An intelligent detection method for railway tunnels based on stress-sensing rods

Abstract

The present invention relates to an intelligent detection method for railway tunnels based on stress sensing rods applied in the detection field. In this method, stress sensing rods are buried inside the surrounding rock, and a detection unit is used to detect the deformation of the surrounding rock in the vertical, lateral, and longitudinal directions. Based on this, the release direction and deformation amount of stress are analyzed. By filling air inside the stress sensing rods, when the stress sensing rods deform, the air is extruded by the extrusion effect, and then the air drives the indicating liquid to be squeezed into a specified position. By observing the length of the indicating liquid, the deformation amount of the surrounding rock can be known, providing an intuitive expression for on-site maintenance personnel. Moreover, this intuitive expression form can be mutually verified with the detection values of the detection unit, effectively improving the accuracy and stability of detection. In addition, according to the detection values, a corresponding support adjustment plan can be provided for maintenance personnel, effectively improving the safety of the tunnel.

Description

Technical Field

[0001] The present invention relates to an intelligent detection method for railway tunnels based on stress-sensing rods, and particularly to an intelligent detection method for railway tunnels based on stress-sensing rods applied to the detection field. Background Art

[0002] Surrounding rock deformation refers to the changes in the shape and volume of the rock mass around an underground cavity and the displacement of the cavity wall. It is the general term for the rheology, creep, creep, displacement, settlement, and floor heave of the surrounding rock. Surrounding rock deformation has a significant impact on the safe operation of railway tunnels. Therefore, it is crucial to carry out deformation detection work during the excavation process.

[0003] At present, there are many detection means for tunnel deformation, and numerous devices are used. For example, the patent with the application number CN202010530033.2 discloses a rock bolt for detection, and the patent with the application number CN202410749911.8 discloses a bolt for detecting large deformation of soft rock. However, through analysis, it is found that the bolts in the above two patents can only detect the deformation of the surrounding rock in the vertical direction. In combination with the actual situation, the deformation of the surrounding rock of railway tunnels is not only vertical but also includes lateral and longitudinal deformations. Obviously, the above two patents cannot achieve such technical effects.

[0004] Moreover, the existing detection methods detect the entire deformation of the tunnel. Not only are a large number of sensors required to be arranged and a large amount of manpower and material resources need to be invested, but also the key deformation areas cannot be accurately detected in all directions. As a result, a corresponding adjustment plan cannot be made during the later support adjustment, leading to the increasingly severe deformation. Summary of the Invention

[0005] Aiming at the above-mentioned existing technologies, the technical problem to be solved by the present invention is to conduct all-round detection in the key deformation areas and formulate a corresponding support adjustment plan according to the detection results.

[0006] To solve the above problems, the present invention provides an intelligent detection method for railway tunnels based on stress-sensing rods, including the following detection steps:

[0007] S1. Excavation and initial monitoring: Excavate the tunnel, install support for the deformed surrounding rock part. In the initial stage, due to the release of in-situ stress, the plastic deformation of the surrounding rock is large, and a total station is used to continuously detect the deformed part.

[0008] S2. Drilling: Wait until the stress of the surrounding rock is balanced and the deformation speed decreases, entering the slow deformation period. Remove the total station, open a hole in the support directly below the deformed part, and use a drill rod to drill a detection hole with a diameter of 10 - 20 cm perpendicular to the ground into the surrounding rock.

[0009] S3. Fix the stress sensing rod: Insert the stress sensing rod into the detection hole so that its lower end is lower than the support, and inflate it with an inflation device to make it expand and get stuck in the hole to complete the fixation;

[0010] S4. Start the detection of the connection device: Connect the measurement box to the lower end of the stress sensing rod and fix it on the support, do a good job in wire insulation and channel sealing, and start the detection after connecting the measurement box to the background detection management platform;

[0011] Among them, the stress sensing rod includes an elastic cylinder. The inner wall of the elastic cylinder is provided with an air storage cavity located in the middle thereof, and a plurality of installation cavities surrounding the air storage cavity. A set of sensing chains are placed inside each installation cavity. The measurement box includes a protection box and a plurality of signal processors installed inside the protection box and respectively signal-connected to multiple sets of sensing chains. The signal processors are signal-connected to the background detection management platform through a remote signal sending device.

