A pressure-reducing well zone pressure backfilling and plugging device and method

Abstract

The application relates to a pressure-reducing well pressure-bearing backfilling and plugging device and method, which adopts a pressure-reducing well pressure-bearing backfilling and plugging device and a plugging process of filling materials in stages. First, an axial compression rubber sealing ring is used to make the rubber sealing ring radially expand and tightly contact with the inner wall of a well pipe to form a sealing structure, then the sealing structure is used to control the water body pressure and flow trend in the well to form a water isolation section, and a pressure pump of a filling material function module is used to pump the first filling material into the space below the sealing structure in the well pipe through the steel pipe to complete the first filling material pumping; after the first filling material solidification is completed, the second filling material is poured into the space above the sealing structure in the well pipe, and after the second filling solidification is completed, the backfilling and plugging complete the second filling material pumping. Through the characteristics that the rubber ring is more compact after being radially extruded and deformed, the rubber ring and the pressure-reducing well wall are tightly compacted, so that the water isolation and sealing effects are achieved.

Description

A pressure-reducing well backfilling and plugging device and method Technical Field

[0001] This invention relates to the field of pressurized backfilling and sealing technology for depressurization wells in deep foundation pit dewatering projects, specifically a device and process for achieving staged backfilling and sealing of depressurization wells by compressing rubber rings to expand and seal. Background Technology

[0002] Currently, the depth of urban underground space development is increasing, leading to higher pressures in the confined water and significantly increasing the difficulty of controlling it. In deep foundation pit engineering, confined water control mainly relies on depressurization and pumping techniques. This involves drilling holes in the ground before excavation and lowering well pipes with filter sections at the bottom. During excavation, the confined water in the well pipes is pumped out to reduce the water head and pressure, minimizing its impact on the foundation pit excavation. After the internal structure of the foundation pit is completed, the depressurization wells need to be sealed to disconnect the confined water from the internal space of the structure. The conventional sealing process involves first restoring the water level in the well pipe to its natural level, stabilizing the water, and then injecting filler material into the well pipe. This filler material solidifies under static water conditions, forming a stable and well-sealed plug. However, during underground structure construction, issues such as changes in drawings often cause conflicts between the location of the depressurization wells and the main structure. This necessitates first removing the well pipes within the excavation depth range, then constructing the internal structure, and finally backfilling and sealing. Because the natural water level of the pressurized water is higher than the bottom of the pit, it is impossible to restore the water level in the well to its natural state under this condition. When the direct backfilling method is used for sealing, the dynamic water pressure in the well is relatively large during the solidification process of the backfill material, and the water tends to flow upward. After the backfill material is solidified, seepage channels are very likely to appear, resulting in incomplete sealing and substandard sealing effect.

[0003] To solve the aforementioned problems of pressurized plugging, it is necessary to improve the plugging process for depressurization wells. The main improvement is to maintain the water level in the well after the well casing is removed and to achieve dense filling of the filler material under relatively stable water conditions. In the existing technology, the invention patents "A Water-Sealing Structure for Depressurization Wells and Its Construction Method" (CN111926841A) and "Rapid Sealing Device for Depressurization Wells" (CN108193700A) adopt a plugging process of sealing the well casing with an inflatable (hydraulic) pressure bladder and then filling the upper part of the bladder with filler material. However, the above process has two defects: first, the dynamic water pressure of depressurization wells in ultra-deep foundation pits is high, and the sealing effect of the inflatable (hydraulic) pressure bladder on the well casing is not good; second, the effective backfilling depth of this process is limited to the part above the bladder in the well casing, and the part below the bladder in the well casing is an unfilled section. Compared with the full-depth filling plugging method, the strength and durability of this plugging structure are poor, and there is a risk of long-term water seepage.

[0004] In summary, a new pressurized backfilling and plugging process for depressurized wells is needed to maintain the water level in the well after the well casing is removed, and to achieve dense filling of the filler material under conditions of high water pressure and flow tendency in the well. Summary of the Invention

[0005] The purpose of this invention is to improve the pressurized backfilling and sealing process of depressurization wells, and to provide a pressurized backfilling and sealing device and method for depressurization wells. After cutting off the part of the well pipe above the foundation pit bottom plate, it can still effectively control the water level and water flow in the well, and under the condition that the water pressure is large and there is a flow trend, it can completely and densely fill the part of the well pipe below the foundation pit bottom plate.

