CN115962012A - Device for monitoring front stability of gas tunnel excavation face and using method thereof - Google Patents

Abstract

The invention provides a device for monitoring the stability in front of the excavation face of a gas tunnel and a method for using the device, which includes a monitoring device for deformation and displacement of surrounding rock, a device for monitoring drilling gas pressure, and a data collection and processing terminal; the device for monitoring displacement of surrounding rock is set at In the surrounding rock drilling of the excavation face, the surrounding rock displacement monitoring device includes a multi-point displacement meter, an exhaust pipe for exhausting the borehole, a grouting pipe for grouting, and multiple displacement measurement points on the surrounding rock of the tunnel And the terminal reading display system for receiving, processing, and displaying data, the wireless transmission module and lead-out cable for data transmission, the sensor for receiving and processing the dowel signal, and the displacement sensor casing for protection. The present invention realizes the reading display of drilling gas pressure and surrounding rock displacement and deformation at multiple points through its terminal reading display system, intuitively reflects the overall deformation and displacement of the surrounding rock of the gas tunnel and the distribution of gas pressure, and can monitor gas Advance forecasting of gas outburst hazard at tunnel excavation face.

Description

A device for monitoring the stability in front of the excavation face of a gas tunnel and its application method

technical field

The invention relates to the technical field of tunnel geological disaster monitoring and forecasting, in particular to a device for monitoring the stability in front of a gas tunnel excavation face and a method for using the same.

Background technique

In recent years, my country's modern basic transportation construction has achieved rapid development. In addition, my country is a mountainous country. The number of tunnels in our country continues to increase at a high speed. More and more tunnels pass through strata with various adverse geological conditions, especially through strata containing harmful gases. There are more and more tunnel engineering projects in my country, not only common coal-measure strata, but also more and more tunnels passing through non-coal-measure strata. The high concentration of gas in the tunnel can easily lead to gas disasters, mainly including poisoning and suffocation of construction workers, gas burning and explosion, gas outburst, etc., which directly threaten the life safety of construction workers and the safety of project property. At present, for gas-bearing formations in tunnels, the main prevention and treatment measures in the early stage are the advance prediction of formation gas.

In the advance prediction of gas tunnels, most gas tunnels adopt geological analysis as the basis, supplemented by means of geophysical prospecting, to predict the disaster for the stratum in front of the tunnel excavation face. The existing methods for preventing gas disasters in tunnels are mainly through After manually measuring parameters and obtaining various parameters of formation gas, the tunnel gas formation is graded, and then its risk level is predicted. Because the monitoring parameters of this method are relatively single, only relying on its gas parameters as the basis of prediction data, the measurement of gas parameters does not monitor the displacement and deformation of surrounding rocks in gas formations disturbed by excavation, and it is difficult to simultaneously acquire data from multiple locations of surrounding rocks , the analysis of the gas distribution ahead and the stability of the surrounding rock has great limitations, and improper prediction can easily lead to large gas accidents.

Therefore, it is necessary to provide a method that can simultaneously monitor the distribution of gas in the surrounding rock in front of the excavation face and the deformation and displacement of the surrounding rock under the action of excavation disturbance and gas pressure, and then obtain the risk level of gas disasters in the formation in front of the excavation face based on the analysis of the monitoring data. The multi-point monitoring device and monitoring method for monitoring the stability of the surrounding rock in front of the excavation face of the gas tunnel can quickly make corresponding gas prevention and control measures according to the data analysis results, and can adjust the corresponding prevention and control measures according to the dynamic changes of the monitoring values. method worthy of study.

Contents of the invention

In view of the above problems, the present invention provides a multi-point dynamic monitoring of the surrounding rock drilling gas pressure and deformation displacement of the surrounding rock on the excavation face and realizes real-time transmission to the data collection and processing display terminal. The data collection and processing display terminal can intuitively reflect the surrounding Rock gas pressure distribution and surrounding rock deformation and displacement provide scientific basis for further taking corresponding tunnel gas prevention and control measures. It is used to monitor the stability of the surrounding rock in front of the excavation face of the gas tunnel. The device for monitoring the stability of the front of the excavation face of the gas tunnel and its Instructions.

