Open caisson structure suitable for urban water-rich silty-fine sand stratum

Abstract

The utility model provides an open caisson structure suitable for an urban water-rich silty-fine sand stratum. The open caisson structure comprises an open caisson, the open caisson sealing bottom is arranged at the bottom end of the open caisson; the waterproof curtain is arranged around the open caisson, and the bottom of the waterproof curtain is connected with the open caisson sealing bottom; the dewatering well is arranged on the periphery of the waterproof curtain, and the dewatering well is used for being connected with a water suction pump to pump underground water on the periphery of the waterproof curtain. Underground water of a surrounding soil layer is continuously pumped through the precipitation well in the sinking process of the open caisson, quicksand is prevented from interfering with construction operation, the waterproof curtain and the open caisson sealing bottom are arranged, the underground water is prevented from flowing into the open caisson, and construction interference is reduced through the measures.

Description

Technical Field

[0001] The utility model relates to the technical field of underground engineering design, in particular to a caisson structure applicable to urban water-rich fine sand strata. Background Technique

[0002] Caisson structures are widely used in the construction of urban pipe network facilities. Especially for the laying of urban power grids, underground engineering is often adopted. At this time, caisson structures are needed as nodes or maintenance stations for cable laying.

[0003] At present, in areas with high groundwater levels, large soil permeability, and prone to flow or collapse, the non-draining soil extraction and sinking method is often adopted. However, the non-draining soil extraction and sinking operation conditions are poor, the construction efficiency is low, there are many restricted factors in the construction process, and it is easy to disturb the surrounding soil and cause quicksand and collapse.

[0004] Considering factors such as construction feasibility, construction risks, costs, and construction periods, it is very necessary to develop a caisson sinking plan applicable to urban complex hydrogeological conditions. Content of the Utility Model

[0005] The purpose of the utility model is to provide a caisson structure applicable to urban water-rich fine sand strata in view of the defects of the prior art.

[0006] The utility model provides a caisson structure applicable to urban water-rich fine sand strata, including: a caisson; a caisson bottom seal, which is arranged at the bottom end of the caisson; a water-stop curtain, which is arranged around the caisson, and the bottom of the water-stop curtain is connected with the caisson bottom seal; a dewatering well, which is arranged around the water-stop curtain, and the dewatering well is used to connect a water pump to extract the groundwater outside the water-stop curtain.

[0007] Furthermore, it also includes: a jacking pipe, which is connected with the side wall of the caisson.

[0008] Furthermore, it also includes: the soil body reinforced at the jacking pipe portal, which is arranged outside the water-stop curtain.

[0009] Furthermore, the water-stop curtain is double-layered, including a first layer of curtain and a second layer of curtain.

[0010] Still further, the first layer of curtain is cement stabilized soil, and the second layer of curtain is cement stabilized soil with H-shaped steel inside.

[0011] Furthermore, the water-stop curtain also includes a capping beam, which is arranged at the top of the water-stop curtain.

[0012] Furthermore, the distance between the water-stop curtain and the caisson is 0.6 - 1 m.

[0013] Furthermore, the distance between the precipitation well and the water-stop curtain is 1 to 2 m.

[0014] Furthermore, several precipitation wells are arranged around the water-stop curtain, and the number of precipitation wells is determined by the precipitation requirement.

[0015] Furthermore, the diameter of the precipitation well is 200 - 300 mm.

[0016] The beneficial effects of the present utility model are as follows:

[0017] 1. Compared with the current drainage and sinking scheme, in this technical solution, during the sinking process of the open caisson, the groundwater in the surrounding soil layer is continuously pumped out through the precipitation well to prevent quicksand from interfering with the construction operation. Moreover, a water-stop curtain and the bottom sealing of the open caisson are provided to prevent groundwater from flowing into the open caisson, thereby reducing construction interference through the above measures.

[0018] 2. By setting a double-layer water-stop curtain and arranging H-shaped steel in the second layer of the curtain, the structural strength of the water-stop curtain is enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of an embodiment of the present utility model;

[0020] Figure 2 is Figure 1 the top view of

[0021] Figure 3 is a schematic structural diagram of the water-stop curtain 3 in the embodiment of the present utility model.

[0022] Reference numerals: 1 - open caisson; 2 - bottom sealing of the open caisson; 3 - water-stop curtain; 31 - first layer of curtain; 32 - second layer of curtain; 33 - capping beam; 4 - reinforced soil mass of the pipe jacking portal; 5 - pipe jacking; 6 - precipitation well. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer and more understandable, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0024] Referring to Figures 1 - 3 , an open caisson structure applicable to urban water-rich fine sand strata includes:

[0025] An open caisson 1, and the open caisson 1 can be used as a node or maintenance point for cable laying.

[0026] The bottom sealing 2 of the open caisson is arranged at the bottom end of the open caisson 1, and the bottom sealing 2 of the open caisson is used to prevent groundwater from flowing in.

[0027] The water-stop curtain 3 is arranged around the open caisson 1, and the bottom of the water-stop curtain 3 is connected to the bottom sealing of the open caisson 2 to form a closed cup-shaped structure. The water-stop curtain 3 is double-layered and includes a first-layer curtain 31 and a second-layer curtain 32. The first-layer curtain 31 is cement stabilized soil, and the second-layer curtain 32 is cement stabilized soil with H-shaped steel embedded therein, so as to enhance the structural strength of the water-stop curtain 3. The water-stop curtain 3 further includes a capping beam 33, and the capping beam 33 is arranged at the top of the water-stop curtain 3. The distance between the water-stop curtain 3 and the open caisson 1 is 0.8 m. Keeping a certain distance between the water-stop curtain 3 and the open caisson 1 is beneficial to the earth excavation and sinking process of the open caisson 1. The water-stop curtain 3 is assembled by densely arranging cement-soil mixing piles.