[0006] To achieve the above objectives, the technical solution of the present invention is: a pressure-reducing well pressurized backfilling and plugging device, comprising a pressurized water control module and a pumping filler material module. The pressurized water control module consists of a rubber sealing ring, a first steel pipe, a second steel pipe, a nut, a limiting block, a water pump, a first valve, and a constant pressure check valve. The first steel pipe is inserted into the second steel pipe inside the well casing. The bottom of the first steel pipe has a steel ring for axially limiting the rubber sealing ring and a through hole for connecting the constant pressure check valve. A threaded connection is provided at the top of the pipe. The threaded section matches the thread of the nut, and the top end is tightly connected to valve one through a three-way structure; it is also connected to a water pump through valve one. A rubber sealing ring is provided between the bottom of the outer expansion structure at the lower part of steel pipe two and the steel ring at the bottom of steel pipe one. A vertical through hole is provided at the bottom of the outer expansion structure at the lower part of steel pipe two. A thin round pipe is provided at the lower part of the outer expansion structure, which extends vertically upward through the through hole. A constant pressure one-way valve is installed at the top of the thin round pipe. The pumping filler functional module includes a pressure pump and valve two. The pressure pump is connected to the three-way structure through valve two.

[0007] Furthermore, the limiting block is fixed to the base plate to limit the vertical displacement of the steel pipe.

[0008] Furthermore, the constant pressure check valve is set with reference to the pressure head value here. When the fluid pressure in the thin circular pipe reaches 1.5 times the pressure head value, the constant pressure check valve opens.

[0009] A method for pressurized backfilling and plugging of depressurized wells employs a pressurized backfilling and plugging device and a staged injection of filler material. First, the rubber sealing ring is axially compressed, causing it to expand radially and form a tight seal with the inner wall of the well casing. Then, this seal structure is used to control the water pressure and flow trend in the well to form a water-blocking section. The first filler material is injected through a pressure pump in the filler material pumping module into the space below the sealing structure inside the well casing via a steel pipe, completing the first pumping of filler material. After the first filler material has cured, a second filler material is injected into the space above the sealing structure inside the well casing. After the second filler material has cured, the backfilling and plugging process is completed, thus completing the second pumping of filler material.

[0010] Furthermore, the specific operational steps for forming the water-proof section are as follows: connect the rubber sealing ring to the first steel pipe, align the through hole of the second steel pipe with the through hole of the first steel pipe and place them together into the well, install the nut, then install the limiting block, and install valve one and valve two at the tee structure at the top of the first steel pipe; then, install the water pump, open the water pump and valve one, and then tighten the nut to drive the second steel pipe to rotate downward, squeezing the rubber sealing ring, causing the rubber sealing ring to expand radially, and the rubber sealing ring to make tight contact with the inner wall of the pressure-reducing well pipe to form a sealed water-proof section.

[0011] Furthermore, the specific operation steps for the primary pumping of filler material are as follows: First, install the pressure pump, close the water pump and valve one, fill the pressure pump with filler material, open valve two and the pressure pump, and pump the filler material downwards so that the filler material fills from bottom to top at the bottom of the pressure-reducing well pipe; during the filling process, the water pressure below the rubber sealing ring increases accordingly. When the water pressure reaches the set pressure value, the constant pressure check valve opens to drain water, ensuring stable water pressure in the primary filling section; when the primary filler material fills to the lower end face of the outer expansion section of steel pipe one, close valve two and the pressure pump, and the primary filling is completed.

[0012] Furthermore, the specific operation steps of the secondary pumping filler are as follows: after the filler pumped in the first pump reaches the required strength, remove the water pump, pressure pump, valve one, valve two, limit block, nut and steel pipe two, cut off the excess components above the top surface of the bottom plate, pump out the water from the gaps in the pressure-reducing well pipe, and then inject the secondary filler to completely fill the gaps in the pressure-reducing well pipe on the bottom plate. After the secondary filler reaches the curing period, the filling and sealing work is completed.

[0013] The beneficial effects of this invention are:

[0014] This invention utilizes the characteristic of the rubber ring to become increasingly compact as it is radially compressed and deformed, ensuring a tight seal between the rubber ring and the pressure-reducing well wall, thus achieving a water-proof sealing effect.

[0015] After cutting off the portion of the well pipe above the foundation pit floor, the water level and flow within the well can still be effectively controlled, and the portion of the well pipe below the foundation pit floor can be completely and densely filled under conditions of high water pressure and a tendency to flow.

