Plugging structure of deep foundation pit dewatering well

Abstract

The utility model discloses a blocking structure of a deep foundation pit dewatering well. The blocking structure comprises a dewatering well pipe and a blocking assembly. The plugging assembly comprises a plugging pipe, a water stop steel ring, a connector pipe, a plug and a plugging pit. The lower portion of the plugging pipe is fixed in the dewatering well pipe, and the top end of the plugging pipe is located on the height upper portion of the deep foundation pit bottom plate. The water stop steel ring is welded on the outer surface of the middle part of the plugging pipe; the joint pipe is an internal thread pipe and is connected with external threads at the top of the plugging pipe; the plug is an external thread cylinder and is in threaded connection with the upper part of the inner cavity of the joint pipe; the plugging pit is reserved on the top surface of the bottom plate of the deep foundation pit corresponding to the joint pipe, the inner diameter of the plugging pit is slightly larger than the outer diameter of the joint pipe, and the depth of the plugging pit is half of the height of the joint pipe; micro-expansive concrete is filled in the dewatering well pipe and the plugging pipe and below the top surface of the plugging pipe, and sealant is filled between the top surface of the micro-expansive concrete and the top surface of the joint pipe; and waterproof mortar is filled in the plugging pit. The plugging device can improve plugging quality and construction efficiency of the dewatering well.

Description

Technical Field

[0001] This utility model relates to a sealing structure for a deep foundation pit dewatering well. Background Technology

[0002] In the construction of deep foundation pits for underground engineering, dewatering technology is inevitably used. The underground station structures of urban rail transit projects in coastal cities are mostly in water-rich environments. The underground cast-in-place structures are prone to varying degrees of leakage from dewatering wells. Treating the leakage is time-consuming and difficult, and will affect the operational safety of the station.

[0003] When constructing the bottom slab of a deep foundation pit, the sealing pipes of the dewatering wells must first be inserted into the dewatering well pipes and welded in place before installing the bottom slab reinforcement. Since the opening of the sealing pipe requires a steel liner 22 with an outer diameter larger than that of the sealing pipe itself, special attention must be paid to the layout and misalignment of the reinforcement bars during installation. This ensures that the bottom layer of reinforcement bars is staggered from the sealing pipes, and when cutting the upper row of reinforcement bars, a sealing pit 100 (with an inner diameter of 800mm and a depth of 250mm) with a planar dimension larger than that of the steel liner 22 must be reserved. Cutting the reinforcing bars will damage their integrity, so it is necessary to add reinforcing bars around the sealing pit 100. Then, the bottom slab formwork is installed in the sealing pit 100. Because the outer surface of the top of the sealing pipe 2 in the sealing pit 100 has a flange plate 20 that connects to the steel lining plate 22, the bottom formwork cannot be installed stably. When pouring the bottom slab concrete, the bottom formwork often shakes or deforms, making it difficult to ensure that the poured bottom slab concrete can achieve the expected strength and shape. Moreover, the bottom formwork is difficult to remove after the bottom slab concrete is poured, and it is difficult to roughen the concrete surface at the bottom of the sealing pit 100. When the station main construction is fully in line with the design requirements and dewatering is stopped, the water pump should first be removed from the dewatering well pipe 1. Then, micro-expansion concrete 6 and sealant 7 are used to seal the dewatering well pipe 1. Then, rubber sealing ring plate 21 and steel lining plate 22 are installed on the flange plate 20 at the top of the sealing pipe 2. Finally, polymer waterproof mortar 8 is used to fill the sealing pit 100 (see Figure 1 Because it is difficult to roughen the concrete surface at the bottom of the sealing pit, it affects the good bonding between the waterproof mortar 8 and the concrete of the base slab 10. Utility Model Content

[0004] The purpose of this utility model is to overcome the defects of the prior art and provide a sealing structure for deep foundation pit dewatering wells. It can not only ensure the sealing quality of the dewatering wells and reduce leakage, but also improve construction efficiency.

