A method for treating water gushing from foundation pits in unsealed exploration holes

Abstract

The present invention discloses a method for treating water gushing from an unsealed exploration hole foundation pit. The method is characterized in that an inverted filter layer is used in combination with a local well point pipe dewatering method to achieve local drainage and drainage of water gushing from an unsealed exploration hole foundation pit. The method specifically includes the following steps: burying the well point pipe, setting the inverted filter layer, and assisting the well point dewatering. Compared with the prior art, the present invention has the advantages of convenient construction, fast dewatering, and good treatment effect. The well point pipe flower pipe filter head for well point dewatering adopts a long and short filter pipe setting, and the top of the well point pipe does not need to adopt clay or other sealing means. It mainly drains the clear water gathered by the inverted filter layer, and takes into account the dewatering of the soil within a certain depth range under the inverted filter layer. The main function of the inverted filter layer is to prevent the loss of the top plate soil, and to play the role of weighting and collecting water. It can achieve well point dewatering quickly and solve safety hazards. It is a powerful auxiliary dewatering method for dewatering foundation pits with potential upper and lower hydraulic communication channels, and has certain prospects for promotion and application.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit well point dewatering, in particular to a method for treating water gushing from an unsealed exploration hole foundation pit. Background Art

[0002] In foundation pit projects in soft soil areas with abundant groundwater, dewatering designs are often carried out to facilitate earthwork excavation and prevent sudden surges at the bottom of the foundation pit. For example, water-stop curtains, drainage wells, and pressure relief wells are installed, and dewatering is carried out as needed. When designing the pressure relief wells, the designers will fully consider the weight of the aquitard at the bottom of the foundation pit on the confined water. The dewatering requirements of the pressure relief wells are based on the principle of not penetrating the top plate of the aquitard and dewatering as needed. The implicit premise of this principle is that the top plate of the aquitard is intact and there is no potential hydraulic connection channel between the confined water layer and the bottom of the foundation pit. If there are missed, unsealed, or ineffectively sealed exploration holes on the site, they will serve as potential hydraulic connection channels between the bottom of the foundation pit and the confined water layer, becoming a potential safety hazard for foundation pit excavation. It often occurs suddenly and catches people off guard. Summary of the Invention

[0003] The purpose of the present invention is to design a method for treating water gushing from foundation pits of unsealed exploration holes in response to the deficiencies of the existing technology. The method adopts a filter layer in combination with local well point pipe dewatering to achieve local drainage of pressurized water gushing within a certain range and depth around the foundation pits of unsealed exploration holes. The method specifically includes: excavation and temporary drainage of hidden dangers, burying of well point pipes, setting of filter layers and well point auxiliary dewatering. It can quickly resolve safety hazards and is a powerful auxiliary dewatering method for foundation pits with potential upper and lower hydraulic communication channels. The method is convenient in construction, has fast dewatering, and good treatment effect, and has certain prospects for promotion and application.

[0004] The specific technical solution for implementing the present invention is: a method for treating water gushing from an unsealed exploration hole foundation pit, which is characterized by using an inverted filter layer in combination with a local well point pipe dewatering method to achieve local drainage and drainage of water gushing from the unsealed exploration hole foundation pit, specifically comprising the following steps:

[0005] Step a: During the excavation process, if water begins to gush from an unsealed exploration hole, suspend the excavation of the foundation pit at that location and immediately organize the laying of well point pipes;

[0006] Step b: Installing a well point pipe A in the unsealed exploration hole for draining open water, and installing four well point pipes B in the soil surrounding the unsealed exploration hole for draining the soil. The well point pipes B are installed at the four corners of a square with a side length of 1.5m centered on the unsealed exploration hole; the well point pipes A and B are both 5m long and made of φ57×3.5 steel pipes, with the top exposed 30cm above the excavation surface. The well point pipe B is entirely provided with a filter pipe section from 70cm below the excavation surface to the bottom of the pipe, and the well point pipe A is provided with a filter pipe section within 1m of the bottom; the filter pipe section is wrapped with 80-mesh copper wire mesh;

