in the soil and forms a drainage channel during the drainage consolidation process. The cap is provided to provide a connection for recovery of the structural main body, while ensuring that the drainage efficiency is not affected. The first geotextile ensures that the drainage channel is unobstructed during the construction process, and isolates the soil from the structural main body during recovery. At the same time, a gap is formed between the first geotextile and the structural main body by using a filler of pressurized gas or fluid to reduce damage to the structural main body during recovery, thereby realizing the recovery of the drainage structure, reducing construction costs and environmental pollution, and avoiding long-term post-construction settlement caused by retaining the drainage structure. The present invention is applied to the technical field of foundation treatment in geotechnical engineering.

Description

Technical Field

[0001] The present invention is applied to the technical field of foundation treatment in geotechnical engineering, and particularly relates to a recyclable drainage structure in soft foundation soil and a construction method. Background Art

[0002] Soft clay soils are common in coastal areas, deltas and inland lakes, with characteristics such as high water content, low strength and lack of solidity. Engineering construction in these areas usually requires drainage and consolidation of the soft foundation soil by vacuum preloading to avoid or reduce ground settlement and uneven settlement after construction, and to improve the bearing capacity of the foundation. In the drainage consolidation method, the vertical drainage channels buried in the foundation soil are usually plastic drainage boards or bagged sand wells. The plastic drainage boards or bagged sand wells invested cannot be recycled, which increases the construction cost. Plastic drainage boards are harmful substances that are difficult to decompose. Their long-term burial in the foundation soil is undoubtedly a long-term pollution to the environment. In addition, since the plastic drainage boards or bagged sand wells remain in the foundation soil for a long time, the drainage channels that remain for a long time after construction will still undergo consolidation, which will lead to continuous post-construction settlement and affect the post-construction use effect.

[0003] For example, the Chinese patent with publication number CN114215040A discloses a method for vacuum preloading construction of soft foundation in coastal areas. Through vacuum preloading, under the action of vacuum negative pressure, a pressure difference is formed between the soil body, the drainage channel and the cushion layer. Under the action of the pressure difference, the pore water in the soil body is continuously discharged from the drainage channel, so that the soil body is consolidated; and mud is used as a curing agent to force the soft soil and the curing agent to be stirred deep in the foundation. A series of physical and chemical reactions between the curing agent and the soft soil are used to harden the soft soil into a high-quality foundation with integrity, water stability and a certain strength, so that the soft soil foundation can reach the designed bearing capacity faster. However, the plastic drain board in this scheme is buried in the foundation soil and is not taken out. On the one hand, leaving the plastic will cause long-term pollution to the environment and increase the cost; on the other hand, because the plastic drain board is left in the foundation soil, when the use load occurs, the drainage channel formed by the plastic drain board will still undergo consolidation, which will lead to post-construction settlement and uneven settlement caused by the uneven use load. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a recyclable drainage structure and construction method in soft foundation soil that reduces construction costs, avoids long-term post-construction settlement caused by retaining a drainage structure, and reduces environmental pollution.

[0005] The technical solution adopted by the present invention is: the recyclable drainage structure in the soft foundation soil includes a structural body, a cap and a first geotextile, the outer surface array of the structural body is provided with a plurality of convex tooth structures, the convex tooth structures are arranged parallel to the length direction of the structural body, and a drainage channel groove is formed between two adjacent convex tooth structures, the top of the structural body is provided with a plurality of first connecting holes, the plurality of first connecting holes are arrayed on the convex tooth structures, the cap is provided with profiling grooves adapted to the plurality of convex tooth structures and the plurality of drainage channel grooves, the profiling groove is correspondingly provided with a plurality of second connecting holes matched with the plurality of first connecting holes, the top of the cap is provided with a lifting hole, and the first geotextile is rolled around the lower circumference of the structural body.