In order to achieve the above object, the technical scheme provided by the invention is as follows:

A device for monitoring the stability in front of the excavation face of a gas tunnel, comprising a monitoring device for deformation and displacement of surrounding rock, a device for monitoring gas pressure in a borehole, and a data collection and processing display terminal 12; In the surrounding rock borehole 23 in the surface borehole 22, the surrounding rock displacement monitoring device includes a multi-point displacement meter, an exhaust pipe 4 for exhaust in the borehole, a grouting pipe 8 for grouting, a tunnel A plurality of displacement measuring points 10 on the surrounding rock, a data collection and processing display terminal 12 for receiving, processing, and displaying data, the multi-point displacement meter includes a deformation displacement sensing anchor head 1 of the anchorage displacement meter, and transmits rock mass deformation The displacement dowel 2, the wireless transmission module 9 and the lead cable (5) for data transmission, the displacement sensor 7 for receiving and processing the dowel signal, the displacement sensor casing 3 for protecting the displacement sensor 7 and the wireless transmission module 9;

The device for monitoring drilling gas pressure includes a casing 13 that is installed in the surrounding rock borehole. The outer wall of the casing 13 is provided with three sealing rubber airbags 14 at intervals. The casing 13 is pierced with There are three inner air guide tubes 16; the inner air guide tubes 16 are respectively connected to each of the sealing rubber airbags 14, and the end of the air guide tube 16 is connected to a gas pressure gauge 17, and the gas pressure gauge 17 is jointly connected to a nitrogen delivery bottle, Also be provided with a control valve 18 on each described outer air guide pipe 16, be used for controlling nitrogen to deliver gas to each described sealing rubber airbag 14 and make the airbag expand and seal surrounding rock borehole, make adjacent two described A sealed pressure measuring chamber is formed between the sealing rubber airbags 14; an explosion-proof gas pressure sensor 15 is arranged in each said pressure measuring chamber, and each said explosion-proof gas pressure sensor 15 is connected to a gas pressure wire 20, each said The outer ends of the internal pressure wires 20 are respectively connected to a pressure value converter 21; the other end of each pressure value converter 21 is connected to the data collection and processing display terminal 12 through a data optical fiber.

The deformation displacement sensing anchor head 1, the displacement dowel 2 and the displacement sensor 7 are sequentially connected; the displacement dowel 2 is wrapped by the displacement dowel protection tube 6, and the displacement sensor 7 is wrapped by the displacement sensor casing 3.

The lead-out cable 5 is a displacement meter lead-out cable, which can be connected with the data collection and processing display terminal 12;

The data collection and processing display terminal 12 is connected to the signals of multiple outgoing cables 5 or multiple wireless transmission modules 9, the system can record the positions of the multi-point displacement measurement points 10, and convert the frequency transmitted by each cable into the deformation amount for display.

The wireless transmission module 9 is arranged in the sensor casing 3 .

The nitrogen delivery bottle 19, the pressure value converter 21 and the data collection and processing display terminal 12 are all set at the inverted arch setting position near the excavation surface in the tunnel.

The sealing rubber airbag 14 adopts a size specification with a length ranging from 100 mm to 200 mm, and the distance between each of the sealing rubber rings ranges from 7 m to 8 m.

The inner air guide tube 16 and the gas pressure wire 20 are all placed inside the casing 13, through which a small hole is pierced to connect the explosion-proof gas pressure sensor 15 and the sealing rubber airbag 14.

A method for using a device for monitoring the stability in front of a gas tunnel excavation face includes the following steps:

a. Determine the monitoring range of the surrounding rock of the tunnel, and check the position and direction of the drilling;

Drilling operations are carried out according to the drilling depth and diameter required by the size of the surrounding rock displacement and deformation measuring device and the casing of the gas pressure measuring device;

b. After drilling, rinse the hole with clean water and check the drilling quality;

c. Assembly of surrounding rock displacement and deformation measurement device: assemble deformation displacement sensing anchor head 1, displacement dowel 2 and displacement sensor 7, and wrap displacement dowel 2 and displacement dowel 2 with displacement sensor casing 3 respectively The displacement sensor 7 is protected, and the support plate is set to ensure the relative stability of the displacement dowel 2, and the data transmission cable is drawn out; the gas pressure measurement device is assembled: the explosion-proof gas pressure sensor 15 is assembled, and the gas pressure wire 20 passes through the surface of the displacement sensor casing 3 The line hole is connected to the explosion-proof gas pressure sensor 15 and the pressure value converter 21 through the displacement sensor casing 3, and the inner ring of the sealing rubber airbag 14 is bonded to the surface of the metal casing through anti-corrosion glue;

