High-water-level sandy silty soil texture deep foundation pit supporting structure and construction method thereof

Abstract

The invention provides a high-water-level sandy silty soil texture deep foundation pit supporting structure and a construction method thereof, and relates to the field of foundation pit supporting structures.The high-water-level sandy silty soil texture deep foundation pit supporting structure comprises a supporting plate assembly and a supporting reinforcing assembly, a water collecting cavity is formed in the supporting plate assembly, and a drainage assembly communicating with the exterior of the supporting plate assembly is arranged in the water collecting cavity; the surface of one side of the supporting plate assembly is covered with a filter screen, a water channel communicating with the water collecting cavity is formed in the surface of the side, close to the filter screen, of the supporting plate assembly, and the water channel stretches across the side surface of the supporting plate assembly; the supporting plate assembly is formed by splicing a plurality of first supporting plates and a plurality of second supporting plates, vertical clamping grooves are formed in the surfaces of the sides, away from the filter screen, of the second supporting plates, and the supporting and reinforcing assembly is connected with the second supporting plates in a clamped mode through the clamping grooves and can gradually descend along with excavation forming of the deep foundation pit. Construction safety is guaranteed through prefabrication, assembly, dynamic supporting and a drainage system, and efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of deep foundation pit support, and in particular relates to a high-water-level sandy silt soil deep foundation pit support structure and a construction method thereof. Background Art

[0002] A high-water-level sandy silt deep foundation pit refers to a deep foundation pit in a high-water-level (high groundwater level) environment, in which the soil layer is mainly composed of sand and silt; this type of foundation pit is usually used for infrastructure construction, such as foundation construction of buildings, bridges, tunnels, etc.; foundation pit support is a support, reinforcement and protection measure adopted for the side walls of the foundation pit and the surrounding environment to ensure the safety of underground structure construction and the surrounding environment of the foundation pit. Effective technical measures must be taken to ensure the stability of the foundation pit slope, groundwater pumping and drainage, and safe operation of construction machinery during the excavation of deep foundation pits to ensure the safety of construction personnel and construction machinery.

[0003] Due to the large pores between sand particles, sandy silt has good drainage. However, under high water level conditions, the soil is easily affected by water, and the strength of sandy silt in a wet state is low, making it easy to flow and be affected by water level changes, resulting in unstable foundation pits and affecting the construction workers and equipment inside. In addition, when the existing deep foundation pit support methods are used in high water level sandy silt geology, the sandy silt in a wet state will cause reduced operating efficiency and no safety guarantee. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a support structure for a deep foundation pit in sandy silt soil with high water level and a construction method thereof. By coordinating prefabricated support plate components with support reinforcement components that can be lowered with the excavation depth, and combining a drainage system consisting of a water collection chamber, a waterway and a filter screen, stable support and efficient drainage of a deep foundation pit in sandy silt soil with high water level can be achieved, thereby avoiding soil softening and collapse due to water infiltration. At the same time, standardized construction processes can be used to shorten the construction period and improve construction safety.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] Provided is a deep foundation pit support structure for high-water-level sandy silt soil, comprising: a support plate assembly and a support reinforcement assembly, wherein the support plate assembly is attached to the inner surface of the deep foundation pit and is supported and fixed by the support reinforcement assembly;

[0007] A water collecting chamber is provided inside the support plate assembly, and a drainage assembly connected to the outside of the support plate assembly is provided in the water collecting chamber. One side surface of the support plate assembly is covered with a filter screen, and a water channel connected to the water collecting chamber is provided on the side surface close to the filter screen, and the water channel is provided across the side surface of the support plate assembly; the support plate assembly is composed of a plurality of first support plates and a plurality of second support plates, and a vertical clamping groove is provided on the side surface of the second support plate away from the filter screen. The support reinforcement assembly is clamped with the second support plate through the clamping groove, and can gradually descend as the deep foundation pit is excavated and formed.

[0008] Preferably, the water channel is obliquely opened on the side surface of the supporting plate assembly, and the lowest end of the water channel is communicated with the water collecting chamber.