[0012] In the above railway tunnel deformation detection method, the deformation of the surrounding rock in the vertical, horizontal and longitudinal directions is detected by the stress sensing rod that penetrates deep into the surrounding rock. The stress release direction and deformation amount of the surrounding rock are obtained by using the deformation of the stress sensing rod, which is convenient for maintenance personnel to deeply study and analyze the development trend of the surrounding rock deformation, and provide support for the maintenance personnel to provide a matching support adjustment plan.

[0013] As a further improvement of the present application, the sensing chain includes a plurality of detection units connected in series. Each detection unit includes a spherical base slidably connected to the installation cavity, a rotating ball movably hinged to the spherical base, a flexible film pressure sensor fixedly connected to the inner surface of the spherical base, a touch head fixedly connected directly below the rotating ball and matching the flexible film pressure sensor, and an elastic rotating rod fixedly connected directly above the rotating ball. And each elastic rotating rod is fixedly connected to the bottom of the spherical base above it.

[0014] As a further improvement of the present application, the flexible film pressure sensor is integrally divided into a plurality of equal parts, and coordinate information representing different directions, surrounding rock depth, and the offset angle of the touch head relative to the center point of the flexible film pressure sensor is embedded in each equal part area through the background detection management platform.

[0015] As a supplement to the further improvement of the present application, the touch head is made of a smooth and friction-resistant material, and a spring pad is also laid between the flexible film pressure sensor and the spherical base.

[0016] As a further improvement of the present application, a plurality of LED display boards are fixedly connected to the lower side wall of the protection box and are respectively electrically connected to a plurality of signal processors, and the displayed image of the LED display board is an indicating arrow.

[0017] As another improvement of the present application, the lowermost detection unit in each sensing chain is fixedly connected to the inner wall of the installation cavity. The upper end of the elastic cylinder is fixedly connected with a flexible airbag communicating with the inside of the air storage cavity, and the upper end of the flexible airbag is fixedly connected with a pressing hemisphere. The upper end of the rotation-following ball at the uppermost position in each sensing chain is fixedly connected with a rigid pressing rod, and the rigid pressing rod penetrates above the installation cavity and is fixedly connected with the pressing hemisphere. An inductive displacement sensor is installed inside each rotation-following ball.

[0018] As a supplement to another improvement of the present application, multiple flexible film pressure sensors and inductive displacement sensors in the same sensing chain are all signal-connected to their corresponding signal processors in a parallel manner, and the detection object of the inductive displacement sensor is the spherical base above it, and the spherical base is made of metal material.

[0019] As yet another improvement of the present application, the lower end of the elastic cylinder is also communicated with a one-way air valve, and a liquid storage tank is placed directly below the one-way air valve in the protection box. The liquid storage tank includes a quick connector matching the one-way air valve, a telescopic airbag communicated with the quick connector, and a liquid pushing plate fixedly connected to the lower end of the telescopic airbag and hermetically slidingly connected to the inner wall of the liquid storage tank. The space below the liquid pushing plate in the liquid storage tank is filled with an indicating liquid. The lower side wall of the protection box is fixedly connected with a quantity display strip, and the quantity display strip includes a sliding cavity communicated with the inside of the liquid storage tank, and two measurement blocks hermetically slidingly connected inside the sliding cavity and connected by a return spring.

[0020] As a supplement to yet another improvement of the present application, the quantity display strip is made of a transparent material, and scale lines are engraved at the bottom of the quantity display strip. A fluorescent agent is also mixed in the indicating liquid, and the mixing ratio of the indicating liquid to the fluorescent agent is 2 - 5:1.

