CN-117554413-B - Liquid nitrogen freezing plugging test device and test method under tunnel water and sand burst working condition

CN117554413BCN 117554413 BCN117554413 BCN 117554413BCN-117554413-B

Abstract

The invention discloses a liquid nitrogen freezing plugging test device and a test method under a tunnel water and sand gushing working condition, wherein the device comprises a freezing pipe, a drilling tip, a liquid nitrogen pipeline, a liquid nitrogen tank and a hand wheel, wherein the drilling tip is conical; the end part of the freezing pipe, which is close to the drilling tip, forms a liquid nitrogen outlet and/or a pressure relief exhaust channel in the pipe cavity, liquid nitrogen entering the freezing pipe is discharged from the liquid nitrogen outlet to the water-flushing sand-flushing area and/or discharged from the pressure relief exhaust channel, and the flowing liquid nitrogen directly or indirectly freezes the water-flushing sand-flushing area to form a plug. According to the invention, on one hand, under the dangerous conditions of water and sand gushing in different soil layers under different pressures, liquid nitrogen is directly and/or indirectly frozen by direct insertion, the leakage channel is simply, quickly and effectively plugged, the surrounding soil body is prevented from being disturbed by drilling, the risk is reduced, on the other hand, the device is rotatably inserted, the operation is convenient, and meanwhile, a technical foundation is provided for the practical application of liquid nitrogen in engineering.

Inventors

LI ZONGPING
TAO BOWEN
LIU TAO
Bu Quanlong
ZHANG ZHENGKAI
ZHANG QIUSHI
CAO QI
YAO ZHANHU
LIANG YUQIANG
SUN JINGXIN
REN YANWU
WEI DAIWEI
ZHANG LEI
YANG QIN
ZHAO CHUNLONG

Assignees

中交隧道工程局有限公司

Dates

Publication Date: 20260505
Application Date: 20231108

Claims (10)

