Precipitation well sealing system in foundation pit

Abstract

The utility model provides a dewatering well sealing system in a foundation pit, which comprises a foundation bottom plate and a steel sleeve penetrating through the foundation bottom plate, two ends of the steel sleeve are respectively communicated with a dewatering well pipe and a plugging ball valve, and the plugging ball valve is used for controlling connection and disconnection of the steel sleeve. A water stop ring plate is arranged in the foundation slab, and the outer wall of the steel sleeve is sleeved with the water stop ring plate. According to the plugging ball valve, the dewatering well pipe is sealed through the plugging ball valve which is higher in blocking capacity and bearing capacity, the problem that in the prior art, graded gravel and micro-expansive concrete cannot press gushing water, so that the sealing quality of a pipe well is low or well sealing fails is solved, and the plugging ball valve is high in construction efficiency and low in construction cost; the dewatering well pipe, the steel sleeve and the plugging ball valve are fixed in a welding mode, and the problems of stress damage and leakage caused by the fact that a flange cover and the steel sleeve are connected through bolts in the prior art are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of foundation pit construction, in particular to a closed system for a dewatering well in a foundation pit. Background Art

[0002] With the development of urban construction, there are more and more deep foundation pit projects, and the dewatering of foundation pits has become a big problem. At present, the main method of foundation pit dewatering is to set up dewatering wells in the foundation pit and recharge wells outside the foundation pit. Water is pumped through the dewatering wells and then recharged into the recharge wells to achieve the purpose of dewatering in the foundation pit. After the foundation pit dewatering project is completed, in order to ensure that there is no leakage in the dewatering wells, the dewatering wells need to be effectively closed and partially waterproofed. Therefore, the closure of the dewatering wells after the dewatering is completed has become a difficult point in the waterproof closure of the basement, and it is also an important part of the foundation pit dewatering project.

[0003] In order to achieve effective closure of the dewatering well in the foundation pit, the conventional sealing method is: use a submersible pump to pump the water in the dewatering well to a lower water level, weld a steel casing with 1 to 2 water stop rings to the dewatering well pipe, construct the foundation cushion layer and the foundation bottom plate, use graded sand and gravel to recharge the dewatering well and the steel casing, pour micro-expansive concrete on the top of the graded sand and gravel, and then use the flange cover plate to bolt the steel casing.

[0004] The disadvantage of this construction method is that for foundation pit projects with large foundation pit depths and adjacent to rivers, the head pressure is relatively large and the water output is also relatively large. It is easy for graded sand and gravel and micro-expansive concrete to fail to suppress the gushing water, which ultimately leads to low quality of pipe well closure or even failure to seal the well. In addition, flange connections and the junction between bolts and gaskets are prone to leakage. When the bolts are tightened around the flange, the stress generated may cause damage to the flange and the pipeline. Moreover, the construction process of this construction method is relatively cumbersome, the construction speed is slow, and a large amount of graded sand and gravel, micro-expansive concrete and other materials need to be re-injected, and the cost is relatively high. Utility Model Content

[0005] The utility model aims to provide a closed system for a dewatering well in a foundation pit to solve the problems in the above background.

[0006] The technical solution of the utility model includes: a closed system for a dewatering well in a foundation pit, which includes: a foundation bottom plate and a steel casing penetrating the foundation bottom plate, the two ends of the steel casing are respectively connected to the dewatering well pipe and a sealing ball valve, and the sealing ball valve is used to control the on-off of the steel casing; a water stop ring plate is provided in the foundation bottom plate, and the water stop ring plate is sleeved on the outer wall of the steel casing.

[0007] Preferably, a waterproof coil is provided at the bottom of the base slab, and one end of the waterproof coil is bent toward the sealing ball valve to abut against the outer wall of the steel casing.

[0008] Preferably, a foundation cushion layer is provided at the bottom of the foundation bottom plate. The waterproof coiled material is located between the foundation cushion layer and the foundation bottom plate. The top end of the bent part of the waterproof coiled material is located below the water stop ring plate, and the distance from the bottom end of the steel casing is greater than or equal to 300 mm.

[0009] Preferably, the distance between the top end of the dewatering well pipe and the bottom of the foundation cushion layer is 100 mm to 150 mm.

[0010] Preferably, the plugging ball valve includes a valve body, a valve ball, a valve stem and a seal. The valve ball is rotatably fitted inside the valve body; one end of the valve stem is connected to the valve ball, and the other end extends out of the valve body and is hermetically connected to the valve body through the seal.

