Deep well sealing structure suitable for foundation pit dewatering and construction method thereof

Abstract

The invention provides a deep well sealing structure suitable for foundation pit dewatering and a construction method of the deep well sealing structure, and belongs to the field of drainage construction. The structure comprises a tube well structure, a reinforcing structure, a waterproof structure, a base structure, an upper sealing structure, an outer sealing structure and an inner filling structure. The tube well structure comprises a PVC tube and a coarse sand ring, and the coarse sand ring is located on the periphery of the PVC tube. The base structure is located above the coarse sand ring; the waterproof structure is laid above the base structure; the upper sealing structure is arranged above the PVC pipe; the external sealing structure is arranged above the base structure and located outside the tube well structure. The periphery of the PVC pipe is further sleeved with a reinforcing structure. And the internal filling structure is arranged in the PVC pipe. The method comprises the steps that a base structure is laid, a PVC pipe is sleeved with a reinforcing structure, and a waterproof structure is laid; arranging an external sealing structure; the PVC pipe is cut off, high-capacity water pumping is conducted, and a wellhead is closed; an upper closed structure is provided. The foundation pit dewatering device is matched with the foundation pit bottom plate in strength, construction safety is guaranteed, and the foundation pit dewatering effect is achieved.

Description

Technical Field

[0001] The invention belongs to the field of drainage construction, and in particular relates to a deep well closed structure suitable for foundation pit dewatering and a construction method thereof. Background Art

[0002] Pipe well dewatering is a commonly used method in drainage construction. By setting up pipe well points to lower the groundwater level, the construction area is ensured to be dry and safe. Chinese patent CN107489159A (publication date: December 19, 2017) discloses a vacuum pipe well dewatering construction structure and construction method for deep muddy soft soil layer. The structure includes a dewatering well, the upper end of the inner side of the dewatering well is sleeved with a steel pipe, the outer side of the steel pipe is filled with clay, the lower end of the dewatering well is sleeved with a steel pipe filter, the outer side of the steel pipe filter is filled with medium and coarse sand filter material, the top of the dewatering well is sealed, and the bottom of the dewatering well is filled with sand and gravel to form a filter layer. A submersible pump is provided in the dewatering well, and the submersible pump is connected to a vacuum pump. A drainage pipe is provided at the end of the vacuum pump; the method includes the steps of pre-construction layout, drilling construction, well pipe processing and pipe laying, dewatering construction, and dewatering pipe well closure. The invention effectively reduces the moisture content of the silt layer. After vacuum dewatering, the silt moisture content is reduced to about 20%.

[0003] Chinese patent CN117627026A (publication date: March 1, 2024) discloses a composite dewatering construction method and a pipe well closure device, including a pipe well body, the pipe well body is placed on the basement floor, the pipe well body is welded to the steel bars of the basement floor to form a whole, the bottom of the basement floor is provided with a floor cushion, the inner wall of the pipe well body is welded with two water-stopping rings, and the upper part of the pipe well body is provided with a steel top cover plate. The present invention uses a common construction technology for water collection wells and recharging wells to control the groundwater level as a whole to avoid adverse effects on surrounding buildings and the environment. The deep pipe well dewatering and decompression construction technology is used to control the damage caused by the supporting force of the pressurized water to the foundation pit, reduce the deformation of the enclosure, prevent the occurrence of sudden surges in the foundation pit soil, and ensure the safety of the foundation pit structure.

[0004] The construction of foundation pit drainage requires the installation of deep wells inside the foundation pit, which are lowered as the pit is dug. When muddy water comes out of the deep well during the drainage, it should be scrapped immediately and a new deep well should be set up. If the amount of groundwater is large, additional deep wells or light well points can be used for drainage. This requires repeated deep well closure construction. Therefore, it is necessary to design a deep well closure structure that conforms to the deep well structure and can meet the strength of the foundation pit. Summary of the invention

[0005] In order to ensure that the strength of the foundation pit bottom plate is not affected when the deep well is closed, the present invention provides a deep well closing structure suitable for foundation pit dewatering and a construction method thereof, wherein the structure comprises a pipe well structure, a reinforcement structure, a waterproof structure, a base structure, an upper closing structure, an external closing structure, and an internal filling structure; The pipe well structure comprises a PVC pipe and a coarse sand ring, wherein the coarse sand ring is located outside the PVC pipe; The base structure is a foundation pit leveling layer, the foundation pit leveling layer is located above the coarse sand ring, and the top surface depth of the foundation pit leveling layer is the design elevation of the bottom plate ground; The waterproof structure is laid on top of the base structure; The upper closed structure is arranged above the PVC pipe; The external closed structure is arranged above the foundation pit leveling layer and outside the pipe well structure, and the external closed structure has the same height as the upper closed structure; The outer periphery of the PVC pipe is covered with a reinforcement structure; The internal filling structure is filled inside the PVC tube.