[0021] In summary, by embedding stress sensing rods inside the surrounding rock, using the detection units to detect the deformation of the surrounding rock in the vertical, horizontal, and longitudinal directions, thereby analyzing the release direction and deformation amount of the stress, and by filling air inside the stress sensing rods, using the extrusion effect when the stress sensing rods deform to squeeze out the air, and then letting the air drive the indicating liquid to be squeezed into the designated position, the deformation amount of the surrounding rock can be known by observing the length of the indicating liquid, so as to give an intuitive expression to the on-site maintenance personnel, and this intuitive expression form can be mutually verified with the detection values of the detection units, thereby effectively improving the accuracy and stability of the detection. In addition, according to the detection values, a corresponding support adjustment plan can be provided for the maintenance personnel, effectively improving the safety of the tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flowchart of the detection method for the first embodiment of the present application;

[0023] Figure 2Existing technical solution diagram for the first implementation mode of this application;

[0024] Figure 3 This technical solution diagram for the first implementation mode of this application;

[0025] Figure 4 Front view sectional view of the stress sensing rod and the measuring box for the second implementation mode of this application;

[0026] Figure 5 Three-dimensional split diagram of the sensing chain for the first implementation mode of this application;

[0027] Figure 6 Front view sectional view of the detection unit for the first implementation mode of this application;

[0028] Figure 7 State diagram of the detection unit during measurement for the first implementation mode of this application;

[0029] Figure 8 State diagram of the sensing chain during detection of lateral and vertical deformations for the first implementation mode of this application;

[0030] Figure 9 Front view sectional view of the digital display bar for the second implementation mode of this application.

[0031] Description of the reference numerals in the figure:

[0032] 1 Elastic cylinder, 101 Air storage cavity, 102 Installation cavity, 2 Sensing chain, 3 Protection box, 4 Signal processor, 5 Spherical base, 501 Elastic pad, 6 Rotating ball, 601 Inductive displacement sensor, 7 Flexible film pressure sensor, 8 Touch pressure head, 9 Elastic rotating rod, 10 Pressing hemispherical head, 11 Flexible airbag, 12 Rigid pressing rod, 13 LED display board, 14 One-way air valve, 15 Liquid storage tank, 16 Quick connector, 17 Telescopic airbag, 18 Liquid pushing plate, 19 Digital display bar, 1901 Sliding cavity, 20 Measuring block. Specific implementation mode

[0033] The following will describe in detail the two implementation modes of this application with reference to the accompanying drawings.

[0034] The first implementation mode:

[0035] As Figure 1 shown, it includes the following detection steps:

[0036] S1. Excavation and initial monitoring: Excavate the tunnel, and install supports on the deformed surrounding rock areas (in the initial stage of excavation, the prior art uses anchor bolts to fix unstable rock blocks or soil layers on stable rock masses to prevent collapse or caving, while in this embodiment, supports are used to reinforce the surrounding rock, and the supports are arched steel structures). In the initial stage, due to the release of in-situ stress, the surrounding rock has large plastic deformation, and a total station is used to continuously detect the deformed areas;

[0037] S2. Drilling: Wait until the stress of the surrounding rock is balanced and the deformation speed decreases, entering the slow deformation period. Remove the total station, drill a detection hole with a diameter of 10 - 20 cm and perpendicular to the ground into the surrounding rock through the support at the exact bottom of the deformed area;

[0038] S3. Fix the stress sensing rod: Insert the stress sensing rod into the detection hole so that its lower end is lower than the support, and use an inflation device to inflate it to make it expand and be stuck in the hole to complete the fixation;

[0039] It should be noted that when inflating the stress sensing rod, the inflation pressure is determined according to the diameters of the on-site stress sensing rod and the detection hole, and inflation is carried out until the stress sensing rod expands and can be firmly stuck with the detection hole;

[0040] S4. Connect the device and start detection: As Figure 3 shown, connect a measurement box to the lower end of the stress sensing rod and fix it on the support, ensure the insulation of the wire and the sealing of the channel, and connect the measurement box to the background detection management platform and then start the detection;

[0041] It should be noted that in order to make the stress sensing rod match the detection hole, the diameter of the stress sensing rod is also 10 - 20 cm, and compared with the prior art, as Figure 2 、 3 shown, only one stress sensing rod needs to be arranged in the key monitoring area for this detection method;

[0042] Among them, as Figure 4 shown, the stress sensing rod includes an elastic cylinder 1 (preferably made of polyurethane elastic material, and other materials can also be selected according to actual needs). An air storage cavity 101 is arranged in the middle of the inner wall of the elastic cylinder 1, and a plurality of installation cavities 102 are arranged around the air storage cavity 101. A set of sensing chains 2 are placed inside each installation cavity 102. The measurement box includes a protection box 3 and a plurality of signal processors 4 installed inside the protection box 3 and respectively signal-connected to the multiple groups of sensing chains 2. The signal processors 4 are signal-connected to the background detection management platform through a remote signal sending device. The specific connection structure and working principle of this part are well-known technologies to those skilled in the relevant fields and will not be described in detail here;

