A method and system for detecting surrounding rock pressure during construction of assembled inverted arch in loess tunnel

Abstract

The present invention belongs to the technical field of tunnel construction detection, and relates to a method for detecting surrounding rock pressure in the construction of a prefabricated inverted arch in a loess tunnel, and the specific steps are as follows: surrounding rock pressure monitoring, inverted arch bottom pressure monitoring, secondary lining, surrounding rock pressure follow-up monitoring, data collection and transmission; a system for detecting surrounding rock pressure in the construction of a prefabricated inverted arch in a loess tunnel, comprising a loess tunnel, a steel support detection system, and an inverted arch bottom detection system, wherein the steel support detection system is composed of a steel frame support used as a support, and a retractable detection component for detecting surrounding rock pressure around the inverted arch, and the inverted arch bottom detection system is composed of a guardrail used as a mortar template for the inner lining of the inverted arch, and a bottom detection component for detecting surrounding rock pressure below the inverted arch. The present invention can effectively deal with unexpected situations caused by the incomplete stability of the structure of the just-completed part, and can also solve the problem of abnormal detection data caused by construction vibration.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction detection, and in particular relates to a method and system for detecting surrounding rock pressure during construction of an assembled invert arch of a loess tunnel. Background Art

[0002] The detection of surrounding rock pressure in tunnel prefabricated invert construction is a key link to ensure the safety and stability of tunnel structure. Its monitoring purpose is: surrounding rock pressure monitoring aims to understand the stress state and change trend of surrounding rock in real time, provide a scientific basis for tunnel design and construction, and adjust the construction plan in time through monitoring data to ensure the safety and stability of tunnel structure.

[0003] Problems with existing technologies:

[0004] Lag of monitoring data: Although on-site monitoring can collect data in real time, it takes a certain amount of time to process and analyze the data. Therefore, in the face of emergencies, the monitoring data may not be able to provide effective feedback information in a timely manner, resulting in the construction unit being unable to make decisions quickly. For example, when each invert section is just completed, the tunnel structure is not yet completely stable. At this time, the surrounding rock pressure is very likely to suddenly increase or deform more severely. If the monitoring data cannot be obtained and analyzed in time, the best time to deal with it may be missed.

[0005] Monitoring data is interfered with: On-site monitoring data is easily interfered with by various factors, such as the vibration of construction machinery, the passage of large vehicles, temperature changes, etc. During the construction of the invert arch, cement vibration and assembly hoisting are very likely to cause local vibrations. These interferences may cause fluctuations or errors in the monitoring data, affecting the accurate judgment of the surrounding rock pressure state. Summary of the invention

[0006] The purpose of the present invention is to provide a method and system for detecting surrounding rock pressure in the construction of a prefabricated invert arch in a loess tunnel, which can effectively deal with unexpected situations caused by incomplete structural stability of a newly completed part, and can also solve the problem of abnormal detection data caused by construction vibration.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A method for detecting surrounding rock pressure during construction of a prefabricated inverted arch in a loess tunnel, the specific steps of which are as follows:

[0009] Step 1: Monitoring of surrounding rock pressure. The part of the surrounding rock to be tested above the invert construction section is pre-cut flat, and the vibrating wire pressure cell is installed between the surrounding rock and the initial concrete support. The installation locations are the arch crown, left and right arch waists, left and right wall middles, and left and right wall foots.

[0010] Step 2: Inverted arch bottom pressure monitoring: guardrails and steel mesh are installed before inverted arch construction. Bottom detection components are installed at the middle bottom and both ends of the guardrail. Then, the initial concrete support of the inverted arch is poured and the prefabricated inverted arch is assembled.

[0011] Step 3: Secondary lining: secondary lining is carried out on the part above the prefabricated invert in the tunnel to form the tunnel foundation;

[0012] Step 4: Follow-up monitoring of surrounding rock pressure. Then move the steel frame support to a position close to the loess tunnel and the invert construction section. Install the retractable detection component between the secondary lining support and the steel frame support. The installation locations are the arch crown, left and right arch waists, left and right wall middles, and left and right wall foots.

[0013] Step 5: Data collection and transmission: Use monitoring equipment to collect data such as pressure and deformation of surrounding rocks in real time, and transmit the data to the monitoring center or data processing system.

[0014] A surrounding rock pressure detection system for assembled invert construction of a loess tunnel comprises a loess tunnel, a steel support detection system and an invert bottom detection system, wherein a primary construction area inside the loess tunnel is set as an invert construction section, and an invert prefabricated body is assembled inside the invert construction section, the steel support detection system comprises a steel frame support used as support, and a retractable detection component used to detect surrounding rock pressure above the invert, and the invert bottom detection system comprises a guardrail used as an invert lining mortar template, and a bottom detection component used to detect surrounding rock pressure below the invert.

