A pit-in-pit underground water in-situ dewatering instantaneous plugging device

Abstract

The utility model discloses a pit in pit underground water in situ precipitation instantaneous plugging device, be applicable to the pit in pit construction such as water collecting well, elevator well of underground water level under raft board. The device is arranged in the center of pit in pit, including the temporary water collecting well of vertical setting below the basement, the flange water stop ring of coaxial sleeve setting and the outer wall close well wall steel casing fixed connection in casing top, the plugging plate connected through bolt and water stop ring and the water pump and drain pipe in casing. When construction, after excavating water collecting well, install casing, precipitation and cast floor slab, after maintenance, pump water and remove pump, fill broken stone and install plugging plate, then secondary cast and waterproof. The device realizes local in situ precipitation, does not need global precipitation, and the plugging is fast, cost is reduced, construction period is shortened, leakage rate is low, can also circulate water, is applicable to various pit in pit structures, and the operation is simple.

Description

Technical Field

[0001] This utility model relates to the field of building construction technology, specifically a device for instant sealing of groundwater in situ during basement construction of buildings, which is particularly suitable for dewatering construction of pits such as sump pits and elevator shafts where the groundwater level is below the raft slab. Background Technology

[0002] During the construction of raft foundations in building basements, dewatering is necessary when the groundwater level is high. In particular, areas within pits such as sump pits and elevator shafts require even lower groundwater levels to meet construction requirements. Traditional dewatering methods primarily employ lightweight wellpoint dewatering or manhole dewatering. These methods require lowering the groundwater level throughout the basement area to at least 50cm below the bottom of the pit, and continuous dewatering operations are necessary throughout the construction period.

[0003] However, this traditional dewatering method has obvious drawbacks: First, the engineering work of basement sump wells and elevator shafts is relatively small, and conventional dewatering measures require lowering the water level of the entire basement to below the pit foundation, resulting in poor economic efficiency; second, especially when the original groundwater level is below the raft foundation, wellpoint dewatering measures will complicate the construction process, increase construction difficulty and cost; finally, continuous dewatering operations take a long time, have high investment costs, and may have adverse effects on the surrounding environment. Utility Model Content

[0004] This utility model aims to develop an in-situ groundwater dewatering instant sealing device for pits within pits. By installing a pre-drilled water collection well with a water-stop ring in the middle of the pit and continuously pumping water, the bottom slab of the foundation pit can be poured without water and cured with water. After the bottom slab strength meets the design strength and the water is pumped out, the device can be instantly sealed by installing a blind flange, and the bottom slab can be poured again and subsequent waterproofing construction can be carried out. This simplifies the dewatering process and has the advantages of low cost, fast construction period and simple operation.

[0005] This utility model provides an in-situ groundwater instantaneous sealing device for pit-within-a-pit, which is installed in the central area of ​​the pit-within-a-pit foundation pit, including:

[0006] Temporary water collection wells are vertically installed below the foundation of the pit within the pit;

[0007] A metal sleeve is coaxially fitted inside the temporary water collection well. Its outer wall is closely attached to the well wall, and its top extends above the working surface of the foundation pit. Multiple seepage holes are provided on the bottom side, and the top of the metal sleeve is open.

[0008] The sealing plate is detachably connected to the waterstop ring and has a sealed state with the top opening of the sealing sleeve and a removed state with the top opening open.

[0009] A pumping unit, which is detachably mounted on a metal sleeve, is used to drain seepage water out of the pit.

[0010] In some embodiments, the sealing device further includes a water-stop ring fixed to the periphery of the top end of the metal sleeve, and the sealing plate is adapted to be connected to or removed from the water-stop ring via a connecting assembly.

[0011] In some implementations, the sealing plate is detachably connected to the waterstop ring by a circumferentially distributed set of bolts.

[0012] In some embodiments, the radius of the central well is not less than 50cm and the depth is 60cm~100cm.

[0013] In some embodiments, the metal sleeve is a steel sleeve.

[0014] In some embodiments, the water-stop ring is a flange.

[0015] In some implementations, plum blossom-shaped seepage holes are provided within 20cm of the bottom end of the steel sleeve.

[0016] In some embodiments, the diameter of the plum blossom-shaped seepage holes is 5-7 mm.

[0017] In some embodiments, the pumping unit includes a pump housed in a metal sleeve and a drain pipe connected to the pump.

