Tunnel goaf composite supporting structure capable of being monitored in real time

Abstract

The invention discloses a tunnel goaf composite supporting structure capable of being monitored in real time, and belongs to the technical field of tunnel supporting, the tunnel goaf composite supporting structure comprises an advanced grouting guide pipe arranged outside a tunnel primary lining and an energy dissipation anchor rod arranged on the tunnel primary lining, the energy dissipation anchor rod comprises an anchoring section, an energy dissipation section and a supporting section, the supporting section is fixedly arranged on the tunnel primary lining, and the supporting section is fixedly arranged on the tunnel primary lining. An energy dissipation section and an anchoring section are sequentially arranged on the deviating side, deviating from the tunnel primary lining, of the supporting section, the anchoring section is a threaded rod, the energy dissipation section is composed of an outer sleeve, a friction inner pipe and a high-strength telescopic spring, the outer sleeve is arranged on the supporting section, and the deviating side, deviating from the supporting section, of the outer sleeve is arranged outside the threaded rod in a sleeving mode; a friction inner pipe for increasing friction resistance between the outer sleeve and the threaded rod is fixedly arranged on the inner wall of the outer sleeve, and a high-strength telescopic spring is arranged in the outer sleeve and located at the bottom of the threaded rod; a displacement sensor is arranged on the threaded rod; and a stress sensor is arranged in the tunnel primary lining. According to the supporting structure, through the design of a multi-stage energy dissipation structure, energy can be reliably consumed, impact can be relieved, the stability of the supporting structure can be effectively kept when the surrounding rock of the tunnel goaf collapses suddenly, the health state of a supporting system can be monitored in real time through a displacement sensor and a stress sensor, and the supporting structure is suitable for popularization and application. And an important guarantee is provided for safe operation of tunnel engineering.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel support, and provides a composite support structure for a tunnel goaf area capable of real-time monitoring. Background Art

[0002] Goaf refers to the hollow space or space formed after the underground mining of mineral resources, usually the underground space caused by the extraction of ore. These hollow spaces or spaces may be located in the underground rock or mineral layer, or they may be caves caused by the decline of groundwater level or surface subsidence. Goaf changes and destroys the natural balance of the earth's surface and lithosphere, and will produce geological disasters such as goaf collapse. Goaf collapse is caused by the mining of ore bodies (layers) and the destruction of overburden. After various ore bodies of different sizes buried underground are mined and hollowed out, the mechanical balance of the overburden on the upper part of the ore body will be broken. Under the action of gravity and stress, cracks and faults are generated, and groundwater takes advantage of the opportunity to enter and leak into the goaf through the cracks, which in turn accelerates the destruction of the overburden, causing the movement of rock layers and the surface, and finally forming a goaf collapse area.

[0003] When carrying out tunnel construction, it is inevitable to encounter bad geological sections in goaf areas. Due to the development of the country, the demand for coal resources is increasing, and there are more and more goaf areas. There are situations where tunnel construction passes through multiple goaf areas. Due to the lack of understanding of the potential dangers of goaf areas in the past, various degrees of problems have occurred during the construction and operation stages, such as damage to the lining structure, cracks and deformation, and limited tunnel contours. At present, there have been a lot of research and development on tunnel support system technology. The existing system cannot monitor in real time and effectively respond to the uneven settlement of the tunnel caused by the collapse of the goaf. The existing initial support structure is mostly equipped with ordinary hollow grouting anchor rods, which can provide insufficient anchoring force, the strength of the anchor rod body cannot be effectively utilized, and the effect of controlling the deformation of the surrounding rock is poor. When the goaf suddenly collapses, it will generate huge impact force. This anchor rod cannot play an energy dissipation role and cannot solve the phenomenon of damage to the tunnel support structure caused by the collapse of the goaf. At present, there are some shortcomings in the traditional initial tunnel support, such as slow construction speed, heavy deadweight, high pressure on the surrounding rock, poor adaptability, etc. Measures should be taken to improve it. Moreover, the traditional support structure cannot obtain the working dynamics of the anchor rods and the initial support in time, which makes it inconvenient for relevant personnel to monitor and perform maintenance in real time.

