A critical surge prevention structure

Abstract

The utility model belongs to the field of building construction technology, and specifically discloses a critical sudden surge prevention structure, including a protective structure, a horizontal curtain and a drainage well; the protective structure is arranged around the foundation pit; the horizontal curtain is a full-floor reinforcement body arranged at the bottom of the foundation pit, located in the pressure-bearing aquifer, and its outer periphery is fixedly connected to the protective structure; the drainage well is provided with a plurality of wells in the protective area of ​​the protective structure, and the bottom extends into the pressure-bearing aquifer, and includes a well pipe and a water-stopping structure arranged between the well pipe and the wellbore wall; the water-stopping structure includes a filter material layer, a clay ball layer and a grouting layer from bottom to top, and at least one reserved grouting pipe is inserted in the grouting layer. The critical sudden surge prevention structure of the utility model effectively avoids the problem of sudden surge in the foundation pit through the combination of grouting, drainage, horizontal curtains and reserved grouting pipes, and ensures construction safety.

Description

Technical Field

[0001] The utility model relates to the technical field of building construction, in particular to a critical sudden surge prevention structure used for foundation pit groundwater control. Background Art

[0002] When excavating the foundation pit to the bottom, sudden surge is an issue that needs attention. There is pressurized water under the foundation pit. Excavating the foundation pit reduces the thickness of the impermeable layer overlying the aquifer. When the thickness is reduced to a certain extent, the head pressure of the pressurized water can crack or destroy the bottom plate of the foundation pit, causing sudden surge in the foundation pit. Sudden surge will not only cause the instability of the foundation pit, but may also cause subsequent disasters such as collapse, causing serious harm to construction workers and the surrounding environment.

[0003] In order to prevent sudden outbursts in foundation pits, a suspended water-stop curtain combined with a precipitation well is generally used. The suspended water-stop curtain is used to isolate water circumferentially, and water is pumped out through the precipitation well to reduce pressure and dewater. This can reduce the occurrence of sudden outbursts in foundation pits to a certain extent, but the effect is limited, and there is still a considerable risk of sudden outbursts in foundation pits. Utility Model Content

[0004] In order to solve the above problems, the utility model provides a critical surge prevention structure to further reduce the risk of surge during the construction process and improve the safety of foundation pit construction.

[0005] In order to achieve the above purpose, the specific technical solutions adopted by the utility model are as follows:

[0006] A critical surge prevention structure, comprising:

[0007] The retaining structure is set up around the foundation pit to enclose it; the retaining structure can be underground continuous wall, SMW method pile, TRD method pile and other water-stop curtains;

[0008] A horizontal curtain is arranged in the soil at the bottom of the foundation pit, located in the pressure-bearing aquifer, and its periphery is fixedly connected to the retaining structure; the horizontal curtain can be a high-pressure jet grouting pile, an N-JET method pile, an MJS method pile, a compaction grouting structure, etc.;

[0009] A plurality of dewatering wells are provided in the enclosure area of ​​the enclosure structure, and the bottom thereof extends into the pressurized aquifer; the dewatering wells include a well pipe with filter holes opened on the outer wall of the bottom section and a water-stopping structure provided between the well pipe and the wellbore wall, wherein the water-stopping structure includes a filter material layer, a clay ball layer and a grouting layer from bottom to top.

[0010] In the above-mentioned critical sudden surge prevention structure, the retaining structure and the horizontal curtain form a bottom closed structure to block the vertical channel of groundwater and avoid sudden surges on the foundation pit floor; a grouting layer is set at the top of the water-stop structure of the precipitation well for compaction and consolidation to reduce the possibility of sudden surges on the side wall of the well pipe.

[0011] Preferably, at least one reserved grouting pipe is inserted through the grouting layer, and a plurality of grouting holes are provided in the pipe body of the reserved grouting pipe. When the grouting layer has cracks or depressions, which may cause the side wall of the precipitation well to surge, grouting through the reserved grouting pipe can fill the defects and further reduce the possibility of surge on the side wall of the well pipe.

[0012] Preferably, the top of the filter material layer is not lower than the top of the filter hole setting area on the well pipe to ensure that the filter material layer covers the filter pipe section of the well pipe.

[0013] Preferably, the retaining structure includes bored cast-in-place piles, three-axis cement-soil mixing piles (i.e., ground-type water-stopping curtains) arranged outside the bored cast-in-place piles, and high-pressure jet grouting piles arranged between the bored cast-in-place piles and the three-axis cement-soil mixing piles. Such a setting of the retaining structure can achieve good soil retaining and water-stopping effects and improve the stability of the foundation pit.

[0014] Preferably, the thickness of the horizontal curtain is 4 to 12 m. The thickness of the horizontal curtain is determined based on the principle that the pressure-bearing aquifer below it will not cause a large vertical seepage surge or leakage to the soil layer above it, thus avoiding sudden surges on the foundation pit bottom plate; the depth is set based on the principle that the pressure-bearing aquifer below it does not need to be depressurized.

[0015] The utility model has the following beneficial effects:

[0016] 1. Use horizontal curtains and retaining structures to seal the bottom of the foundation pit, block the vertical channel of groundwater, eliminate the critical point of sudden surge, and avoid sudden surge of the foundation pit floor.

[0017] 2. By setting a grouting layer in the water-stop structure for compaction and reinforcement, the possibility of sudden surges on the side wall of the well pipe can be reduced.

[0018] 3. By setting a reserved grouting pipe in the grouting layer to fill the defects of the grouting layer, the purpose of strengthening water stopping is achieved and the side wall of the well pipe is avoided to surge. In dynamic and emergency conditions, the reserved grouting pipe starts grouting.

