A method and device for sealing a borehole water gushing orifice

Abstract

This invention proposes a method and apparatus for sealing borehole water inflow, specifically comprising the following steps: The bottom end of the sealing body is inserted into the borehole; the top end of the sealing body is connected to an upper piston assembly; when the bottom end of the sealing body moves upward due to water impact, it is blocked by the upper piston assembly; the upper piston assembly is connected to a sensing assembly and a lower piston assembly; a water tank assembly is fixed on the lower piston assembly, allowing the water tank assembly to communicate with the borehole; under the control of the sensing assembly, water in the borehole is pumped out and flows into the water tank assembly; after time t, once the system stabilizes, a mechanical felt grout stopper is fabricated near the borehole opening, followed by the injection of cement-water glass dual-liquid grout. The method and apparatus for sealing borehole water inflow provided by this invention avoids the problems of easy material loss, slow solidification, and low sealing pass rate in existing technologies for sealing borehole water inflow in deep foundation pits and high-pressure water-bearing strata.

Description

Technical Field

[0001] This invention relates to the fields of geotechnical engineering and hydrogeological exploration technology, specifically to a method and apparatus for sealing borehole water inflow. Background Technology

[0002] In urban rail transit and deep foundation pit construction, supplementary exploratory drilling is often required after the foundation pit has been excavated to the base layer to verify the integrity of the pile end bearing stratum (such as spheroidal weathered body). When the borehole penetrates the deep Quaternary confined aquifer (such as gravel layer), high-pressure water inrush often occurs. Existing borehole sealing methods mainly include clay ball backfilling, single-liquid cement grouting, and conventional airbag sealing devices. However, under conditions of high pressure head (e.g., above 20 meters) and fast flow velocity (e.g., 0.2 m / s), the existing technology has the following defects: through-holes are developed in silty clay and gravel layers under the action of pressurized water. Conventional single-stage grouting cannot effectively fill these hidden channels under dynamic water conditions, resulting in leakage points still existing after sealing. In severe cases, the clay ball is dispersed by the high-speed water flow the moment it is put into the borehole and cannot settle into place. The solidification time of single-liquid cement grout is long, and it is diluted and washed away by groundwater before initial setting and cannot be retained, resulting in sealing failure.

[0003] In addition, while conventional airbag sealing devices can temporarily stop water flow, they cannot achieve permanent sealing. Furthermore, airbags are easily punctured or displaced at high flow rates. Traditional grouting methods do not take into account the "supporting" and "diluting" effects of pressurized water on the grout, resulting in a generally low pass rate for sealing quality. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for sealing borehole water inflow, which solves the technical problems of easy loss of sealing materials, slow solidification, and low sealing qualification rate in the existing technology for sealing borehole water inflow in deep foundation pits and high-pressure water-bearing formations.

[0005] A method for sealing the borehole opening where water flows in, specifically including the following steps:

[0006] Step S1: Insert the bottom end of the sealing body into the borehole and connect the top end of the sealing body to the upper piston assembly. When the bottom end of the sealing body moves upward due to the impact of water, it is blocked by the upper piston assembly.

[0007] Step S2: Connect the upper piston assembly to the sensing assembly and the lower piston assembly. When the sensing assembly senses a large pressure, it controls the lower piston assembly to work, causing the upper piston assembly to move downward.

[0008] Step S3: A water tank assembly is fixed on the lower piston assembly, so that the water tank assembly is connected to the borehole. Under the control of the sensing assembly, the water in the borehole is pumped out and flows into the water tank assembly, thereby increasing the weight of the lower piston assembly and preventing the water in the borehole from gushing out.

[0009] Step S4: After time t, once the system has stabilized, a mechanical felt plug is fabricated near the orifice, followed by the injection of cement-water glass grout to reinforce the orifice.

[0010] Mechanical felt grout stoppers and the injection of cement-water glass dual-liquid grout are routine operations for those skilled in the art and will not be described in detail here.

[0011] A device for sealing borehole water inflow, employing a method for sealing borehole water inflow, includes a support frame fixed to the ground by anchor bolts. It also includes a sealing body extending into the borehole at its bottom end, an upper piston assembly connected to the top of the sealing body, and a sensing component connected to the upper piston assembly. The sensing component is fixed to the top of the support frame. The sealing body and the upper piston assembly are vertically movably mounted on the support frame. The upper piston assembly is connected to a lower piston assembly, and the lower piston assembly is controlled to be connected to the sensing component.