[0018] In some embodiments, the metal sleeve is a steel sleeve with a wall thickness of not less than 6 mm, and the sealing plate is a circular steel plate with a thickness of not less than 8 mm, the diameter of which is adapted to the sealing surface size of the flange-type waterstop ring. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the steel sleeve sealing device of this utility model; Figure 2 This is a schematic diagram of a steel sleeve with a water-stop ring. Figure 3 This is an enlarged view of the sealing plate; Figure 4 This is a schematic diagram of the first-floor pouring of the foundation slab; Figure 5 A diagram illustrating the laying of crushed stone; Figure 6 This is a schematic diagram of the secondary pouring of the base slab;

[0020] Among them, 1-pit within pit, 2-temporary sump well, 3-steel sleeve, 4-water stop ring (flange), 5-plum blossom-shaped seepage hole, 6-sealing plate, 7-bolt, 8-nut, 9-water pump, 10-first layer pouring of the base slab, 11-secondary concrete pouring, 12-gravel, 13-drainage pipe, 14-electric wire. Detailed Implementation

[0021] Please see Figures 1-6In this embodiment, the in-situ groundwater dewatering instantaneous sealing device for the pit within a pit is installed in the central area of ​​the pit within a pit 1; the pit within a pit can be a basement sump or an elevator shaft sump.

[0022] The device mainly includes a temporary water collection well 2, a metal casing 3, a water-stop ring 4, a sealing plate 6, and a pumping unit.

[0023] The temporary collection well 2 is vertically located below the foundation of the pit within the pit, with a depth of 80cm and a diameter of 60cm. The well depth and diameter can be adjusted according to specific geological conditions and water inflow, generally ranging from 60-100cm in depth and not less than 50cm in diameter. Optionally, after excavation, manual finishing can be used to ensure the well wall is vertical and does not collapse, and a 5cm thick layer of graded sand and gravel can be laid at the bottom of the well to prevent soil from clogging the seepage holes.

[0024] The metal casing 3 is a 6mm thick steel casing, coaxially fitted inside the temporary sump. The outer wall of the casing is tightly fitted to the well wall, with the top extending 20cm above the working surface of the foundation pit. Within a 20cm height range from the bottom, there are 6mm diameter seepage holes 5 arranged in a quincunx pattern. This ensures rapid groundwater infiltration while preventing sand and gravel blockage. The quincunx pattern also avoids localized stress concentration in the casing, which could lead to cracking.

[0025] The water-stop ring 4 is a flange-type structure made of steel and fixed to the periphery of the top edge of the metal sleeve. Eight M12 nuts 8 are evenly distributed around the flange along its circumference.

[0026] The sealing plate 6 is a 10mm thick circular steel plate with a diameter that matches the sealing surface size of the flange-type waterstop ring 4. Eight M12 bolts 7 are spaced circumferentially around the sealing plate, allowing for detachable connection to the waterstop ring via these bolts, enabling both a sealed top opening and an open top opening removal state.

[0027] The pumping unit includes a pump 9 housed within a metal casing and a drain pipe 13 connected to the pump body. During the foundation slab construction, a pump is installed inside the steel casing to promptly remove groundwater seepage to the outside of the foundation pit. Pumping is stopped 24 hours after the foundation slab concrete is poured for water curing. Once the foundation slab meets the design strength, pumping is stopped, crushed stone is filled into the casing, and sealing plates are installed and bolts tightened. Then, the foundation slab is poured a second time, smoothed, and cured. Finally, waterproofing of the foundation pit is carried out.

[0028] This invention, through the above-described embodiments, achieves localized, in-situ dewatering in confined spaces, avoiding the high costs and long construction periods associated with large-scale dewatering. Its core lies in the combination of a sleeve with a water-stop ring and a detachable sealing plate, which seamlessly integrates dewatering operations with the pouring and curing of the foundation slab. It also enables rapid and reliable permanent sealing, is easy to operate, and offers significant economic benefits. It is particularly suitable for construction in pit-within-pit systems where the groundwater level is below the raft foundation.

[0029] The in-situ groundwater instantaneous sealing device for pit-within-pits provided by this utility model can be constructed according to the following method:

[0030] Step 1: Construction Preparation. Based on the dimensions of the pit-within-pit 1 and the geological and hydrological conditions, determine the depth and diameter of the temporary sump well 2. Subsequently, prepare materials and equipment of appropriate size, such as steel sleeves 3, flange water-stop rings 4, sealing plates 6, water pumps 9, drainage pipes 13, and bolts 7.

[0031] Step 2: Excavate a temporary water collection well

[0032] At the center of the pit within the pit 1, a temporary sump well 2 is excavated vertically downwards using mechanical methods. During the excavation process, it is necessary to ensure that the well wall is stable and vertical, and the bottom of the well is flat, in preparation for the installation of the casing.