[0015] The steel structure support is composed of a steel beam frame, a gantry frame and an edge support steel plate. The edge support steel plate is composed of a top protection steel plate located at the top, a waist protection steel plate located in the middle and upper part of both sides and a bottom protection steel plate located in the middle and lower part of both sides. The steel beam frame is fixedly arranged at the top of the inner side of the two groups of gantries. The bottom lifting type of the gantry is equipped with a hydraulic lifting mechanism, and the bottom of the hydraulic lifting mechanism is equipped with a track machine. The top protection steel plate is fixedly installed above the steel beam frame in a linear array. The waist protection steel plates distributed in a linear array are fixedly combined by a connecting beam 1 arranged on one side of the steel beam frame, and the connecting beam 1 is connected and assembled with the side wall of the steel beam frame by a hydraulic cylinder 1. The bottom protection steel plates distributed in a linear array are fixedly combined by a connecting beam 2 arranged at the oblique bottom of the steel beam frame, and the connecting beam 2 is connected and assembled with the bottom of the steel beam frame by a hydraulic cylinder 2.

[0016] The top guard steel plate, waist guard steel plate and bottom guard steel plate are all provided with through holes at corresponding detection positions, and support frames are fixedly installed on the inner walls of the top guard steel plate and the bottom guard steel plate at corresponding positions.

[0017] The retractable detection component is arranged at the position of each perforation, and the retractable detection component includes a rotating frame and a fixed frame fixedly installed on the inner wall of the edge support steel plate, the outer surface of the rotating frame is rotatably sleeved with a pry frame, the inner walls on both sides of the fixed frame are provided with vertical rails and a vertical groove, and the vertical groove is opened through, and a gear rod is integrally provided on one side of the fixed frame.

[0018] The cam is an angular channel that is fixedly connected to the side panel of the wheel hub, and the cam is connected along the longitudinal direction of the wheel hub to form a circle, the circle being arranged on the horizontal axis of the wheel hub, and the rotation of the cam is effected by the user's movement.

[0019] The inner slide is away from the surface of the ring push plate and is located at the edge of the circular hole and is fixedly connected to a rotating rod in an array, and the ends of the rotating rods are commonly fixedly connected to a ring seat, the outer surface of the ring seat is rotatably sleeved with a ring plate, the outer surfaces of the rotating rods are rotatably sleeved with baffles, and the edge of each baffle is fixedly provided with a through rod, the edge of the ring plate is penetrated by a guide groove for the corresponding through rod to pass through, one side of the edge of the ring plate is provided with local gear teeth, one side of the edge of the inner slide is rotatably installed with a worm gear meshing with the local gear teeth, and both ends of the worm gear are fixedly assembled with gears meshing with the gear rod.

[0020] A hydraulic cylinder three is fixedly installed inside the support frame, and the hydraulic cylinder three is connected to the other end of the corresponding skid frame through a connecting arm. The connecting arm includes a single arm, a main arm, an auxiliary arm and a connecting slot rod. The single arm is arranged on the inner side of the top guard steel plate and is connected to the output end of the corresponding hydraulic cylinder three. The middle part and both ends of the single arm are connected to the corresponding skid frame through a hanging rod. The main arm is arranged on the inner side of the bottom guard steel plate, and the auxiliary arm is arranged on the inner side of the waist guard steel plate. The main arm is connected to the adjacent auxiliary arm by an angle-adjustable connecting slot rod, and the main arm is connected to the output end of the corresponding hydraulic cylinder three.

[0021] The bottom detection assembly is arranged in the middle and both ends of the guardrail, and the bottom detection assembly consists of a protective box, a second pressure detection box, a pressure plate and a seat plate. The second pressure detection box is movably assembled inside the protective box, and a spring three is connected between the second pressure detection box and the inner wall of the protective box. The outer wall of the top of the protective box is fixedly welded with pins in an array, and the number of the pins is three. A pressure block is movably sleeved on the outer surface of the pin, and a spring four is sleeved on the outer surface of the pin and is located between the protective box and the pressure block. The outer walls on both sides of the pressure block are integrally provided with protrusions.

[0022] One end of the pressure plate is detachably assembled with the corresponding pressure block, and the end of the pressure plate is buckled with the protrusion, one end of the seat plate is fixedly installed with a screw, and the seat plate and the corresponding pressure plate are assembled by screwing the nut and the screw, and the seat plates on the adjacent sides inside the two bottom detection components are fixedly connected by steel plates, and the steel plates are fixedly installed on the side walls of the guardrail. In addition to the other seat plates integrated with the steel plates, they are also fixedly installed on the side walls of the guardrail.

[0023] The technical effects achieved by the present invention are:

[0024] The present invention, by adding a process of following monitoring of surrounding rock pressure and utilizing the cooperation of steel frame support and retractable detection components, can detect the surrounding rock pressure of the just-completed portion when each invert construction section is completed, and can timely detect changes in surrounding rock pressure when the tunnel structure tends to be stable, effectively coping with unexpected situations that may occur in the just-completed portion due to incomplete structural stability.

[0025] In the present invention, the structure of the retractable and storable pressure detection box is coordinated with the movable steel frame support, which can realize the process of following the monitoring of the surrounding rock pressure, can follow the construction progress of the invert arch construction section, and realize timely follow-up detection. The retractable and storable pressure detection box can also avoid frequent disassembly and assembly operations, which greatly facilitates the monitoring work; in addition, the setting of each baffle also plays an effect of protecting the pressure detection box, and the baffle can automatically retract and expand following the movement of the pressure detection box.