[0006] Furthermore, the reinforcement structure is a steel pipe, the bottom of the steel pipe exceeds the foundation pit leveling layer by 50-100 mm; the top of the steel pipe exceeds the foundation pit leveling layer by 250-300 mm.

[0007] Furthermore, the waterproof structure includes a waterproof board and a water-stop putty; The waterproof sheet is laid on the foundation pit leveling layer and extended and welded to the surface of the steel pipe; Water-stop putty is applied around the joint between the waterproof board and the steel pipe.

[0008] Further, the external closed structure includes bottom plate steel bars and bottom plate concrete; The bottom plate reinforcement is arranged above the foundation pit leveling layer; The bottom plate concrete is densely poured inside the bottom plate steel bars; The external closed structure reserves space around the top of the steel pipe; The thickness of the external closed structure is consistent with the thickness of the foundation pit bottom plate.

[0009] Furthermore, the upper closed structure includes a steel plate, a thick steel plate, and backfill concrete; The steel plate is vertically welded to the outer periphery of the top of the steel pipe, and the width of the steel plate is 200-300mm; The thick steel plate is arranged on the top of the steel pipe, and the steel plate and the top of the steel pipe are welded and sealed; The filling concrete is filled in the space around the top of the steel pipe reserved in the external closed structure.

[0010] Furthermore, the backfill concrete is micro-expansive concrete, and the strength grade of the micro-expansive concrete is one level higher than the strength grade of the base plate concrete.

[0011] Furthermore, the internal filling structure is yellow sand and cement, and the internal filling structure fills the inside of the PVC pipe until it is flush with the top of the steel pipe.

[0012] A construction method for a deep well closed structure suitable for foundation pit dewatering, comprising the following steps: S1. Excavate the foundation pit to the designed elevation and clean the base surface; S2. Lay the foundation pit leveling layer, put a steel pipe on the outer shell of the PVC pipe, weld a circle of steel plate around the top of the steel pipe, and lay a waterproof board; S3. Lay the bottom plate steel bars. Disconnect and bend the bottom plate steel bars around the top of the steel pipe to reserve space for the closed steel plate. Pour the bottom plate concrete and compact it. S4, cut off the PVC pipe, pump water in large volume, then fill the PVC pipe with sand and cement to seal the wellhead; S5. Weld the closed steel plate, connect the disconnected bottom plate steel bars around the top of the steel pipe, and pour micro-expansive concrete.

[0013] Compared with the prior art, the advantages and effects of this application are as follows: 1. The present invention provides a deep well sealing structure suitable for foundation pit dewatering, which takes into consideration the pipe well structure, reinforcement structure, waterproof structure, base structure, upper sealing structure, external sealing structure, and internal filling structure, seals the deep well, and sets the bottom plate concrete and other structural strengths and dimensions in coordination with the foundation pit bottom plate, so that a good stable structure can be formed with the bottom plate while sealing the deep well.

[0014] 2. The present invention provides a construction method for a deep well closed structure suitable for foundation pit dewatering, which sequentially constructs a pipe well structure, a reinforcement structure, a waterproof structure, a base structure and a closed structure. While ensuring safety, the strength of the deep well closed structure can be improved to the greatest extent, thereby effectively controlling the groundwater level and ensuring the dryness and stability of the foundation pit.

[0015] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application so that it can be implemented in accordance with the contents of the specification, and to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following is a detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings as follows.