d. Put the assembled displacement gauge and gas pressure measuring device into the excavation face borehole 22 and the surrounding rock borehole 23 as a whole, and place them firmly;

e. Insert the grouting pipe 8 and the exhaust pipe 4 into the borehole of the measuring device for displacement and deformation of the surrounding rock, and the grouting pipe 8 needs to be inserted to the bottom of the hole; grouting from the grouting pipe 8, slowly step by step while grouting Pull out the grouting pipe 8 and the exhaust pipe 4, and complete the grouting when the grout reaches the bottom of the displacement sensor casing 3;

f. After the grout is solidified, ensure that the deformation displacement sensing anchor head 1 is integrated with the hole wall anchor;

g. Connect the displacement gauge at the multi-point displacement measurement point 10 to the data collection and processing display terminal 12 through the wireless transmission module 9 or the wired lead-out cable 5;

h, the control valve 18 of the nitrogen delivery bottle 19 of the gas pressure measuring device is used to inflate the sealing rubber air bag 14 according to the set suitable pressure, so that the sealing rubber air bag 14 fills the entire drilling space, and realizes the power measurement chamber. Closed; connect the pressure value converter 21 and the data collection and processing display terminal 12 through a transmission line;

i. Data collection and processing The display terminal 12 is connected to multiple surrounding rock displacement and deformation measuring devices and gas pressure measuring devices, processes the transmitted data and outputs the overall deformation of the tunnel surrounding rock and the dynamic change of drilling gas pressure on the display.

Positive and beneficial effects: 1. The present invention is based on the surrounding rock displacement measurement device and the surrounding rock drilling gas pressure monitoring device with a terminal display system, and simultaneously performs dynamic monitoring of surrounding rock deformation displacement and gas pressure on multiple monitoring points, which can directly reflect the tunnel The stability change of the surrounding rock in front of the excavation face under the influence of excavation disturbance and gas pressure. 2. The present invention realizes the sealing of the gas pressure monitoring chamber by bonding a plurality of rubber airbags on the metal casing of the gas pressure monitoring device, and using nitrogen to inflate the gas pressure monitoring chamber at a fixed rate. At the same time, two adjacent gas pressure monitoring chambers pass through the rubber airbags. Separated, the formation gas pressure under two different surrounding rock distances can be independently monitored; the nitrogen delivery bottle is used as the pressure gas source and connected to the pressure gauge, which can realize the precise inflation of the rubber airbag and avoid bursting or overpressure caused by excessive pressure Small results in incomplete closure. 3. The present invention can realize the real-time dynamic monitoring of deformation and displacement of surrounding rock and formation gas pressure in multiple positions at the same time by setting a data collection and processing display terminal in an open place near the excavation surface, and the accuracy of side measurement information is high, making data collection The terminal can more accurately and quickly analyze multi-transmission data and realize linear dynamic processing, and evaluate the stability of the gas formation in front of the tunnel excavation face and the excavation risk. In summary, the present invention is also widely used in the monitoring of surrounding rock stability and risk prediction of gas tunnels in coal-measure strata and non-coal-measure strata.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention one;

Fig. 2 is a structural schematic diagram of the present invention two;

Fig. 3 is a schematic diagram of a partial enlarged structure outside the borehole of the gas pressure monitoring device;

Fig. 4 is a schematic diagram of a partially enlarged structure of the casing inside the borehole of the gas pressure monitoring device;

Figure 5 is a schematic diagram of the overall layout of the surrounding rock of the tunnel excavation face of the device;