[0026] In the present invention, the seat plate directly fixedly connected to the guardrail provides fixed stress for the protection box by means of the part of the guardrail, while the seat plate directly fixedly connected to the steel plate provides fixed stress for the protection box by means of the part of the guardrail connected to the steel plate. This structural design is used to prevent the guardrail from vibrating partially, resulting in abnormal monitoring data of the pressure detection box 2 at a certain place. Taking the attached figure as an example, when the middle part of the guardrail vibrates, the seat plate directly connected to the guardrail will follow the vibration, and the stress condition of the spring 4 adjacent to the seat plate will change. However, since the connection between the steel plate and the guardrail is far away from the middle part of the guardrail, the steel plate is less affected by the vibration or even not affected at all. This ensures that the spring 4 subjected to the compressive stress of the steel plate has no stress change, thereby maintaining the middle protection box in a state of close contact with the surface to be tested, and the stress condition of the pressure detection box 2 inside it does not change either, thereby solving the problem of abnormal detection data caused by construction vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a simplified construction diagram of a loess tunnel provided by an embodiment of the present invention;

[0028] Figure 2 is a structural diagram of a steel frame support provided by an embodiment of the present invention;

[0029] Figure 3 It is a schematic diagram of the installation of the retractable detection assembly and each connecting arm provided in an embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of the installation of the storage-type detection assembly in the top guard steel plate provided by an embodiment of the present invention;

[0031] Figure 5 yes Figure 4 A local enlarged schematic diagram of the middle A;

[0032] Figure 6 is a structural disassembly diagram of a retractable detection assembly provided by an embodiment of the present invention;

[0033] Figure 7 It is a schematic diagram of the assembly of the guardrail, the bottom detection assembly and the steel plate provided in an embodiment of the present invention;

[0034] Figure 8 is a structural disassembly diagram of a bottom detection assembly provided by an embodiment of the present invention;

[0035] Fig. 9 yes Figure 7 A partial enlarged schematic diagram of point B in the middle;

[0036] Fig.10 It is a flow chart of the pressure detection method provided by an embodiment of the present invention.

[0037] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0038] 1. Loess tunnel; 101. Inverted arch construction section; 2. Steel frame support; 201. Steel beam frame; 202. Gantry frame; 203. Hydraulic lifting mechanism; 204. Track machine; 205. Top guard steel plate; 206. Waist guard steel plate; 207. Bottom guard steel plate; 208. Connecting beam 1; 209. Connecting beam 2; 210. Hydraulic cylinder 1; 211. Hydraulic cylinder 2; 212. Bracket; 213. Perforation; 3. Storage detection assembly; 301. Rotating frame; 302. Pry frame; 303. Fixed frame; 304. Vertical rail; 305. Vertical slot 1; 306. Tooth rod; 307. Inner slide; 308. Vertical slot 2; 309. Ring push plate; 310. Extension rod; 311. Guide rod; 312. Spring 1; 313, pressure detection box one; 314, spring two; 315, rotating rod; 316, ring seat; 317, stop petal; 318, through rod; 319, ring plate; 320, guide groove; 321, worm; 322, gear; 4, hydraulic cylinder three; 5, connecting arm; 51, single arm rod; 52, main arm rod; 53, auxiliary arm rod; 54, connecting groove rod; 55, hanging rod; 6, inverted arch prefabricated body; 7, guardrail; 8, bottom detection assembly; 801, protection box; 802, pressure detection box two; 803, spring three; 804, pin; 805, pressure block; 806, protrusion; 807, spring four; 808, pressure plate; 809, seat plate; 810, screw; 811, nut; 9, steel plate. DETAILED DESCRIPTION

[0039] In order to make the purpose and advantages of the present invention more clearly understood, the present invention is specifically described below in conjunction with embodiments. It should be understood that the following text is only used to describe one or several specific embodiments of the present invention, and does not strictly limit the scope of protection of the specific claims of the present invention.

[0040] like Fig.10 As shown, a method for detecting surrounding rock pressure during construction of a prefabricated inverted arch in a loess tunnel has the following specific steps:

[0041] Step 1: Monitoring surrounding rock pressure. The part of the surrounding rock to be tested above the invert construction section 101 is pre-cut flat, and the vibrating wire pressure cell is installed between the surrounding rock and the initial concrete support. The installation positions are the arch crown, left and right arch waists, left and right wall middles, and left and right wall foots.

[0042] Step 2: Inverted arch bottom pressure monitoring: guardrail 7 and steel mesh are installed before inverted arch construction, bottom detection components 8 are installed at the middle bottom and both ends of the guardrail 7, and then the initial concrete support of the inverted arch is poured and the inverted arch prefabricated body 6 is assembled;

[0043] Step 3: Secondary lining: secondary lining is carried out on the upper part of the tunnel where the invert prefabricated body 6 is installed, and the tunnel foundation is formed;

[0044] Step 4: Follow-up monitoring of surrounding rock pressure, then move the steel frame support 2 to a position close to the loess tunnel 1 and the invert construction section 101, install the retractable detection component 3 between the secondary lining support and the steel frame support 2, and install the components at the arch top, left and right arch waists, left and right wall middles, and left and right wall feet;

[0045] Step 5: Data collection and transmission: Use monitoring equipment to collect data such as pressure and deformation of surrounding rocks in real time, and transmit the data to the monitoring center or data processing system.

