Combined dewatering well structure

Abstract

The present application belongs to the technical field of tube well filtering device, and discloses a combined type precipitation well structure, which comprises a sand-free concrete water filtering pipe, a bridge type water filtering pipe and a sand and pebble filtering material layer; the sand-free concrete water filtering pipe is arranged in a fine-grained soil layer, the bridge type water filtering pipe is arranged in a coarse-grained soil layer, and the sand and pebble filtering material layer is arranged between the sand-free concrete water filtering pipe and the fine-grained soil layer and between the bridge type water filtering pipe and the coarse-grained soil layer. The present application has a safe and reliable structure, can well solve the problem of low precipitation efficiency of single pipe well structure in coarse-grained soil and fine-grained soil interbedded stratum and waste of engineering cost, can ensure the safety and quality of foundation pit engineering, and can be used for precipitation construction of super-large and super-deep foundation pit engineering in coarse-grained soil and fine-grained soil interbedded stratum and high underground water level.

Description

Technical Field

[0001] This invention belongs to the technical field of well filtration devices, and specifically relates to a combined dewatering well structure. Background Technology

[0002] With the continuous development of urban underground space development and utilization technology, there are more and more ultra-deep and ultra-large foundation pit projects. When the engineering geological and hydrogeological conditions of foundation pit projects are complex, in ultra-large and ultra-deep foundation pit projects rich in groundwater, especially those affected by groundwater confined water, dewatering is the guarantee of foundation pit construction safety and quality. Especially in strata where coarse and fine soils are interlayered, it is crucial to take targeted dewatering measures in combination with engineering geological and hydrogeological characteristics.

[0003] Currently, the most common method for dewatering foundation pits is well dewatering, which is characterized by its large drawdown depth and large drainage volume. Typically, in foundation pit projects located in water-rich strata, dewatering should be carried out before excavation to lower the water level to 0.5m below the excavation surface before excavation.

[0004] For example, application number CN202220472312.2 includes a dewatering well body installed in a wellbore and a fine stone drainage layer buried between the dewatering well body and the inner wall of the wellbore. The dewatering well body includes a dense mesh net, a wire mesh, and a steel frame arranged in sequence. The dense mesh net is located on the side of the dewatering well closest to the fine stone drainage layer to reduce the possibility of the sidewall of the dewatering well body being blocked. However, the longitudinal structure of this dewatering well is relatively simple. If the dewatering well structure is not designed according to the geological characteristics, it will often lead to problems such as difficulty in dewatering or increased construction costs. For example, in strata with alternating layers of coarse and fine soil, if only a single well structure is used, not only will it not achieve a good dewatering effect, but the dewatering efficiency will be low and the project cost will be wasted. In severe cases, it may even lead to engineering accidents. Summary of the Invention

[0005] The purpose of this invention is to provide a combined dewatering well structure. Based on the geological conditions, a combined pipe well structure is adopted in the vertical direction to improve dewatering efficiency while saving engineering costs, and at the same time, it can also ensure the safety and quality of the foundation pit project.

[0006] The technical solution adopted in this invention is a combined dewatering well structure, including a sand-free concrete filter pipe, a bridge-type filter pipe, and a sand and gravel filter material layer; the sand-free concrete filter pipe is set in a fine-grained soil layer, the bridge-type filter pipe is set in a coarse-grained soil layer, and the sand and gravel filter material layer is set between the sand-free concrete filter pipe and the fine-grained soil layer and between the bridge-type filter pipe and the coarse-grained soil layer.

[0007] Preferably, the diameter of the well hole is 300-400 mm larger than the diameter of the bridge-type filter pipe.

[0008] Preferably, the length of the sand-free concrete filter pipe is the same as the thickness of the fine-grained soil layer, and the length of the bridge-type filter pipe is the same as the thickness of the coarse-grained soil layer.

[0009] Preferably, the outer wall of the sand-free concrete filter pipe is covered with a nylon filter screen and geotextile.

[0010] Preferably, when the sand-free concrete filter pipe is located at the bottom of the formation, a well bottom plug is provided at the bottom of the sand-free concrete filter pipe, and the material of the well bottom plug is the same as that of the sand-free concrete filter pipe.

[0011] Preferably, the top and bottom ends of the bridge-type water filter pipe are provided with clips, and the clips are fixedly connected to the bridge-type water filter pipe.

[0012] Preferably, the card holder is welded to the bridge-type water filter pipe.

[0013] Preferably, the sand and gravel filter media layer consists of 2-3 mm gravel, which is evenly distributed.

[0014] The beneficial effects of this invention are as follows:

[0015] Compared to the common single-structure vertical dewatering well structure of foundation pits, the combined dewatering well structure of this invention is safe and reliable. It sets up sand-free concrete filter pipes in the fine-grained soil layer and bridge-type filter pipes in the coarse-grained soil layer. It can effectively solve the problem of low dewatering efficiency and waste of engineering costs of single-well structures in strata with alternating layers of coarse and fine soil. At the same time, it can also ensure the safety and quality of foundation pit projects. It can be used for dewatering construction of ultra-large and ultra-deep foundation pit projects in strata with alternating layers of coarse and fine soil and high groundwater levels. Attached Figure Description

[0016] Figure 1 This is a schematic cross-sectional view of a combined dewatering well structure according to the present invention.

[0017] Figure 2 This is a schematic diagram of the bridge-type water filter pipe structure of the present invention.