[0009] Preferably, the first supporting plate and the second supporting plate are both provided with corresponding numbers, and the numbers are arranged in sequence according to the drainage path from the waterway to the water collection chamber.

[0010] Preferably, at least one first supporting plate is spliced ​​between adjacent second supporting plates, and the water collection cavity is opened inside any first supporting plate, and water channels are opened on the first supporting plate and the second supporting plate without the water collection cavity, and the water channels of adjacent supporting plates are connected to each other.

[0011] Preferably, the drainage assembly includes a water inlet, a water pipe and an access port. The water inlet is arranged in the water collecting chamber. One end of the water pipe is connected to the water inlet, and the other end extends to the outside of the support plate assembly and is connected to the access port.

[0012] Preferably, corresponding snap-in grooves and snap-in blocks are provided at both ends of the first supporting plate and the second supporting plate, and the first supporting plates and the first supporting plate and the second supporting plate are connected by the matching snap-in grooves and the snap-in blocks.

[0013] Preferably, the bottom ends of the first supporting plate and the second supporting plate penetrate deep into the sandy silt geology, and a steel cage composed of steel bars is installed on the side of the first supporting plate and the second supporting plate away from the sandy silt geology, and concrete is poured inside the steel cage, and it is fixed in cooperation with the first supporting plate and the second supporting plate.

[0014] Preferably, a seepage groove is provided on one side surface of the support plate assembly where the filter screen is installed, the filter screen covers the seepage groove and is enclosed with the seepage groove to form a seepage cavity, and the water channel is opened on the support plate assembly at the lower end of the seepage cavity.

[0015] Preferably, the mesh size of the filter screen is 10-100 meshes, and can intercept sandy silt particles of corresponding sizes from flowing into the water seepage cavity.

[0016] A construction method for a deep foundation pit support structure in a high-water-level sandy silt soil geology, used for constructing a deep foundation pit support structure in a high-water-level sandy silt soil geology according to any one of the above-mentioned methods, comprises the following steps:

[0017] S1. Obtain hydrogeological information, soil particle composition and physical properties of the soil layer through comprehensive geological survey;

[0018] S2. Prefabricate corresponding first and second supporting plates by selecting a corresponding filter screen according to the survey information, and print corresponding numbers on the first and second supporting plates according to the waterway drainage path;

[0019] S3. Operate the mechanical equipment to excavate a pit at the working location, insert the first support plate into the pit, slide the subsequent prefabricated support plate into the clamping groove of the previous support plate through the clamping block, and insert the second support plate between a fixed number of first support plates until the support plate assembly is completed, and at the same time, align the clamping groove of the second support plate with the reserved installation position of the support reinforcement assembly;

[0020] S4. During the installation of the first and second support plates, simultaneously connect the drainage assembly: connect one end of the water pipe to the water inlet in the water collection chamber, extend the other end through the support plate to the outside and connect to the access port, connect the suction port of the external water pump to the access port of the drainage assembly, and ensure that the water channel can guide the water that penetrates the filter screen into the water collection chamber and drain the accumulated water in the water collection chamber in a timely manner;

[0021] S5. After the support plate components are installed according to the working area, start excavating in layers to form a deep foundation pit. During the excavation process, the mounting components at both ends of the support reinforcement components are simultaneously plugged into the card slots. As the depth of the foundation pit increases, the height of the support reinforcement components is gradually lowered to maintain the support stability of the support plate components. Repeat the excavation and lowering cycle until the designed depth is reached.

[0022] S6. After the deep foundation pit is formed, assemble the steel cage along the inner side of the support plate assembly, connect the adjacent steel cages by tying or welding, check the stability of the steel cage, and pour concrete into the gap between the steel cage and the support plate assembly to form a concrete wall panel to reinforce the side wall of the deep foundation pit.