[0019] In summary, the utility model avoids the problem of sudden surge in the foundation pit and ensures construction safety through the combination of grouting, precipitation, horizontal curtain and reserved grouting pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 : The front view of the critical surge prevention and control structure described in Example 1.

[0021] Figure 2 : A top view of the critical surge prevention structure described in Example 1.

[0022] Figure 3 : An enlarged schematic diagram of the precipitation well described in Example 1.

[0023] In the figure: 1-retaining structure, 2-horizontal curtain, 3-dewatering well, 4-ground, 5-foundation pit, 6-pressure aquifer; 11-bored cast-in-place piles, 12-high-pressure rotary jet piles, 13-triaxial cement-soil mixing piles, 31-well pipe, 32-filter material layer, 33-clay ball layer, 34-grouting layer, 35-reserved grouting pipe. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0025] Example 1

[0026] A critical surge prevention structure, such as Figure 1-2 As shown, the critical sudden surge prevention structure for groundwater control of the foundation pit 5 opened on the ground 4 includes a retaining structure 1, a horizontal curtain 2 and a drainage well 3. The retaining structure 1 is arranged around the foundation pit 5; the horizontal curtain 2 is a full-floor reinforcement body arranged at the bottom of the foundation pit 5, located in the confined aquifer 6, and its outer periphery is fixedly connected to the retaining structure 1, thereby blocking the vertical channel of groundwater. In this embodiment, the horizontal curtain 2 is formed by compaction grouting and has a thickness of 8m. Several drainage wells 3 are arranged in the retaining area of ​​the retaining structure 1, and the bottom extends into the confined aquifer 6; it includes a well pipe 31 with filter holes opened on the outer wall of the bottom section and a water-stopping structure arranged between the well pipe 31 and the wall of the wellbore for preventing sudden surges on the side wall of the well pipe.

[0027] More specifically, Figure 3 As shown, the water-stopping structure includes a filter material layer 32, a clay ball layer 33 and a grouting layer 34 from bottom to top; the top of the filter material layer 32 is set beyond the top of the filter hole setting area on the well pipe 31; two reserved grouting pipes 35 are inserted in the grouting layer 34, and the pipe body of the reserved grouting pipe 35 is provided with a plurality of grouting holes, and the top pipe mouth is exposed to facilitate subsequent grouting. In this embodiment, the filter material used in the filter material layer 2 is yellow sand and gravel, and the two are mixed and filled to obtain the filter material layer 2. After the filter material is backfilled in place for more than 20 minutes, high-quality clay balls are backfilled, and then the grouting layer 34 is strengthened to stop water after the clay balls are in rest period; in dynamic and emergency conditions, the reserved grouting pipe 35 starts grouting to fill the gap and suppress the sudden surge of the side wall of the well pipe 31.

[0028] The enclosure structure 1 includes bored cast-in-place piles 11, triaxial cement-soil mixing piles 13 disposed outside the bored cast-in-place piles 11, and high-pressure rotary jet piles 12 disposed between the bored cast-in-place piles 11 and the triaxial cement-soil mixing piles 13. The structure of the combination of the bored cast-in-place piles 11, the high-pressure rotary jet piles 12, and the triaxial cement-soil mixing piles 13 strengthens the water-stopping and soil-retaining effect on the surrounding areas, thereby improving the stability of the foundation pit structure.

[0029] The above-mentioned critical sudden surge prevention structure closes the lower part of the foundation pit 5 through the retaining structure 1 and the horizontal curtain 2, reduces the water level by pumping water from the well pipe 31, and strengthens the water stopping of the side wall of the well pipe 31 by setting a water stopping structure with a grouting layer 34 and a reserved grouting pipe 35, thereby realizing combined prevention of sudden surge.

[0030] This specific implementation method is only an explanation of the utility model, not a limitation of the utility model. Any changes made by those skilled in the art after reading the specification of the utility model will be protected by the patent law as long as they are within the scope of the claims of the utility model.

Claims

1. A critical surge prevention structure, characterized in that: include: A retaining structure (1) is arranged around the foundation pit (5); A horizontal curtain (2) is arranged in the soil at the bottom of the foundation pit (5) and located in the confined aquifer (6), and its outer periphery is fixedly connected to the enclosure structure (1); A plurality of dewatering wells (3) are provided in the enclosure area of ​​the enclosure structure (1), and the bottom of the wells extends into the pressure-bearing aquifer (6); the wells (3) include a well pipe (31) with filter holes formed on the outer wall of the bottom section, and a water-stopping structure provided between the well pipe (31) and the wellbore wall, wherein the water-stopping structure includes, from bottom to top, a filter material layer (32), a clay ball layer (33), and a grouting layer (34).

2. The critical surge prevention structure according to claim 1, characterized in that: At least one reserved grouting pipe (35) is inserted through the grouting layer (34), and a plurality of grouting holes are provided on the pipe body of the reserved grouting pipe (35).

3. The critical surge prevention structure according to claim 1, characterized in that: The top of the filter material layer (32) is arranged not lower than the top of the filter hole setting area on the well pipe (31).

4. The critical surge prevention structure according to claim 1, characterized in that: The enclosure structure (1) comprises a bored cast-in-place pile (11), a three-axis cement-soil mixing pile (13) arranged outside the bored cast-in-place pile (11), and a high-pressure jet grouting pile (12) arranged between the bored cast-in-place pile (11) and the three-axis cement-soil mixing pile (13).

5. The critical surge prevention structure according to claim 1, characterized in that: The thickness of the horizontal curtain (2) is 4 to 12 m.

6. The critical surge prevention structure according to claim 1, characterized in that: The horizontal curtain (2) is a high-pressure jet grouting pile, an N-JET method pile, an MJS method pile or a compaction grouting structure.

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