[0046] The principle of this method is: by adding a process of surrounding rock pressure follow-up monitoring, using the cooperation of the steel structure support 2 and the retractable detection component 3, the surrounding rock pressure of the just completed part can be detected when each arch construction section 101 is completed, and the changes in the surrounding rock pressure when the tunnel structure tends to be stable can be detected in time, effectively dealing with unexpected situations caused by the incomplete stability of the structure of the just completed part.

[0047] like Figure 1-Figure 9 As shown, a surrounding rock pressure detection system for assembled invert construction of a loess tunnel comprises a loess tunnel 1, a steel support detection system and an invert bottom detection system, wherein the primary construction area inside the loess tunnel 1 is set as an invert construction section 101, and an invert prefabricated body 6 is assembled inside the invert construction section 101, the steel support detection system comprises a steel frame support 2 used as support, and a retractable detection component 3 used to detect the surrounding rock pressure above the invert, and the invert bottom detection system comprises a guardrail 7 used as a mortar template for the inner lining of the invert, and a bottom detection component 8 used to detect the surrounding rock pressure below the invert.

[0048] Refer to the attached Figure 2The steel frame support 2 is composed of a steel beam frame 201, a gantry frame 202 and an edge support steel plate. The edge support steel plate is composed of a top protection steel plate 205 located at the top, a waist protection steel plate 206 located in the middle and upper part of both sides, and a bottom protection steel plate 207 located in the middle and lower part of both sides. The steel beam frame 201 is fixedly arranged at the top of the inner side of the two groups of gantry frames 202. The bottom lifting type of the gantry frame 202 is equipped with a hydraulic lifting mechanism 203, and the bottom of the hydraulic lifting mechanism 203 is equipped with a track machine 204. The top protection steel plate 205 is The linear array-type waist guard steel plates 206 are fixedly installed above the steel beam frame 201, and the linear array-type waist guard steel plates 206 are fixedly assembled by a connecting beam 208 arranged on one side of the steel beam frame 201, and the connecting beam 208 and the side wall of the steel beam frame 201 are connected and assembled by a hydraulic cylinder 210. The linear array-type bottom guard steel plates 207 are fixedly assembled by a connecting beam 209 arranged obliquely below the steel beam frame 201, and the connecting beam 209 and the bottom of the steel beam frame 201 are connected and assembled by a hydraulic cylinder 211.

[0049] Refer to the attached Figure 4-Figure 5 The top guard steel plate 205 , the waist guard steel plate 206 and the bottom guard steel plate 207 are all provided with through holes 213 at the corresponding detection positions, and the inner walls of the top guard steel plate 205 and the bottom guard steel plate 207 at the corresponding positions are fixedly installed with support frames 212 .

[0050] According to the above structure, when it is necessary to control the steel frame support 2 to move to a position close to the invert arch construction section 101, the hydraulic lifting mechanism 203 controls the edge support steel plate to move downward as a whole, each hydraulic cylinder 1 210 controls each waist protection steel plate 206 to move away from the inner wall of the tunnel, and each hydraulic cylinder 2 211 controls each bottom protection steel plate 207 to move away from the inner wall of the tunnel. Then, the track machine 204 controls the support to move as a whole. When it moves to the specified position, the top protection steel plate 205, the waist protection steel plate 206 and the bottom protection steel plate 207 are controlled to move and unfold and re-support the inner wall of the tunnel.

[0051] Embodiment 1:

[0052] Refer to the attached Figure 5-Figure 6 The retractable detection component 3 is arranged at the position of each through hole 213, and the retractable detection component 3 includes a rotating frame 301 and a fixed frame 303 fixedly installed on the inner wall of the edge support steel plate, and a pry frame 302 is rotatably sleeved on the outer surface of the rotating frame 301, and vertical rails 304 and vertical grooves 305 are opened on the inner walls on both sides of the fixed frame 303, and the vertical grooves 305 are opened through, and a gear rod 306 is integrally set on one side of the fixed frame 303.

[0053] Refer to the attached Figure 5-Figure 6The inner side of the fixed frame 303 is installed with an inner slide 307 which is slidably assembled with the vertical rail 304. The two side walls of the inner slide 307 are penetrated with a second vertical groove 308. The inner side of the inner slide 307 is slidably assembled with a ring push plate 309. The two ends of the ring push plate 309 are fixedly connected with an extension rod 310, and the extension rod 310 penetrates the corresponding second vertical groove 308 and the first vertical groove 305. One end of the pry frame 302 is connected to the end of the corresponding extension rod 310. The inner slide 307 is close to the surface of the ring push plate 309. The edge of the surface is fixedly connected with a guide rod 311 in an array manner, and the guide rod 311 movably passes through the ring push plate 309, and a spring 312 is sleeved on the outer surface of the guide rod 311 and is located between the inner slide 307 and the ring push plate 309, and a pressure detection box 313 is movably assembled on the inner side at the center of the inner slide 307, and a circular hole for the pressure detection box 313 to pass through is opened at the center of the inner slide 307, and a spring 2 314 is connected between the pressure detection box 313 and the surface of the ring push plate 309.