[0043] The sensing chain 2 includes a plurality of detection units connected in series, such as Figure 5 、 6It is shown that each detection unit includes a spherical base 5 slidably connected to the installation cavity 102, a rotating ball 6 movably hinged to the spherical base 5, a flexible film pressure sensor 7 fixedly connected to the inner surface of the spherical base 5 (the specific model is selected according to actual needs and will not be described in detail here), a touch head 8 fixedly connected directly below the rotating ball 6 and matching with the flexible film pressure sensor 7, and an elastic rotating rod 9 fixedly connected directly above the rotating ball 6 (rubber material is preferably used, and other materials can also be selected according to actual needs). Each elastic rotating rod 9 is fixedly connected to the bottom of the spherical base 5 above it. After the detection unit is squeezed by the deformation of the surrounding rock, it will bend in the direction of stress release. At this time, the rotation of the rotating ball 6 in the spherical base 5 will cause the touch head 8 to deviate from the center point of the flexible film pressure sensor 7, so as to detect the direction of the deformation of the surrounding rock. Moreover, the rotating ball 6 can rotate 360° relative to the spherical base 5, so the deformation detection of the surrounding rock in the horizontal and vertical directions can be realized;

[0044] As Figure 5 shown, the flexible film pressure sensor 7 is integrally divided into multiple equal parts, and coordinate information representing different directions, the depth of the surrounding rock, and the offset angle of the touch head 8 relative to the center point of the flexible film pressure sensor 7 is embedded in each equal part area through the background detection and management platform (the specific embedding method and working principle are well-known technologies for those skilled in the relevant fields and will not be described in detail here). After the rotating ball 6 rotates relative to the spherical base 5, the touch head 8 deviates from the center point of the flexible film pressure sensor 7 to any one of the equal part areas of the flexible film pressure sensor 7. Then, the touch head 8 generates a pressure electrical signal in this area. This electrical signal includes information such as the depth of the detection unit in the surrounding rock, the direction of the bending of the detection unit affected by stress release, and the offset angle of the touch head 8 relative to the center point of the flexible film pressure sensor 7. The background detection and management platform can obtain the direction of stress release according to the bending direction of the detection unit, and can obtain the displacement amount during the deformation of the surrounding rock according to the offset angle of the touch head 8 relative to the center point of the flexible film pressure sensor 7. Therefore, the specific parameters of the deformation of the surrounding rock can be detected through the detection unit, which is convenient for maintenance personnel to conduct in-depth research and analysis. The touch head 8 is made of a smooth and friction-resistant material, and a spring pad 501 is also laid between the flexible film pressure sensor 7 and the spherical base 5. In order to extend the service life of the touch head 8, a smooth and wear-resistant material is used. In order to enable the touch head 8 to generate a pressure signal on the flexible film pressure sensor 7, the spring force of the spring pad 501 is used to press the flexible film pressure sensor 7 against the touch head 8, effectively avoiding the generation of invalid electrical signals;

[0045] As Figure 4As shown in the figure, the lowermost detection unit in each group of sensing chains 2 is fixedly connected to the inner wall of the installation cavity 102. The upper end of the elastic cylinder 1 is fixedly connected to a flexible airbag 11 that communicates with the inside of the air storage cavity 101, and the upper end of the flexible airbag 11 is fixedly connected to a pressing hemispherical body 10. The upper end of the rotating ball 6 at the uppermost position in each group of sensing chains 2 is fixedly connected to a rigid pressing rod 12, and the rigid pressing rod 12 penetrates above the installation cavity 102 and is fixedly connected to the pressing hemispherical body 10. An inductive displacement sensor 601 is installed inside each rotating ball 6. The pressing hemispherical body 10 can press the detection unit downward through the rigid pressing rod 12, shortening the distance between adjacent two detection units. At this time, the inductive displacement sensor 601 detects the change in the distance between the two detection units, thereby realizing the detection of the surrounding rock in the vertical direction. Moreover, the detection value of the inductive displacement sensor 601 can reflect the vertical deformation amount of the surrounding rock;