1. A liquid nitrogen freezing plugging test device under a tunnel water and sand burst working condition is characterized by comprising a freezing pipe, a drilling tip, a liquid nitrogen pipeline, a liquid nitrogen tank and a hand wheel, wherein a pipe cavity is formed in the freezing pipe, the drilling tip is packaged at one end part of the freezing pipe, the tip part of the drilling tip is outwards, the liquid nitrogen pipeline is communicated with the other end part of the freezing pipe, the hand wheel is concentrically arranged on the periphery of the freezing pipe, the drilling tip is conical, the conical center line coincides with the center line of the freezing pipe, the conical bottom outer diameter is larger than the outer diameter of the freezing pipe, a plurality of liquid nitrogen outlets are formed at the end part of the freezing pipe, which is close to the drilling tip, a pressure relief exhaust channel is formed in the pipe cavity, one or more layers of plastic film sealing layers are wound on the periphery of the corresponding sections of the liquid nitrogen outlets, the plastic film sealing layers are stretched along with the increase of the internal pressure of the freezing pipe, liquid nitrogen entering the freezing pipe is discharged from the liquid nitrogen outlet to a water and sand burst area and discharged from the pressure relief exhaust channel, and flowing liquid nitrogen freezes the water and sand burst area directly or indirectly to form the plugging test device.
2. The device for testing freezing and plugging of liquid nitrogen under the working condition of water and sand gushing of a tunnel according to claim 1, wherein the liquid nitrogen outlets are divided into a plurality of liquid nitrogen outlet rows which are uniformly distributed around the circumference of the freezing pipe, and each liquid nitrogen outlet row comprises a plurality of liquid nitrogen outlets which are distributed at intervals along the length direction of the freezing pipe.
3. The device for testing freezing and plugging of liquid nitrogen under the working condition of water and sand gushing of a tunnel according to claim 2, wherein the liquid nitrogen pipeline comprises a liquid nitrogen transmission pipe inserted from a tube plate at the other end part of the freezing pipe and provided with an inner port close to the liquid nitrogen outlet, and a hose for communicating the liquid nitrogen transmission pipe with the liquid nitrogen tank, a liquid nitrogen cavity is formed in a part between the liquid nitrogen transmission pipe and the freezing pipe, a drainage branch communicated with the liquid nitrogen cavity, a pressure release valve arranged on the drainage branch and an exhaust pipe are further arranged on the freezing pipe, and the liquid nitrogen cavity, the drainage branch and the exhaust pipe are communicated in the three pipe cavities to form the pressure release exhaust channel.
4. The device for testing freezing and plugging of liquid nitrogen under the working condition of water and sand gushing of a tunnel according to claim 3, wherein in the cross section of the freezing pipe, the cross section area formed by the liquid nitrogen conveying pipe is larger than the cross section area formed by the liquid nitrogen cavity.
5. The device for testing freezing and plugging of liquid nitrogen under the working condition of water and sand gushing of a tunnel according to claim 3, wherein the inner diameter of the drainage branch is larger than the inner diameter of the liquid nitrogen transmission pipe, and the inner diameter of the drainage branch is smaller than the inner diameter of the freezing pipe.
6. The device for freezing and plugging the liquid nitrogen under the working condition of water and sand gushing in a tunnel according to claim 1 is characterized in that a first pipe body and a second pipe body which are respectively fixed on the inner wall are further arranged in the freezing pipe, the outer end parts of the first pipe body and the second pipe body respectively penetrate out of the freezing pipe, the length of the second pipe body extending into the freezing pipe is smaller than that of the first pipe body extending into the freezing pipe, the liquid nitrogen pipeline is communicated with the outer end part of the first pipe body, the outer end of the second pipe body is communicated with an exhaust pipe, and liquid nitrogen entering the interior of the freezing pipe is discharged from the second pipe body and the exhaust pipe to form circulation after indirectly contacting with a water and sand gushing area.
7. The device for testing freezing and plugging of liquid nitrogen under the working condition of water and sand gushing of a tunnel according to claim 6, wherein the inner end of the first pipe body is close to the drilling tip, and the inner end of the second pipe body is close to the middle of the freezing pipe.
8. The device for testing freezing and plugging of liquid nitrogen under tunnel water and sand gushing working conditions according to claim 6, wherein the inner diameter of the first pipe body is larger than the inner diameter of the second pipe body.
9. The device for testing the freezing and plugging of liquid nitrogen under the working condition of water and sand gushing of a tunnel according to claim 1 is characterized in that a cone angle formed by the drilling tip is an acute angle and is internally and solid, and/or the outer diameter of the cone bottom is D1, and the outer diameter of the freezing pipe is D2, and D1-D2 is more than or equal to 5mm.
10. The liquid nitrogen freezing plugging test method under the simulated tunnel water and sand gushing working condition is characterized by comprising the liquid nitrogen freezing plugging test device under the tunnel water and sand gushing working condition according to any one of claims 1 to 9, and further comprising a limiting baffle plate concentrically arranged on a freezing pipe, a ball valve and a pressure gauge, wherein the ball valve and the pressure gauge are communicated with a liquid nitrogen cavity in the freezing pipe, the limiting baffle plate, the hand wheel, the ball valve and the pressure gauge are distributed at intervals from the middle part of the freezing pipe to the other end part, the simulated tunnel water and sand gushing working condition further comprises a test box for simulating filling layers with different pressures and different materials, a test ball valve and a test temperature measuring sleeve, and the test ball valve and the test temperature measuring sleeve are positioned on the test box, and the method comprises the following steps: S1, preparation before plugging: (1) The periphery of the freezing pipe provided with the section where the liquid nitrogen outlet is positioned is tightly adhered and plugged by winding a plastic film, the winding number is 2-6, and the plastic film and the freezing pipe are fixedly wound by adopting an adhesive tape; (2) Adjusting the ball valve and the pressure relief exhaust passage to be in a closed state; (3) The liquid nitrogen pipeline is communicated with the freezing pipe and is fixedly connected through screw threads on the flange; (4) Inserting a temperature measuring tube into a test temperature measuring sleeve, preparing an ice-water mixture as a temperature measuring reference temperature, completing the connection of a temperature measuring series circuit, testing, and checking whether the reading is normal; (5) Filling a material filling layer to be detected in a lower space of the test box, and forming a water pressure layer with settable pressure above the material filling layer to be detected so as to simulate a water and sand inrush condition which accords with the actual occurrence of a tunnel; s2, plugging: (1) Completely opening a test ball valve for forming water and sand gushes on the test box; (2) After water sand flows out, a freezing pipe matched with the caliber of the ball valve to be tested is adopted, a hand wheel is controlled, and a self-drilling tip is rotated to drill into a water gushing sand leakage area, wherein the drilling depth is 25-30 cm; (3) After the insertion is finished, fixing the freezing pipe by using an iron wire, and then opening a ball valve on the freezing pipe; (4) The liquid nitrogen outlet is then opened, the liquid nitrogen outlet pressure is regulated to be 1.0+/-0.1 MPa, then pressurized supply is started, liquid nitrogen entering the freezing pipe is discharged from the liquid nitrogen outlet to a water and sand gushing area and/or is discharged from an opened pressure relief exhaust channel, and the flowing liquid nitrogen is directly or indirectly blocked in the frozen water and sand gushing area; (5) Synchronous timing and temperature measurement are carried out after liquid nitrogen is supplied; (6) Observing the water and sand gushing state in the freezing process; (7) When the pressure count value on the test box is larger than a set value, a pressure relief safety valve on the test box is automatically opened for pressure relief, and freezing under the required water pressure is simulated; (8) And after the water flow is completely stopped, closing the ball valve on the freezing pipe to complete the blocking.