[0054] Refer to the attached Figure 5-Figure 6 The inner slide 307 is away from the surface of the ring push plate 309 and is located at the edge of the circular hole and is fixedly connected to a rotating rod 315 in an array, and the ends of the rotating rod 315 are commonly fixedly connected to a ring seat 316, and the outer surface of the ring seat 316 is rotatably sleeved with a ring plate 319, and the outer surfaces of the rotating rod 315 are rotatably sleeved with a baffle 317, and the edge of each baffle 317 is fixedly provided with a through rod 318, and the edge of the ring plate 319 is penetrated by a guide groove 320 for the corresponding through rod 318 to pass through, and one side of the edge of the ring plate 319 is provided with partial gear teeth, and one side of the edge of the inner slide 307 is rotatably installed with a worm 321 meshing with the partial gear teeth, and both ends of the worm 321 are fixedly assembled with gears 322 meshing with the gear rod 306.

[0055] Refer to the attached Figure 3-Figure 5 , a hydraulic cylinder three 4 is fixedly installed inside the support frame 212, and the hydraulic cylinder three 4 is connected to the other end of the corresponding skid frame 302 through a connecting arm 5. The connecting arm 5 includes a single arm rod 51, a main arm rod 52, an auxiliary arm rod 53 and a connecting groove rod 54. The single arm rod 51 is arranged on the inner side of the top guard steel plate 205 and is connected to the output end of the corresponding hydraulic cylinder three 4. The middle and both ends of the single arm rod 51 are connected to the corresponding skid frame 302 through a hanging rod 55. The main arm rod 52 is arranged on the inner side of the bottom guard steel plate 207, and the auxiliary arm rod 53 is arranged on the inner side of the waist guard steel plate 206. The main arm rod 52 and the adjacent auxiliary arm rod 53 are connected in an angle-adjustable manner through a connecting groove rod 54, and the main arm rod 52 is connected to the output end of the corresponding hydraulic cylinder three 4.

[0056] According to the above structure, after the steel frame support 2 moves to the designated position, each pressure detection box 313 is controlled to pass through the corresponding through hole 213 and contact the inner wall of the tunnel to perform surrounding rock stress detection. The specific process is as follows: the hydraulic cylinder 3 4 at the corresponding position is started, and the hydraulic cylinder 3 4 operates and controls the single arm 51, the main arm 52 and the auxiliary arm 53 to move linearly, wherein the structure of connecting the main arm 52 and the auxiliary arm 53 through the connecting slot rod 54 facilitates the change of the angle between the main arm 52 and the auxiliary arm 53. The single arm 51, the main arm 52 and the auxiliary arm 53 are connected by the hanging rod 55 to drive the pry frame 302 to rotate with the rotating frame 301 as the center of the circle, and because one end of the pry frame 302 is connected to the corresponding extension rod 310, the ring push plate 309 is driven to move toward the through hole 213;

[0057] At the initial stage of the movement of the ring push plate 309, with the help of the elastic force of each spring 312, the ring push plate 309 will move toward the direction of the through hole 213 together with the inner slide 307. During the process, the gear 322 will contact and mesh with the gear rod 306, thereby driving the worm 321 to rotate, and then the ring plate 319 is driven to rotate with the help of the meshing of the worm 321 and the local gear teeth. Since the penetration rod 318 passes through the guide groove 320, it will eventually drive the baffles 317 to rotate with the rotating rod 315 as the center of the circle. The baffles 317 then spread out to open the circular hole. Then, when the inner slide 307 moves along the vertical rail 304 to When the inner slide 307 is at the limit position, the inner slide 307 stops moving while the ring push plate 309 continues to move. At this time, the spring 1 312 is compressed, and the ring push plate 309 will push the pressure detection box 1 313 to move under the elastic force of the spring 2 314. The pressure detection box 1 313 will eventually pass through the perforation 213 until it fits with the inner wall of the tunnel. When the pressure detection boxes 1 313 at each position are in contact with the inner wall of the corresponding detection position of the tunnel, the surrounding rock stress monitoring work can be carried out. On the contrary, when the steel frame support 2 moves, the hydraulic cylinders 3 4 are controlled in the reverse direction to reset the pressure detection boxes 1 313.

[0058] In the above process, the retractable pressure detection box 313 structure cooperates with the movable steel frame support 2 to realize the process of following the monitoring of the surrounding rock pressure, and can follow the construction progress of the arch construction section 101 to achieve timely follow-up detection. The retractable pressure detection box 313 can also avoid frequent disassembly and assembly operations, which greatly facilitates the monitoring work; in addition, the setting of each baffle 317 also plays a role in protecting the pressure detection box 313, and the baffle 317 can automatically retract and expand following the movement of the pressure detection box 313.