The figure shows: deformation displacement sensing anchor head 1, displacement dowel rod 2, displacement sensor casing 3, exhaust pipe 4, lead cable 5, displacement dowel rod protection tube 6, displacement sensor 7, grouting pipe 8, wireless Transmission module 9, displacement measurement point 10, excavation surface 11, data collection and processing display terminal 12, casing 13, sealing rubber airbag 14, explosion-proof gas pressure sensor 15, inner air guide pipe 16, gas pressure gauge 17, control valve 18. Nitrogen delivery bottle 19, gas pressure wire 20, pressure value converter 21, excavation surface drilling 22, surrounding rock drilling 23, optical fiber 24.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Example 1

As shown in Figure 1 and Figure 2, a device for monitoring the stability in front of the excavation face of a gas tunnel includes a monitoring device for deformation and displacement of surrounding rock, a device for monitoring drilling gas pressure and a data collection and processing display terminal 12; The surrounding rock displacement monitoring device is arranged in the surrounding rock borehole 23 in the excavation surface borehole 22, and the surrounding rock displacement monitoring device includes an exhaust pipe 4 arranged on a multi-point displacement meter for exhausting in the borehole, The grouting pipe 8 of grouting, as shown in Figure 5, a plurality of displacement measuring points 10 on the surrounding rock of the tunnel, a data collection and processing display terminal 12 for receiving, processing and displaying data, the multi-point displacement meter includes Deformation displacement sensing anchor head 1 of anchorage displacement meter, displacement dowel 2 for transmitting rock mass deformation, wireless transmission module 9 and lead-out cable 5 for data transmission, displacement sensor 7 for receiving and processing dowel signal, protection displacement sensor 7 and the displacement sensor casing 3 of the wireless transmission module 9;

The device for monitoring drilling gas pressure includes a casing 13 that is installed in the surrounding rock borehole. The outer wall of the casing 13 is provided with three sealing rubber airbags 14 at intervals. The casing 13 is pierced with There are three inner air guide tubes 16; the inner air guide tubes 16 are respectively connected to each of the sealing rubber airbags 14, as shown in Figure 3, the end of the air guide tube 16 is connected to a gas pressure gauge 17, and the gas pressure gauge 17 is in common A nitrogen delivery bottle is connected, and a control valve 18 is also arranged on each of the outer air guide pipes 16, which is used to control the nitrogen to deliver gas to each of the sealing rubber airbags 14 so that the airbags expand to block the surrounding rock drilling, As shown in Figure 4, a sealed pressure measuring chamber is formed between the adjacent two described sealing rubber airbags 14; an explosion-proof gas pressure sensor 15 is arranged in each described pressure measuring chamber, and each described explosion-proof gas pressure sensor 15 is connected to a gas pressure wire 20, and the outer end of each said internal pressure wire 20 is respectively connected to a pressure value converter 21; the other end of each said pressure value converter 21 is connected with said data collection processing display Terminal 12 is connected.

The deformation displacement sensing anchor head 1, the displacement dowel 2 and the displacement sensor 7 are sequentially connected; the displacement dowel 2 is wrapped by the displacement dowel protection tube 6, and the displacement sensor 7 is wrapped by the displacement sensor casing 3.

The lead-out cable 5 is a displacement meter lead-out cable, which can be connected with the data collection and processing display terminal 12;

The data collection and processing display terminal 12 is connected to the signals of multiple outgoing cables 5 or multiple wireless transmission modules 9, the system can record the positions of the multi-point displacement measurement points 10, and convert the frequency transmitted by each cable into the deformation amount for display.

The wireless transmission module 9 is arranged in the sensor casing 3 .

The nitrogen delivery bottle 19, the pressure value converter 21 and the data collection and processing display terminal 12 are all set at the inverted arch setting position near the excavation surface in the tunnel.

The inner air guide tube 16 and the gas pressure wire 20 are all placed inside the casing 13, through which a small hole is pierced to connect the explosion-proof gas pressure sensor 15 and the sealing rubber airbag 14.

In the above embodiment, the sealing rubber airbag 14 is selected to have a size ranging from 100 mm to 200 mm in length. The interval between two adjacent sealing rubber airbags is determined according to actual needs. If the gas pressure measurement is to be carried out on the surrounding rock in the range of 5m-20m in front of the excavation face, the range of 7m-8m can be used.

In the foregoing embodiment, the diameter of the gas pressure measurement borehole is determined by the diameter of the sealing rubber air bag 14 inflated, such as adopting a diameter range of 70mm-110mm; The range of counting and predicting the surrounding rock is 10-25m.