[0016] Based on the detailed description of the specific embodiments of the present application in combination with the accompanying drawings below, those skilled in the art will become more aware of the above and other objects, advantages and features of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings without creative work. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0018] in: Figure 1 A schematic diagram of a deep well closure structure suitable for foundation pit dewatering according to an embodiment of the present invention; Reference numerals: 1. PVC pipe; 2. coarse sand ring; 3. foundation pit leveling layer; 4. steel pipe; 5. waterproof board; 6. water-stop putty; 7. external closed structure; 8. steel plate; 9. thick steel plate; 10. backfilling concrete; 11. internal filling structure; Figure 2 The present invention is based on Example 1 of a construction method of a deep well closed structure suitable for foundation pit dewatering. Specific embodiments To make the purpose, technical scheme and advantages of the embodiment of the present application clearer, the technical scheme in the embodiment of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present application. Obviously, the described embodiment is a part of the embodiment of the present application, rather than all of the embodiments. In the following description, specific details such as specific configuration and components are provided only to help fully understand the embodiments of the present application. Therefore, it should be clear to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. In addition, for clarity and brevity, the description of known functions and structures is omitted in the embodiment.

[0020] It should be understood that the references to "one embodiment" or "this embodiment" throughout the specification mean that the specific features, structures, or characteristics associated with the embodiment are included in at least one embodiment of the present application. Therefore, the references to "one embodiment" or "this embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0021] In addition, the present application may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplicity and clarity, and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0022] The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist at the same time. The term " / and" in this article describes another type of association object relationship, indicating that there can be two relationships. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0023] The term "at least one" in this article is merely a description of the association relationship of associated objects, indicating that there may be three relationships. For example, at least one of A and B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0024] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusions.

[0025] Example 1 like Figure 1 The embodiment shown relates to a deep well enclosed structure suitable for foundation pit dewatering, including a pipe well structure, a reinforcement structure, a waterproof structure, a base structure, an upper enclosed structure, an external enclosed structure 7, and an internal filling structure 11; The pipe well structure includes a PVC pipe 1 and a coarse sand ring 2, and the coarse sand ring 2 is located outside the PVC pipe; the PVC pipe is a reinforced pipe with a diameter of 300 mm, and the pipe wall is made of 10 mm filter holes with a hole spacing of 50 mm. It adopts a plum blossom shape and is wrapped with 1 layer of 7-wood galvanized wire mesh and 3 layers of 60-mesh nylon mesh.

[0026] The base structure is a foundation pit leveling layer 3, The foundation pit leveling layer 3 is located above the coarse sand ring 2, and the top surface depth of the foundation pit leveling layer 3 is the design elevation of the bottom plate ground; The waterproof structure is laid on top of the base structure The upper closed structure is arranged above the PVC pipe 1; The external closed structure 7 is arranged above the foundation pit leveling layer 3 and outside the pipe well structure. The external closed structure 7 has the same height as the upper closed structure. The outer periphery of the PVC pipe 1 is also covered with a reinforcement structure; The internal filling structure 11 is filled in the PVC tube 1 .

[0027] Furthermore, the reinforcement structure is a steel pipe 4, the bottom of the steel pipe exceeds the foundation pit leveling layer by 50-100mm; the top of the steel pipe exceeds the foundation pit leveling layer by 250-300mm, and the steel pipe is an 8mm steel pipe.

[0028] Furthermore, the waterproof structure includes a waterproof board 5, a water-stop putty 6, and a waterproof board protective layer; The waterproof board 5 is laid on the foundation pit leveling layer 3 and extended to the surface of the steel pipe by heat welding; A water-stop putty 6 is applied around the joint between the waterproof board 5 and the steel pipe 4; and the waterproof board protective layer is laid on top of the waterproof board.

[0029] Furthermore, the external closed structure 7 includes bottom plate steel bars and bottom plate concrete; The bottom plate steel bars are arranged above the foundation pit leveling layer; The bottom plate concrete is densely poured inside the bottom plate steel bars, and space is reserved around the top of the steel pipe; The thickness of the external closed structure 7 is consistent with the thickness of the foundation pit bottom plate.

[0030] Furthermore, the upper closed structure includes a steel plate 8, a thick steel plate 9, and backfill concrete 10; the steel plate is an 8mm steel plate, the thick steel plate is an 8mm thick steel plate, and both ends extend beyond the steel pipe by 40mm.

[0031] The steel plate 8 is vertically welded to the outer periphery of the top of the steel pipe 4, and its width is 200-300mm; the width of the steel plate is 200mm, and 1 / 3 of the steel plate is located inside the bottom plate concrete, forming a good fixed connection with the external closed structure and connected to the support.

[0032] The thick steel plate 9 is arranged on the top of the steel pipe 4, and the steel plate 8 and the top of the steel pipe 4 are welded and sealed; the thick steel plate is fully welded and sealed to the steel plate and the steel pipe.