[0012] The sealing body includes an upper movable column and a lower movable column that are coaxially and separately connected, and a plurality of conical blocks that are coaxially fixed on the outside of the lower movable column. An embedded column is coaxially fixed to the top of the lower movable column, and the embedded column is separately inserted into the bottom of the upper movable column. The bottom of the lower movable column is open and the top is closed, forming a shell shape.

[0013] The upper piston assembly includes a piston cylinder, a piston block that slides vertically within the piston cylinder, a piston column whose bottom end is coaxially connected to the piston block, a limiting post that is coaxially connected to the top end of the piston column, and a spring sleeved on the outside of the limiting post. The limiting post slides vertically on the bracket, and the spring is disposed between the bracket and the piston column.

[0014] The sensing component includes a pressure sensor and a microcontroller connected to the pressure sensor. The pressure sensor is fixed in an embedded hole on the bracket, and the top end of the spring contacts the pressure sensor.

[0015] The bottom end of the piston cylinder is connected to the sealing groove plate through the upper air pipe. The sealing groove plate is connected to one end of the lower air pipe. The other end of the lower air pipe passes through multiple conical blocks and is sealed. The sealing groove plate is fixedly sleeved on the lower movable column.

[0016] The lower piston assembly includes a slide rod with one end fixedly connected to the outside of the piston rod, a piston rod with one end fixedly connected to the bottom end of the slide rod, an air cylinder connected to the bottom end of the piston rod, and an air extraction pipe with one end connected to the air cylinder. The other end of the air extraction pipe is connected to an air pump. The outside of the slide rod is slidably mounted on the crossbar.

[0017] The slide bar is also externally fixed with a weight-increasing mechanism; the weight-increasing mechanism includes a water tank fixed to the outside of the slide bar, a water pipe connected to the water tank at one end, and a water level gauge fixed to the inner side of the top of the water tank. The water pipe is equipped with a solenoid valve, and the other end of the water pipe is connected to a connecting pipe via a micro pump. The connecting pipe is equipped with a valve, and one end of the connecting pipe is connected to the outside of the lower movable column.

[0018] The technical details not described in this solution are based on the conventional understanding of those skilled in the art and can be implemented in conjunction with existing technologies, and will not be elaborated further here.

[0019] The beneficial effects of this invention are as follows:

[0020] (1) The solution is equipped with a sealing body. On the one hand, the cone-shaped block is used to achieve multiple sealing of the drilling position, which helps to improve the sealing effect. On the other hand, the sealing body includes an upper movable column and a lower movable column connected by coaxial separation. After the sealing is completed and stabilized, the subsequent pouring operation is carried out, which is convenient and quick. After the pouring material solidifies, the upper movable column and the lower movable column are finally disassembled to ensure the stability of the sealing.

[0021] (2) An upper piston assembly is provided, which works in conjunction with a conical block and a lower air pipe. Firstly, the interaction between the piston cylinder and the piston block helps to buffer the flow and prevent the sealing body from being washed out under the huge impact of the surging water. Secondly, when the air pressure in the piston cylinder increases, the pressure is transmitted to the conical block through the lower air pipe. At this time, the volume of the conical block expands slightly, which helps to increase the contact force between the conical block and the inner wall of the borehole, resulting in a better sealing effect.

[0022] (3) It is equipped with a sensing component and a lower piston component. On the one hand, when the upper piston component acts on the sensing component under the impact of external force, the sensing component senses the pressure and starts the lower piston component to work. At this time, under the action of the air pump and the air extraction pipe, the piston rod descends, which drives the upper piston component to descend, thus preventing the sealing body from being impacted by the water surge.

[0023] (4) A weight-increasing mechanism is provided to cleverly draw the gushing water into the water tank. On the one hand, this prevents the water from gushing out. On the other hand, the increased weight of the water tank assists the lower piston assembly in descending, ensuring the downward force of the lower piston assembly so that the sealing body can stably seal the borehole.