[0006] It can be seen from the above scheme that the drainage channel groove is formed by the cooperation of the several convex tooth structures arranged on the main body of the structure, thereby further increasing the contact area and improving the water diversion efficiency on the basis of the conventional drainage board. At the same time, the convex tooth structure provides sufficient connection thickness, and the first connection hole is arranged on the convex tooth structure to ensure reliable connection during recycling and improve the connection strength. The cap is connected to the main body of the structure through the second connection hole and the bolt, thereby completing the sleeve connection during recycling, and at the same time ensuring that the drainage channel is not affected by the cap structure during the consolidation and drainage process, and the lifting hole is used to connect with the external lifting equipment. The first geotextile is used to isolate the main body of the structure from the soil, prevent the soil from sticking to the main body of the structure, ensure the smooth flow of the drainage channel, and reduce the resistance during recycling, so as to ensure smooth recycling. By setting the first geotextile and cooperating with the cap and the lifting equipment, the drainage structure is recycled, thereby avoiding the plastic structure being left in the soil to cause environmental pollution, and at the same time removing the continuous consolidation effect to avoid continuous post-construction settlement of the soil. Through the recyclable drainage structure, the production cost and construction cost can be reduced, the generation of construction waste can be reduced, and the environment can be protected.

[0007] A preferred solution is that the structural body is cylindrical, and a plurality of the convex tooth structures are distributed in a circular array on the outer surface of the structural body, each of the convex tooth structures is provided with at least two first connection holes, and the two first connection holes are distributed along a length direction parallel to the convex tooth structure.

[0008] It can be seen from the above scheme that the cylindrical drainage structure can further expand the contact area with the soil, thereby increasing the drainage speed and shortening the construction period. The two first connection holes provide connection fulcrums to ensure sufficient connection strength.

[0009] A preferred solution is that the bottom of the structural body is conical.

[0010] As can be seen from the above scheme, the conical bottom structure plays a guiding role in the process of inserting the structural main body, avoiding the situation of being stuck and unable to move during insertion. In addition, it plays a role in drainage and stability in the soil.

[0011] A preferred solution is that a hollow structure is provided in the cylinder of the structural main body, and the plurality of first connecting holes are all connected to the hollow structure.

[0012] It can be seen from the above solution that by providing the hollow structure, materials can be saved and the connection of bolts or latches can be facilitated.

[0013] A preferred solution is that the structural body is a long plate-shaped structure, and a plurality of the convex tooth structures are symmetrically distributed on the two wide surfaces of the structural body, each of the convex tooth structures is provided with at least two first connecting holes, and the first connecting holes on the two symmetrically distributed convex tooth structures are correspondingly connected.

[0014] As can be seen from the above scheme, the long plate-shaped structure is easy to process and has low cost. The plurality of convex tooth structures can provide a larger contact area and improve drainage efficiency. At the same time, the first connection holes of the two symmetrically distributed convex tooth structures are connected, thereby improving the structural strength of the connection position and ensuring the connection effect.

[0015] A preferred solution is that both side ends of the bottom of the structural body are provided with guiding inclined surfaces, and the ends of two groups of the guiding inclined surfaces are connected.

[0016] It can be seen from the above scheme that the cone is formed by the cooperation of the two guiding inclined surfaces, so that it plays a guiding role in the process of inserting the structural main body, avoiding the situation of being stuck and unable to move during the insertion.

[0017] The soft foundation soil construction method comprises the following steps:

[0018] Step S1, drilling a drainage hole on the foundation soil that needs to be drained and consolidated by using an insertion device, and inserting the structural body covered with the first geotextile into the drainage hole by using the insertion device, and removing the insertion device after the insertion is completed;

[0019] Step S2, laying a drainage sand cushion layer on the foundation soil in the area centered on the drainage hole, and setting a water filter pipe in the drainage sand cushion layer, and marking the position of the drainage hole;

[0020] Step S3, excavating the surrounding edges of the foundation soil in the area where the drainage sand cushion layer is laid to set up a sealing wall, and at the same time opening a laying channel for setting up a sealing membrane, laying the second geotextile and the multi-layer sealing membrane in the opened laying channel in sequence, checking and repairing the leaks when laying each layer of the sealing membrane, and then sealing the regional foundation soil, and filling the laying channel after the laying is completed;

[0021] Step S4, connecting the film outlet elbow pipe to the water filter pipe, and performing sealing treatment between the film outlet elbow pipe and the sealing film;

[0022] Step S5, connecting the film outlet elbow to the vacuum jet pump, detecting the sealing status of each location and the connection sealing, and then starting the vacuum jet pump to evacuate the water, so that the water in the foundation soil passes along the main structure and is extracted through the water filter pipe, thereby achieving drainage and consolidation of the foundation soil;

[0023] Step S6, after the drainage and consolidation are completed, the top cover of the structural main body is removed according to the marked position in step S2, and after the removal is completed, the first geotextile tightly attached to the surface of the structural main body during the vacuum preloading process is removed, so that a gap is generated between the first geotextile and the surface of the structural main body;

[0024] Step S7, after the first geotextile is removed, the cap is connected to the structural body through a plurality of connecting bolts, and the connecting bolts are matched with the second connecting hole and the first connecting hole in sequence;

[0025] Step S8, after the connection between the cap and the main structure is completed, the movable part of the insertion device is connected to the lifting hole, and the cap and the main structure are pulled out, and then the cavity in the first geotextile is backfilled with dense clay soil;

[0026] Step S9, completing the drainage and consolidation of the foundation soil and recovering the recyclable drainage structure in the soft foundation soil.