[0011] Preferably, the seal includes a sealing filler and a filler pressing plate. The filler pressing plate is detachably arranged outside the valve body, and the sealing filler is pressed by the filler pressing plate into the gap between the valve stem and the valve body.

[0012] Preferably, a rotating handwheel is provided at the end of the valve stem extending out of the valve body.

[0013] Preferably, the valve body includes an upper valve body and a lower valve body. An upper limit valve seat is provided between the upper valve body and the valve ball, and a lower limit valve seat is provided between the lower valve body and the valve ball.

[0014] The beneficial effects of the present utility model are as follows: By using a plugging ball valve with stronger barrier ability and bearing pressure to seal the dewatering well pipe, it avoids the situation in the prior art where graded sand and slightly expanded concrete cannot hold back the gushing water, ultimately leading to low quality of pipe well sealing or even well sealing failure. Moreover, the operation of the plugging ball valve is simple and the cost is lower, improving the construction efficiency and reducing the construction cost. The dewatering well pipe, steel casing and plugging ball valve are fixed by welding, avoiding the stress damage and leakage problems to the structure caused by using bolt connection of the flange cover and the steel casing in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is the overall structure diagram of an embodiment of the present utility model;

[0016] Figure 2 is the structure diagram of the plugging ball valve in an embodiment of the present utility model.

[0017] In the figure:

[0018] 10. Foundation cushion layer;

[0019] 20. Foundation bottom plate;

[0020] 30. Dewatering well pipe;

[0021] 40. Steel casing

[0022] 50. Waterstop ring plate

[0023] 60. Plugging ball valve; 61. Valve body; 61a. Upper valve body; 61b. Lower valve body; 62. Valve ball; 63. Valve stem; 64. Seal; 64a. Sealing packing; 64b. Packing pressing plate; 65. Rotating handwheel; 66. Upper limit valve seat; 67. Lower limit valve seat

[0024] 70. Waterproof coiled material Detailed implementation manners

[0025] The technical solutions of the present utility model will be clearly and completely described below in conjunction with the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without making creative efforts shall fall within the protection scope of the present utility model.

[0026] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, the meaning of "plural" is two or more.

[0027] In the description of the present utility model, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0028] Refer to the attached Figure 1-2, this embodiment provides a dewatering well sealing system in a foundation pit, including: a foundation cushion 10, a foundation slab 20, a dewatering well pipe 30, a steel casing 40, a water stop ring plate 50, a plugging ball valve 60, and a waterproof coiled material 70. The dewatering well pipe 30 is located below the foundation cushion 10; the bottom end of the steel casing 40 is connected to the top end of the dewatering well pipe 30, and the other end of the steel casing 40 sequentially penetrates through the foundation cushion 10 and the foundation slab 20 and then is connected to the plugging ball valve 60; the plugging ball valve 60 is used to control the on-off of the steel casing 40; the water stop ring plate 50 is located in the foundation slab 20, sleeved on the outer wall of the steel casing 40, and fixedly connected to the steel casing 40 to prevent seepage on both the top and bottom sides of the foundation slab 20; the waterproof coiled material 70 is located between the foundation cushion 10 and the foundation slab 20, one end of which is bent towards the plugging ball valve 60 and abuts against the outer wall of the steel casing 40 to prevent seepage at the joint of the foundation slab 20, the foundation cushion 10, and the steel casing 40.

[0029] In this system, the plugging ball valve 60 is used to plug the dewatering well pipe 30 and the steel casing 40. During the construction of the foundation cushion 10 and the foundation slab 20, pumping and drainage can always be carried out through the steel casing 40 and the plugging ball valve 60. After the construction of the foundation cushion 10 and the foundation slab 20 is completed, the plugging ball valve 60 is closed, that is, the dewatering well pipe 30 and the steel casing 40 are plugged. Among them, the plugging ball valve 60, the steel casing 40, and the dewatering well pipe 30 are all welded and fixed, with stable connection and good sealing performance, avoiding the stress damage and leakage problems caused by bolt connection of the flange cover and the steel casing in the prior art; by adjusting the opening and closing state of the plugging ball valve 60, the dewatering well pipe 30 and the steel casing 40 can be opened or closed. The blocking ability and bearing pressure of the plugging ball valve 60 are stronger, which can not only avoid the problem of graded sand and slightly expanded concrete being washed out by water in the prior art, but also the construction of the plugging ball valve 60 is more convenient and the cost is lower.