[0004] Based on the above situation, the present invention provides a composite support structure for tunnel goaf that can be monitored in real time, which is used to solve the problems that the current initial support system cannot cope with the huge impact force generated when the goaf suddenly collapses and cannot monitor the health status of the support system in real time. Summary of the invention

[0005] In view of this, in order to solve the problems existing in the background technology, the present invention proposes a composite support structure for tunnel goaf that can be monitored in real time, so as to solve the problems that the current initial support system cannot cope with the huge impact force generated when the goaf suddenly collapses and cannot monitor the health status of the support system in real time.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The invention provides a composite supporting structure for a tunnel goaf capable of real-time monitoring, comprising an advance grouting conduit arranged outside a primary tunnel lining and an energy dissipation anchor rod arranged on the primary tunnel lining, the energy dissipation anchor rod comprising an anchoring section, an energy dissipation section and a supporting section, the supporting section being fixedly arranged on the primary tunnel lining, and the supporting section being sequentially provided with an energy dissipation section and an anchoring section on a departure side away from the primary tunnel lining, the anchoring section being a threaded rod, the energy dissipation section being composed of an outer sleeve, a friction inner tube and a high-strength telescopic spring, the outer sleeve being arranged on the supporting section, and the departure side away from the supporting section being sleeved outside the threaded rod, a friction inner tube being fixedly arranged on the inner wall of the outer sleeve for increasing the friction resistance between the outer sleeve and the threaded rod, a high-strength telescopic spring being arranged in the outer sleeve and at the bottom of the threaded rod; a displacement sensor being arranged on the threaded rod; and a stress sensor being arranged in the primary tunnel lining. With the above solution, when the surrounding rock of the tunnel goaf suddenly collapses, the energy dissipation anchor can effectively disperse and reduce the instantaneous load on the support structure through internal friction sliding and buffer deformation, ensuring the stability and safety of the structure. At the same time, the energy dissipation anchor design can not only adapt to different types of surrounding rocks, but also adjust the parameters of the energy dissipation section according to actual needs, such as friction coefficient, spring elastic force, etc., to meet different engineering needs. It can also monitor the health status of the entire support system in real time through displacement sensors and stress sensors, providing important guarantees for the safe operation of tunnel engineering.

[0008] Preferably, the energy dissipation section also includes a first energy dissipation plate located below the threaded rod and used to connect the high-strength telescopic spring. The first energy dissipation plate is arranged in the friction inner tube and slides frictionally with it. This design ensures that under the action of load, the first energy dissipation plate can effectively participate in the energy dissipation process, that is, it can cooperate with the high-strength tension spring to effectively absorb part of the kinetic energy and reduce the impact on the anchor rod. This process can slow down the load transfer speed and reduce damage to the overall support structure. The friction resistance of the friction inner tube increases from top to bottom. In this way, through this gradually increasing friction resistance design, the overall energy dissipation process becomes smoother and more efficient. The energy dissipation effect of each component is carried out in an orderly manner, avoiding structural damage caused by excessive instantaneous loads and enhancing the impact resistance of the anchor system.

[0009] Preferably, a multi-layer support ring is arranged on the friction inner tube and between the threaded rod and the first energy dissipation plate. Through the design of the multi-layer support ring, the function of the entire energy dissipation section is enhanced, so that the energy dissipation anchor rod can better absorb and disperse energy when facing sudden loads, and effectively protect the surrounding structure.

[0010] Preferably, the energy dissipation section further includes a retractable bracket and a high-strength laminated spring disposed between the outer sleeve and the support section, and the high-strength laminated spring is located in the retractable bracket. In this way, by introducing the retractable bracket and the high-strength laminated spring, the multi-stage energy dissipation structure constructed greatly enhances the energy dissipation capacity of the energy dissipation anchor rod, so that it can more effectively absorb and disperse energy when facing sudden loads, thereby improving the safety and stability of the overall anchor rod.

[0011] Preferably, the support section is composed of a second energy dissipation plate, a square tray, and a connecting rod. The second energy dissipation plate is arranged on the square tray, and the two are tightened by the connecting rod. A retractable bracket and a high-strength laminated spring are arranged on the second energy dissipation plate. This support section design ensures that the entire energy dissipation anchor is firmly connected to the tunnel support structure through the second energy dissipation plate to form a stable energy dissipation platform.