[0024] (5) This solution effectively solves the problem of high flow velocity scouring and damage to the sealing material by adopting the combination of "upper and lower piston assembly + mechanical pumping". The rapid solidification characteristics of the dual liquid slurry (initial solidification in about 3 minutes) ensure that the slurry can form strength before being washed away by water, which significantly improves the sealing quality and pass rate. The sealing efficiency is high and the quality is reliable. It can also effectively fill the hidden seepage channels in the formation and form a continuous and dense waterproof structure.

[0025] (6) The core idea of ​​the method of the present invention is "gradual risk reduction from bottom to top, rapid construction of water-stopping barrier at the orifice, and double liquid rapid setting to strengthen consolidation". Specifically, a cone-shaped block is used to form a throttling damping in the water inflow channel. With the help of mechanical pumping, the dynamic water environment with high pressure and fast flow is artificially transformed into a low pressure, slow flow or even still water environment. A mechanical felt grout stopper is made near the orifice. The grout stopper is enhanced by soaking in water glass, which can form a high-strength sealing section within a depth of several meters. Finally, the cement-water glass double liquid grout (ratio 1:0.6) is used to fill the orifice section rapidly under pressure, with a short initial setting time (about 3 minutes) and strong erosion resistance. The surrounding disturbed strata are reinforced by grouting. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the orifice sealing device in an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of the external structure of the sealing body in an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the internal structure of the sealing body in an embodiment of the present invention.

[0029] Figure 4 This is a schematic diagram of the weight-adding mechanism in an embodiment of the present invention.

[0030] Figure 5 This is a schematic diagram of the connection structure between the upper movable column and the lower movable column in an embodiment of the present invention.

[0031] Figure 6 This is a schematic diagram of the connection structure between the bracket and the sensing component in an embodiment of the present invention.

[0032] The attached diagram is labeled as follows: 1. Support; 2. Air cylinder; 21. Suction pipe; 3. Piston rod; 4. Crossbar; 5. Slide rod; 6. Water tank; 61. Water level gauge; 7. Water pipe; 8. Piston cylinder; 9. Piston column; 91. Piston block; 10. Spring; 101. Pressure sensor; 102. Limiting post; 11. Upper air pipe; 12. Sealing slot plate; 13. Lower air pipe; 14. Drill hole; 15. Upper movable column; 151. Lower movable column; 152. Embedded column; 16. Conical block; 17. Connecting pipe. Detailed Implementation

[0033] To more clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0034] Example 1

[0035] A method for sealing the borehole opening where water flows in, specifically including the following steps:

[0036] Step S1: Insert the bottom end of the sealing body into the borehole 14, and connect the top end of the sealing body to the upper piston assembly. When the bottom end of the sealing body moves upward due to the impact of water, it is blocked by the upper piston assembly.

[0037] Step S2: Connect the upper piston assembly to the sensing assembly and the lower piston assembly. When the sensing assembly senses a large pressure, it controls the lower piston assembly to work, causing the upper piston assembly to move downward.

[0038] Step S3: A water tank 6 assembly is fixed on the lower piston assembly, so that the water tank 6 assembly is connected to the drill hole 14. Under the control of the sensing assembly, the water in the drill hole 14 is drawn out and flows into the water tank 6 assembly, thereby increasing the weight of the lower piston assembly and preventing the water in the drill hole 14 from gushing out.

[0039] Step S4: After time t, once the system has stabilized, a mechanical felt plug is fabricated near the orifice, followed by the injection of cement-water glass grout to reinforce the orifice.

[0040] Example 2

[0041] See Figures 1-6 A device for sealing the borehole opening where water inflow occurs, employing a method for sealing the borehole opening where water inflow occurs, includes a support 1, which is fixed to the ground by anchor bolts. It also includes a sealing body whose bottom end extends into a borehole 14, an upper piston assembly connected to the top end of the sealing body, and a sensing assembly connected to the upper piston assembly. The sensing assembly is fixed to the top end of the support 1. The sealing body and the upper piston assembly are movably mounted on the support 1. The upper piston assembly is connected to a lower piston assembly, and the lower piston assembly is controlled to be connected to the sensing assembly.