[0028] The soil mass for reinforcing the top pipe portal 4 is arranged outside the water-stop curtain 3 and is used to reinforce the soil layer around the top pipe portal and is cement stabilized soil.

[0029] The top pipe 5 is connected to the side wall of the open caisson 1.

[0030] The dewatering well 6 is arranged around the water-stop curtain 3. The dewatering well 6 is used to connect a water pump to pump out the groundwater outside the water-stop curtain 3 to prevent the occurrence of quicksand phenomenon in the surrounding fine silt sand stratum and affect the construction operation. The distance between the dewatering well 6 and the water-stop curtain 3 is 1.5 m. The purpose is to keep the soil layer in a certain range around stable and avoid the occurrence of quicksand phenomenon. Too large a range will affect the stability of the surrounding site and the foundation of buildings and structures. A number of dewatering wells 6 are arranged around the water-stop curtain 3. The dewatering wells dewater as required, and the quantity is determined by the dewatering need. The dewatering amplitude and range should be reasonably controlled. The diameter of the dewatering well 6 is 250 mm.

[0031] In actual use, after construction layout and positioning, the water-stop curtain 3 is constructed first. To ensure the smooth sinking of the open caisson 1, a certain gap is left between the water-stop curtain 3 and the outer wall of the open caisson 1. Then, the soil of the pipe jacking portal is reinforced 4, and the dewatering wells 6 and the bottom sealing of the open caisson 2 are constructed synchronously. The bottom sealing of the open caisson 2 is formed by directly grouting by inserting a pipeline into the corresponding depth of the soil layer through relevant special equipment. Then, the working pit is excavated and the open caisson 1 is poured, and the capping beam 33 is constructed synchronously. After the open caisson 1 reaches the design strength, the drainage and soil removal for sinking inside the caisson are started. At the same time, the dewatering wells 6 start to dewater as needed synchronously. The drainage inside the open caisson 1 keeps the inside of the open caisson 1 in a water-free state during the soil removal operation. Outside the open caisson 1, the dewatering is gradually carried out as needed through the dewatering wells 6 with the sinking depth of the open caisson 1 to balance the soil pressure difference inside and outside the open caisson 1. As the open caisson 1 keeps sinking, the dewatering depth outside the open caisson 1 gradually increases until it drops below the pipe jacking portal. During the dewatering process, if the settlement and deformation of the surrounding site and buildings are significant and approaching the warning value, the dewatering should be stopped and treatment measures such as grouting to reinforce the surrounding soil should be taken as appropriate. After the treatment is completed, the dewatering and the sinking of the open caisson 1 continue until the open caisson 1 sinks in place and the bottom slab of the open caisson is poured.

[0032] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included within the protection scope of the present application.

Claims

1. A caisson structure applicable to the urban water-rich fine silt sand stratum, characterized in that Comprising: Open caisson (1); Bottom sealing of open caisson (2), which is arranged at the bottom end of the open caisson (1) and is used to block the inflow of groundwater; Cut-off wall (3), which is arranged around the open caisson (1), the bottom of the cut-off wall (3) is connected to the bottom sealing of open caisson (2), and the cut-off wall (3) is used to block the inflow of surrounding groundwater into the open caisson (1); Dewatering well (6), which is arranged around the cut-off wall (3) and is used to connect a water pump to extract the groundwater outside the cut-off wall (3).

2. The open caisson structure applicable to the urban water-rich fine sand stratum according to claim 1, characterized in that, Also comprising: Jacked pipe (5), which is connected to the side wall of the open caisson (1).

3. The open caisson structure applicable to the urban rich water silt and fine sand stratum according to claim 2, characterized in that, Also comprising: Reinforced soil for the jacked pipe portal (4), which is arranged outside the cut-off wall (3).

4. The open caisson structure applicable to urban water-rich fine sand stratum according to claim 1, characterized in that: The cut-off wall (3) is double-layered, including a first-layer curtain (31) and a second-layer curtain (32).

5. The open caisson structure applicable to urban water-rich fine sand stratum according to claim 4, characterized in that: The first-layer curtain (31) is cement stabilized soil, and the second-layer curtain (32) is cement stabilized soil with H-shaped steel inside.

6. The open caisson structure applicable to urban water-rich fine sand stratum according to claim 1, characterized in that: The cut-off wall (3) further includes a capping beam (33), and the capping beam (33) is arranged at the top of the cut-off wall (3).

7. The open caisson structure applicable to urban water-rich fine sand stratum according to claim 1, characterized in that: The distance between the cut-off wall (3) and the open caisson (1) is 0.6 - 1 m.

8. The open caisson structure applicable to the urban water-rich fine sand stratum according to claim 1, characterized in that: The distance between the dewatering well (6) and the cut-off wall (3) is 1 - 2 m.

9. The open caisson structure applicable to the urban water-rich fine sand stratum according to claim 1, characterized in that: A number of dewatering wells (6) are arranged around the cut-off wall (3).

10. The open caisson structure applicable to urban water-rich silty fine sand stratum according to claim 9, characterized in that: The diameter of the dewatering well (6) is 200 - 300 mm.

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