Device and method for fixing the entire length of a freezing hole

Abstract

The present invention discloses a device and method for fixing the entire length of a freezing hole, and relates to the technical field of mine construction engineering. The device includes three parts: a freezing pipe, a liquid supply pipe, and a quick-plug connector. The freezing pipe, the liquid supply pipe, and the quick-plug connector are combined and split to form a slow-setting cement grouting system, a pipe washing system, and a freezing system. During implementation, the method is mainly implemented through six steps: S1, making and sinking the freezing pipe, S2, making and installing the liquid supply pipe, S3, pressure testing the fixing pipe system, S4, injecting slow-setting cement, S5, cleaning the pipeline, and S6, carrying out the freezing work. The present invention utilizes a brand-new backstop grouting system to fix the entire length of the freezing hole, and quickly cleans the slow-setting cement in the liquid supply pipe and the freezing pipe, thereby minimizing the scope of contamination of the inside of the freezing pipe by the slow-setting cement, reducing the requirements for the slow-setting cement and the aperture of the freezing hole, and greatly reducing the risk of freezing pipe sinking being blocked due to premature solidification of the slow-setting cement.

Description

Technical Field

[0001] The invention relates to the technical field of mine construction engineering, and in particular to a device and method for fixing a full-length pipe of a freezing hole. Background Art

[0002] In mining construction, vertical shafts in water-rich and soft strata are mostly excavated using artificial freezing methods. The current freezing construction process usually requires the construction of dozens or hundreds of freezing holes around the shaft for the installation of freezing pipes. Among them, most freezing holes need to pass through different underground strata, penetrate the impermeable layer in the soil or rock layer, and form a water conduction channel at the freezing hole, which may cause damage such as loss of cold water in the freezing hole, flooding of the well and mine, water leakage between aquifers, and substantial subsidence of the strata after the head of the water-rich strata decreases. In previous actual construction, many coal mines have experienced well flooding accidents due to water conduction from freezing holes, causing serious economic and social losses.

[0003] At present, there are three main measures for preventing and controlling water diversion in freezing holes: the first is to inject a certain amount of slow-setting cement into the hole through the drill pipe after the freezing hole is constructed, so as to replace part of the mud in the hole, and then put the freezing pipe into the bottom of the freezing hole. The freezing pipe sinks and gradually squeezes the slow-setting cement at the bottom. However, due to the high density of slow-setting cement, it forms a large buoyancy on the freezing pipe. Therefore, this method can only achieve partial pipe fixation at the bottom of the freezing hole, and cannot achieve full-length pipe fixation. In addition, it has high requirements on the slow-setting cement and the size of the freezing hole, and there is a risk of the freezing pipe being blocked from sinking. The second is to inject a certain amount of slow-setting cement into the hole after the freezing hole is constructed. After that, directly freeze the lower pipe, and after the freezing is completed, circulate high-temperature brine to carry out thawing work within a radius of about 0.5 meters, then pull out the liquid supply pipe, use tools to break the wall of the frozen pipe at the designated position, and perform fixed-point grouting or full-length grouting. However, this process will damage the frozen pipe, making it impossible to freeze the frozen pipe, and the construction steps are complex, expensive, and take up a long time at the wellhead; the third method is to drill directional holes from the wellbore to the annulus area of ​​each frozen hole and inject grout to block the water diversion channel of the frozen hole, but the success rate of drilling directional holes is low and the wellbore is occupied for a long time. As can be seen from the above, the existing technologies for preventing and controlling water diversion in frozen holes have serious deficiencies and cannot completely eliminate the potential hazards caused by water diversion in frozen holes.

[0004] How to develop a device and method for fixing the entire length of the freezing hole, achieve the fixing of the entire length of the freezing hole, and minimize the contamination range of the slow-setting cement on the inside of the freezing pipe has become a technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0005] The purpose of the present invention is to provide a device and method for fixing the pipe of the entire length of a freezing hole, which utilizes a new backstop grouting system to achieve the fixing of the pipe of the entire length of the freezing hole, and after the slow-setting cement is injected, the quick plug-in joint is separated, and the liquid supply pipe and the slow-setting cement in the freezing pipe are quickly cleaned by reverse circulation pipe washing with clean water, thereby minimizing the contamination range of the slow-setting cement on the inside of the freezing pipe, reducing the requirements for the slow-setting cement and the aperture of the freezing hole, greatly reducing the risk of obstruction of the freezing pipe sinking caused by the premature solidification of the slow-setting cement, and solving the related problems of the current freezing hole water diversion prevention and control measures having many and complicated construction steps, high costs, and long wellhead occupancy time.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention discloses a device for fixing a full-length pipe of a freezing hole, comprising a freezing pipe, a liquid supply pipe and a quick plug-in connector. The liquid supply pipe is located at the center of the freezing pipe and the bottom is connected by a quick plug-in connector.

[0008] The freezing pipe, the liquid supply pipe and the quick plug-in connector are combined and disassembled to form a slow-setting cement grouting system, a pipe washing system and a freezing system.