[0012] The present invention also provides another composite support structure for tunnel goaf that can be monitored in real time, including an advance grouting conduit arranged outside the primary lining of the tunnel and an energy dissipation anchor rod arranged on the primary lining of the tunnel, the energy dissipation anchor rod including an anchoring section, an energy dissipation section and a supporting section, the supporting section is fixed on the primary lining of the tunnel, and the supporting section is sequentially provided with an energy dissipation section and an anchoring section on the side away from the primary lining of the tunnel, wherein the anchoring section is a threaded rod, the energy dissipation section is composed of an outer sleeve, a friction inner tube, a high-strength laminated spring, and a tube cover, the outer sleeve is arranged on the supporting section, and a threaded rod is arranged on the side away from the supporting section, the outer sleeve is axially provided with an expansion joint, the inner wall of the outer sleeve is fixed with a friction inner tube for increasing the friction resistance between it and the tube cover, the high-strength laminated spring is arranged on the tube cover; a displacement sensor is arranged on the tube cover; and a stress sensor is arranged in the primary lining of the tunnel. Similarly, when the surrounding rock of the tunnel goaf suddenly collapses, the energy dissipation anchor rod can effectively disperse and reduce the instantaneous load on the support structure through internal friction sliding and buffering deformation, ensuring the stability and safety of the structure. At the same time, the energy dissipation anchor rod design can not only adapt to different types of surrounding rocks, but also adjust the parameters of the energy dissipation section according to actual needs, such as friction coefficient, spring elastic force, etc., to meet different engineering needs. It can also monitor the health status of the entire support system in real time through displacement sensors and stress sensors, providing important guarantees for the safe operation of tunnel engineering.

[0013] Preferably, the anchoring section also includes a high-strength annular spring arranged under the cylinder cover and in a multi-layer overlapping structure, which can provide better energy absorption and buffering effects, and a horizontal plate with balls is arranged between two adjacent layers of high-strength annular springs, and multiple balls that slide with the inner wall of the outer sleeve are arranged on the edge of at most half of the outer circle of the horizontal plate. The ball design can adapt to the axial and radial deformation of the multi-layer high-strength annular spring during compression, so that the stable support of the horizontal plate is better, which helps to improve the smoothness of movement, so that the spring can better absorb and disperse the load applied to the structure; and the horizontal plate arranged at the bottom of the bottom layer of high-strength annular spring is fixedly installed on the supporting section through a stable bracket. Such a design not only improves the stability of the supporting structure, but also ensures that when subjected to external loads, the high-strength annular spring can effectively play its buffering role and reduce the instantaneous impact on the supporting structure.

[0014] Preferably, the support section is formed by stacking at least two layers of high-strength leaf springs. When the force is transmitted to the high-strength leaf springs, the load can be effectively dispersed to enhance the bearing capacity and energy absorption effect of the support section and ensure the stability of the lining structure. That is, the stacked high-strength leaf springs can disperse the stress in a more uniform manner when subjected to force, reducing the failure risk of a single layer of leaf springs due to local overload. This design can also adapt to different engineering needs and geological conditions by adjusting the number of stacked layers and the parameters of each layer, so that the support section has good adaptability under various working conditions.

[0015] Preferably, the anchoring section also includes an anchoring agent wrapped around the threaded rod, and the anchoring agent is a resin roll anchoring agent. This anchoring agent has excellent bonding properties and fast curing characteristics. The resin roll anchoring agent can effectively fill the gap between the threaded rod and the surrounding rock to form a solid anchoring interface, thereby improving the pull-out resistance and stability of the anchor rod. In addition, a barb is provided on the front end of the threaded rod. The barb can further enhance the stability of the threaded rod of the anchoring section.

[0016] Preferably, the primary lining of the tunnel also includes high-strength prestressed steel plates and lightweight concrete, and the high-strength prestressed steel plates and stress sensors are both arranged in the lightweight concrete; the displacement sensor is a fiber grating displacement sensor.