[0042] The sealing body includes an upper movable column 15 and a lower movable column 151 connected coaxially and separately, and a plurality of conical blocks 16 coaxially fixed on the outside of the lower movable column 151. An embedded column 152 is coaxially fixed to the top of the lower movable column 151, and the embedded column 152 is separately inserted into the bottom of the upper movable column 15. The bottom of the lower movable column 151 is open and the top is closed, forming a shell shape.

[0043] The conical block 16 is made of rubber, and its bottom diameter is slightly smaller than its top diameter. Its bottom diameter is similar to the inner diameter of the borehole, so that the conical block 16 is squeezed into the borehole 14 to ensure the water sealing effect.

[0044] The lower movable column 151 is connected to the bottom of the upper movable column 15 by inserting the embedded column 152. After the entire sealing is completed, the lower movable column 151 and the upper movable column 15 are manually separated.

[0045] The upper piston assembly includes a piston cylinder 8, a piston block 91 that slides up and down inside the piston cylinder 8, a piston column 9 whose bottom end is coaxially connected to the piston block 91, a limiting post 102 that is coaxially connected to the top end of the piston column 9, and a spring 10 sleeved on the outside of the limiting post 102. The limiting post 102 slides up and down on the bracket 1, and the spring 10 is disposed between the bracket 1 and the piston column 9.

[0046] When piston block 91 descends, the pressure in the space between piston cylinder 8 and piston block 91 increases; conversely, it decreases, thus having a certain buffering effect.

[0047] The sensing assembly includes a pressure sensor 101 and a microcontroller connected to the pressure sensor 101. The pressure sensor 101 is fixed in an embedded hole on the bracket 1, and the top end of the spring 10 contacts the pressure sensor 101. The working principle of the microcontroller and the pressure sensor 101 is existing technology and will not be described in detail here.

[0048] The bottom end of the piston cylinder 8 is connected to the sealing groove plate 12 through the upper air pipe 11. The sealing groove plate 12 is connected to one end of the lower air pipe 13. The other end of the lower air pipe 13 passes through multiple conical blocks 16 and is sealed. The sealing groove plate 12 is fixedly sleeved on the lower movable column 151.

[0049] Specifically, the upper air pipe 11, the closed groove plate 12, and the lower air pipe 13 are connected. When the air pressure in the piston cylinder 8 increases, the air pressure in the lower air pipe 13 also increases, which will slightly increase the volume of the cone block 16, thereby helping to increase the adhesion force with the inner wall of the borehole.

[0050] The lower piston assembly includes a slide rod 5 fixedly connected at one end to the outside of the piston rod 9, a piston rod 3 fixedly connected at one end to the bottom of the slide rod 5, an air cylinder 2 connected to the bottom of the piston rod 3, and an air extraction pipe 21 connected at one end to the air cylinder 2. The other end of the air extraction pipe 21 is connected to an air pump. The outside of the slide rod 5 is slidably mounted on the crossbar 4. Under the action of the air pump 21, the air pressure inside the air cylinder 2 decreases, and the slide rod 5 moves downward.

[0051] An external weight-increasing mechanism is also attached to the outside of the slide rod 5. This mechanism includes a water tank 6 fixed to the outside of the slide rod 5, a water pipe 7 connected at one end to the water tank 6, and a water level gauge 61 fixed to the inner side of the top of the water tank 6. A solenoid valve is installed on the water pipe 7, and the other end of the water pipe 7 is connected to a connecting pipe 17 via a micro pump. A valve is installed on the connecting pipe 17, and one end of the connecting pipe 17 is connected to the outside of the lower movable column 151. When the entire process is complete and the upper movable column 15 and lower movable column 151 need to be separated, the connecting pipe 17 is separated from the water pipe 7, and the connecting pipe 17 is connected to the lower movable column 151, which is then filled with a cement-water glass double-liquid grout.

[0052] Example 3

[0053] Taking a deep foundation pit project of a rail transit complex in Huaiyin District, Jinan City as an example. The site has Quaternary confined water below the foundation, with a confined water head of approximately 28 meters. The water flow velocity in borehole 14 is approximately 0.2 m / s, and conventional sealing methods have failed. The method of this invention was used to seal borehole 14 (B40#), which has a diameter of 110 mm and a depth of 40 meters.