[0009] Preferably, the quick plug-in connector includes a plug part and a base part, the top of the plug part matches the inner hole of the base part, and one-way valves are installed inside both ends of the plug part, a second sealing groove is provided on the side wall of the inner hole of the base part, a second sealing ring is installed in the second sealing groove, and the second sealing ring is tightly matched with the outer wall of the plug part; the plug part is fixedly connected to the bottom of the freezing pipe, and the base part is fixedly connected to the bottom of the liquid supply pipe.

[0010] Preferably, the freezing pipe comprises an upper end port of the freezing pipe, an upper end sealing pipe, a freezing pipe body and a freezing pipe bottom cone, wherein the upper end sealing pipe is connected to the top of the freezing pipe body, the freezing pipe bottom cone is fixedly connected to the bottom end of the freezing pipe body, and the upper end port of the freezing pipe is connected to one side of the upper part of the upper end sealing pipe; the upper end port of the freezing pipe, the upper end sealing pipe, the freezing pipe body and the freezing pipe bottom cone are connected as a whole and then inserted into the freezing hole, and the original mud in the freezing hole surrounds the outer periphery of the freezing pipe body;

[0011] The plug part is fixedly connected in the central hole of the freezing pipe bottom cone.

[0012] Preferably, a reinforcing rib is provided between the outer wall of the plug portion and the inner wall of the freezing pipe bottom cone, and the reinforcing rib is located in the middle of the inner cavity of the freezing pipe bottom cone.

[0013] Preferably, the liquid supply pipe comprises an upper port of the liquid supply pipe, an upper steel pipe of the liquid supply pipe and a liquid supply pipe body, wherein the upper port of the liquid supply pipe is located at the top of the upper steel pipe of the liquid supply pipe, the bottom end of the upper steel pipe of the liquid supply pipe is fixedly connected to the top of the liquid supply pipe body, and the liquid supply pipe body is movably arranged in the inner cavity of the freezing pipe body; the base portion is fixedly connected to the bottom end of the liquid supply pipe body;

[0014] The steel pipe at the upper end of the liquid supply pipe is connected to the top through hole of the upper end sealing pipe. A first sealing groove is opened on the inner wall of the top through hole. A first sealing ring is installed in the first sealing groove. The first sealing ring fits tightly on the outer wall of the steel pipe at the upper end of the liquid supply pipe.

[0015] Preferably, a centralizer is provided at the bottom of the liquid supply pipe body, and the outer contour of the centralizer matches the inner diameter of the freezing pipe body.

[0016] Preferably, the liquid supply pipe body is made of polyethylene plastic pipe, and the freezing pipe body is formed by butt welding of seamless steel pipes.

[0017] Preferably, after the top end of the plug part is embedded in the inner hole of the base part, a closed connection is formed through the internal sealing device and the second sealing ring, and the upper port of the liquid supply pipe, the liquid supply pipe body, the base part and the central hole of the plug part are connected to each other to form a flow channel for the slow-setting cement;

[0018] The liquid supply pipe drives the base part to be lifted up and separated from the plug part, and the upper port of the freezing pipe, the inner cavity of the freezing pipe body, the base part and the inner cavity of the liquid supply pipe body are connected to form a backwash channel for clean water.

[0019] A method for fixing a pipe in the entire length of a freezing hole is accomplished by using the device for fixing a pipe in the entire length of a freezing hole as described above, and is characterized in that it comprises the following steps:

[0020] S1, making and sinking freezing tube:

[0021] After the freezing hole is constructed and inspected to be qualified, first, the bottom cone of the freezing pipe is lowered to the opening of the freezing hole, and then the corresponding seamless steel pipe is butt-welded to the bottom cone of the freezing pipe, and it is sunk by the length of a seamless steel pipe, and the welding operation is repeated to continuously lengthen the seamless steel pipe until the freezing pipe sinks to the bottom of the freezing hole; at this time, a plurality of seamless steel pipes are welded to form a freezing pipe body, and the top of the freezing pipe body is not lower than the opening of the freezing hole;

[0022] S2, make and install the liquid supply pipe:

[0023] S21: Assemble the pre-designed upper steel pipe of the liquid supply pipe, the main body of the liquid supply pipe, the centralizer, the base part of the quick-plug connector and the second sealing groove, and complete the sealing inspection of the liquid supply pipe on the ground;

[0024] S22: The liquid supply pipe prepared in step S21 is installed as a whole and sunk to the bottom of the freezing pipe body, so that the plug part of the quick plug connector is connected with the base part, and automatic sealing is achieved through the second sealing groove and the second sealing ring inside;

[0025] S23: firstly, the upper sealing tube connected to the upper port of the freezing tube is embedded into the inner hole of the uppermost freezing tube body, and at the same time, the upper steel tube of the liquid supply tube passes through the through hole of the upper sealing tube, and the first sealing ring is used to achieve the sealing work at the intersection of the upper steel tube of the liquid supply tube and the upper sealing tube; finally, the upper sealing tube is welded to the freezing tube body;

[0026] S3, solid pipe system pressure test:

[0027] First, keep the upper port of the liquid supply pipe in a closed state, and perform a water injection pressure test through the upper port of the freezing pipe. When the water pressure value at the bottom of the freezing pipe calculated according to the pressure value of the water injection port during the pressurization process is the maximum, it is determined as the design value of the opening pressure of the one-way valve in the quick-plug connector; then, raise the liquid supply pipe and then drop it, re-complete the docking work of the quick-plug connector, and then perform a pressure test again, and repeat the above steps until the water pressure at the bottom of the freezing pipe can be pressurized to be greater than the design value of the opening pressure of the one-way valve in the quick-plug connector, and the design value is the valve one-way opening threshold;

[0028] One-way valve opening threshold Calculation formula:

[0029] When the weight of the retarded cement in the pipe is greater than the weight of the original mud outside the pipe, it is calculated according to the following formula:

[0030]

[0031] When the weight of the retarded cement in the pipe is less than or equal to the weight of the original mud outside the pipe, it is calculated according to the following formula:

[0032]

[0033] Among them, the one-way opening threshold of the valve is At this time, the inside of the frozen pipe is slow-setting cement and the outside of the pipe is original mud; is the weight of the original mud outside the pipe; is the density of the slow-setting cement in the pipe; H is the depth of the freezing hole / m; is the safety factor, generally 1.3 to 1.5;

[0034] S4, injection of slow setting cement:

[0035] S41: Keep the freezing pipe filled with clean water and close the upper port of the freezing pipe;

[0036] S42: injecting slow-setting cement through the upper port of the liquid supply pipe, and as the slow-setting cement is discharged from the quick-plug connector and the one-way valve at the lower part of the freezing pipe, the slow-setting cement gradually displaces the original mud in the freezing hole upward;

[0037] S43: when it is found that the slow-setting cement returns to the opening of the freezing hole, the injection of the slow-setting cement is immediately stopped;

[0038] S5, pipeline cleaning:

[0039] S51: After the injection of slow-setting cement is stopped, the liquid supply pipe is quickly raised to completely separate the plug part of the quick-disconnect connector from the base part;

[0040] S52: Keep the upper port of the liquid supply pipe in an open state, and quickly inject clean water through the upper port of the freezing pipe to clean the slow-setting cement in the liquid supply pipe until the clean water is discharged from the upper port of the liquid supply pipe;

[0041] S6, carry out freezing work:

[0042] After the slow-setting cement reaches the specified solidification time and the corresponding freezing preparation work is completed, the clean water inside the system is pumped out through the upper port of the liquid supply pipe, and then the low-temperature brine is circulated through the upper port of the freezing pipe and the upper port of the liquid supply pipe to carry out subsequent freezing work.

[0043] Preferably, in S1, the bottom cone of the freezing pipe is internally connected with the plug part of the quick-plug connector, the one-way valve inside the plug and the reinforcing ribs; in S23, the steel pipe at the upper end of the liquid supply pipe passes through the top through hole of the upper end sealing pipe, and a first sealing ring is installed in the first sealing groove at the intersection of the two for sealing.

[0044] Compared with the prior art, the beneficial technical effects of the present invention are:

[0045] The present invention discloses a device for fixing the full length of a freezing hole, which comprises a freezing pipe, a liquid supply pipe and a quick-plug connector. The freezing pipe, the liquid supply pipe and the quick-plug connector are combined and split to form a slow-setting cement grouting system, a pipe washing system and a freezing system. When in use, the device for fixing the full length of a freezing hole is mainly used to complete a total of six steps, namely, S1, making and sinking the freezing pipe; S2, making and installing the liquid supply pipe; S3, pressure testing the fixing pipe system; S4, injecting slow-setting cement; S5, cleaning the pipeline; S6, carrying out the freezing work.

[0046] The present invention utilizes a liquid supply pipe, a one-way valve and a quick-plug connector to form a backstop grouting system independent of the freezing pipe. The slow-setting cement is gradually injected from the bottom of the freezing pipe to displace the original mud in the freezing hole, thereby achieving full-length pipe solidification of the freezing hole. After the slow-setting cement is injected, the liquid supply pipe can be provided to separate the quick-plug connector, and then the principle of clean water reverse circulation pipe washing is utilized to quickly clean the slow-setting cement in the liquid supply pipe and the freezing pipe, thereby minimizing the contamination range of the slow-setting cement on the inside of the freezing pipe. The device of the present invention has a compact structure and a simple construction process, and has relatively low requirements on the slow-setting cement and the aperture of the freezing hole, thereby greatly reducing the risk of obstruction of the freezing pipe sinking due to premature solidification of the slow-setting cement. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present invention will be further described below in conjunction with the accompanying drawings.

[0048] Figure 1 It is a schematic diagram of the device for fixing the entire length of the freezing hole of the present invention (stage of injecting slow-setting cement slurry);

[0049] Figure 2 It is a schematic diagram of the device for fixing the full length pipe of the freezing hole of the present invention (pipe washing stage);

[0050] Figure 3 For the present invention Figure 1 Sectional view at the middle AA position;

[0051] Figure 4 The present invention is a flow chart of the method for fixing the entire length of a freezing hole.