[0005] The purpose of this utility model is achieved as follows: a sealing structure for a deep foundation pit dewatering well, comprising a dewatering well pipe and a sealing assembly; wherein,

[0006] The dewatering well pipe extends below the cushion layer of the deep foundation pit bottom slab, and the top of the dewatering well pipe is above the cushion layer;

[0007] The sealing assembly includes a sealing pipe, a water-stop steel ring, a connector pipe, a plug, and a sealing pit;

[0008] The length of the sealing pipe is greater than the thickness of the deep foundation pit bottom plate. The top of the sealing pipe is provided with external threads. The lower part of the sealing pipe is inserted into the dewatering well pipe in a manner that is close to the inner wall of the dewatering well pipe. The sealing pipe is fixed to the top of the dewatering well by welding. The top of the sealing pipe is located above the height of the deep foundation pit bottom plate.

[0009] The water-stop steel ring is welded to the outer surface of the middle part of the sealing pipe;

[0010] The connector tube is an internally threaded tube, which is connected to the top external thread of the sealing tube;

[0011] The plug is an externally threaded cylinder, which is threadedly connected to the upper part of the inner cavity of the connector tube;

[0012] The sealing pit corresponds to the joint pipe pre-reserved on the upper part of the deep foundation pit bottom plate. The inner diameter of the sealing pit is 5-10cm larger than the outer diameter of the joint pipe, and the depth of the sealing pit is up to half the height of the joint pipe.

[0013] The well pipe and the sealing pipe are filled with micro-expansion concrete 5-10cm below the top surface of the sealing pipe, and the top surface of the micro-expansion concrete is filled with sealant between the top surface of the micro-expansion concrete and the top surface of the joint pipe; the sealing pit is filled with waterproof mortar.

[0014] The aforementioned sealing structure for the deep foundation pit dewatering well, wherein the sealing pipe is made of seamless galvanized steel pipe.

[0015] In the aforementioned sealing structure for the deep foundation pit dewatering well, the top surface of the water-stopping steel ring is also provided with a layer of water-stopping adhesive.

[0016] In the aforementioned sealing structure for the deep foundation pit dewatering well, a rubber sealing ring is provided between the top of the plug and the top of the connector pipe.

[0017] The sealing structure for deep foundation pit dewatering wells of this utility model has the following characteristics:

[0018] 1. The sealing structure of this utility model does not require cutting off and reinforcing the top row of steel bars on the bottom plate at the location of the sealing pipe. If the top row of steel bars on the bottom plate conflicts with the sealing pipe, the steel bars can be slightly adjusted to bypass the sealing pipe without affecting the structural quality of the bottom plate.

[0019] 2. The threads between the plug and the connector, as well as the threads between the connector and the plug, are fully sealed with sealant to prevent leakage.

[0020] 3. Since the planar dimensions of the sealing pit are only slightly larger than those of the joint pipe, the volume of waterproof mortar used for backfilling is small, which can speed up the sealing construction. Although the planar dimensions of the sealing pit are small, there are no protrusions on the outer surface of the joint pipe, making it easy to install and disassemble the bottom formwork. It is also easy to roughen the concrete at the bottom of the sealing pit, so that the waterproof mortar can bond well with the bottom slab concrete, ensuring the sealing quality of the dewatering well. Attached Figure Description

[0021] Figure 1 It is an axial cross-sectional view of the sealing structure of the deep foundation pit dewatering well in the existing technology;

[0022] Figure 2 This is an axial cross-sectional view of the sealing structure of the deep foundation pit dewatering well of this utility model;

[0023] Figure 3 This is an axial cross-sectional view of the joint pipe in the sealing structure of the deep foundation pit dewatering well of this utility model;

[0024] Figure 4 This is a front view of the plug in the sealing structure of the deep foundation pit dewatering well of this utility model. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] Please see Figures 2 to 4 The sealing structure of the deep foundation pit dewatering well of this utility model includes a dewatering well pipe 1 and a sealing component.