[0023] Beneficial effects of the present invention:

[0024] The present invention provides a deep foundation pit support structure in high-water-level sandy silt soil. This structure achieves rapid construction and dynamic stable support through the combination of prefabricated and assembled support plate assemblies and support reinforcement assemblies that can be lowered with the excavation depth. The composite drainage network composed of the internal water collection chamber and inclined waterway, combined with a filter screen filtration design, can efficiently drain water seepage from the foundation pit and prevent sand clogging. Combined with reinforced concrete cage reinforcement and a standardized installation process guided by numbering, this structure can shorten construction time and reduce the risk of collapse in high-water-level sandy silt soil. Furthermore, the structure can ensure the strength of the foundation pit sidewalls through systematic construction steps, significantly improving construction safety and efficiency.

[0025] Also provided is a construction method for a deep foundation pit support structure in high-water-level sandy silt soil. The method facilitates the construction of the deep foundation pit by providing support in advance with prefabricated components. At the same time, in the process of forming the deep foundation pit, the supporting components of the prefabricated components descend with the depth, reducing collapse caused by the pressure of the surrounding water-level sandy silt soil, greatly improving the construction safety of the deep foundation pit in high-water-level sandy silt soil, and reducing the risk of collapse. Moreover, since the prefabricated components can be manufactured in advance before the start of construction, the construction period is shortened. During the installation of the prefabricated components, the moisture inside the supported high-water-level sandy silt soil is initially blocked, thereby improving construction efficiency and reducing construction losses caused by unstable soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the installation structure of a deep foundation pit support structure in high water level sandy silt soil according to Example 1 of the present invention.

[0027] Figure 2 This is a diagram showing the usage status of a deep foundation pit support structure in sandy silt soil with high water level according to Example 1 of the present invention.

[0028] Figure 3 This is a transverse cross-sectional view of the water collecting chamber portion of the support plate assembly of Example 1 of the present invention.

[0029] Figure 4 This is a longitudinal cross-sectional view of the first supporting plate with water channel in Example 1 of the present invention.

[0030] In the figure: 1. First supporting plate; 2. Second supporting plate; 3. Embedding groove; 4. Embedding block; 5. Snap-in groove; 6. Filter screen; 7. Water channel; 8. Water collection chamber; 9. Drainage assembly; 91. Water inlet; 92. Water pipe; 93. Access port; 10. Number; 11. Support and reinforcement assembly; 12. Steel cage; 13. Seepage chamber.

[0031] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] Example 1

[0034] like Figures 1-4 As shown, a deep foundation pit support structure in high-water-level sandy silt soil includes: a support plate assembly and a support reinforcement assembly 11. The support plate assembly is attached to the inner surface of the deep foundation pit and is supported and fixed by the support reinforcement assembly 11;

[0035] A water collecting chamber 8 is provided inside the support plate assembly, and a drainage assembly 9 connected to the outside of the support plate assembly is provided in the water collecting chamber 8. One side surface of the support plate assembly is covered with a filter screen 6, and a water channel 7 connected to the water collecting chamber 8 is provided on the side surface close to the filter screen 6, and the water channel 7 is provided across the side surface of the support plate assembly; the support plate assembly is composed of a plurality of first support plates 1 and a plurality of second support plates 2, and a vertical clamping groove 5 is provided on the side surface of the second support plate 2 away from the filter screen 6. The support reinforcement assembly 11 is clamped with the second support plate 2 through the clamping groove 5, and can gradually descend as the deep foundation pit is excavated and formed.

[0036] It should be noted that the support plate assembly forms a continuous support structure through modular splicing, and the support structure is installed by utilizing the clamping cooperation between the support reinforcement assembly 11 and the vertical clamping groove 5 of the second support plate 2, so that the support plate assembly is stably attached to the inner wall of the foundation pit, providing basic support for the foundation pit to prevent side wall collapse; and the support reinforcement assembly 11 dynamically adjusts the support position according to the excavation depth, which can ensure the stability of the support structure at different excavation depths; the seepage water from the foundation pit is filtered by the filter screen 6 and flows into the water collection chamber 8 through the water channel 7. The filter screen 6 blocks the sandy silt and can prevent the water channel 7 from being blocked, keeping the water flow unobstructed, and then the drainage assembly 9 discharges the accumulated water in the water collection chamber 8, effectively lowering the water level in the foundation pit to avoid the softening of the sandy silt due to water immersion.