[0059] The working principle of the present invention is as follows: after the steel frame support 2 moves to the designated position, the hydraulic cylinder 3 4 at the corresponding position is started, which operates and controls the single arm 51, the main arm 52 and the auxiliary arm 53 to move linearly, wherein the structure of connecting the main arm 52 and the auxiliary arm 53 through the connecting slot rod 54 facilitates the change of the angle between the main arm 52 and the auxiliary arm 53, and the single arm 51, the main arm 52 and the auxiliary arm 53 drive the pry frame 302 to rotate with the rotating frame 301 as the center through the connection of the hanging rod 55, and because one end of the pry frame 302 is connected to the corresponding extension rod 310, the ring push plate 309 is driven to move toward the through hole 213;

[0060] At the initial stage of the movement of the ring push plate 309, with the help of the elastic force of each spring 312, the ring push plate 309 will move toward the direction of the through hole 213 together with the inner slide 307. During the process, the gear 322 will contact and mesh with the gear rod 306, thereby driving the worm 321 to rotate, and then the ring plate 319 is driven to rotate with the help of the meshing of the worm 321 and the local gear teeth. Since the penetration rod 318 passes through the guide groove 320, it will eventually drive the baffles 317 to rotate with the rotating rod 315 as the center of the circle. The baffles 317 then spread out to open the circular hole. Then, when the inner slide 307 moves along the vertical rail 304 to When in the extreme position, the inner slide 307 stops moving and the ring push plate 309 continues to move. At this time, the spring 1 312 is compressed, and the ring push plate 309 will push the pressure detection box 1 313 to move under the elastic force of the spring 2 314. The pressure detection box 1 313 will eventually pass through the perforation 213 until it fits with the inner wall of the tunnel. When the pressure detection boxes 1 313 at each position are in contact with the inner wall of the corresponding detection position of the tunnel, the surrounding rock stress monitoring work can be carried out. On the contrary, when the steel structure support 2 moves, the hydraulic cylinders 3 4 are controlled in reverse to reset the pressure detection boxes 1 313.

[0061] Embodiment 2:

[0062] Refer to the attached Figure 7-Figure 9 The bottom detection assembly 8 is arranged in the middle and both ends of the guardrail 7. The bottom detection assembly 8 is composed of a protective box 801, a pressure detection box 802, a pressure plate 808 and a seat plate 809. The pressure detection box 802 is movably assembled inside the protective box 801, and a spring 3 803 is connected between the pressure detection box 802 and the inner wall of the protective box 801. The outer wall of the top of the protective box 801 is fixedly welded with pins 804 in an array, and the number of the pins 804 is three. The outer surface of the pin 804 is movably sleeved with a pressure block 805, and the outer surface of the pin 804 is sleeved with a spring 4 807 between the protective box 801 and the pressure block 805, and the outer walls on both sides of the pressure block 805 are integrally provided with protrusions 806.

[0063] Refer to the attached Figure 7-Figure 9One end of the pressure plate 808 is detachably assembled with the corresponding pressure block 805, and the end of the pressure plate 808 is buckled with the protrusion 806. A screw 810 is fixedly installed at one end of the seat plate 809. The seat plate 809 and the corresponding pressure plate 808 are assembled by screwing the nut 811 with the screw 810. The seat plates 809 on the adjacent side inside the two bottom detection components 8 are fixedly connected by the steel plate 9, and the steel plate 9 is fixedly installed on the side wall of the guardrail 7. In addition to the other seat plates 809 that are integrated with the steel plate 9, they are also fixedly installed on the side wall of the guardrail 7, so that the elastic force of the deformation of a single spring four 807 is greater than the sum of the elastic forces that cause all springs three 803 to deform at the same time.

[0064] According to the above structure, the bottom detection assembly 8 located on one side of the inverted arch guardrail 7 is used to monitor the surrounding rock pressure below the inverted arch and provide stress data support for the construction of the inverted arch construction section 101. During the installation operation of the pressure detection box 802, the pressure detection box 802 is placed in the protection box 801 and supported by the spring 803, and then the pressure plate 808 is buckled with the corresponding pressure block 805, and then the fixed installation of each seat plate 809 is completed and the screw rod 810 passes through the pressure plate 808, and finally the nut 811 is screwed on each screw rod 810. When the nut 811 is screwed, the seat plate 809 and each pressure plate 808 are fully fixed, and the spring 807 is in a compressed state at the same time. In addition, the seat plates 809 on the adjacent side inside the two bottom detection assemblies 8 are connected by the steel plate 9, and the middle part of each steel plate 9 is fixedly connected to the guardrail 7;

[0065] In the above structure, the seat plate 809 directly fixedly connected to the guardrail 7 provides a fixed stress for the protection box 801 by the part of the guardrail 7, and the seat plate 809 directly fixedly connected to the steel plate 9 provides a fixed stress for the protection box 801 by the part of the guardrail 7 connected to the steel plate 9. This structural design is used to avoid the situation where the monitoring data of a certain pressure detection box 802 is abnormal due to partial vibration of the guardrail 7, so as to attach Figure 7 For example, when the middle part of the guardrail 7 vibrates, the seat plate 809 directly connected to the guardrail 7 will follow the vibration, and the stress condition of the spring four 807 adjacent to the seat plate 809 will change. However, since the connection between the steel plate 9 and the guardrail 7 is far away from the middle of the guardrail 7, the steel plate 9 is less affected by the vibration or even not affected at all, which makes the spring four 807 subjected to the compressive stress of the steel plate 9 have no stress change, thereby keeping the middle protection box 801 in close contact with the surface to be tested, and the stress state of the pressure detection box two 802 inside it does not change, which can solve the problem of abnormal detection data caused by construction vibration.