[0052] Explanation of the reference numerals in the accompanying drawings: 11. upper port of the freezing pipe; 12. upper sealing pipe; 121. first sealing groove; 13. freezing pipe body; 14. freezing pipe bottom cone; 15. plug part; 151. one-way valve; 16. reinforcing rib; 21. upper port of the liquid supply pipe; 22. steel pipe at the upper end of the liquid supply pipe; 23. liquid supply pipe body; 24. centralizer; 25. base part; 251. second sealing groove; 3. stratum rock and soil; 4. original mud in the freezing hole; 5. clean water; 6. slow-setting cement. DETAILED DESCRIPTION

[0053] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0054] like Figure 1-Figure 3 As shown, a device for fixing the entire length of a freezing hole comprises a freezing pipe, a liquid supply pipe and a quick-plug connector. The liquid supply pipe is located at the center of the freezing pipe and the bottom is connected by a quick-plug connector.

[0055] The freezing pipe, the liquid supply pipe and the quick plug-in connector are combined and disassembled to form a slow-setting cement grouting system, a pipe washing system and a freezing system.

[0056] Specifically, the quick-plug connector includes a plug part 15 and a base part 25, the top of the plug part 15 matches the inner hole of the base part 25, and one-way valves 151 are installed inside the two ends of the plug part 15 to ensure that the slow-setting cement in the central channel can only move in one direction; a second sealing groove 251 is provided on the side wall of the inner hole of the base part 25, and a second sealing ring is installed in the second sealing groove 251, and the second sealing ring is tightly matched with the outer wall of the plug part 15, so that the two are automatically sealed after being plugged in and connected; the plug part 15 is fixedly connected to the bottom of the freezing pipe, and the base part 25 is fixedly connected to the bottom of the liquid supply pipe. Specifically, when the freezing pipe falls to the bottom, the plug part 15 of the quick-plug connector is inserted into the base part 25 of the quick-plug connector, and the two complete docking and automatic sealing, and the internal fluid can only flow in one direction under a threshold value greater than the one-way opening of the valve; when the specified work is completed, the base part 25 of the plug connector is quickly lifted up to separate the plug part 15 from the base part 25.

[0057] Specifically, the freezing pipe includes an upper port 11 of the freezing pipe, an upper sealing pipe 12, a freezing pipe body 13 and a freezing pipe bottom cone 14, wherein the upper sealing pipe 12 is connected to the top of the freezing pipe body 13, the freezing pipe bottom cone 14 is fixedly connected to the bottom end of the freezing pipe body 13, and the upper port 11 of the freezing pipe is connected to one side of the upper part of the upper sealing pipe 12; wherein the upper port 11 of the freezing pipe, the upper sealing pipe 12, the freezing pipe body 13 and the freezing pipe bottom cone 14 are connected as a whole by welding and then inserted into the freezing hole, and the original mud 4 in the freezing hole surrounds the outer periphery of the freezing pipe body 13; the plug part 15 is fixedly connected to the center hole of the freezing pipe bottom cone 14, and specifically the plug part 15 is welded to the center hole of the freezing pipe bottom cone 14.

[0058] Specifically, a reinforcing rib 16 is provided between the outer wall of the plug part 15 and the inner wall of the freezing pipe bottom cone 14, and the reinforcing rib 16 is located in the middle of the inner cavity of the freezing pipe bottom cone 14. The design of the reinforcing rib 16 not only plays a good positioning role, but also increases the connection strength and prolongs its service life.

[0059] Specifically, the liquid supply pipe includes an upper port 21, an upper steel pipe 22 and a main body 23. The upper port 21 is located at the top of the upper steel pipe 22. The bottom of the upper steel pipe 22 is fixedly connected to the top of the main body 23. The main body 23 is movably arranged in the inner cavity of the freezing pipe body 13. The base portion 25 is fixedly connected to the bottom of the main body 23. The upper steel pipe 22 is connected to the top through hole of the upper sealing pipe 12. The inner wall of the top through hole is provided with a first sealing groove 121. A first sealing ring is installed in the first sealing groove 121. The first sealing ring is tightly attached to the outer wall of the upper steel pipe 22. The bottom of the upper port 21 is embedded in the top inner hole of the main body 23 and connected together by welding.

[0060] Specifically, a centralizer 24 is provided at the bottom of the liquid supply pipe body 23, and the outer contour of the centralizer 24 matches the inner diameter of the freezing pipe body 13. The centralizer 24 is configured as an arc plate, and a plurality of arc plates are distributed in a circumference, and the opening side is fixedly connected to the outer wall of the liquid supply pipe body 23. The maximum outer diameter of the arc plate is slightly smaller than the inner diameter of the freezing pipe body 13, so as to ensure good positioning and guiding effect when moving up and down, so that the liquid supply pipe body 23 and the freezing pipe body 13 remain coaxial.

[0061] Specifically, the liquid supply pipe body 23 is made of a polyethylene plastic pipe, and the freezing pipe body 13 is formed by butt welding of seamless steel pipes.