[0027] The dewatering well pipe 1 extends below the cushion layer of the deep foundation pit bottom slab 10, and the top of the dewatering well pipe 2 is located 10-20cm above the cushion layer.

[0028] The sealing assembly includes a sealing pipe 2, a water-stop ring 3, a connector pipe 4, a plug 5, and a sealing pit 100; among which,

[0029] The sealing pipe 2 is made of seamless galvanized steel pipe. The length of the sealing pipe 2 is greater than the thickness of the deep foundation pit bottom plate 10. The top of the sealing pipe 2 is provided with external threads. The lower part of the sealing pipe 2 is inserted into the dewatering well pipe 1 in a way that is close to the outer wall of the dewatering well pipe 1. The sealing pipe 2 is fixed inside the dewatering well pipe 1 by welding at the top of the sealing pipe 2. The top of the sealing pipe 2 is located above the height of the deep foundation pit bottom plate 10, that is, the top of the sealing pipe 2 is 10cm lower than the top surface of the deep foundation pit bottom plate.

[0030] The water-stop steel ring 3 is welded to the upper outer surface of the sealing pipe 2 and is located in the lower middle part of the height of the deep foundation pit bottom plate 10; a layer of water-stop adhesive 30 is provided on the top surface of the water-stop steel ring 3;

[0031] The connector tube 4 is an internally threaded tube, and the connector tube 4 is connected to the top external thread of the sealing tube 2;

[0032] The plug 5 is an externally threaded cylinder, which is threaded to the upper part of the inner cavity of the connector tube 4; a rubber sealing ring 50 is provided between the top of the plug 5 and the top of the connector tube 4.

[0033] The sealing pit 100 corresponds to the joint pipe 4 which is reserved on the top surface of the deep foundation pit bottom plate 10. The inner diameter of the sealing pit 100 is 5-10cm larger than the outer diameter of the joint pipe 4, and the depth of the sealing pit 100 is up to half the height of the joint pipe 4.

[0034] Micro-expansion concrete 6 is filled inside the dewatering well pipe 1 and the sealing pipe 2 up to 5-10cm below the top surface of the sealing pipe 2. Sealant 7 is filled between the top surface of the micro-expansion concrete 6 and the top surface of the joint pipe 4. Waterproof mortar 8 is filled inside the sealing pit 100.

[0035] The sealing structure for the deep foundation pit dewatering well of this utility model is constructed according to the following steps:

[0036] S1. Prepare well sealing components

[0037] 1) The dewatering well pipe 1 is a steel pipe with a diameter of 127mm. The plugging pipe 2 is a seamless galvanized steel pipe of DN100*5mm. The length of the plugging pipe 2 is the thickness of the deep foundation pit bottom plate 10 + 50cm, and the top 50mm of the plugging pipe 2 is machined with external threads; the outer diameter of the connector pipe 4 is 110mm, and the length of the connector pipe 4 is 100mm. The connector pipe 4 (see...) Figure 3 ) Connected to the top external thread of the plug tube 2; the length of the plug 5 is 25mm (see Figure 4 ), do not install plug 5 inside connector pipe 4 first;

[0038] 2) Weld a water-stop steel ring 3 onto the sealing pipe 2. The water-stop steel ring 3 is made of 100mm thick steel plate. The welding position of the water-stop steel ring 3 is from the top of the joint pipe 4 down to 1 / 2 of the thickness of the deep foundation pit bottom plate 10, and then down 50mm. When welding the water-stop steel ring 3, the quality of the weld should be guaranteed and there should be no air leakage or weld leakage.

[0039] S2, Cut off the dewatering well pipe

[0040] Under the premise of ensuring safety, use professional cutting tools to precisely cut off the dewatering well pipe 1, which is 10-20cm above the cushion layer of the deep foundation pit bottom slab 10, leaving enough length to weld with the sealing pipe 2, in order to prepare for the subsequent sealing work and ensure a tighter connection between the dewatering well pipe 1 and the sealing pipe 2.