[0046] Multiple flexible film pressure sensors 7 and inductive displacement sensors 601 in the same group of sensing chains 2 are all signal-connected to their corresponding signal processors 4 in a parallel manner. The detection object of the inductive displacement sensor 601 is the spherical base 5 located above it. The spherical base 5 is made of metal. The working principle of the inductive displacement sensor 601 is that when the measured object approaches or moves away from the coil, the inductance value of the coil will change, and the effect is the best when the measured object is metal. Therefore, the spherical base 5 is made of metal, and the displacement amount of the spherical base 5 detected by the inductive displacement sensor 601 can reflect the deformation amount of the surrounding rock;

[0047] This embodiment realizes the detection of the deformation of the surrounding rock in the vertical, horizontal and longitudinal directions. It can not only detect the direction of the deformation, but also detect the corresponding deformation amount, which is convenient for maintenance personnel to deeply study and analyze the development trend of the surrounding rock deformation, and provide support for the maintenance personnel to provide a matching support adjustment plan.

[0048] The second embodiment:

[0049] Although the first embodiment can detect the direction and amount of deformation, it mainly relies on electrical signal detection, and there may be deficiencies in the reliability and working stability of electrical signal detection. Therefore, on the basis that the rest of this embodiment is the same as the first embodiment, a structure that can intuitively express the deformation amount of the surrounding rock is additionally provided. It can not only provide technical support for the support adjustment plan for on-site maintenance personnel, but also form a mutual verification mechanism with the electrical signal detection method, effectively improving the accuracy of detection. The specific structure is as follows:

[0050] Such as Figure 4As shown in the figure, a plurality of LED display boards 13 that are fixedly connected to the lower side wall of the protection box 3 and are respectively electrically connected to a plurality of signal processors 4 are distributed in a surrounding manner, and the displayed image of the LED display board 13 is an indicating arrow. After the background detection and management platform analyzes the detection value of the detection unit to obtain the direction of the surrounding rock deformation, it controls the LED display board 13 to display the indicating arrow in the corresponding direction. In this way, the maintenance staff on-site can intuitively know the direction of the next support adjustment, effectively improving the accuracy of the support adjustment;

[0051] As Figure 4 、 9 shown, a one-way air valve 14 is also connected to the lower end of the elastic cylinder 1, and a liquid storage tank 15 is placed directly below the one-way air valve 14 in the protection box 3. The liquid storage tank 15 includes a quick connector 16 that matches the one-way air valve 14, a telescopic airbag 17 that is connected to the quick connector 16, and a liquid pushing plate 18 that is fixedly connected to the lower end of the telescopic airbag 17 and is hermetically slidably connected to the inner wall of the liquid storage tank 15. The specific connection structure and working principle of the one-way air valve 14 and the quick connector 16 are well-known technologies to those skilled in the relevant art and will not be described in detail here. The space in the liquid storage tank 15 below the liquid pushing plate 18 is filled with an indicating liquid. A measuring strip 19 is fixedly connected to the lower side wall of the protection box 3, and the measuring strip 19 includes a sliding cavity 1901 that is internally connected to the liquid storage tank 15, and two measuring blocks 20 that are hermetically slidably connected inside the sliding cavity 1901 and are connected by a return spring. The measuring strip 19 is made of a transparent material, and scale lines are engraved at the bottom of the measuring strip 19. A fluorescent agent is also mixed in the indicating liquid, and the mixing ratio of the indicating liquid to the fluorescent agent is 2 - 5:1. Since the light in the tunnel is relatively dim and the line of sight is not very good, the display effect is improved by adding a fluorescent agent to the indicating liquid. As Figure 9 shown, whether the elastic cylinder 1 is subjected to vertical deformation, lateral and longitudinal deformation extrusion of the surrounding rock, it can squeeze the pre-filled air inside into the telescopic airbag 17. After the telescopic airbag 17 receives the external air and expands downward accordingly, it further squeezes the indicating liquid into the measuring strip 19 to move the measuring blocks 20. In this way, the distance between the two measuring blocks 20 can reflect the deformation amount of the surrounding rock, thus giving an intuitive expression form to the on-site maintenance personnel, effectively improving the interaction between people and equipment. At the same time, the intuitive expression of the deformation amount and the detection unit form a mutual verification mechanism. When there is a difference between the two, it can be known that there is a problem with one of them, so as to timely troubleshoot the problem and effectively improve the detection accuracy.