[0062] Specifically, after the top end of the plug part 15 is embedded in the inner hole of the base part 25, a closed connection is formed through the second sealing groove 251 and the second sealing ring inside. The upper port 21 of the liquid supply pipe, the upper end steel pipe 22 of the liquid supply pipe, the liquid supply pipe body 23, the base part 25 and the center hole of the plug part 15 are connected to each other to form a flow channel for the slow-setting cement 6; during implementation, the liquid supply pipe drives the base part 25 to be lifted up and separated from the plug part 15, and the inner cavity of the upper port 11 of the freezing pipe, the upper end sealing pipe 12, and the freezing pipe body 13 is connected to the inner cavity of the base part 25 and the liquid supply pipe body 23 to form a backwash channel for clean water 5.

[0063] like Figure 1As shown, in the state of slow-setting cement grouting, after the liquid supply pipe is installed and sinks to the bottom of the freezing pipe, the plug part 15 of the quick-plug connector is inserted into the base part 25, the two are docked and automatically sealed, and the internal fluid can only flow in one direction when it is greater than the one-way opening threshold of the valve, thereby forming a grouting system that can inject slow-setting cement from the bottom of the freezing pipe into the freezing hole. The system realizes non-return one-way grouting through the one-way valve 151 in the quick-plug connector to prevent the original mud and slow-setting cement in the freezing hole from flowing back into the liquid supply pipe or the freezing pipe. The device uses the liquid supply pipe, the one-way valve and the quick-plug connector to form a non-return grouting system independent of the freezing pipe. The slow-setting cement is gradually injected from the bottom of the freezing pipe to displace the original mud in the freezing hole, thereby realizing the full-length pipe fixing operation of the freezing hole.

[0064] like Figure 2 As shown, the schematic diagram of the pipe washing stage, in which the pipe washing system is also composed of three parts: a freezing pipe, a liquid supply pipe and a quick-plug connector. After the grouting is completed, the liquid supply pipe is raised to a specified height so that the plug part 15 of the quick-plug connector is separated from the base part 25; the upper port 21 of the liquid supply pipe is kept in an open state, and clean water is quickly injected through the upper port 11 of the freezing pipe to form a reverse circulation pipe washing system to clean the inside of the liquid supply pipe and the freezing pipe; if necessary, the upper port 11 of the freezing pipe can also be kept in an open state, and clean water is quickly injected through the upper port 21 of the liquid supply pipe to form a positive circulation pipe washing system to clean the inside of the liquid supply pipe and the freezing pipe. This operation uses the principle of reverse circulation pipe washing with clean water to quickly clean the retarded cement in the liquid supply pipe and the freezing pipe, and minimize the scope of contamination of the retarded cement on the inside of the freezing pipe.

[0065] The freezing system is also composed of three parts: a freezing pipe, a liquid supply pipe and a quick-disconnect connector. After completing the pipe washing step and ensuring internal cleanliness, the internal clean water is pumped out from the upper port 21 of the liquid supply pipe, and then low-temperature brine is injected through the upper port 21 of the liquid supply pipe, and the low-temperature brine is recovered from the upper port 11 of the freezing pipe, thereby forming a freezing system.

[0066] like Figure 4 As shown, a method for fixing a pipe with a full length of a freezing hole is completed by using the device for fixing a pipe with a full length of a freezing hole as described above, and is characterized in that it includes the following steps:

[0067] S1, making and sinking freezing tube:

[0068] After the freezing hole is constructed and inspected to be qualified, first, the freezing pipe bottom cone 14 is lowered to the opening of the freezing hole, and then the corresponding seamless steel pipe is butt-welded to the freezing pipe bottom cone 14, and it is sunk by the length of a seamless steel pipe, and the welding operation is repeated to continuously lengthen the seamless steel pipe until the freezing pipe sinks to the bottom of the freezing hole; at this time, a plurality of seamless steel pipes are welded to form a freezing pipe body 13, and the top of the freezing pipe body 13 is not lower than the opening of the freezing hole; the freezing hole is excavated on the stratum rock and soil body 3 at the designated position as required;

[0069] S2, make and install the liquid supply pipe:

[0070] S21: Assemble the pre-designed upper steel pipe 22 of the liquid supply pipe, the liquid supply pipe body 23, the centralizer 24, the base part 25 of the quick plug-in connector and the second sealing groove 251, and complete the sealing inspection of the liquid supply pipe on the ground;

[0071] S22: The liquid supply pipe prepared in step S21 is installed as a whole and sunk to the bottom of the freezing pipe body 13, so that the plug part 15 of the quick plug connector is connected with the base part 25, and automatic sealing is achieved through the second sealing groove 251 and the second sealing ring inside;

[0072] S23: first, the upper sealing tube 12 connected to the upper port 11 of the freezing tube is embedded into the inner hole of the uppermost freezing tube body 13, and at the same time, the upper steel tube 22 of the liquid supply tube passes through the through hole of the upper sealing tube 12, and the sealing work at the intersection of the upper steel tube 22 of the liquid supply tube and the upper sealing tube 12 is achieved through the first sealing ring; finally, the upper sealing tube 12 is welded to the freezing tube body 13;

[0073] At this point, the freezing pipe and the liquid supply pipe are assembled and located in the freezing hole of the formation rock and soil body 3;

[0074] S3, solid pipe system pressure test:

[0075] First, keep the upper port 21 of the liquid supply pipe in a closed state, and perform water injection pressure test through the upper port 11 of the freezing pipe. When the water pressure value at the bottom of the freezing pipe calculated according to the pressure value of the water injection port during the pressurization process is the maximum, it is determined as the design value of the opening pressure of the one-way valve 151 in the quick-plug connector; then, the liquid supply pipe is raised and then lowered, the docking work of the quick-plug connector is completed again, and then the pressure test is performed again, and the above steps are repeated until the water pressure at the bottom of the freezing pipe can be pressurized to be greater than the design value of the opening pressure of the one-way valve in the quick-plug connector, and the design value is the valve one-way opening threshold;

[0076] One-way valve opening threshold Calculation formula:

[0077] When the weight of the retarded cement in the pipe is greater than the weight of the original mud outside the pipe, it is calculated according to the following formula:

[0078]

[0079] When the weight of the retarded cement in the pipe is less than or equal to the weight of the original mud outside the pipe, it is calculated according to the following formula:

[0080]

[0081] Among them, the one-way opening threshold of the valve is At this time, the inside of the frozen pipe is slow-setting cement 6, and the outside of the pipe is original mud 4; is the weight of the original mud outside the pipe; is the density of the slow-setting cement in the pipe; H is the depth of the freezing hole / m; is the safety factor, generally 1.3 to 1.5;

[0082] Specifically, the weight of the original mud outside the pipe is initially obtained through the mud data of the early on-site detection hole, and is secondary checked by the buoyancy value of the frozen pipe when the frozen pipe is lowered; the weight of the slow-setting cement in the pipe is obtained through indoor tests; the one-way opening threshold of the valve is calculated by the above formula , and then select a suitable one-way valve 151 according to the calculation result and assemble it into the device. The one-way valve 151 can be customized according to the needs;

[0083] S4, injection of slow setting cement:

[0084] S41: Keep the freezing pipe filled with clean water 5, and close the upper port 11 of the freezing pipe;

[0085] S42: injecting slow-setting cement 6 through the upper port 21 of the liquid supply pipe, and as the slow-setting cement 6 is discharged from the quick plug-in connector and the one-way valve 151 at the lower part of the freezing pipe, the slow-setting cement gradually displaces the original mud 4 in the freezing hole upward;

[0086] S43: when it is found that the slow-setting cement 6 returns to the opening of the freezing hole, the injection of the slow-setting cement is immediately stopped;

[0087] S5, pipeline cleaning:

[0088] S51: After the injection of slow-setting cement is stopped, the liquid pipe is quickly provided to completely separate the plug part 15 and the base part 25 of the quick-disconnect connector, and the plug part 15 and the base part 25 are lifted to a specified height according to the actual matching length to achieve a complete separation operation;

[0089] S52: Keep the upper port 21 of the liquid supply pipe in an open state, and quickly inject clean water 5 through the upper port 11 of the freezing pipe to clean the slow-setting cement 6 in the liquid supply pipe until the clean water is discharged from the upper port 21 of the liquid supply pipe;

[0090] S6, carry out freezing work:

[0091] After the slow-setting cement reaches the specified solidification time and the corresponding freezing preparation work is completed, the clean water inside the system is pumped out through the upper port 21 of the liquid supply pipe, and then the low-temperature brine is circulated through the upper port 11 of the freezing pipe and the upper port 21 of the liquid supply pipe to carry out subsequent freezing work.

[0092] Specifically, in S1, the bottom cone 14 of the freezing pipe is internally connected with the plug part 15 of the quick plug-in connector, the one-way valve 151 inside the plug and the reinforcing ribs 16; in S23, the steel pipe 22 at the upper end of the liquid supply pipe passes through the top through hole of the upper end sealing tube 12, and can move up and down in the top through hole when in use, and a first sealing ring is installed in the first sealing groove 121 at the intersection of the two to achieve dynamic sealing between the two.

[0093] Specifically, the upper end steel pipe 22 of the liquid supply pipe and the liquid supply pipe body 23 are designed as a split structure or an integrated structure, such as Figure 1-2 As shown, when the split structure is designed, the diameter of the steel pipe 22 at the upper end of the liquid supply pipe is smaller than the diameter of the liquid supply pipe body 23 and the opposite ends of the two are welded or fused together for fixation; when designed as an integrated structure, the diameters of the steel pipe 22 at the upper end of the liquid supply pipe and the liquid supply pipe body 23 are the same, that is, they are designed as straight-through tubes; the steel pipe 22 at the upper end of the liquid supply pipe and the liquid supply pipe body 23 are connected to form the liquid supply pipe.

[0094] Specifically, in an embodiment of the split structure, the material of the steel pipe 22 at the upper end of the liquid supply pipe is preferably stainless steel metal, and the material of the liquid supply pipe body 23 is preferably polyethylene plastic pipe; in an embodiment of the integrated structure, polyethylene plastic pipe is preferably used because during the freezing process, the liquid supply pipe needs to isolate the heat transfer process between the internal and external liquids to a certain extent, and the effect of polyethylene pipe is better.