[0030] Before constructing the foundation cushion layer 10, dewater the inside of the dewatering well pipe 30 to avoid the influence of water gushing from the pipe orifice on the subsequent welding construction. Cut the top of the dewatering well pipe 30 to a level 100 mm - 150 mm below the bottom elevation of the foundation cushion layer 10, ensuring that the cut is smooth and free of cracks. Determine the length of the steel casing 40 based on the elevations and thicknesses of the foundation cushion layer 10 and the foundation slab 20, ensuring that the top of the steel casing 40 is higher than the foundation slab 20 and the bottom is lower than the foundation cushion layer 10. Weld the steel casing 40 to the top of the dewatering well pipe 30 using arc welding, setting the weld width and height according to relevant construction standards. The steel casing 40 and the dewatering well pipe 30 are fixed by welding, with a firm connection and strong sealing performance. Determine the position of the water stop ring plate 50 based on the elevation and thickness of the foundation slab 20. Sleeve the water stop ring plate 50 outside the steel casing 40 and weld it to the outer wall of the steel casing 40 (which can be done before or after connecting the steel casing 40 and the dewatering well pipe 30, without limitation). The position of the water stop ring plate 50 is preferably at the mid-thickness of the foundation slab 20. The width of the water stop ring plate 50 is greater than or equal to 150 mm, and the thickness is greater than or equal to 10 mm. Then weld the plugging ball valve 60 to the top of the steel casing 40, and then the construction of the foundation cushion layer 10 and the foundation slab 20 can be carried out.

[0031] During the above welding process, dewatering of the dewatering well pipe 30 can be carried out while welding, ensuring that the height of the gushing water is below the weld joint to avoid the influence of gushing water on the welding quality. After the steel casing 40 and the plugging ball valve 60 are welded, the dewatering well pipe 30 can be tested for closure through the plugging ball valve 60. Close the plugging ball valve 60 and observe whether there is water leakage at the weld position. If there is water leakage, additional welding treatment shall be taken.

[0032] During the construction of the foundation cushion layer 10 and the foundation slab 20, open the plugging ball valve 60, and continuously pump out the water in the dewatering well pipe 30 through the plugging ball valve 60 and the steel casing 40 to keep the water level within the range required by the construction specifications. After the construction of the foundation cushion layer 10 is completed, lay the waterproof coiled material 70 on the top of the foundation cushion layer 10. Bend the end of the waterproof coiled material 70 close to the outer wall of the steel casing 40 towards the plugging ball valve 60, and make the bent part press tightly against the outer wall of the steel casing 40 to prevent seepage at the connection part of the foundation slab 20, the foundation cushion layer 10, and the steel casing 40. Then construct the foundation slab 20 above the waterproof coiled material 70. After reaching the designed condition for stopping dewatering, close the plugging ball valve 60.

[0033] When closing the dewatering well pipe 30, follow the principle of from low to high, from large to small, and from the periphery to the middle. First, close the dewatering wells with large water head pressure and large water gushing volume, and then close the dewatering wells with small water head pressure and small water gushing volume, gradually closing from the periphery of the foundation pit to the middle.

[0034] Preferably, the top of the bent part of the waterproof coiled material 70 is located below the water stop ring plate 50, and the distance from the bottom end of the steel casing 40 is greater than or equal to 300 mm. The waterproof coiled material 70 is strengthened, and the width of the waterproof additional layer is greater than or equal to 500 mm to improve the anti-seepage effect.

[0035] Reference appendix Figure 2 , the plugging ball valve 60 includes a valve body 61, a valve ball 62, a valve stem 63 and a seal 64. The valve body 61 includes an upper valve body 61a and a lower valve body 61b, which are detachably connected (for example, bolt connection). The valve ball 62 is rotatably fitted inside the valve body 61. An upper limit valve seat 66 is provided between the upper valve body 61a and the valve ball 62, and a lower limit valve seat 67 is provided between the lower valve body 61b and the valve ball 62. The upper limit valve seat 66 and the lower limit valve seat 67 fix the position of the valve ball 62, reduce the unplanned vibration of the valve ball 62, and prevent leakage; the valve stem 63 is used to rotate the valve ball 62. One end of the valve stem 63 is connected to the valve ball 62, and the other end extends out of the valve body 61 and is hermetically connected to the valve body 61 through the seal 64 to prevent leakage at the connection between the valve stem 63 and the valve body 61. When the plugging ball valve 60 is in the open state, the medium channel on the valve ball 62 extends in the same direction as the steel casing 40 and is communicated. When it is necessary to close the dewatering well pipe 30, rotate the valve stem 63 to make the valve ball 62 rotate with it, drive the medium channel on the valve ball 62 to rotate to be perpendicular to the extension direction of the steel casing 40, and the outer wall of the valve ball 62 plugs the steel casing 40.