In the above-mentioned embodiments, the data collection and processing display terminal 12 is a mobile computer, and relevant data processing software is installed in the computer to collect and process gas pressure data and surrounding rock deformation and displacement data in real time, process the data through the output function, and import professional drawing software to obtain The gas pressure and surrounding rock deformation and displacement data curves visually show the longitudinal deformation and displacement of the surrounding rock in front of the tunnel excavation face and the change law of the surrounding rock gas pressure.

In the above-mentioned embodiments, the data collection and processing display terminal 12 and the gas pressure value converter 21 are placed in the open space of the inverted arch of the tunnel, and a simple operation console is set up for terminal operation.

A method for using a device for monitoring the stability in front of a gas tunnel excavation face includes the following steps:

b. Determine the monitoring range of the surrounding rock of the tunnel, and check the position and direction of the drilling;

Drilling operations are carried out according to the drilling depth and diameter required by the size of the surrounding rock displacement and deformation measuring device and the casing of the gas pressure measuring device;

b. After drilling, rinse the hole with clean water and check the drilling quality;

c. Assembly of surrounding rock displacement and deformation measurement device: assemble deformation displacement sensing anchor head 1, displacement dowel 2 and displacement sensor 7, and wrap displacement dowel 2 and displacement dowel 2 with displacement sensor casing 3 respectively The displacement sensor 7 is protected, and the support plate is set to ensure the relative stability of the displacement dowel 2, and the data transmission cable is drawn out; the gas pressure measurement device is assembled: the explosion-proof gas pressure sensor 15 is assembled, and the gas pressure wire 20 passes through the surface of the displacement sensor casing 3 The line hole is connected to the explosion-proof gas pressure sensor 15 and the pressure value converter 21 through the displacement sensor casing 3, and the inner ring of the sealing rubber airbag 14 is bonded to the surface of the metal casing through anti-corrosion glue;

d. Put the assembled displacement gauge and gas pressure measuring device into the excavation face borehole 22 and the surrounding rock borehole 23 as a whole, and place them firmly;

e. Insert the grouting pipe 8 and the exhaust pipe 4 into the borehole of the measuring device for displacement and deformation of the surrounding rock, and the grouting pipe 8 needs to be inserted to the bottom of the hole; grouting from the grouting pipe 8, slowly step by step while grouting Pull out the grouting pipe 8 and the exhaust pipe 4, and complete the grouting when the grout reaches the bottom of the displacement sensor casing 3;

f. After the grout is solidified, ensure that the deformation displacement sensing anchor head 1 is integrated with the hole wall anchor;

g. Connect the displacement gauge at the multi-point displacement measurement point 10 to the data collection and processing display terminal 12 through the wireless transmission module 9 or the wired lead-out cable 5;

h, the control valve 18 of the nitrogen delivery bottle 19 of the gas pressure measuring device is used to inflate the sealing rubber air bag 14 according to the set suitable pressure, so that the sealing rubber air bag 14 fills the entire drilling space, and realizes the power measurement chamber. Closed; connect the pressure value converter 21 and the data collection and processing display terminal 12 through a transmission line;

i. Data collection and processing The display terminal 12 is connected to multiple surrounding rock displacement and deformation measuring devices and gas pressure measuring devices, processes the transmitted data and outputs the overall deformation of the tunnel surrounding rock and the dynamic change of drilling gas pressure on the display.

1. The present invention is based on the surrounding rock displacement measurement device and the surrounding rock drilling gas pressure monitoring device with a terminal display system, and simultaneously performs dynamic monitoring of surrounding rock deformation displacement and gas pressure at multiple monitoring points, which can directly reflect the front of the tunnel excavation face Stability changes of surrounding rock under the influence of excavation disturbance and gas pressure. 2. The present invention realizes the sealing of the gas pressure monitoring chamber by bonding a plurality of rubber airbags on the metal casing of the gas pressure monitoring device, and using nitrogen to inflate the gas pressure monitoring chamber at a fixed rate. At the same time, two adjacent gas pressure monitoring chambers pass through the rubber airbags. Separated, the formation gas pressure under two different surrounding rock distances can be independently monitored; the nitrogen delivery bottle is used as the pressure gas source and connected to the pressure gauge, which can realize the precise inflation of the rubber airbag and avoid bursting or overpressure caused by excessive pressure Small results in incomplete closure. 3. The present invention can realize the real-time dynamic monitoring of deformation and displacement of surrounding rock and formation gas pressure in multiple positions at the same time by setting a data collection and processing display terminal in an open place near the excavation surface, and the accuracy of side measurement information is high, making data collection The terminal can more accurately and quickly analyze multi-transmission data and realize linear dynamic processing, and evaluate the stability of the gas formation in front of the tunnel excavation face and the excavation risk. In summary, the present invention is also widely used in the monitoring of surrounding rock stability and risk prediction of gas tunnels in coal-measure strata and non-coal-measure strata.