[0095] The device of the present invention has a compact structure, a simple construction process, and relatively low requirements for the retarding cement and the aperture of the freezing hole, thereby greatly reducing the risk of obstruction of the freezing pipe sinking caused by premature solidification of the retarding cement.

[0096] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0097] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A device for fixing the entire length of a freezing hole, characterized in that: It includes three parts: a freezing pipe, a liquid supply pipe and a quick plug-in connector. The liquid supply pipe is located at the center of the freezing pipe and the bottom is connected by a quick plug-in connector. The freezing pipe, the liquid supply pipe and the quick-plug connector are combined and separated to form a slow-setting cement grouting system, a pipe washing system and a freezing system; The quick plug connector comprises a plug part (15) and a base part (25), the top end of the plug part (15) matches the inner hole of the base part (25), and one-way valves (151) are installed inside both ends of the plug part (15); the plug part (15) is fixedly connected to the bottom of the freezing pipe, and the base part (25) is fixedly connected to the bottom of the liquid supply pipe; When the top end of the plug part (15) is embedded in the inner hole of the base part (25), the inner cavity of the liquid supply pipe, the base part (25) and the central hole of the plug part (15) are connected to each other to form a flow channel for the slow-setting cement (6); When the liquid supply pipe drives the base part (25) to be lifted up and separated from the plug part (15), the inner cavity of the freezing pipe is connected with the base part (25) and the inner cavity of the liquid supply pipe to form a backwash channel for clean water (5).

2. The device for fixing the full-length pipe of a freezing hole according to claim 1, characterized in that: A second sealing groove (251) is provided on the side wall of the inner hole of the base portion (25), a second sealing ring is installed in the second sealing groove (251), and the second sealing ring is tightly matched with the outer wall of the plug portion (15).

3. The device for fixing the full-length pipe of a freezing hole according to claim 2, characterized in that: The freezing pipe comprises an upper end port (11) of the freezing pipe, an upper end sealing pipe (12), a freezing pipe body (13) and a freezing pipe bottom cone (14); the upper end sealing pipe (12) is connected to the top of the freezing pipe body (13); the freezing pipe bottom cone (14) is fixedly connected to the bottom of the freezing pipe body (13); the upper end port (11) of the freezing pipe is connected to one side of the upper part of the upper end sealing pipe (12); the upper end port (11), the upper end sealing pipe (12), the freezing pipe body (13) and the freezing pipe bottom cone (14) are connected as a whole and then inserted into the freezing hole, and the original mud (4) in the freezing hole surrounds the outer periphery of the freezing pipe body (13); The plug part (15) is fixedly connected in the central hole of the freezing pipe bottom cone (14).

4. The device for fixing the full-length pipe of a freezing hole according to claim 3 is characterized in that: A reinforcing rib (16) is provided between the outer wall of the plug portion (15) and the inner wall of the freezing pipe bottom cone (14), and the reinforcing rib (16) is located in the middle of the inner cavity of the freezing pipe bottom cone (14).

5. The device for fixing the full-length pipe of a freezing hole according to claim 3, characterized in that: The liquid supply pipe comprises an upper port (21) of the liquid supply pipe, an upper steel pipe (22) of the liquid supply pipe and a liquid supply pipe body (23); the upper port (21) of the liquid supply pipe is located at the top of the upper steel pipe (22) of the liquid supply pipe, the bottom end of the upper steel pipe (22) of the liquid supply pipe is fixedly connected to the top of the liquid supply pipe body (23), and the liquid supply pipe body (23) is movably arranged in the inner cavity of the freezing pipe body (13); the base portion (25) is fixedly connected to the bottom end of the liquid supply pipe body (23); The steel pipe (22) at the upper end of the liquid supply pipe is connected to the top through hole of the upper end sealing pipe (12), and a first sealing groove (121) is provided on the inner wall of the top through hole. A first sealing ring is installed in the first sealing groove (121), and the first sealing ring is tightly fitted on the outer wall of the steel pipe (22) at the upper end of the liquid supply pipe.

6. The device for fixing the full-length pipe of a freezing hole according to claim 5, characterized in that: A centralizer (24) is provided at the bottom of the liquid supply pipe body (23), and the outer contour of the centralizer (24) matches the inner diameter of the freezing pipe body (13).

7. The device for fixing the full-length pipe of a freezing hole according to claim 5, characterized in that: The liquid supply pipe body (23) is made of a polyethylene plastic pipe, and the freezing pipe body (13) is formed by butt welding of seamless steel pipes.

8. The device for fixing the full-length pipe of a freezing hole according to claim 5, characterized in that: The top end of the plug part (15) is embedded in the inner hole of the base part (25) to form a closed connection through the second sealing groove (251) and the second sealing ring, and the upper port (21) of the liquid supply pipe, the liquid supply pipe body (23), the base part (25) and the central hole of the plug part (15) are connected to each other to form a flow channel for the slow-setting cement (6); The liquid supply pipe drives the base part (25) to be lifted up and separated from the plug part (15), and the inner cavity of the freezing pipe upper port (11) and the freezing pipe body (13) are connected with the base part (25) and the inner cavity of the liquid supply pipe body (23) to form a backwash channel for clean water (5).