[0027] It can be seen from the above scheme that during the laying of the drainage structure, a drainage hole is first opened through the insertion device to provide a storage space for the drainage structure. On the one hand, it can ensure that the drainage structure does not rub against the soil during the placement process, thereby reducing the wear on the drainage structure; on the other hand, it can ensure that the first geotextile can be covered on the outer wall of the structural body and will not separate during the placement process, thereby ensuring that the structural body can be quickly separated and recovered later. Then, the drainage consolidation operation is completed through sealing and vacuum drainage, thereby condensing the soil to increase the bearing capacity. By removing the first geotextile, a gap is generated between the first geotextile and the structural body, thereby reducing the friction between the structural body and the first geotextile, achieving rapid recovery while reducing damage to the structural body. The movable part of the insertion device is connected to the lifting hole, so that the structural body can be pulled out of the first geotextile through the cap to complete the recovery of the structural body. The cavity in the first geotextile is backfilled with dense clay soil to ensure the continuity and stability of the soil structure, while avoiding the continuous consolidation effect of the filling of the sand and gravel structure, thereby avoiding the continuous post-construction settlement.

[0028] A preferred solution is that the insertion equipment in step S1 includes a moving device, a power head and a steel pipe, the power head is suspended on the moving device and connected to a driving source on the moving device, the steel pipe is connected to the power head, a conical hinge mechanism is provided at the bottom of the steel pipe, and an insertion port is provided at the top of the steel pipe.

[0029] As can be seen from the above scheme, the main body of the insertion device is a pile driving device commonly used in construction. Through the conical loose-leaf structure and the insertion port, the drainage structure is inserted into the drainage hole after the drainage hole is punched. The drainage structure is placed into the cavity in the steel pipe through the insertion port. The conical loose-leaf structure is used to push away the soil and finally open a reserved channel to leave the drainage structure in the soil.

[0030] A preferred solution is that the removal of the first geotextile in step S6 includes the following specific steps:

[0031] Step S6.1, removing the top cover of the structural body to expose the top of the first geotextile, fixing the top periphery of the first geotextile by a fixing structure, so that the top of the first geotextile is pressed against the surface of the structural body;

[0032] Step S6.2, connect the pressurizing equipment to the external atmosphere or lubricating foam storage container, and connect the output interface of the pressurizing equipment to the top of the first geotextile, start the pressurizing equipment and inject air or lubricating foam into the space between the first geotextile and the main structure, thereby creating a gap between the first geotextile and the main structure, and completing the removal of the first geotextile.

[0033] As can be seen from the above scheme, the fixed structure is a rope, which is used to tie the edge of the first geotextile to the main structure, so that the main structure and the first geotextile are relatively sealed, and the sealing of the surrounding side of the first geotextile is achieved by wrapping the consolidated and drained soil outside the first geotextile. Air or lubricating foam is injected into the space between the first geotextile and the main structure through the pressurizing equipment, thereby opening a gap, so that the main structure can be quickly pulled out, while reducing the wear of the main structure. Among them, lubricating foam is a better choice for stamping. On the one hand, there is more air in the foam, which makes it easier to open the gap. At the same time, the lubricating foam itself has lubricity, which can improve the smoothness and reduce wear during the subsequent extraction of the main structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the three-dimensional structure of the recyclable drainage structure in the soft foundation soil described in the first embodiment;

[0035] Figure 2 It is a first decomposed structural schematic diagram of the recyclable drainage structure in the soft foundation soil described in the first embodiment;

[0036] Figure 3 It is a second decomposed structural schematic diagram of the recyclable drainage structure in the soft foundation soil described in the first embodiment;

[0037] Figure 4 is a schematic diagram of a first three-dimensional structure of the cap in the first embodiment;

[0038] Figure 5 is a schematic diagram of a second three-dimensional structure of the cap in the first embodiment;