[0054] Borehole wall pretreatment: When drilling reached the gravel layer, the mud ratio was adjusted from 6% bentonite to 10% bentonite, the density was controlled at 1.3 g / cm³, and the drilling rig speed was reduced to level 1 (approximately 80 rpm). After drilling, the borehole wall was stable and no collapse occurred.

[0055] Water blocking of the main body: The cone block 16 is lowered to 1 meter above the top plate of the aquifer (depth 18.6 meters). The cone block 16 is made of rubber material and the bottom diameter is equal to the inner diameter of the borehole 14. The water flow rate is reduced from the original 8 m³ / h to 3.5 m³ / h, which is lower than the preset threshold of 4 m³ / h.

[0056] The upper and lower piston assemblies, sensing assemblies, and weight-adding mechanism work to buffer and maintain stability.

[0057] Top sealing and grouting: The calculated volume of borehole 14 is approximately 161L. A felt roll encasing the grouting pipe is pressed down to 3 meters below the borehole opening, applying a pressure of 0.8MPa to form a grout stop. The volume ratio of cement grout (PO 42.5) to water glass (modulus 2.4, 40°Bé) is 1:0.6, with a measured initial setting time of 2.9 minutes. The two-component grout is injected using a grouting pump, with the grouting pressure controlled at 0.6MPa, reaching an instantaneous pressure of 0.8MPa. After initial setting, grout is injected again through the grouting pipe, increasing the pressure to 0.85MPa.

[0058] Results verification: After 24 hours of curing following the sealing, on-site inspection revealed no water seepage points in borehole 14 and the surrounding strata. This method was subsequently used to seal seven similar water-bearing boreholes (14) on-site, achieving a 100% pass rate. Calculations show that this method saved 20 days of construction time and approximately 100,000 yuan in costs. Finally, the upper and lower movable columns 151 were separated and dismantled.

[0059] Specifically, the volume ratio of cement grout to water glass is 1:0.5 to 1:0.6, with the water glass modulus being 2.4 and the Baume degree being 40°Bé. The ambient temperature is controlled at 8-12℃. Before grouting, the theoretical grouting volume is calculated based on the borehole diameter and depth of borehole 14, and the pumping time is set to be synchronized with or slightly shorter than the initial setting time of the two-component grout. The sealing assembly, located at the borehole opening of borehole 14, includes a grouting pipe and a sealing felt roll wrapped around the grouting pipe. The grouting system, connected to the grouting pipe, is used to inject the two-component grout into the borehole opening. The sealing felt roll is soaked in water glass solution, and its winding diameter is larger than the borehole diameter. A pressure of 0.5-1.0 MPa is applied through the drill rod to mechanically engage with the borehole wall. The top of each grouting pipe extends 0.5 meters above the borehole opening and is equipped with a ball valve for pressure-maintaining grouting. The sealing and grouting processes are routine operations for those skilled in the art and will not be described in detail here.

[0060] This invention is particularly applicable to the emergency treatment and permanent sealing of water inrush in borehole 14 when drilling through multiple confined aquifers is required during the construction of deep foundation pits for urban subways and large underground complexes for exploration or construction purposes. Its operation method is simple and has a significant effect on ensuring the safety of the foundation pit and the progress of construction.

[0061] Comparative Example

[0062] When traditional pure cement grout (water-cement ratio 0.5) is used for grouting, the grout retention rate is less than 30% due to the scouring effect of pressurized water. Even after 48 hours of curing, there is still obvious water seepage, requiring rework.

[0063] Finally, in the above embodiments and comparative examples, where the data range of relevant parameters is not explicitly described, the minimum value of the range is used to reduce experimental costs. Materials, structures, operations, etc., not mentioned above, are all carried out according to conventional methods of existing technology and will not be described in detail here.

[0064] The technical features of this invention not described can be implemented by or using existing technology, and will not be repeated here. Of course, the above description is not a limitation of this invention, and this invention is not limited to the examples above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention should also be within the protection scope of this invention.