[0037] like Figure 3 As shown, the water channel 7 is obliquely opened on the side surface of the supporting plate assembly, and the lowest end of the water channel 7 is connected to the water collecting chamber 8.

[0038] It should be noted that the inclined waterway 7 uses gravity to allow the water filtered by the filter screen 6 to flow naturally along the inclined waterway 7 to the water collection chamber 8, ensuring the continuity of the drainage process, improving the drainage efficiency, and avoiding water accumulation in the waterway 7, which leads to the deposition and blockage of sandy silt particles.

[0039] like Figure 1 As shown, the first supporting plate 1 and the second supporting plate 2 are both provided with corresponding numbers 10, and the numbers 10 are arranged in sequence according to the drainage path from the water channel 7 to the water collection chamber 8.

[0040] It should be noted that by marking the number 10 corresponding to the drainage path on the support plate, clear splicing sequence guidance is provided to the installers to ensure that when the support plates are spliced ​​in the order of number 10, the water channel 7 can form a coherent drainage channel from the side of the filter screen 6 to the water collection chamber 8, avoiding the failure of the connectivity of the water channel 7 due to misalignment of the support plate splicing, and ensuring the accuracy of the drainage network.

[0041] like Figure 1 As shown, two first support plates 1 are spliced ​​between adjacent second support plates 2, and the water collection cavity 8 is opened inside any first support plate 1. The first support plate 1 and the second support plate 2 without the water collection cavity 8 are provided with a water channel 7, and the water channels 7 of adjacent support plates are connected to each other.

[0042] It should be noted that the number of first support plates 1 between adjacent second support plates 2 can be adjusted in time according to the size of the deep foundation pit, and the water collection chamber 8 can be set not only in the first support plate 1, but also in the second support plate 2, which can be achieved by simply setting it in advance when prefabricating the support plate assembly; this solution uses the water collection chamber 8 set in the first support plate 1 as a drainage node, and forms a graded drainage path from the filter screen 6 side to the water collection chamber 8 through the end-to-end connection of adjacent water channels 7, so that the water collection chamber 8 and the water channel 7 are regularly distributed in the support plate assembly, avoiding excessive concentration of the water collection chamber 8 and causing local structural weakness.

[0043] like Figure 3 As shown, the drainage assembly 9 includes a water inlet 91, a water pipe 92 and an access port 93. The water inlet 91 is arranged in the water collecting chamber 8. One end of the water pipe 92 is connected to the water inlet 91, and the other end extends to the outside of the support plate assembly and is connected to the access port 93.

[0044] It should be noted that the water inlet 91 is arranged in the water collecting chamber 8 to collect the accumulated water in the chamber. One end of the water pipe 92 is connected to the water inlet 91, and the other end extends to the outside of the support plate assembly and is connected to the access port 93. The accumulated water is sucked out from the access port 93 through the water inlet 91 and the water pipe 92 by an external water pump, thereby realizing the directional transportation and drainage of the accumulated water. The modular drainage component 9 is designed to ensure the real-time discharge of foundation pit seepage water in high-water-level sandy silt geology, thereby preventing the accumulated water from soaking the support structure and surrounding soil.

[0045] like Figure 1As shown, corresponding snap-in grooves 3 and snap-in blocks 4 are provided at both ends of the first supporting plate 1 and the second supporting plate 2, and the first supporting plates 1 and the first supporting plates 1 and the second supporting plates 2 are connected by the matching snap-in grooves 3 and the snap-in blocks 4.

[0046] It should be noted that the mechanical interlocking structure of the embedded block 4 inserted into the embedded groove 3 is used to achieve rapid splicing between the support plates, and a stable connection node is formed through the precise cooperation of the protrusion and the groove, so that each support plate forms a continuous overall support structure after splicing, ensuring the continuity of force transmission, greatly improving on-site installation efficiency, reducing the tedious process of welding or bolt connection, and improving work efficiency.