[0033] The filling concrete 10 is filled in the space around the top of the steel pipe 4 reserved in the external closed structure 7 .

[0034] The distance from the top of the foundation pit leveling layer to the steel plate is half the thickness of the foundation pit bottom plate, forming a good and stable structure with the bottom plate.

[0035] Furthermore, the backfill concrete 10 is micro-expansive concrete, and the strength grade of the micro-expansive concrete is one level higher than that of the base plate concrete.

[0036] Furthermore, the internal filling structure 11 is yellow sand and cement, and the internal filling structure fills the interior of the PVC pipe 1 until it is flush with the top of the steel pipe 4 .

[0037] Technical effect of this embodiment: This embodiment provides a deep well closure structure suitable for foundation pit dewatering. The structural strength is set according to the strength of the bottom plate, and the structural thickness and size are set, so as to form a good and stable structure with the bottom plate.

[0038] Example 2 like Figure 2 As shown, this embodiment provides a construction method of a deep well closed structure suitable for foundation pit dewatering based on Embodiment 1, comprising the following steps: S1. Excavate the foundation pit to the designed elevation and clean the base surface; S2. Lay the foundation pit leveling layer 3, put the steel pipe 4 on the outer cover of the PVC pipe 1, weld a circle of steel plate 8 around the top of the steel pipe 4, and lay the waterproof board 5; the bottom depth of the PVC pipe is -16m or reaches the middle weathering layer.

[0039] S3, laying the waterproof board protection layer and the bottom plate steel bars, first disconnecting and bending the bottom plate steel bars around the top of the steel pipe 4 to reserve the space for the construction of the closed steel plate, pouring the bottom plate concrete and tamping it densely; S4, cut off the PVC pipe 1 to the height of the steel plate, pump water with a large capacity, and then fill the PVC pipe 1 with yellow sand and cement to seal the wellhead; S5. The welded closed steel plate 8 is required to be fully welded and sealed, and the bottom plate steel bars disconnected around the top of the steel pipe 4 are connected. The slightly expansive concrete is poured into the construction closed steel plate space reserved in step S3.

[0040] Technical effect of this embodiment: This embodiment provides a construction method for a deep well closed structure suitable for foundation pit dewatering Example 3 Based on Example 1 and Example 2, this embodiment provides a construction method of a deep well closed structure suitable for foundation pit dewatering, comprising the following steps: S1. Excavate the foundation pit to the designed elevation and clean the base surface; S2. Lay the foundation pit leveling layer 3, put the steel pipe 4 on the outer sleeve of the PVC pipe 1, weld a circle of steel plate 8 around the top of the steel pipe 4, and lay the waterproof board 5; the bottom depth of the PVC pipe is -16m or reaches the middle weathering layer; S3, laying the waterproof board protection layer and the bottom plate steel bars, first disconnecting and bending the bottom plate steel bars around the top of the steel pipe 4 to reserve the space for the construction of the closed steel plate, pouring the bottom plate concrete and tamping it densely; S4, cut off the PVC pipe 1 to the height of the steel plate, pump water with a large capacity, and then fill the PVC pipe 1 with yellow sand and cement to seal the wellhead; S5. The welded closed steel plate 8 is required to be fully welded and sealed, and the bottom plate steel bars disconnected around the top of the steel pipe 4 are connected. The slightly expansive concrete is poured into the construction closed steel plate space reserved in step S3.

[0041] When carrying out deep well closure construction, the following safeguards can also be adopted: make open ditches with a size of 300×400 around the top of the foundation pit slope to prevent surface water from flowing into the foundation pit and affecting the construction. Once leakage occurs, it should be repaired in time; during the excavation process, a temporary collection pit can be dug in the center of the foundation pit according to the actual situation to remove the open water in the foundation pit. After the construction reaches the base, drainage ditches and collection wells are arranged around the bottom of the pit according to the actual situation; the drainage ditch at the bottom of the foundation pit should be more than 4m away from the edge of the foundation pit; a number of drainage holes are set on the pit wall according to the actual situation. The drainage holes use 48mm PVC pipes, and a circular hole is set on the pipe wall every 50mm rotated 90 degrees, and the outside of the pipe is wrapped with filter cloth.

[0042] Technical effect of this embodiment: This embodiment provides a construction method and safeguard measures for a deep well enclosed structure suitable for foundation pit dewatering to ensure dewatering effect and construction safety.