[0039] Figure 6 is a structural schematic diagram of the plug-in device;

[0040] Figure 7 It is a schematic diagram of the three-dimensional structure of the recyclable drainage structure in the soft foundation soil described in the second embodiment;

[0041] Figure 8 It is a first decomposed structural schematic diagram of the recyclable drainage structure in the soft foundation soil described in the second embodiment;

[0042] Fig. 9It is a second decomposed structural schematic diagram of the recyclable drainage structure in the soft foundation soil described in the second embodiment;

[0043] Fig.10 It is a schematic diagram of the three-dimensional structure of the cap in the second embodiment. DETAILED DESCRIPTION Example

[0044] like Figures 1 to 5 As shown, in this embodiment, the recyclable drainage structure in the soft foundation soil includes a structural body 1, a cap 2 and a first geotextile 3. The outer surface of the structural body 1 is arrayed with a plurality of convex tooth structures 4, and the convex tooth structures 4 are arranged parallel to the length direction of the structural body 1. A drainage channel groove 5 is formed between two adjacent convex tooth structures 4. The top of the structural body 1 is provided with a plurality of first connecting holes 6, and the plurality of first connecting holes 6 are arrayed on the convex tooth structures 4. The cap 2 is provided with profiling grooves 7 matched with the plurality of convex tooth structures 4 and the plurality of drainage channel grooves 5, and the profiling grooves 7 are correspondingly provided with a plurality of second connecting holes 8 matched with the plurality of first connecting holes 6. The top of the cap 2 is provided with a lifting hole 9, and the first geotextile 3 is covered on the lower circumference of the structural body 1.

[0045] In this embodiment, the structural body 1 is cylindrical, and the plurality of convex tooth structures 4 are distributed in a circumferential array on the outer surface of the structural body 1. Two first connection holes 6 are provided on each convex tooth structure 4, and the two first connection holes 6 are distributed along a length direction parallel to the convex tooth structure 4. The bottom of the structural body 1 is conical. A hollow structure is provided in the cylinder of the structural body 1, and the plurality of first connection holes 6 are all connected to the hollow structure.

[0046] In this embodiment, the length of the structural body 1 is 100 to 250 cm, and the length of the structural body 1 is adaptively adjusted according to the depth of the soft foundation treatment. The diameter of the structural body 1 is 10 cm, the thickness from the outer surface of the convex tooth structure 4 to the inner diameter of the structural body 1 is 2 cm, and the thickness from the bottom surface of the drainage channel groove 5 to the inner diameter of the structural body 1 is 1 cm.

[0047] The soft foundation soil construction method comprises the following steps:

[0048] Step S1, drilling a drainage hole on the foundation soil that needs to be drained and consolidated by using the insertion device 11, and inserting the structural body 1 covered with the first geotextile 3 into the drainage hole by using the insertion device 11, and removing the insertion device 11 after the insertion is completed;

[0049] Step S2, laying a drainage sand cushion layer on the foundation soil in the area centered on the drainage hole, and setting a water filter pipe in the drainage sand cushion layer, and marking the position of the drainage hole;

[0050] Step S3, excavating the surrounding edges of the foundation soil in the area where the drainage sand cushion layer is laid to set up a sealing wall, and at the same time opening a laying channel for setting up a sealing membrane, laying the second geotextile and the multi-layer sealing membrane in the opened laying channel in sequence, checking and repairing the leaks when laying each layer of the sealing membrane, and then sealing the regional foundation soil, and filling the laying channel after the laying is completed;

[0051] Step S4, connecting the film outlet elbow pipe to the water filter pipe, and performing sealing treatment between the film outlet elbow pipe and the sealing film;

[0052] Step S5, connecting the film outlet elbow to the vacuum jet pump, detecting the sealing status of each part and the connection sealing, and then starting the vacuum jet pump to evacuate the water, so that the water in the foundation soil passes along the structural body 1 and is extracted through the water filter pipe, thereby achieving drainage and consolidation of the foundation soil;

[0053] Step S6, after the drainage and consolidation are completed, the top cover of the structural main body 1 is removed according to the marked position in step S2, and after the removal is completed, the first geotextile 3 tightly attached to the surface of the structural main body 1 during the vacuum preloading process is removed, so that a gap is generated between the first geotextile 3 and the surface of the structural main body 1;

[0054] Step S7, after the first geotextile 3 is removed, the cap 2 is connected to the structural body 1 through a plurality of connecting bolts 12, and the connecting bolts 12 are matched with the second connecting holes 8 and the first connecting holes 6 in sequence;

[0055] Step S8, after the connection between the cap 2 and the structural body 1 is completed, the movable part of the insertion device 11 is connected to the lifting hole 9, and the cap 2 and the structural body 1 are driven to be pulled out, and then the cavity in the first geotextile 3 is backfilled with dense clay soil;

[0056] Step S9, completing the drainage consolidation of the soft foundation soil and recovering the recyclable drainage structure in the soft foundation soil.