[0016] This invention pumps the filler material to the bottom of the pressure-reducing well pipe through a central pipe, and displaces the water below the rubber ring in the well pipe through a constant pressure check valve to ensure a dense filling effect and prevent seepage channels. Attached Figure Description

[0017] Figure 1 is a schematic diagram of the pressure-reducing well backfilling and plugging device of the present invention;

[0018] Figure 2 is a schematic diagram of the completed state of one pumping of filler material according to the present invention;

[0019] Figure 3 is a schematic diagram of the completed state of the secondary pumping filler material according to the present invention;

[0020] In the diagram: 1-Rubber sealing ring, 2-Steel pipe one, 3-Steel pipe two, 4-Nut, 5-Limit block, 6-Constant pressure check valve, 7-Pressure pump, 8-Valve one, 9-Pressure pump, 10-Valve two. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] As shown in Figure 1, an embodiment of the present invention provides a pressure-reducing well backfilling and sealing device, which includes a pressure-controlling water control module and a pumping filler material module.

[0023] The pressurized water control module consists of a rubber sealing ring 1, steel pipe 1 2, steel pipe 2 3, nut 4, limit block 5, water pump 7, valve 1 8, valve 2 10, and constant pressure check valve 6. Steel pipe 1 2 is inserted into steel pipe 2 3 inside the well casing. Steel pipe 1 2 has a steel ring at its bottom to axially limit the rubber sealing ring 1 and has a through hole for connecting to the constant pressure check valve 6. A threaded section at the top of the pipe matches the threads of nut 4. The top end is tightly connected to valve 1 8 and valve 2 10 via a tee structure. Water pump 7 is connected via valve 1 8, and pressure pump 9 is connected via valve 2 10. A rubber sealing ring 1 is provided between the bottom of the outer expansion structure of steel pipe 2 3 and the steel ring at the bottom of steel pipe 1 2. A vertical through hole is provided at the bottom of the outer expansion structure of steel pipe 2 3. A thin round pipe is provided in the outer expansion structure of steel pipe 1 2, which passes vertically upward through the through hole. A constant pressure one-way valve 6 is installed at the top of the thin round pipe. The limiting block 5 is fixed on the base plate to limit the vertical displacement of steel pipe 1 2.

[0024] The pumping filler module consists of a constant pressure check valve 6, a pressure pump 9, and a second valve 10. The constant pressure check valve 6 is set with reference to the pressure head value here. When the fluid pressure in the thin circular tube reaches 1.5 times the pressure head value, the constant pressure check valve 6 opens.

[0025] As shown in Figures 2 and 3, an embodiment of the present invention provides a pressurized backfilling and sealing method for depressurized wells. This method employs a pressurized backfilling and sealing device and a staged injection of filler material. First, the rubber sealing ring is axially compressed, causing it to expand radially and form a tight seal with the inner wall of the well casing. Then, this seal is used to control the water pressure and flow trend within the well. The first filler material is injected through the pressure pump 9 of the filler material pumping module into the space below the sealing structure within the well casing via the steel pipe 2. After the first filler material has cured, a second filler material is injected into the space above the sealing structure within the well casing. After the second filler material has cured, the backfilling and sealing is complete.

[0026] The pressure-reducing well backfilling and sealing device mainly consists of two functions: controlling the pressurized water and pumping the filler material.

[0027] The operation process consists of three steps: the first step is to form a water-blocking section, the second step is to pump the filler material once, and the third step is to pump the filler material a second time.

[0028] Step 1: The specific operation for forming the water-proof section is as follows: Connect the rubber sealing ring 1 to the steel pipe 2, align the through hole of the steel pipe 3 with the through hole of the steel pipe 2 and put them into the well together, install the nut 4, and then install the limiting block 5. Install valve 8 and valve 10 at the tee structure at the top of the steel pipe 2; then, install the water pump 7, open the water pump 7 and valve 8, and then tighten the nut 4 to drive the steel pipe 3 to rotate downward, squeezing the rubber sealing ring 1, so that the rubber sealing ring 1 expands radially, and the rubber sealing ring 1 is in close contact with the inner wall of the pressure-reducing well pipe to form a sealed water-proof section.

[0029] Step 2: The specific operation of pumping filler material is as follows: First, install pressure pump 9, close water pump 7 and valve 1 8, fill pressure pump 9 with filler material, open valve 2 10 and pressure pump 9, and pump the filler material downwards so that the filler material fills from bottom to top at the bottom of the pressure-reducing well pipe; during the filling process, the water pressure below rubber sealing ring 1 increases accordingly. When the water pressure reaches the set pressure value, the constant pressure check valve 6 opens to drain water, ensuring that the water pressure in the primary filling section is stable; when the primary filler material fills to the lower end face of the outer expansion section of steel pipe 1 2, close valve 2 10 and pressure pump 9, and the primary filling is completed.