[0007] Step c: Connect the B well point pipe and the A well point pipe to the drainage main pipe with drainage branch pipes, and connect the drainage main pipe to the vacuum pump;

[0008] Step d: Start the vacuum pump to pre-precipitate water in the 2m×2m area around the unsealed exploration hole;

[0009] Step e: When the water level drops to 1m below the excavation surface, use a small excavator to dig a 50cm deep filtration collection pit in a square area with a side length of 2.0m, centered on the unsealed exploration hole. Quickly backfill the filtration collection pit with bagged graded gravel to the excavation surface.

[0010] Step f: Continue to dewater the 2m×2m area around the unsealed exploration hole until the water level drops to 3m below the original excavation surface;

[0011] Step g: Resume the excavation of the foundation pit at that location until it reaches 1m above the existing water level in the unsealed exploration hole;

[0012] Step h: Remove the B and A well point pipes, and re-bury the B and A well point pipes in the unsealed exploration hole according to step a, and repeat steps b to g until the water level in the 2m×2m area around the unsealed exploration hole drops to 2m below the foundation pit;

[0013] i. Step: Use small excavators to dig a square concrete plugging pit with a side length of 2.0m, with the unsealed exploration hole as the center. The depth of the concrete plugging pit should be calculated for the hydraulic balance of the pressurized water. Quickly remove the B well point pipe and the A well point pipe. Consider the dock bottom plate condition of the foundation pit and promptly fill with quick-setting micro-expansion concrete for plugging.

[0014] Compared with the prior art, the present invention has the advantages of convenient construction, fast dewatering and good treatment effect. The well point pipe flower pipe filter head for well point dewatering adopts a long and short filter pipe arrangement, and no clay or other sealing means are required at the top of the well point pipe. It mainly drains the clear water gathered by the filter layer, and takes into account the dewatering of the soil within a certain depth range under the filter layer. The main function of the filter layer is to prevent the loss of the top plate soil, and to play a role in weighting and collecting water. It can realize well point dewatering more quickly and solve safety hazards. It is a powerful auxiliary dewatering method for foundation pit dewatering with potential upper and lower hydraulic communication channels, and has certain prospects for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the plan layout of the unsealed exploration hole foundation pit water gushing treatment in Example 1;

[0016] Figure 2 for Figure 1 AA cross-sectional diagram of . DETAILED DESCRIPTION Example

[0017] See Figures 1 and 2 The present invention adopts a method of using a filter layer in combination with local well point pipe dewatering to achieve local drainage and drainage of water gushing from unsealed exploration holes, specifically including the following steps:

[0018] Step a: During the excavation process, when water begins to gush from an unsealed exploration hole 4, the excavation of the foundation pit 1 at that location is suspended, and the burial of the well point pipe is immediately organized.

[0019] Step b: A well point pipe 7 is set in the unsealed exploration hole 4 for open water drainage, and four B well point pipes 5 are set in the soil 2 around the unsealed exploration hole 4 for draining the soil.

[0020] See Figure 1 The B well point pipe 5 is set at the four corners of a square with a side length of 1.5m and the unclosed exploration hole 4 as the center; the A well point pipe 7 is set at the center of the unclosed exploration hole 4; the length of the A well point pipe 7 and the B well point pipe 5 are both 5m, the pipe material is φ57*3.5 steel pipe, the top is 30cm exposed from the excavation surface, the B well point pipe 5 is all set as a filter pipe section 6 from 70cm below the excavation surface to the bottom of the pipe, and the A well point pipe 7 is set with a filter pipe section 6 within 1m of the bottom; the filter pipe section 6 is wrapped with 80-mesh copper wire mesh.

[0021] Step c: Connect the B well point pipe 5 and the A well point pipe 7 to the drainage main pipe 10 equipped with a vacuum pump 9 through the drainage branch pipe 11.

[0022] Step d: Start the vacuum pump 9 to pre-precipitate the soil 2 within a range of 2m×2m around the unsealed exploration hole 4.