The specific implementation manner described above has further improved the purpose, technical solutions and beneficial effects of the present invention.

For detailed description, it should be understood that the above description is only a specific implementation of the present invention, and is not used to limit the protection scope of the present invention. Any modification, equivalent Replacement, improvement, etc. should all be included within the protection scope of the present invention.

Claims (9)

1. The utility model provides a device of monitoring gas tunnel excavation face front stability which characterized in that: comprises a surrounding rock deformation displacement monitoring device, a device for monitoring the gas pressure of a drilled hole and a data collecting, processing and displaying terminal (12); the surrounding rock displacement monitoring device is arranged in a surrounding rock drilling hole (23) in an excavation face drilling hole (22), and comprises a multipoint displacement meter, an exhaust pipe (4) used for exhausting gas in the drilling hole, a grouting pipe (8) used for grouting, a plurality of displacement meter measuring points (10) on tunnel surrounding rock, a data collecting, processing and displaying terminal (12) used for receiving, processing and displaying data, wherein the multipoint displacement meter comprises a deformation displacement sensing anchor head (1) for anchoring the displacement meter, a displacement dowel bar (2) for transmitting deformation of a rock mass, a wireless transmission module (9) used for data transmission, a leading-out cable (5), a displacement sensor (7) for receiving and processing a dowel bar signal, and a displacement sensor protective cylinder (3) for protecting the displacement sensor (7) and the wireless transmission module (9);

the device for monitoring the gas pressure of the drilled hole comprises a sleeve (13) penetrating into the surrounding rock drilled hole, three hole sealing rubber airbags (14) are sleeved on the outer wall of the sleeve (13) at intervals, and three inner gas guide pipes (16) penetrate into the sleeve (13); the inner air guide tubes (16) are respectively connected with the hole sealing rubber air bags (14), the tail ends of the air guide tubes (16) are connected with a gas pressure gauge (17), the gas pressure gauges (17) are jointly connected with a nitrogen gas conveying bottle, and each outer air guide tube (16) is also provided with a control valve (18) for controlling the nitrogen gas to convey gas to the hole sealing rubber air bags (14) to enable the air bags to expand to seal the surrounding rock drilled holes, so that a sealed pressure measuring chamber is formed between every two adjacent hole sealing rubber air bags (14); an explosion-proof gas pressure sensor (15) is arranged in each pressure measuring chamber, each explosion-proof gas pressure sensor (15) is connected with a gas pressure lead (20), and the outer end of each internal pressure lead (20) is respectively connected with a pressure value converter (21); the other end of each pressure value converter (21) is connected with the data collection, processing and display terminal (12) through a data optical fiber.

2. The device of claim 1, wherein the device for monitoring the stability of the front of the excavation face of the gas tunnel comprises: the deformation displacement sensing anchor head (1), the displacement dowel bar (2) and the displacement sensor (7) are connected in sequence; the displacement dowel bar (2) is wrapped by a displacement dowel bar protecting tube (6), and the displacement sensor (7) is wrapped by a displacement sensor protecting tube (3).

3. The device of claim 1, wherein the device is used for monitoring the stability of the front of the excavation face of the gas tunnel, and comprises: the leading-out cable (5) is a displacement meter leading-out cable and can be connected with a data collection processing display terminal (12).