[0047] like Figure 2 As shown, the bottom ends of the first supporting plate 1 and the second supporting plate 2 penetrate deep into the sandy silt geology, and a steel cage 12 composed of steel bars is installed on the side of the first supporting plate 1 and the second supporting plate 2 away from the sandy silt geology, and concrete is poured inside the steel cage 12, and it is fixed with the first supporting plate 1 and the second supporting plate 2.

[0048] It should be noted that by inserting the bottom end of the support plate into the soil layer, the foundation anchoring is achieved by utilizing the friction of the soil and the embedding effect. At the same time, the high strength and rigidity of the steel cage 12 are utilized to form a composite support system with the support plate to jointly withstand the soil pressure and water pressure of the side wall of the foundation pit, thereby improving the overall bending and shear resistance of the support structure, enhancing the integrity and reliability of the support system, and larger stones can also be installed at the bottom of the first support plate 1 and the second support plate 2 to increase their supporting force.

[0049] like Figure 4 As shown, a seepage groove is provided on one side surface of the support plate assembly where the filter screen 6 is installed. The filter screen 6 covers the seepage groove and is enclosed with the seepage groove to form a seepage cavity 13. The waterway 7 is provided on the support plate assembly at the lower end of the seepage cavity 13.

[0050] It should be noted that a seepage groove is formed by reserving a groove on the surface of the support plate, and the filter screen 6 covers the seepage groove and is enclosed with the seepage groove to form a seepage cavity 13, providing a gathering space for the seepage water, so that the seepage water can flow smoothly into the waterway 7 through the seepage cavity 13, effectively improving the drainage efficiency of the seepage water.

[0051] The mesh size of the filter screen 6 is 50 mesh (0.3 mm aperture), and is capable of intercepting sandy silt particles of corresponding size from flowing into the water seepage cavity 13 .

[0052] It should be noted that by setting the aperture size of the sieve, physical screening is used to allow water to penetrate through and block sandy silt particles from entering the seepage cavity 13 and the waterway 7, thereby achieving efficient separation of water and soil particles and ensuring the smooth flow of the drainage channel; avoiding sand particles clogging the drainage system and causing a decrease in drainage efficiency, ensuring the long-term stable operation of the drainage system of the foundation pit support structure in high-water-level sandy silt geology, and improving the reliability and service life of the support structure.

[0053] The working principle and use method of a high-water-level sandy silt geology deep foundation pit support structure of this embodiment are as follows:

[0054] Working principle: The support plate assembly is spliced ​​into a continuous structure through the snap-in groove 3 and the snap-in block 4 of the first support plate 1 and the second support plate 2. After being attached to the inner surface of the foundation pit, the support reinforcement assembly 11 is snapped into the vertical snap-in groove 5 of the second support plate 2, and is synchronously lowered as the foundation pit is excavated in layers to provide dynamic support; the seepage water from the foundation pit is filtered through the filter screen 6 (50 mesh), and then gathered along the seepage cavity 13 enclosed by the seepage groove and the filter screen 6, and flows to the water collection cavity 8 in the first support plate 1 through the inclined waterway 7 (the lowest end is connected to the water collection cavity 8), and then is pumped out of the foundation pit by an external water pump of the drainage assembly 9 composed of the water inlet 91, the water pipe 92 and the access port 93, forming a complete system of "filtration-drainage-water collection-drainage"; the bottom end of the support plate is inserted into the soil layer, and the outer steel cage 12 is poured with concrete and fixed to the support plate to form a composite support structure to resist soil pressure and water pressure.