[0043] The above description is only the preferred embodiment of the present invention, which does not limit the protection scope of the present invention. For those skilled in the art, the present invention can be modified and varied in various ways. Within the spirit and principle of the present invention, any change, modification, replacement, integration and parameter change of these embodiments by conventional substitution or capable of achieving the same function without departing from the principle and spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A deep well closure structure suitable for foundation pit dewatering, characterized in that: It includes a pipe well structure, a reinforcement structure, a waterproof structure, a base structure, an upper closed structure, an external closed structure (7), and an internal filling structure (11); The pipe well structure comprises a PVC pipe (1) and a coarse sand ring (2), wherein the coarse sand ring (2) is located outside the PVC pipe; The base structure is a foundation pit leveling layer (3), the foundation pit leveling layer (3) is located above the coarse sand ring (2), and the top surface depth of the foundation pit leveling layer (3) is the design elevation of the bottom plate ground; The waterproof structure is laid on top of the base structure; The upper closed structure is arranged above the PVC pipe (1); The external closed structure (7) is arranged above the foundation pit leveling layer (3) and is located outside the pipe well structure. The external closed structure (7) has the same height as the upper closed structure. The outer periphery of the PVC pipe (1) is provided with a reinforcement structure; The internal filling structure (11) is filled inside the PVC tube (1).

2. A deep well closed structure suitable for foundation pit dewatering according to claim 1, characterized in that: The reinforcement structure is a steel pipe (4), the bottom of the steel pipe exceeds the foundation pit leveling layer by 50-100 mm; the top of the steel pipe exceeds the foundation pit leveling layer by 250-300 mm.

3. A deep well closed structure suitable for foundation pit dewatering according to claim 2, characterized in that: The waterproof structure comprises a waterproof board (5) and a water-stop putty (6); The waterproof board (5) is laid on the foundation pit leveling layer (3) and extended and welded to the surface of the steel pipe; Water-stop putty (6) is applied around the joint between the waterproof board (5) and the steel pipe (4).

4. A deep well closed structure suitable for foundation pit dewatering according to claim 1, characterized in that: The external closed structure (7) includes bottom plate steel bars and bottom plate concrete; The bottom plate reinforcement is arranged above the foundation pit leveling layer; The bottom plate concrete is densely poured inside the bottom plate steel bars; The external closed structure (7) reserves space around the top of the steel pipe; The thickness of the external closed structure (7) is consistent with the thickness of the foundation pit bottom plate.

5. A deep well closed structure suitable for foundation pit dewatering according to claim 4, characterized in that: The upper closed structure comprises a steel plate (8), a thick steel plate (9), and backfill concrete (10); The steel plate (8) is vertically welded to the outer periphery of the top of the steel pipe (4), and the width of the steel plate (8) is 200-300 mm; The thick steel plate (9) is arranged on the top of the steel pipe (4), and the steel plate (8) and the top of the steel pipe (4) are welded and sealed; The filling concrete (10) is filled in the space around the top of the steel pipe (4) reserved by the external closed structure (7).

6. A deep well closure structure suitable for foundation pit dewatering according to any one of claims 4 or 5, characterized in that: The backfill concrete (10) is micro-expansive concrete, and the strength grade of the micro-expansive concrete is one level higher than the strength grade of the base plate concrete.

7. A deep well closed structure suitable for foundation pit dewatering according to claim 6, characterized in that: The internal filling structure (11) is yellow sand and cement, and the internal filling structure (11) fills the inside of the PVC pipe (1) until it is flush with the top of the steel pipe (4).

8. A construction method for a deep well closed structure suitable for foundation pit dewatering as claimed in any one of claims 1 to 7, comprising the following steps: S1. Excavate the foundation pit to the designed elevation and clean the base surface; S2, laying a foundation pit leveling layer (3), putting a steel pipe (4) on the outer cover of the PVC pipe (1), welding a circle of steel plate (8) around the top of the steel pipe (4), and laying a waterproof board (5); S3, laying the bottom plate steel bars, first disconnecting and bending the bottom plate steel bars around the top of the steel pipe (4) to reserve space for the construction of the closed steel plate, pouring the bottom plate concrete and tamping it to make it dense; S4, cut off the PVC pipe (1), pump out a large amount of water, then fill the PVC pipe (1) with sand and cement to seal the wellhead; S5, welding the closed steel plate (8), connecting the bottom plate steel bars disconnected around the top of the steel pipe (4), and pouring micro-expansion concrete.

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