Claims

1. A method of sealing a borehole gushing orifice, characterized in that, Specifically, the steps include the following: Step S1: Insert the bottom end of the sealing body into the borehole (14), connect the top end of the sealing body to the upper piston assembly, and when the bottom end of the sealing body moves upward due to the impact of water, it is blocked by the upper piston assembly. Step S2: Connect the upper piston assembly to the sensing assembly and the lower piston assembly. When the sensing assembly senses a large pressure, it controls the lower piston assembly to work, causing the upper piston assembly to move downward. Step S3: A water tank (6) assembly is fixed on the lower piston assembly, so that the water tank (6) assembly is connected to the borehole (14). Under the control of the sensing assembly, the water in the borehole (14) is extracted and flows into the water tank (6) assembly, thereby increasing the weight of the lower piston assembly and preventing the water in the borehole (14) from gushing out. Step S4: After time t, once the system is stable, a mechanical felt plug is made near the borehole (14) opening, and then cement-water glass double liquid grout is injected to reinforce the borehole opening.

2. A device for sealing borehole water inflow, employing the method for sealing borehole water inflow as described in claim 1, comprising a support (1), wherein the support (1) is fixed to the ground by anchor bolts, characterized in that, It also includes a sealing body that extends into the borehole (14) at its bottom end, an upper piston assembly connected to the top of the sealing body, and a sensing assembly connected to the upper piston assembly. The sensing assembly is fixed to the top of the bracket (1). The sealing body and the upper piston assembly are movably mounted on the bracket (1). The upper piston assembly is connected to the lower piston assembly, and the lower piston assembly is controlled to be connected to the sensing assembly.

3. The borehole water inflow sealing device according to claim 2, characterized in that, The sealing body includes an upper movable column (15) and a lower movable column (151) connected coaxially and separately, and a plurality of conical blocks (16) coaxially fixed on the outside of the lower movable column (151). An embedded column (152) is coaxially fixed to the top of the lower movable column (151), and the embedded column (152) is separately inserted into the bottom of the upper movable column (15). The bottom of the lower movable column (151) is open and the top is closed, forming a shell shape.

4. The borehole water inflow sealing device according to claim 2, characterized in that, The upper piston assembly includes a piston cylinder (8), a piston block (91) that slides up and down inside the piston cylinder (8), a piston column (9) whose bottom end is coaxially connected to the piston block (91), a limiting post (102) that is coaxially connected to the top end of the piston column (9), and a spring (10) sleeved on the outside of the limiting post (102). The limiting post (102) slides up and down on the bracket (1), and the spring (10) is disposed between the bracket (1) and the piston column (9).

5. A borehole water inflow sealing device according to claim 2, characterized in that, The sensing component includes a pressure sensor (101) and a microcontroller connected to the pressure sensor (101). The pressure sensor (101) is fixed in an embedded hole on the bracket (1), and the top end of the spring (10) is in contact with the pressure sensor (101).

6. The borehole water inflow sealing device according to claim 2, characterized in that, The bottom end of the piston cylinder (8) is connected to the closed groove plate (12) through the upper air pipe (11). The closed groove plate (12) is connected to one end of the lower air pipe (13). The other end of the lower air pipe (13) passes through multiple conical blocks (16) and is closed. The closed groove plate (12) is fixedly sleeved on the lower movable column (151).

7. The borehole water inflow sealing device according to claim 2, characterized in that, The lower piston assembly includes a slide rod (5) with one end fixedly connected to the outside of the piston rod (9), a piston rod (3) with one end fixedly connected to the bottom end of the slide rod (5), an air cylinder (2) connected to the bottom end of the piston rod (3), and an air extraction pipe (21) with one end connected to the air cylinder (2). The other end of the air extraction pipe (21) is connected to an air pump. The outside of the slide rod (5) is slidably mounted on the crossbar (4).

8. A borehole water inflow sealing device according to claim 2, characterized in that, The slide bar (5) is also externally fixed with a weight-increasing mechanism; the weight-increasing mechanism includes a water tank (6) fixed to the outside of the slide bar (5), a water pipe (7) connected to the water tank (6) at one end, and a water level gauge (61) fixed to the inner side of the top of the water tank (6). A solenoid valve is provided on the water pipe (7), and the other end of the water pipe (7) is connected to the connecting pipe through a micro pump. A valve is provided on the connecting pipe, and one end of the connecting pipe is connected to the outside of the lower movable column (151).

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