[0030] Step 3: The specific operation of secondary pumping of filler material is as follows: After the filler material pumped in the first stage reaches the required strength, remove the water pump 7, pressure pump 9, valve 1 8, valve 2 10, limit block 5, nut 4 and steel pipe 2 3, cut off the excess components above the top surface of the bottom plate, pump out the water from the gaps in the pressure-reducing well pipe, and then inject secondary filler material to completely fill and compact the gaps in the pressure-reducing well pipe on the bottom plate surface. After the secondary filler material reaches the curing period, the filling and sealing work is completed.

Claims

1. A pressure-reducing well backfilling and plugging device, characterized in that: The system includes a pressurized water control module and a filler pumping module. The pressurized water control module consists of a rubber sealing ring, a first steel pipe, a second steel pipe, a nut, a limiting block, a water pump, a first valve, and a constant pressure check valve. The first steel pipe is inserted into the second steel pipe inside the well casing. The bottom of the first steel pipe has a steel ring for axial limiting of the rubber sealing ring and a through hole for connecting the constant pressure check valve. A threaded section at the top of the pipe matches the threads of the nut, and the top end is tightly connected to the first valve via a tee structure. The second steel pipe is connected to the water pump via the first valve. A rubber sealing ring is provided between the bottom of the outer expansion structure of the first steel pipe and the steel ring at the bottom of the second steel pipe. A vertical through hole is provided at the bottom of the outer expansion structure of the second steel pipe. A thin round pipe is provided in the outer expansion structure of the lower part of the second steel pipe, which vertically passes through the through hole. A constant pressure check valve is installed at the top of the thin round pipe. The pumping filling material function module includes a pressure pump and a second valve. The pressure pump is connected to a three-way structure through the second valve. The constant pressure check valve is set with reference to the pressure head value here. When the fluid pressure in the thin round pipe reaches 1.5 times the pressure head value, the constant pressure check valve opens.

2. The pressure-reducing well backfilling and plugging device according to claim 1, characterized in that: The limiting block is fixed to the base plate and is used to limit the vertical displacement of the steel pipe.

3. A method for sealing a depressurized well with pressurized backfilling, employing the sealing device and staged injection of filler material as described in claim 1, characterized in that: First, the rubber sealing ring is axially compressed to expand radially and form a tight seal with the inner wall of the well pipe. Then, this seal is used to control the water pressure and flow trend in the well to form a water-blocking section. The first pumping of filler material is then pumped through the steel pipe into the space below the sealing structure inside the well pipe using the pressure pump of the pumping filler material module. After the first filling material has cured, the second filling material is injected into the space above the sealing structure inside the well pipe. After the second filling has cured, the backfilling and sealing are completed to finish the second pumping of filler material.

4. The method for backfilling and sealing a depressurized well according to claim 3, characterized in that: The specific steps for forming the water-proof section are as follows: connect the rubber sealing ring to steel pipe one, align the through hole of steel pipe two with the through hole of steel pipe one and put them into the well together, install the nut, then install the limiting block, and install valve one and valve two at the tee structure at the top of steel pipe one; then, install the water pump, open the water pump and valve one, and then tighten the nut to drive steel pipe two to rotate downward, squeeze the rubber sealing ring, so that the rubber sealing ring expands radially, and the rubber sealing ring is in close contact with the inner wall of the pressure-reducing well pipe to form a sealed water-proof section.

5. The method for backfilling and sealing a depressurized well according to claim 3, characterized in that: The specific operation steps for pumping the filler material in one operation are as follows: First, install the pressure pump, close the water pump and valve one, fill the pressure pump with filler material, open valve two and the pressure pump, and pump the filler material downwards so that the filler material fills the bottom of the pressure-reducing well pipe from bottom to top; during the filling process, the water pressure below the rubber sealing ring increases accordingly. When the water pressure reaches the set pressure value, the constant pressure check valve opens to drain water, ensuring that the water pressure in the primary filling section is stable; when the primary filler material fills to the lower end face of the outer expansion section of steel pipe one, close valve two and the pressure pump, and the primary filling is completed.

6. The method for backfilling and sealing a depressurized well according to claim 3, characterized in that: The specific operation steps for the secondary pumping of filler material are as follows: After the filler material pumped in the first stage reaches the required strength, remove the water pump, pressure pump, valve one, valve two, limit block, nut and steel pipe two, cut off the excess components above the top surface of the bottom plate, pump out the water from the gaps in the pressure-reducing well pipe, and then inject the secondary filler material to completely fill and compact the gaps in the pressure-reducing well pipe on the bottom plate surface. After the secondary filler material reaches the curing period, the filling and sealing work is completed.

Images