[0055] Usage method: A construction method for a deep foundation pit support structure in high-water-level sandy silt soil, comprising the following steps:

[0056] S1. Obtain hydrogeological information, soil particle composition and physical properties of the soil layer through comprehensive geological survey;

[0057] S2. Select a corresponding 50-mesh filter screen 6 according to the survey information to prefabricate the corresponding first support plate 1 and second support plate 2, and print corresponding numbers 10 on the first support plate 1 and second support plate 2 according to the drainage path of the waterway 7;

[0058] S3. Operate the mechanical equipment to excavate a pit at the working location, insert the first supporting plate 1 into the pit, slide the subsequent supporting plates into the snap-fitting groove 5 of the previous supporting plate through the snap-fitting block, and insert the second supporting plates 2 between a fixed number of the first supporting plates 1 until the assembly of the supporting plate assembly is completed, and at the same time, align the snap-fitting groove 5 of the second supporting plate 2 with the reserved installation position of the support reinforcement assembly 11;

[0059] S4. During the installation of the first and second support plates 1 and 2, simultaneously connect the drainage assembly 9: connect one end of the water pipe 92 to the water inlet 91 in the water collection chamber 8, and extend the other end through the support plate to the outside and connect to the access port 93. Connect the suction port of the external water pump to the access port 93 of the drainage assembly 9. At the same time, ensure that the water channel 7 can guide the water that has penetrated the filter screen 6 into the water collection chamber 8 and drain the accumulated water in the water collection chamber 8 in a timely manner;

[0060] S5. After the support plate assemblies are installed according to the working area, start excavating in layers to form a deep foundation pit. During the excavation process, the mounting assemblies at both ends of the support reinforcement assembly 11 are simultaneously clipped into the clip grooves 5. As the depth of the foundation pit increases, the height of the support reinforcement assembly 11 is gradually lowered to maintain the support stability of the support plate assembly. Repeat the excavation and lowering cycle until the designed depth is reached.

[0061] S6. After the deep foundation pit is formed, assemble the steel cage along the inner side of the support plate assembly, connect the adjacent steel cages by tying or welding, check the stability of the steel cage, and pour concrete into the gap between the steel cage and the support plate assembly to form a concrete wall panel to reinforce the side wall of the deep foundation pit.

[0062] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is intended only to illustrate the technical solution of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

[0063] In the description of the present invention, it should be understood that the terms "upper", "lower", "upper end", "lower end", "upper surface", "lower surface", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. 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 orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0064] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," and "disposed" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

Claims

1. A deep foundation pit support structure in high-water-level sandy silt soil, comprising: A support plate assembly and a support reinforcement assembly (11), wherein the support plate assembly is attached to the inner surface of a deep foundation pit and is supported and fixed by the support reinforcement assembly (11); characterized in that: A water collecting chamber (8) is provided inside the support plate assembly, and a drainage assembly (9) communicating with the outside of the support plate assembly is provided in the water collecting chamber (8); one side surface of the support plate assembly is covered with a filter screen (6), and a water channel (7) communicating with the water collecting chamber (8) is provided on the side surface close to the filter screen (6); the water channel (7) is provided across the side surface of the support plate assembly; the support plate assembly is formed by splicing a plurality of first support plates (1) and a plurality of second support plates (2); a vertical clamping groove (5) is provided on the side surface of the second support plate (2) away from the filter screen (6); the support reinforcement assembly (11) is clamped with the second support plate (2) through the clamping groove (5), and can be gradually lowered as the deep foundation pit is excavated and formed.

2. The deep foundation pit support structure for high water level sandy silt soil according to claim 1, characterized in that: The water channel (7) is obliquely opened on the side surface of the supporting plate assembly, and the lowest end of the water channel (7) is communicated with the water collecting chamber (8).

3. The deep foundation pit support structure for high water level sandy silt soil according to claim 2, characterized in that: The first supporting plate (1) and the second supporting plate (2) are both provided with corresponding numbers (10), and the numbers (10) are arranged in sequence according to the drainage path from the waterway (7) to the water collection chamber (8).

4. The deep foundation pit support structure for high water level sandy silt soil according to claim 1, characterized in that: At least one first supporting plate (1) is spliced ​​between adjacent second supporting plates (2), and the water collecting cavity (8) is provided inside any first supporting plate (1), and water channels (7) are provided on the first supporting plate (1) and the second supporting plate (2) that are not provided with the water collecting cavity (8), and the water channels (7) of adjacent supporting plates are interconnected.