[0066] The working principle of the present invention is as follows: the bottom detection assembly 8 located on one side of the inverted arch guardrail 7 is used to monitor the surrounding rock pressure below the inverted arch and provide stress data support for the construction of the inverted arch construction section 101. During the installation operation of the pressure detection box 802, the pressure detection box 802 is placed in the protection box 801 and supported by the spring 3 803, and then the pressure plate 808 is buckled with the corresponding pressure block 805, and then the fixed installation of each seat plate 809 is completed and the screw rod 810 is passed through the pressure plate 808, and finally the nut 811 is screwed onto each screw rod 810. When the nut 811 is screwed, the seat plate 809 and each pressure plate 808 are fully fixed, and at the same time the spring 4 807 is in a compressed state. In addition, the seat plates 809 on the adjacent side inside the two bottom detection assemblies 8 are connected by the steel plate 9, and the middle part of each steel plate 9 is fixedly connected to the guardrail 7.

[0067] The above is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to the conventional means in the art unless otherwise specified and limited.

Claims

1. A surrounding rock pressure detection system for loess tunnel prefabricated invert construction, characterized by: The invention comprises a loess tunnel (1), a steel support detection system and an inverted arch bottom detection system, wherein the primary construction area inside the loess tunnel (1) is set as an inverted arch construction section (101), and an inverted arch prefabricated body (6) is assembled and constructed inside the inverted arch construction section (101); the steel support detection system comprises a steel frame support (2) used as a support, and a retractable detection component (3) used for detecting the surrounding rock pressure above the inverted arch; and the inverted arch bottom detection system comprises a guardrail (7) used as a mortar template for the inner lining of the inverted arch, and a bottom detection component (8) used for detecting the surrounding rock pressure below the inverted arch; The steel frame support (2) is composed of a steel beam frame (201), a gantry frame (202) and an edge support steel plate. The edge support steel plate is composed of a top protection steel plate (205) located at the top, a waist protection steel plate (206) located at the middle and upper part of both sides, and a bottom protection steel plate (207) located at the middle and lower part of both sides. The steel beam frame (201) is fixedly arranged at the top of the inner side of the two groups of gantry frames (202). The bottom of the gantry frame (202) is equipped with a hydraulic lifting mechanism (203), and the bottom of the hydraulic lifting mechanism (203) is equipped with a track machine (204). The top protection steel plate (205) is arranged at the top of the gantry frame (202). 05) are fixedly installed on the top of the steel beam frame (201) in a linear array, the waist guard steel plates (206) distributed in a linear array are fixedly assembled by a connecting beam (208) arranged on one side of the steel beam frame (201), and the connecting beam (208) and the side wall of the steel beam frame (201) are connected and assembled by a hydraulic cylinder (210), and the bottom guard steel plates (207) distributed in a linear array are fixedly assembled by a connecting beam (209) arranged obliquely below the steel beam frame (201), and the connecting beam (209) and the bottom of the steel beam frame (201) are connected and assembled by a hydraulic cylinder (211); The top guard steel plate (205), the waist guard steel plate (206) and the bottom guard steel plate (207) are all provided with through holes (213) at corresponding detection positions, and the inner walls of the top guard steel plate (205) and the bottom guard steel plate (207) at corresponding positions are fixed with support frames (212); The retractable detection assembly (3) is arranged at the position of each perforation (213), and the retractable detection assembly (3) comprises a rotating frame (301) fixedly mounted on the inner wall of the edge support steel plate and a fixed frame (303), the outer surface of the rotating frame (301) is rotatably sleeved with a pry frame (302), the inner walls on both sides of the fixed frame (303) are provided with vertical rails (304) and a vertical groove (305), and the vertical groove (305) is opened through, and a gear rod (306) is integrally provided on one side of the fixed frame (303); The bottom detection assembly (8) is arranged at the middle and both ends of the guardrail (7), and the bottom detection assembly (8) is composed of a protection box (801), a second pressure detection box (802), a pressure plate (808) and a seat plate (809). The second pressure detection box (802) is movably assembled inside the protection box (801), and a third spring (803) is connected between the second pressure detection box (802) and the inner wall of the protection box (801). The outer wall of the top of the protection box (801) is fixedly welded with pins (804) in an array, and the number of the pins (804) is three. The outer surface of the pin (804) is movably sleeved with a pressure block (805), and the outer surface of the pin (804) is sleeved with a spring four (807) located between the protection box (801) and the pressure block (805), and the outer walls on both sides of the pressure block (805) are integrally provided with protrusions (806); One end of the pressure plate (808) is detachably assembled with the corresponding pressure block (805), and the end of the pressure plate (808) is buckled with the protrusion (806). One end of the seat plate (809) is fixedly installed with a screw (810). The seat plate (809) and the corresponding pressure plate (808) are assembled by screwing a nut (811) and the screw (810). The seat plates (809) on the adjacent sides inside the two bottom detection components (8) are fixedly connected by a steel plate (9), and the steel plate (9) is fixedly installed on the side wall of the guardrail (7). In addition to the seat plates (809) that are integrated with the steel plate (9), the other seat plates (809) are also fixedly installed on the side wall of the guardrail (7).