Description

Liquid nitrogen freezing plugging test device and test method under tunnel water and sand burst working condition Technical Field The invention belongs to the technical field of shield tunnel construction, and particularly relates to a liquid nitrogen freezing and plugging test device under a tunnel water and sand gushing working condition, and a liquid nitrogen freezing and plugging test method under a simulated tunnel water and sand gushing working condition. Background In the construction process of the underwater tunnel in recent years, the risk of water and sand gushing on the tunnel excavation surface is extremely easy to occur due to the existence of abundant underground water, and the application of freezing and blocking by adopting liquid nitrogen in the tunnel rescue is wider and wider in face of the construction difficulty, such as actual projects of shield tunneling, secondary water sealing of tunnel working wells and the like. The liquid nitrogen freezing is used as a novel freezing mode, has the characteristics of simple system, high freezing speed, no pollution, small frost heaving and thawing settlement and the like, and adopts the principle that the direct gasification of the liquid nitrogen is used as a cold source to realize heat exchange with surrounding media, and water is quickly frozen, so that quick freezing is realized. At present, the engineering application requires drilling holes on a rock soil layer around a leakage point, so that a freezing pipe is arranged, for example, the Chinese patent application number is 202310124676.0, and the invention name is a mining liquid nitrogen quick freezing water sealing rescue device and an implementation method. The invention relates to a mining liquid nitrogen rapid plugging device and an actual construction method, wherein the method is used for plugging a coal mine water damage area by a method combining liquid nitrogen freezing and grouting reinforcement. In short, the current liquid nitrogen emergency mode is required to be used for plugging leakage points through processes of drilling, freezing calandria installation, freezing and the like, and under the condition that a leakage channel is not good for some special projects such as freezing wall intersection rings, the surrounding freezing walls can be quickly melted by drilling, so that the leakage channel is continuously enlarged, the water and sand gushing flow and velocity are continuously increased, and the risk is suddenly increased, therefore, under the condition of sudden high water pressure leakage, the plugging is required to be realized in a fastest and direct mode, so that the construction risk is reduced. Disclosure of Invention The invention aims to solve the technical problem of overcoming the defects of the prior art and providing a liquid nitrogen freezing plugging test device under a brand new tunnel water and sand gushing working condition. Meanwhile, the invention also relates to a liquid nitrogen freezing plugging test method under the working condition of simulating water and sand gushing of the tunnel. In order to solve the technical problems, the invention adopts the following technical scheme: A liquid nitrogen freezing plugging test device under a tunnel water and sand bursting working condition comprises a freezing pipe, a drilling tip, a liquid nitrogen pipeline, a liquid nitrogen tank and a hand wheel, wherein a pipe cavity is formed in the freezing pipe, the drilling tip is packaged at one end part of the freezing pipe, the tip part of the drilling tip faces outwards, the liquid nitrogen pipeline is communicated with the other end part of the freezing pipe, the hand wheel is concentrically arranged on the periphery of the freezing pipe, the drilling tip is conical, the conical center line coincides with the center line of the freezing pipe, the outer diameter of the conical bottom is larger than the outer diameter of the freezing pipe, a liquid nitrogen outlet and a pressure relief exhaust channel are formed in the pipe cavity, liquid nitrogen entering the freezing pipe is discharged from the liquid nitrogen outlet to a water and sand bursting area and discharged from the pressure relief exhaust channel, and flowing liquid nitrogen freezes the water and sand bursting area directly or indirectly to form a plug. According to a specific and preferred aspect of the invention, a plurality of liquid nitrogen outlets are distributed at the end of the freezing tube near the drilling tip, wherein the plurality of liquid nitrogen outlets are divided into a plurality of liquid nitrogen outlet rows uniformly distributed circumferentially around the freezing tube, each liquid nitrogen outlet row comprising a plurality of liquid nitrogen outlets spaced apart along the length of the freezing tube. In this case, a rapid and relatively uniform escape of liquid nitrogen is facilitated in order to achieve an optimal progressive freezing effect, while the freezing is carried