[0057] like Figure 6As shown, in step S1, the insertion device 11 includes a moving device 13, a power head 14 and a steel pipe 15. The power head 14 is suspended on the moving device 13 and connected to the driving source on the moving device 13. The steel pipe 15 is connected to the power head 14. A conical loose-leaf mechanism 16 is provided at the bottom of the steel pipe 15, and an insertion port 17 is provided at the top of the steel pipe 15. The conical loose-leaf mechanism 16 includes a plurality of groups of triangular loose-leafs and a transmission mechanism. The transmission mechanism is connected to the power source on the moving device 13. A plurality of groups of triangular loose-leafs are hingedly matched at the bottom of the steel pipe 15. A reset spring matched with the triangular loose-leafs is provided in the steel pipe 15. The transmission mechanism includes a push rod driving a plurality of triangular loose-leafs to expand outward. A guide plate matched with the structural main body 1 is provided in the steel pipe 15. The guide plate is located on the inner side of the conical loose-leaf mechanism 16, thereby preventing the structural main body 1 from interfering with the mechanical parts of the conical loose-leaf mechanism 16. The insertion port 17 includes a guide plate that is arranged obliquely to the length direction of the steel tube 15 , and the included angle between the guide plate and the axis of the steel tube 15 is 30 degrees to 60 degrees.

[0058] The removal of the first geotextile 3 in step S6 includes the following specific steps:

[0059] Step S6.1, removing the top cover of the structural body 1 to expose the top of the first geotextile 3, fixing the top periphery of the first geotextile 3 by a fixing structure so that the top of the first geotextile 3 is pressed against the surface of the structural body 1;

[0060] Step S6.2, connect the pressurizing equipment to the external atmosphere or lubricating foam storage container, and connect the output interface of the pressurizing equipment to the top of the first geotextile 3, start the pressurizing equipment and inject air or lubricating foam into the space between the first geotextile 3 and the structural body 1, thereby creating a gap between the first geotextile 3 and the structural body 1, and completing the removal of the first geotextile 3.

[0061] The pressurizing device is a gas booster pump or a liquid booster pump, which is inserted between the first geotextile 3 and the structural body 1 through a small pipe to inject air or lubricating foam. Example

[0062] like Figures 7 to 10As shown, the difference between this embodiment and the first embodiment is that: the structural body 1 is a long plate-shaped structure, a plurality of the convex tooth structures 4 are symmetrically distributed on the two wide faces of the structural body 1, each of the convex tooth structures 4 is provided with at least two first connection holes 6, and the first connection holes 6 on the two symmetrically distributed convex tooth structures 4 are correspondingly connected. Both side ends of the bottom of the structural body 1 are provided with guide slopes 10, and the ends of the two groups of the guide slopes 10 are connected.

[0063] In this embodiment, the length of the structural body 1 is 100 to 250 cm, the length of the structural body 1 is adaptively adjusted according to the depth of the soft foundation treatment, the width of the structural body 1 is 10 cm, the spacing between the outer surfaces of the two symmetrically distributed convex tooth structures 4 is 3 cm, and the spacing between the bottom surfaces of the two symmetrically distributed drainage channel grooves 5 is 1 cm.