[0023] Step e: When the water level drops to 1m below the excavation surface, use small excavation machinery to excavate a 50cm deep filtration collection pit 8 in the soil body 2 with a square range of 2.0m on the unsealed exploration hole 4 as the center, and quickly backfill the filtration collection pit with bagged graded gravel to the excavation surface.

[0024] Step f: Continue to dewater the soil 2 in the 2m×2m range around the unsealed exploration hole 4 until the water level drops to 3m below the original excavation surface.

[0025] Step g: Resume the excavation of the foundation pit 1 until the water level of the unsealed exploration hole 4 is 1m above the existing water level.

[0026] Step h: Remove the B well point pipe 5 and the A well point pipe 7, and re-bury the B well point pipe 5 and the A well point pipe 7 in the unsealed exploration hole 4 according to step a, and repeat steps b to g until the water level in the soil 2 within the 2m×2m range around the unsealed exploration hole 4 drops to 2m below the foundation pit 1.

[0027] Step i: Use small excavation machinery to excavate a square concrete plugging pit with a side length of 2.0m, with the unsealed exploration hole 4 as the center. The depth of the concrete plugging pit should be calculated for the hydraulic balance of the pressurized water. Quickly remove the B well point pipe 5 and the A well point pipe 7. Combined with the head conditions of the aquifer 3 of the foundation pit 1, fill the pit with quick-setting micro-expansion concrete in time for plugging.

[0028] The above specific implementations are only for further explanation of the present invention and are not intended to limit this patent. Any equivalent implementation of the present invention should be included in the scope of the claims of this patent.

Claims

1. A method for treating water gushing from an unsealed exploration hole foundation pit, characterized in that: The method of using a filter layer in combination with local well point pipe dewatering is used to achieve local drainage and drainage of water gushing from the unsealed exploration hole foundation pit. The specific steps include the following: Step a: During the excavation process, if water begins to gush from an unsealed exploration hole, suspend the excavation of the foundation pit at that location and immediately organize the laying of well point pipes; Step b: Installing a well point pipe A in the unsealed exploration hole for draining open water, and installing four well point pipes B in the soil surrounding the unsealed exploration hole for draining the soil. The well point pipes B are installed at the four corners of a square with a side length of 1.5m centered on the unsealed exploration hole; the well point pipes A and B are both 5m long and made of φ57×3.5 steel pipes, with the top exposed 30cm above the excavation surface. The well point pipe B is entirely provided with a filter pipe section from 70cm below the excavation surface to the bottom of the pipe, and the well point pipe A is provided with a filter pipe section within 1m of the bottom; the filter pipe section is wrapped with 80-mesh copper wire mesh; Step c: Connect the B well point pipe and the A well point pipe to the drainage main pipe equipped with a vacuum pump through the drainage branch pipe; Step d: Start the vacuum pump to pre-precipitate water in the 2m×2m area around the unsealed exploration hole; Step e: When the water level drops to 1m below the excavation surface, a 50cm deep filtration collection pit is excavated in a square area with a side length of 2.0m, centered on the unsealed exploration hole, and bagged graded gravel is quickly backfilled in the filtration collection pit to the excavation surface; Step f: Continue to dewater the 2m×2m area around the unsealed exploration hole until the water level drops to 3m below the original excavation surface; Step g: Resume the excavation of the foundation pit until it reaches 1m above the existing water level in the unsealed exploration hole; Step h: Remove the B and A well point pipes, and re-bury the B and A well point pipes in the unsealed exploration hole according to step a, and repeat steps b to g until the water level in the 2m×2m area around the unsealed exploration hole drops to 2m below the foundation pit; i. Step: With the unsealed exploration hole as the center, excavate a square concrete plugging pit with a side length of 2.0m. The depth of the concrete plugging pit should be calculated for the hydraulic balance of the pressurized water. Quickly remove the B well point pipe and the A well point pipe. Considering the bottom plate condition of the foundation pit, fill the pit with quick-setting micro-expansion concrete in time for plugging.

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