[0041] S3, Welded sealing pipe

[0042] After the dewatering well pipe 1 is cut off, the sealing pipe 2 with the welded water-stop steel ring 3 is precisely connected to the dewatering well pipe 1 and fixed with special tools to ensure that the connection between the sealing pipe 2 and the dewatering well pipe 1 is tight and there is no leakage.

[0043] S4, Well Filling

[0044] First, remove the sediment and debris from the bottom of the dewatering well pipe 1 to ensure that the inside of the dewatering well pipe 1 is clean and the water level is reduced to the lowest level. Then, fill the dewatering well pipe 1 in layers with micro-expansion concrete 6 from the top of the joint pipe 4 until it reaches 50-20cm below the bottom surface of the deep foundation pit slab 10. Use a vibrator to compact it. Then, fill the pipe with quick-drying cement to absorb water until there is no standing water. Then, pour micro-expansion concrete 6 to 5-10cm below the top of the sealing pipe 2.

[0045] S5. Install the plug.

[0046] First, pour the base slab concrete around the perimeter of the sealing pipe 2, and reserve a sealing pit 100 on the top surface of the base slab concrete, which is coaxial with the joint pipe 4 and has an inner diameter φ of 150mm and a depth of 250mm. Then, fill the space between the top surface of the micro-expansion concrete 6 inside the sealing pipe 2 and the top surface of the joint pipe 4 with polysulfide sealant 7. Then, install the plug 5 on the joint pipe 4 and tighten it. A rubber sealing ring 50 is also provided between the top of the plug 5 and the top of the joint pipe 4 to ensure sealing performance and corrosion resistance, so as to ensure that the wellhead is sealed for a long time without leakage. After inspection and approval, backfill the sealing pit 100 with polymer waterproof mortar 8 until it is level with the top surface of the deep foundation pit bottom slab 10.

[0047] The above embodiments are for illustrative purposes only and are not intended to limit the present invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of the present invention and should be defined by the claims.

Claims

1. A sealing structure for a deep foundation pit dewatering well, comprising a dewatering well pipe and a sealing assembly; the dewatering well pipe extends below the cushion layer of the deep foundation pit floor slab, and the top end of the dewatering well pipe is located above the cushion layer; characterized in that, The sealing assembly includes a sealing pipe, a water-stop steel ring, a connector pipe, a plug, and a sealing pit; The length of the sealing pipe is greater than the thickness of the deep foundation pit bottom plate. The top of the sealing pipe is provided with external threads. The lower part of the sealing pipe is inserted into the dewatering well pipe in a manner that is close to the inner wall of the dewatering well pipe. The sealing pipe is fixed to the top of the dewatering well by welding. The top of the sealing pipe is located above the height of the deep foundation pit bottom plate. The water-stop steel ring is welded to the outer surface of the middle part of the sealing pipe; The connector tube is an internally threaded tube, which is connected to the top external thread of the sealing tube; The plug is an externally threaded cylinder, which is threadedly connected to the upper part of the inner cavity of the connector tube; The sealing pit corresponds to the joint pipe pre-reserved on the upper part of the deep foundation pit bottom plate. The inner diameter of the sealing pit is 5-10cm larger than the outer diameter of the joint pipe, and the depth of the sealing pit is up to half the height of the joint pipe. The well pipe and the sealing pipe are filled with micro-expansion concrete 5-10cm below the top surface of the sealing pipe, and the top surface of the micro-expansion concrete is filled with sealant between the top surface of the micro-expansion concrete and the top surface of the joint pipe; the sealing pit is filled with waterproof mortar.

2. The sealing structure for deep foundation pit dewatering wells according to claim 1, characterized in that, The sealing tube is made of seamless galvanized steel pipe.

3. The sealing structure for deep foundation pit dewatering wells according to claim 1, characterized in that, The top surface of the water-stop steel ring is also provided with a layer of water-stop adhesive.

4. The sealing structure for deep foundation pit dewatering wells according to claim 1, characterized in that, A rubber sealing ring is provided between the top of the plug and the top of the connector pipe.

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