2. The surrounding rock pressure detection system for loess tunnel prefabricated invert construction according to claim 1 is characterized by: The inner side of the fixed frame (303) is installed with an inner slide (307) which is slidably assembled with the vertical rail (304), and the two side walls of the inner slide (307) are penetrated with a second vertical groove (308), and the inner side of the inner slide (307) is slidably assembled with a ring push plate (309), and the two ends of the ring push plate (309) are fixedly connected with an extension rod (310), and the extension rod (310) penetrates the corresponding second vertical groove (308) and the first vertical groove (305), and one end of the pry frame (302) is connected to the end of the corresponding extension rod (310), and the inner slide (307) is close to the ring push plate ( The edge of the surface of the inner slide (309) is fixedly connected with a guide rod (311) in an array manner, and the guide rod (311) movably passes through the ring push plate (309), and a spring (312) is sleeved on the outer surface of the guide rod (311) and located between the inner slide (307) and the ring push plate (309), and a pressure detection box (313) is movably assembled on the inner side at the center of the inner slide (307), and a circular hole for the pressure detection box (313) to pass through is opened at the center of the inner slide (307), and a spring (314) is connected between the pressure detection box (313) and the surface of the ring push plate (309).

3. The surrounding rock pressure detection system for loess tunnel prefabricated invert construction according to claim 2 is characterized by: The inner slide (307) is away from the surface of the ring push plate (309) and is located at the edge of the circular hole and is fixedly connected to a rotating rod (315) in an array, and the ends of the rotating rods (315) are commonly fixedly connected to a ring seat (316), the outer surface of the ring seat (316) is rotatably sleeved with a ring plate (319), the outer surface of the rotating rod (315) is rotatably sleeved with a retaining flap (317), and the edge of each retaining flap (317) is fixedly provided with a through rod (318), the edge of the ring plate (319) is penetrated by a guide groove (320) for the corresponding through rod (318) to pass through, one side of the edge of the ring plate (319) is provided with partial gear teeth, one side of the edge of the inner slide (307) is rotatably installed with a worm (321) meshing with the partial gear teeth, and both ends of the worm (321) are fixedly assembled with gears (322) meshing with the gear rod (306).

4. The surrounding rock pressure detection system for loess tunnel prefabricated invert construction according to claim 3 is characterized by: A hydraulic cylinder three (4) is fixedly installed inside the support frame (212). The hydraulic cylinder three (4) is connected to the other end of the corresponding skid frame (302) through a connecting arm (5). The connecting arm (5) includes a single arm rod (51), a main arm rod (52), an auxiliary arm rod (53) and a connecting slot rod (54). The single arm rod (51) is arranged on the inner side of the top guard steel plate (205) and is connected to the output end of the corresponding hydraulic cylinder three (4). The middle part and both ends of the single arm rod (51) are connected to the corresponding skid frame (302) through a hanging rod (55). The main arm rod (52) is arranged on the inner side of the bottom guard steel plate (207), and the auxiliary arm rod (53) is arranged on the inner side of the waist guard steel plate (206). The main arm rod (52) and the adjacent auxiliary arm rod (53) are connected in an angle-adjustable manner through a connecting slot rod (54). The main arm rod (52) is connected to the output end of the corresponding hydraulic cylinder three (4).

5. A method for detecting surrounding rock pressure during construction of a loess tunnel prefabricated invert arch, which is used to detect surrounding rock pressure during construction of a loess tunnel prefabricated invert arch according to any one of claims 1 to 4, characterized in that: The specific steps are as follows: Step 1: Monitoring surrounding rock pressure. The surrounding rock to be tested above the invert construction section (101) is pre-cut flat, and a vibrating wire pressure cell is installed between the surrounding rock and the initial concrete support. The installation locations are the arch crown, left and right arch haunches, left and right wall middles, and left and right wall foots. Step 2: monitoring the bottom pressure of the inverted arch. Before the inverted arch is constructed, the guardrail (7) and the steel mesh are installed, and the bottom detection components (8) are installed at the middle bottom and both ends of the guardrail (7). Then, the initial concrete support of the inverted arch is poured and the inverted arch prefabricated body (6) is assembled. Step 3: Secondary lining: secondary lining is performed on the upper part of the tunnel where the invert prefabricated body (6) is installed, and the tunnel foundation is formed; Step 4: Follow-up monitoring of surrounding rock pressure, then move the steel frame support (2) to a position close to the loess tunnel (1) and the invert construction section (101), and install the retractable detection component (3) between the secondary lining support and the steel frame support (2), and the installation positions are respectively the arch crown, left and right arch waists, left and right wall middles, and left and right wall feet; Step 5: Data collection and transmission: Use monitoring equipment to collect the pressure and deformation data of the surrounding rock in real time, and transmit the data to the monitoring center or data processing system.

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