[0018] The meanings of the symbols in the above diagram are as follows: 1. Sand-free concrete filter pipe, 2. Card, 3. Bridge-type filter pipe, 4. Bridge-type filter hole, 5. Sand and gravel filter layer, 6. Pipe well hole, 7. Bottom plug of well. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] For the combined dewatering well structure of this invention, please refer to [link / reference]. Figure 1 It includes a sand-free concrete filter pipe 1, a bridge-type filter pipe 3, and a sand and gravel filter media layer 5.

[0021] The sand-free concrete filter pipe 1, based on geological conditions, is buried in a fine-grained soil layer. The outer wall of the sand-free concrete filter pipe 1 is wrapped with two layers of nylon filter mesh and geotextile. The nylon filter mesh and geotextile prevent soil from flowing into the sand-free concrete filter pipe 1, improving the filtration effect. When the sand-free concrete filter pipe 1 is located at the bottom of the stratum, a well bottom plug 7 is installed at the bottom of the sand-free concrete filter pipe 1. The well bottom plug 7 is made of the same material as the sand-free concrete filter pipe 1, and it isolates soil from the bottom of the well from entering the sand-free concrete filter pipe 1.

[0022] Bridge-type filter pipe 3 is buried in coarse-grained soil layers according to geological conditions. Please refer to [link / reference]. Figure 2 The bridge-type filter pipe 3 is equipped with brackets 2 and bridge-type filter holes 4. Several bridge-type filter holes 4 are spaced apart. The bridge-type filter holes 4 have the advantages of uniform water intake and strong water permeability, which improves the dewatering effect while saving construction time. Brackets 2 are provided at the top and bottom of the bridge-type filter pipe 3. The brackets 2 are welded to the bridge-type filter pipe 3 to form a whole, which facilitates the connection with the sand-free concrete filter pipes 1 above and below, and ensures the integrity of the pipe well structure.

[0023] The sand and gravel filter material layer 5 is filled between the sandless concrete filter pipe 1 and the fine soil layer, and between the bridge-type filter pipe 3 and the coarse soil layer. The sand and gravel filter material layer 5 uses 2-3mm well rounded gravel, which is continuously and evenly added along the edge of the well hole in a single direction to ensure that the filled sand and gravel filter material layer 5 is more uniform and it is not easy for the height of the upper end of the annular sand and gravel layer to be significantly different.

[0024] The lengths of the sand-free concrete filter pipe 1 and the bridge-type filter pipe 3 can be adjusted according to the geological conditions. This allows the well structure to better adapt to the geological conditions. The bridge-type filter pipe 3 is installed in coarse-grained soil, while the sand-free concrete pipe 1 is installed in fine-grained soil, thereby improving the dewatering efficiency of the dewatering well.

[0025] The diameter of the well hole 6 is 300-400mm larger than that of the bridge-type filter pipe 3, which facilitates the installation of the sand-free concrete filter pipe 1 and the bridge-type filter pipe 3 after the well hole 6 is constructed.

[0026] The combined dewatering well structure of this invention is safe and reliable. The sand-free concrete filter pipe 1 and the bridge-type filter pipe 3 are installed inside the well hole 6. The space between the sand-free concrete filter pipe 1, the bridge-type filter pipe 3 and the well hole 6 is filled with a sand and gravel filter material layer 5. This can effectively solve the problem of low dewatering efficiency and wasted engineering costs of a single well structure in strata with alternating layers of coarse and fine soil. At the same time, it can also ensure the safety and quality of the foundation pit project. It can be used for dewatering construction of ultra-large and ultra-deep foundation pit projects in strata with coarse and fine soil and high groundwater levels.

Claims

1. A combined dewatering well structure, installed in a coarse-grained soil layer, characterized in that, The system includes a sand-free concrete filter pipe, a bridge-type filter pipe, and a sand and gravel filter media layer. The sand-free concrete filter pipe is placed within a fine-grained soil layer, the bridge-type filter pipe is placed within a coarse-grained soil layer, and the sand and gravel filter media layer is placed between the sand-free concrete filter pipe and the fine-grained soil layer, and between the bridge-type filter pipe and the coarse-grained soil layer. The top and bottom ends of the bridge-type filter pipe are provided with clips, which are fixedly connected to the bridge-type filter pipe for connecting with the sand-free concrete filter pipes above and below.

2. The combined dewatering well structure according to claim 1, characterized in that, The diameter of the combined dewatering well structure is 300-400 mm larger than that of the bridge-type filter pipe.

3. The combined dewatering well structure according to claim 1, characterized in that, The length of the sand-free concrete filter pipe is the same as the thickness of the fine-grained soil layer, and the length of the bridge-type filter pipe is the same as the thickness of the coarse-grained soil layer.

4. The combined dewatering well structure according to claim 1, characterized in that, The outer wall of the sand-free concrete filter pipe is covered with nylon filter mesh and geotextile.

5. The combined dewatering well structure according to claim 1, characterized in that, When the sand-free concrete filter pipe is located at the bottom of the formation, a well bottom plug is provided at the bottom of the sand-free concrete filter pipe, and the material of the well bottom plug is the same as that of the sand-free concrete filter pipe.

6. The combined dewatering well structure according to claim 1, characterized in that, The card holder is welded to the bridge-type water filter pipe.

7. The combined dewatering well structure according to any one of claims 1-6, characterized in that, The sand and gravel filter media layer consists of 2-3 mm gravel, which is evenly distributed.

Images