9. A method for fixing a full-length pipe in a freezing hole, which is accomplished by using the device for fixing a full-length pipe in a freezing hole according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, making freezing tube with sink: After the freezing hole is constructed and inspected to be qualified, first, the freezing pipe bottom cone (14) is lowered to the opening of the freezing hole, and then the corresponding seamless steel pipe is butt-welded to the freezing pipe bottom cone (14), and the seamless steel pipe is sunk by the length of a seamless steel pipe. The welding operation is repeated to continuously lengthen the seamless steel pipe until the freezing pipe is sunk to the bottom of the freezing hole. At this time, a plurality of seamless steel pipes are welded to form a freezing pipe body (13), and the top of the freezing pipe body (13) is not lower than the opening of the freezing hole. S2, make and install the liquid supply pipe: S21: assembling the pre-designed upper steel pipe (22) of the liquid supply pipe, the liquid supply pipe body (23), the centralizer (24), the base portion (25) of the quick plug-in connector and the second sealing groove (251), and completing the liquid supply pipe sealing inspection work on the ground; S22: The liquid supply pipe prepared in step S21 is installed as a whole and sunk to the bottom of the freezing pipe body (13), so that the plug part (15) of the quick plug connector and the base part (25) are docked, and automatic sealing is achieved through the second sealing groove (251) and the second sealing ring inside; S23: first, the upper sealing tube (12) connected to the upper port (11) of the freezing tube is embedded into the inner hole of the uppermost freezing tube body (13), and at the same time, the upper steel tube (22) of the liquid supply tube passes through the through hole of the upper sealing tube (12), and the sealing work at the intersection of the upper steel tube (22) of the liquid supply tube and the upper sealing tube (12) is achieved through the first sealing ring; finally, the upper sealing tube (12) and the freezing tube body (13) are welded together; S3, solid pipe system pressure test: First, keep the upper port (21) of the liquid supply pipe in a closed state, and perform water injection pressure test through the upper port (11) of the freezing pipe. When the water pressure value at the bottom of the freezing pipe calculated according to the pressure value of the water injection port during the pressurization process is the maximum, it is determined as the design value of the opening pressure of the one-way valve (151) in the quick plug-in connector; then, the liquid supply pipe is raised and then lowered, the docking work of the quick plug-in connector is completed again, and then the pressure test is performed again, and the above steps are repeated until the water pressure at the bottom of the freezing pipe can be pressurized to be greater than the design value of the opening pressure of the one-way valve in the quick plug-in connector, and the design value is the valve one-way opening threshold; Valve one-way opening threshold p s Calculation formula: When the weight of the retarded cement in the pipe is greater than the weight of the original mud outside the pipe, it is calculated according to the following formula: p s =[(γ w -c c )·H+2]·c When the weight of the retarded cement in the pipe is less than or equal to the weight of the original mud outside the pipe, it is calculated according to the following formula: p s =0.5·H / 100·g Among them, the one-way opening threshold of the valve is p s / MPa, at this time, the inside of the frozen pipe is slow-setting cement (6) and the outside of the pipe is original mud (4); γ c is the weight of the original mud outside the pipe; γ w is the weight of the slow-setting cement in the pipe; H is the depth of the freezing hole / m; γ is the safety factor, which is generally 1.3 to 1.5; S4, injection of slow setting cement: S41: Keep the freezing pipe filled with clean water (5) and close the upper port (11) of the freezing pipe; S42: injecting slow-setting cement (6) through the upper port (21) of the liquid supply pipe, and as the slow-setting cement (6) is discharged from the quick plug-in connector and the one-way valve (151) at the lower part of the freezing pipe, the slow-setting cement gradually displaces the original mud (4) in the freezing hole upwards; S43: when it is found that the slow-setting cement (6) returns to the opening of the freezing hole, the injection of the slow-setting cement is immediately stopped; S5, pipeline cleaning: S51: After the injection of slow-setting cement is stopped, the liquid supply pipe is quickly raised to completely separate the plug part (15) and the base part (25) of the quick-disconnect connector; S52: Keep the upper port (21) of the liquid supply pipe in an open state, and quickly inject clean water (5) through the upper port (11) of the freezing pipe to clean the slow-setting cement (6) in the liquid supply pipe until the clean water is discharged from the upper port (21) of the liquid supply pipe; S6, carry out freezing work: After the slow-setting cement reaches the specified solidification time and the corresponding freezing preparation work is completed, the clean water inside the system is pumped out through the upper port (21) of the liquid supply pipe, and then the low-temperature brine is circulated through the upper port (11) of the freezing pipe and the upper port (21) of the liquid supply pipe to carry out the subsequent freezing work.

10. The method for fixing the full length of a freezing hole according to claim 9, characterized in that: In S1, the bottom cone (14) of the freezing pipe is internally connected with the plug part (15) of the quick plug-in connector, the one-way valve (151) inside the plug and the reinforcing ribs (16); in S23, the upper end steel pipe (22) of the liquid supply pipe passes through the top through hole of the upper end sealing pipe (12), and a first sealing ring is installed in the first sealing groove (121) at the intersection of the two for sealing.

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