4. The device of claim 3, wherein the device is used for monitoring the stability of the front of the excavation face of the gas tunnel: the data collection processing display terminal (12) is connected with signals of a plurality of leading-out cables (5) or a plurality of wireless transmission modules (9), and the system can record the positions of the multipoint displacement measuring points (10) and convert the frequencies transmitted by the cables into deformation quantities for display.

5. The device of claim 1, wherein the device for monitoring the stability of the front of the excavation face of the gas tunnel comprises: the wireless transmission module (9) is arranged in the sensor casing (3).

6. The device of claim 1, wherein the device is used for monitoring the stability of the front of the excavation face of the gas tunnel, and comprises: the nitrogen conveying bottle (19), the pressure value converter (21) and the data collecting, processing and displaying terminal (12) are all arranged at the position of an inverted arch near the excavation surface in the tunnel.

7. The device of claim 1, wherein the device is used for monitoring the stability of the front of the excavation face of the gas tunnel, and comprises: the hole sealing rubber air bag (14) adopts the size specification with the length range of 100 mm-200 mm, and the interval range of each hole sealing rubber ring is 7m-8 m.

8. The device of claim 1, wherein the device is used for monitoring the stability of the front of the excavation face of the gas tunnel, and comprises: the inner gas guide tube (16) and the gas pressure lead (20) are arranged inside the sleeve (13), and the small holes are penetrated through the sleeve to connect the explosion-proof gas pressure sensor (15) and the hole sealing rubber air bag (14).

9. The use method of the device for monitoring the stability of the front of the gas tunnel excavation face of claim 1, characterized by comprising the following steps:

determining a tunnel surrounding rock monitoring range, and checking the position and direction of a drilling hole; drilling according to the drilling depth and diameter required by the dimensions of the protective cylinder of the surrounding rock displacement deformation measuring device and the gas pressure measuring device;

b. after drilling, washing the hole with clear water and checking the drilling quality;

c. assembling a surrounding rock displacement deformation measuring device: assembling a deformation displacement sensing anchor head (1), a displacement dowel bar (2) and a displacement sensor (7), respectively wrapping the displacement dowel bar (2) and the displacement sensor (7) by using a displacement dowel bar protective tube (6) and a displacement sensor protective cylinder (3) for protection, arranging a supporting disc to ensure the relative stability of the displacement dowel bar (2), and leading out a data transmission cable; assembling a gas pressure measuring device: assembling an explosion-proof gas pressure sensor (15), wherein a gas pressure lead (20) passes through a wire hole on the surface of a displacement sensor protective cylinder (3), the explosion-proof gas pressure sensor (15) and a pressure numerical value converter (21) are connected with the inside of the displacement sensor protective cylinder (3), and the inner ring of a hole-sealing rubber air bag (14) is adhered to the surface of a metal protective cylinder through an anti-corrosion glue solution;

d. integrally placing the assembled displacement meter and the gas pressure measuring device into an excavation face drilling hole (22) and a surrounding rock drilling hole 23, and firmly placing;

e. inserting the grouting pipe (8) and the exhaust pipe (4) into a hole of the surrounding rock displacement deformation measuring device, wherein the grouting pipe (8) needs to be inserted to the bottom of the hole; grouting is carried out from the grouting pipe (8), the grouting pipe (8) and the exhaust pipe (4) are gradually and slowly pulled out while grouting is carried out, and grouting is finished when grout reaches the bottom of the displacement sensor pile casing (3);

f. when the slurry is solidified, the deformation displacement induction anchor head (1) and the hole wall anchor are integrated;

g. displacement meters of the multipoint displacement measuring points (10) and a data collecting, processing and displaying terminal (12) are connected in a wireless transmission module (9) or a wired leading-out cable (5) mode;

h. a control valve (18) of a nitrogen conveying bottle (19) of the gas pressure measuring device is used for inflating the hole sealing rubber air bag (14) according to set proper pressure, so that the hole sealing rubber air bag (14) fills the whole drilling space, and the sealing of the tile force measuring chamber is realized; the pressure value converter (21) and the data collection processing display terminal (12) are connected through a transmission line;

i. the data collection processing display terminal (12) is connected with the plurality of surrounding rock displacement deformation measuring devices and the gas pressure measuring device, processes the output data and outputs the whole deformation condition of the tunnel surrounding rock and the dynamic change of the gas pressure of the drilled hole on the display.

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