[0036] To ensure the sealing effect of the plugging ball valve 60, the above-mentioned seal 64 includes a sealing packing 64a and a packing pressing plate 64b. The packing pressing plate 64b is detachably arranged outside the valve body 61 (for example, bolt connection). The sealing packing 64a is pressed by the packing pressing plate 64b into the gap between the valve stem 63 and the valve body 61 to perform secondary plugging on the sealing packing 64a and improve the sealing effect.

[0037] To facilitate the opening and closing of the plugging ball valve 60, a rotating handwheel 65 is provided at the end of the valve stem 63 extending out of the valve body 61 in this embodiment, which increases the contact area between the human hand and the valve stem 63 and saves effort.

[0038] Compared with the prior art, the beneficial effects of the present utility model are as follows: The dewatering well pipe 30 is closed by the plugging ball valve 60 with stronger barrier ability and bearing pressure, avoiding the situation in the prior art that graded sand and slightly expanded concrete cannot hold back the gushing water, which ultimately leads to low quality of well pipe closure or even well sealing failure. Moreover, the operation of the plugging ball valve 60 is simple and the cost is lower, improving the construction efficiency and reducing the construction cost. The dewatering well pipe 30, the steel casing 40 and the plugging ball valve 60 are fixed by welding, avoiding the stress damage and leakage problems to the structure caused by bolt connection of the flange cover and the steel casing 40 in the prior art.

[0039] The above are the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present utility model.

Claims

1. A dewatering well sealing system in a foundation pit, characterized in that, Comprising: A foundation bottom plate and a steel casing penetrating the foundation bottom plate, both ends of the steel casing are respectively communicated with a dewatering well pipe and a plugging ball valve, and the plugging ball valve is used to control the on-off of the steel casing; A water stop ring plate is provided in the foundation bottom plate, and the water stop ring plate is sleeved on the outer wall of the steel casing.

2. The dewatering well sealing system in the foundation pit according to claim 1, characterized in that, A waterproof coiled material is provided at the bottom of the foundation bottom plate, and one end of the waterproof coiled material is bent towards the plugging ball valve and abuts against the outer wall of the steel casing.

3. The dewatering well sealing system in the foundation pit according to claim 2, characterized in that, A foundation cushion is provided at the bottom of the foundation bottom plate, the waterproof coiled material is located between the foundation cushion and the foundation bottom plate, and the top end of the bent part of the waterproof coiled material is below the water stop ring plate and the distance from the bottom end of the steel casing is greater than or equal to 300mm.

4. The dewatering well sealing system in the foundation pit according to claim 3, characterized in that, The distance between the top end of the dewatering well pipe and the bottom of the foundation cushion is 100mm - 150mm.

5. The dewatering well sealing system in the foundation pit according to any one of claims 1-4, characterized in that, The plugging ball valve includes a valve body, a valve ball, a valve stem and a seal, the valve ball is rotatably fitted inside the valve body; one end of the valve stem is connected to the valve ball, and the other end extends out of the valve body and is hermetically connected to the valve body through the seal.

6. The dewatering well sealing system in the foundation pit according to claim 5, characterized in that, The seal includes a sealing packing and a packing pressing plate, the packing pressing plate is detachably arranged outside the valve body, and the sealing packing is pressed by the packing pressing plate in the gap between the valve stem and the valve body.

7. The dewatering well sealing system in the foundation pit according to claim 5, characterized in that, A rotary handwheel is provided at the end of the valve stem extending out of the valve body.

8. The dewatering well sealing system in the foundation pit according to claim 5, wherein, The valve body includes an upper valve body and a lower valve body, an upper limit valve seat is provided between the upper valve body and the valve ball, and a lower limit valve seat is provided between the lower valve body and the valve ball.

Images