Claims

1. A construction method for a recyclable drainage structure in soft foundation soil, the recyclable drainage structure in soft foundation soil comprising a structural body (1), a cap (2) and a first geotextile (3), the outer surface of the structural body (1) being provided with a plurality of convex tooth structures (4) in an array, the convex tooth structures (4) being arranged parallel to the length direction of the structural body (1), a drainage channel groove (5) being formed between two adjacent convex tooth structures (4), the top of the structural body (1) being provided with a plurality of first connection holes (6), the plurality of first connection holes (6) being distributed in an array on the convex tooth structures (4), the cap (2) being provided with contour grooves (7) adapted to the plurality of convex tooth structures (4) and the plurality of drainage channel grooves (5), the contour grooves (7) being provided in the interior of the cap (2), the contour grooves (7) being provided with a plurality of convex tooth structures (4) and the plurality of drainage channel grooves (5), ) are provided with a plurality of second connection holes (8) correspondingly connected to the plurality of first connection holes (6), the top of the sleeve cap (2) is provided with a lifting hole (9), and the first geotextile (3) is rolled up on the lower circumference of the structural body (1); the structural body (1) is cylindrical, and the plurality of convex tooth structures (4) are distributed in a circular array on the outer surface of the structural body (1), and each of the convex tooth structures (4) is provided with two first connection holes (6), and the two first connection holes (6) are distributed along the length direction parallel to the convex tooth structure (4); the bottom of the structural body (1) is conical; a hollow structure is provided in the cylinder of the structural body (1), and the plurality of first connection holes (6) are all connected to the hollow structure; it is characterized in that The construction method comprises the following steps: Step S1, using an insertion device (11) to drill a drainage hole on the foundation soil that needs to be drained and consolidated, and using the insertion device (11) to place the structural body (1) coated with the first geotextile (3) into the drainage hole, and after the placement is completed, the insertion device (11) is removed; Step S2, laying a drainage sand cushion layer on the foundation soil in the area centered on the drainage hole, and setting a water filter pipe in the drainage sand cushion layer, and marking the position of the drainage hole; Step S3, excavating the surrounding edges of the foundation soil in the area where the drainage sand cushion layer is laid to set up a sealing wall, and at the same time opening a laying channel for setting up a sealing membrane, laying the second geotextile and the multi-layer sealing membrane in the opened laying channel in sequence, checking and repairing the leaks when laying each layer of the sealing membrane, and then sealing the regional foundation soil, and filling the laying channel after the laying is completed; Step S4, connecting the film outlet elbow pipe to the water filter pipe, and performing sealing treatment between the film outlet elbow pipe and the sealing film; Step S5, connecting the film outlet elbow to the vacuum jet pump, detecting the sealing status of each location and the connection tightness, and then starting the vacuum jet pump to evacuate the water, so that the water in the foundation soil flows along the structural body (1) and is extracted through the water filter pipe, thereby achieving drainage and consolidation of the foundation soil; Step S6: after the drainage and consolidation are completed, the top covering of the structural main body (1) is removed according to the marked position in step S2, and after the removal is completed, the first geotextile (3) that is tightly attached to the surface of the structural main body (1) during the vacuum preloading process is removed, so that a gap is generated between the first geotextile (3) and the surface of the structural main body (1); Step S7, after the first geotextile (3) is removed, the cap (2) is connected to the structural body (1) via a plurality of connecting bolts (12), wherein the connecting bolts (12) are sequentially engaged with the second connecting holes (8) and the first connecting holes (6); Step S8, after the connection between the cap (2) and the main structure (1) is completed, the movable part of the insertion device (11) is connected to the lifting hole (9), and the cap (2) and the main structure (1) are driven to be pulled out, and then the cavity in the first geotextile (3) is backfilled with dense clay soil; Step S9, completing the drainage and consolidation of the foundation soil and recovering the recyclable drainage structure in the soft foundation soil; The removal of the first geotextile (3) in step S6 comprises the following specific steps: Step S6.1, removing the top covering of the structural main body (1) to expose the top of the first geotextile (3), fixing the top peripheral side of the first geotextile (3) by means of a fixing structure, so that the top of the first geotextile (3) is pressed against the surface of the structural main body (1); Step S6.2, connect the pressurizing device to the external atmosphere or the lubricating foam storage container, and connect the output interface of the pressurizing device to the top of the first geotextile (3), start the pressurizing device and inject air or lubricating foam into the space between the first geotextile (3) and the main structure (1), thereby creating a gap between the first geotextile (3) and the main structure (1), and completing the removal of the first geotextile (3).

2. The construction method according to claim 1, characterized in that: The insertion device (11) in step S1 comprises a moving device (13), a power head (14) and a steel pipe (15); the power head (14) is suspended on the moving device (13) and connected to a driving source on the moving device (13); the steel pipe (15) is connected to the power head (14); a conical hinge mechanism (16) is provided at the bottom of the steel pipe (15); and an insertion port (17) is provided at the top of the steel pipe (15).

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