[0033] Step 3: Install the steel casing. Slowly and vertically place the prefabricated steel casing 3, with a flange water-stop ring 4 welded to the top, into the temporary water collection well 2, ensuring that the outer wall of the casing fits tightly against the well wall. A quincunx-shaped seepage hole 5 is provided within a 20cm range from the bottom of the casing.

[0034] Step 4: Rainfall Operations

[0035] The bottom slab reinforcement is tied, and the sleeve position is reserved. Then, the pumping unit is installed: the pump 9 is placed inside the steel sleeve 3, and the drainage pipe 13 and power line 14 are connected. Continuous dewatering begins, keeping the working surface at the bottom of the pit dry, and then the first layer of concrete 10 for the bottom slab is poured. Pumping can be stopped 24 hours after pouring, and groundwater is used for curing. After curing, once the bottom slab strength meets the requirements, the water in the well is pumped out again, and then the pump 9 is removed.

[0036] Step 5: Sealing and Backfilling

[0037] After the water pump is withdrawn, immediately fill the steel sleeve 3 with crushed stone 12 to the predetermined height. Then, cover the sealing plate 6 on the flange water-stop ring 4 and tighten it evenly around the circumference using bolts 7 and nuts 8 to achieve instant sealing.

[0038] Step 6: Secondary pouring

[0039] Above the sealed device, a second concrete pour is carried out to pour the bottom slab of the pit to the design elevation, thus completing the construction of the entire bottom slab.

[0040] The device provided by this utility model is particularly suitable for the construction of pit-within-pit structures such as sump wells or elevator shafts where the original groundwater level is below the raft foundation. The core of this technology lies in achieving localized in-situ dewatering by pre-installing a steel sleeve with a water-stop ring at the center of the pit, thus avoiding the high costs and lengthy construction period of large-scale dewatering. It utilizes a traditional water pump for pumping water and achieves rapid and reliable sealing through bolted connections to the sealing plate. The entire device has the advantages of low investment, high efficiency, simple operation, and good sealing effect, and can be widely used in the construction of pit-within-pit foundation slabs in various building construction projects.

Claims

1. A device for instantaneous sealing of groundwater in situ in pits, characterized in that, Located in the central area of ​​the pit within a pit, including: Temporary water collection well (2) is set vertically below the foundation of the pit; A metal sleeve (3) is coaxially fitted inside the temporary water collection well. Its outer wall is closely attached to the well wall, and its top extends above the working surface of the foundation pit. Multiple seepage holes (5) are provided on the bottom side. The top of the metal sleeve is open. The sealing plate (6) and the water-stop ring are detachably connected, and have a sealing state with the top opening of the sealing sleeve and a removal state with the top opening open. A pumping unit, which is detachably mounted on a metal sleeve, is used to drain seepage water out of the pit.

2. The instantaneous sealing device for in-situ groundwater dewatering in pits according to claim 1, characterized in that, The water-stop ring is fixed to the periphery of the top edge of the metal sleeve, and the sealing plate is adapted to be connected to or removed from the water-stop ring via a connecting assembly.

3. The instantaneous sealing device for in-situ groundwater dewatering in pits according to claim 2, characterized in that, The sealing plate (6) is detachably connected to the waterstop ring by a circumferentially distributed bolt group (7).

4. The instantaneous sealing device for in-situ groundwater dewatering in pits according to claim 1, characterized in that, The temporary water collection well (2) has a radius of not less than 50cm and a depth of 60cm~100cm.

5. The instantaneous sealing device for in-situ groundwater dewatering in pits according to claim 1, characterized in that, The metal sleeve is a steel sleeve.

6. The instantaneous sealing device for in-situ groundwater dewatering in pits according to claim 2, characterized in that, The aforementioned water-stop ring is a flange.

7. The instantaneous sealing device for in-situ groundwater dewatering in pits according to claim 1, characterized in that, A plum blossom-shaped drainage hole is provided within 20cm of the bottom end of the steel sleeve.

8. The instantaneous sealing device for in-situ groundwater dewatering in pits according to claim 7, characterized in that, The diameter of the plum blossom-shaped seepage holes is 5~7mm.

9. The instantaneous sealing device for in-situ groundwater dewatering in pits according to claim 1, characterized in that, The pumping unit includes a pump (9) housed in a metal casing and a drain pipe (13) connected to the pump.

10. The instantaneous sealing device for in-situ groundwater dewatering in pits according to claim 1, characterized in that, The metal sleeve (3) is a steel sleeve with a wall thickness of not less than 6 mm, and the sealing plate (6) is a circular steel plate with a thickness of not less than 8 mm, the diameter of which is compatible with the sealing surface size of the flange-type water-stop ring (4).

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