5. The deep foundation pit support structure in high water level sandy silt soil according to claim 1, characterized in that: The drainage assembly (9) comprises a water inlet (91), a water pipe (92) and an access port (93); the water inlet (91) is arranged in the water collecting chamber (8); one end of the water pipe (92) is connected to the water inlet (91), and the other end extends to the outside of the support plate assembly and is connected to the access port (93).

6. The deep foundation pit support structure in high water level sandy silt soil according to claim 1, characterized in that: Both ends of the first supporting plate (1) and the second supporting plate (2) are provided with corresponding snap-fitting grooves (3) and snap-fitting blocks (4), and the first supporting plates (1) and the first supporting plates (1) and the second supporting plates (2) are connected by the snap-fitting grooves (3) and the snap-fitting blocks (4).

7. The deep foundation pit support structure for high water level sandy silt soil according to claim 1, characterized in that: The bottom ends of the first supporting plate (1) and the second supporting plate (2) are inserted deep into the sandy silt soil. A steel cage (12) composed of steel bars is installed on the side of the first supporting plate (1) and the second supporting plate (2) away from the sandy silt soil. Concrete is poured inside the steel cage (12) and the steel cage is fixed to the first supporting plate (1) and the second supporting plate (2).

8. The deep foundation pit support structure in high water level sandy silt soil according to claim 1, characterized in that: A water seepage groove is provided on the surface of one side of the support plate assembly on which the filter screen (6) is installed. The filter screen (6) covers the water seepage groove and is enclosed with the water seepage groove to form a water seepage cavity (13). The water channel (7) is provided on the support plate assembly at the lower end of the water seepage cavity (13).

9. The deep foundation pit support structure in high water level sandy silt soil according to claim 8, characterized in that: The mesh size of the filter screen (6) is 10-100 meshes, and it is capable of intercepting sandy silt particles of corresponding sizes from flowing into the water seepage cavity (13).

10. A construction method for a deep foundation pit support structure in high water level sandy silt soil, characterized in that: The method for constructing a deep foundation pit support structure in high-water-level sandy silt soil according to any one of claims 1 to 9 comprises the following steps: S1. Obtain hydrogeological information, soil particle composition and physical properties of the soil layer through comprehensive geological survey; S2. Selecting a corresponding filter screen (6) according to the survey information to prefabricate a corresponding first support plate (1) and a second support plate (2), and printing corresponding numbers (10) on the first support plate (1) and the second support plate (2) according to the drainage path of the waterway (7); S3, operating the mechanical equipment to dig a pit at the working position, inserting the first supporting plate (1) into the pit, then sliding the first supporting plate (1) into the clamping groove (5) of the previous supporting plate through the clamping block, inserting the second supporting plate (2) between a fixed number of first supporting plates (1), until the assembly of the supporting plate assembly is completed, and at the same time aligning the clamping groove (5) of the second supporting plate (2) with the reserved installation position of the support reinforcement assembly (11); S4. During the installation of the first supporting plate (1) and the second supporting plate (2), the drainage assembly (9) is connected synchronously: one end of the water pipe (92) is connected to the water inlet (91) in the water collection chamber (8), and the other end is extended through the supporting plate to the outside and connected to the access port (93), and the suction port of the external water pump is connected to the access port (93) of the drainage assembly (9), while ensuring that the water channel (7) can guide the water infiltrated by the filter screen (6) into the water collection chamber (8), and timely pump out the water in the water collection chamber (8); S5. After the support plate assembly is installed according to the working area, start layered excavation to form a deep foundation pit. During the excavation process, the mounting components at both ends of the support reinforcement assembly (11) are simultaneously plugged into the card slots (5). As the depth of the foundation pit increases, the height of the support reinforcement assembly (11) is gradually lowered to maintain the support stability of the support plate assembly. Repeat the excavation-descent cycle until the designed depth; S6. After the deep foundation pit is formed, assemble the steel cage along the inner side of the support plate assembly, connect the adjacent steel cages by tying or welding, check the stability of the steel cage, and pour concrete into the gap between the steel cage and the support plate assembly to form a concrete wall panel to reinforce the side wall of the deep foundation pit.

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