[0052] It should be added that the detection method of the stress sensing rod and the measuring box in step S4 is as follows:

[0053] S41. Lateral and longitudinal deformation monitoring: As Figure 7 、 8As shown, when the surrounding rock deforms horizontally and vertically, it causes the stress sensing rod to bend, and the sensing chain 2 bends accordingly. Multiple detection units in the same group bend to varying degrees and generate electrical signals. The position where the electrical signal is generated is determined by the position of the touch head 8 on the flexible film pressure sensor 7, representing the stress direction. The signal processor 4 transmits the electrical signal to the background detection and management platform. The platform analyzes the electrical signals of the same group and multiple groups, selects the maximum offset angle as the detection value, and based on this, analyzes the stress release direction and the deformation amount of the surrounding rock to guide the on-site maintenance personnel to adjust the support plan;

[0054] S42. Vertical deformation monitoring: As Figure 8 shown, when the surrounding rock deforms vertically, it presses down on the top pressure hemisphere 10, and through the rigid pressure rod 12, presses down on the sensing chain 2, causing the spherical base 5 to move. The measured value of the inductive displacement sensor 601 changes and emits an electrical signal. The electrical signal is the difference before and after the movement of the spherical base 5, representing the vertical deformation amount. The background detection and management platform compares the differences of the same group and multiple groups, selects the maximum difference as the detection value, and the maintenance personnel adjust the support accordingly;

[0055] S43. On-site intuitive viewing method: In addition to obtaining the support adjustment plan from the background, the on-site maintenance personnel can also view it intuitively on-site. The background controls the LED display board 13 to display the stress release direction indication arrow according to the detection value. After the stress sensing rod is squeezed, the gas is squeezed into the telescopic airbag 17 to make it expand, and the indicating liquid is squeezed into the quantity display bar 19 to push the measuring block 20 to move. The distance between the measuring blocks 20 corresponds to the deformation amount of the surrounding rock, and the same is true for the vertical direction.

[0056] In addition, it should be additionally noted that after the stress sensing rod completes the detection task, in the principle of saving, the measuring box can be disassembled from the support, and then the air inside the stress sensing rod can be released completely through the one-way air valve 14, so that the stress sensing rod can be taken out and reused, saving costs.

[0057] Combined with the current actual requirements, the above implementation methods adopted in this application, the protection scope is not limited to this. Within the knowledge scope of those skilled in the art, various changes made without departing from the concept of this application still fall within the protection scope of the present invention.

Claims

1. An intelligent detection method for railway tunnels based on stress-sensing rods, characterized in that: It includes the following detection steps: S1. Excavation and initial monitoring: Excavate the tunnel, install supports on the deformed surrounding rock area. Initially, due to the release of in-situ stress, the surrounding rock has large plastic deformation. Continuously detect the deformed area with a total station instrument. S2. Drilling: Wait until the stress of the surrounding rock is balanced and the deformation speed decreases, entering the slow deformation period. Remove the total station instrument, drill holes in the support directly below the deformed area, and drill detection holes with a diameter of 10 - 20 cm perpendicular to the ground into the surrounding rock with a drill rod. S3. Fix the stress sensing rod: Insert the stress sensing rod into the detection hole so that its lower end is lower than the support. Inflate it with an inflation device to make it expand and get stuck in the hole to complete the fixation. S4. Connect the equipment and start detection: Connect a measurement box to the lower end of the stress sensing rod and fix it on the support. Do a good job in wire insulation and channel sealing. After connecting the measurement box to the background detection management platform, start the detection. Among them, the stress sensing rod includes an elastic cylinder (1). An air storage cavity (101) is arranged in the middle of the inner wall of the elastic cylinder (1), and a plurality of installation cavities (102) are distributed around the air storage cavity (101). A set of sensing chains (2) is placed inside each installation cavity (102). The measurement box includes a protection box (3) and a plurality of signal processors (4) installed inside the protection box (3) and respectively signal-connected to multiple sets of sensing chains (2). The signal processor (4) is signal-connected to the background detection management platform through a remote signal sending device. The sensing chain (2) includes a plurality of detection units connected in series. Each detection unit includes a spherical base (5) slidably connected to the installation cavity (102), a rotating ball (6) movably hinged to the spherical base (5), a flexible film pressure sensor (7) fixedly connected to the inner surface of the spherical base (5), a touch head (8) fixedly connected directly below the rotating ball (6) and matching with the flexible film pressure sensor (7), and an elastic rotating rod (9) fixedly connected directly above the rotating ball (6). Each elastic rotating rod (9) is fixedly connected to the bottom of the spherical base (5) above it. The lowermost detection unit in each set of sensing chains (2) is fixedly connected to the inner wall of the installation cavity (102). The upper end of the elastic cylinder (1) is fixedly connected with a flexible airbag (11) communicating with the inside of the air storage cavity (101). The upper end of the flexible airbag (11) is fixedly connected with a pressing hemisphere (10). A rigid pressing rod (12) is fixedly connected to the upper end of the rotating ball (6) at the uppermost part of each set of sensing chains (2). The rigid pressing rod (12) penetrates above the installation cavity (102) and is fixedly connected to the pressing hemisphere (10). An inductive displacement sensor (601) is installed inside each rotating ball (6).

2. The intelligent detection method for railway tunnels based on stress-sensing rods according to claim 1, characterized in that: The flexible film pressure sensor (7) is integrally divided into a plurality of equal parts areas, and coordinate information representing different directions, surrounding rock depths, and the offset angle of the touch head (8) relative to the center point of the flexible film pressure sensor (7) is embedded in each equal parts area through the background detection management platform.

3. The intelligent detection method for railway tunnels based on a stress sensing rod according to claim 1, wherein: The touch head (8) is made of a smooth and friction-resistant material, and a spring pad (501) is also laid between the flexible film pressure sensor (7) and the spherical base (5).

4. The intelligent detection method for railway tunnels based on stress-sensing rods according to claim 1, wherein: A plurality of LED display boards (13) which are circumferentially distributed and are respectively electrically connected to a plurality of signal processors (4) are fixedly connected to the lower side wall of the protection box (3), and the displayed image of the LED display board (13) is an indicating arrow.

5. The intelligent detection method for railway tunnels based on stress-sensing rods according to claim 1, wherein: A plurality of the flexible film pressure sensors (7) and inductive displacement sensors (601) in the same group of sensing chains (2) are all signal-connected to their corresponding signal processors (4) in a parallel manner, and the detection object of the inductive displacement sensor (601) is the spherical base (5) above it, and the spherical base (5) is made of a metal material.

6. The intelligent detection method for railway tunnels based on stress sensing rods according to claim 1, characterized in that: A one-way air valve (14) is also communicated with the lower end of the elastic cylinder (1), and a liquid storage tank (15) is placed directly below the one-way air valve (14) in the protection box (3). The liquid storage tank (15) includes a quick connector (16) matching the one-way air valve (14), a telescopic airbag (17) communicated with the quick connector (16), and a liquid pushing plate (18) fixedly connected to the lower end of the telescopic airbag (17) and hermetically sliding-connected to the inner wall of the liquid storage tank (15). An indicating liquid is filled in the space below the liquid pushing plate (18) in the liquid storage tank (15). A quantity display bar (19) is fixedly connected to the lower side wall of the protection box (3), and the quantity display bar (19) includes a sliding cavity (1901) communicated with the inside of the liquid storage tank (15), and two quantity measuring blocks (20) hermetically sliding-connected inside the sliding cavity (1901) and connected by a return spring.

7. A method for intelligent detection of railway tunnels based on stress-sensing rods according to claim 6, characterized in that: The quantity display bar (19) is made of a transparent material, and scale lines are engraved on the bottom of the quantity display bar (19). A fluorescent agent is also mixed in the indicating liquid, and the mixing ratio of the indicating liquid to the fluorescent agent is 2 - 5:1.

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