[0017] The beneficial effects of the present invention are:

[0018] (1) When most existing tunnels pass through goafs, ordinary hollow grouting anchor rods are arranged for initial support. The anchoring force provided is insufficient, the strength of the anchor rod body cannot be effectively utilized, and the effect of controlling the deformation of the surrounding rock is poor. When the goaf suddenly collapses, a huge impact force will be generated, and this anchor rod cannot play an energy dissipation role. This composite support device uses a new type of monitoring and multi-level energy dissipation anchor rod, which can dissipate energy through deformation when the goaf suddenly collapses, ensuring the stability of the support structure, and cooperates with the advance grouting guide tube to reinforce the broken surrounding rock and prevent the damage of the support structure.

[0019] (2) The secondary lining of the tunnel of the present invention is composed of new thin-walled light steel and light concrete, which has many advantages over traditional reinforced concrete. The combination of new thin-walled light steel and light concrete makes the primary lining of the tunnel have high strength characteristics and can withstand greater loads and pressures. Due to its low dead weight, a lot of man-hours and material costs are saved during installation and transportation. In addition, this material combination has good corrosion resistance and can be used stably for a long time in harsh environments, extending its service life. Most importantly, the use of light concrete is also in line with the concept of low-carbon environmental protection, reduces the negative impact on the environment, and meets the requirements of sustainable development.

[0020] (3) This support structure can not only monitor the displacement of energy dissipation anchors and the stress of the tunnel's primary lining in real time, but also respond quickly and carry out necessary processing and maintenance work. Through this advanced monitoring system, potential problems can be discovered in a timely manner and preventive measures can be taken, effectively reducing the risk of economic losses and casualties.

[0021] (4) This support structure can not only effectively prevent and deal with the collapse of the goaf and ensure the stability of the tunnel and surrounding rock, but also has the ability to cope with various sudden loads. For example, during blasting operations or earthquakes, the structure can effectively absorb and disperse the impact force and protect the tunnel from external impacts, thereby ensuring the overall stability and safety of the tunnel. This design not only takes into account the impact of static loads, but also fully considers the impact of dynamic loads, providing comprehensive protection measures for tunnel projects.

[0022] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0024] Figure 1 It is a schematic diagram of the application of the composite support structure of the tunnel goaf area capable of real-time monitoring of the present invention;

[0025] Figure 2 for Figure 1 The structural schematic diagram of the energy dissipation anchor rod in the static state;

[0026] Figure 3 for Figure 1 The schematic diagram of the structure of the energy dissipation anchor in the first stage of deformation and energy dissipation;

[0027] Figure 4 for Figure 1 The schematic diagram of the structure of the energy dissipation anchor in the second stage of deformation and energy dissipation;

[0028] Figure 5 for Figure 1 Schematic diagram of the initial lining structure of the tunnel;

[0029] Figure 6 It is another partial schematic diagram of the application of the composite supporting structure of the tunnel goaf area capable of real-time monitoring of the present invention;

[0030] Figure 7 for Figure 6 Schematic diagram of the structure of the middle energy dissipation anchor rod;

[0031] Figure numerals: 1 is the initial lining of the tunnel, 11 is the high-strength prestressed steel plate, 12 is the lightweight concrete, 13 is the stress sensor; 2 is the energy dissipation anchor rod, 21 is the threaded rod, 22 is the outer sleeve, 23 is the friction inner tube, 24 is the support ring, 25 is the high-strength telescopic spring, 26 is the first energy dissipation plate, 27 is the telescopic bracket, 28 is the high-strength laminated spring, 29 is the second energy dissipation plate, 210 is the square tray, 211 is the connecting rod, 212 is the high-strength leaf spring, 213 is the stabilizing bracket, 214 is the ball, 215 is the cross plate, 216 is the high-strength annular spring, 217 is the cylinder cover, 218 is the telescopic joint, and 219 is the barb; 3 is the advance grouting conduit; 4 is the displacement sensor. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with specific implementation methods. The accompanying drawings are only used for exemplary descriptions and are only schematic diagrams, not actual drawings, and cannot be understood as limiting this patent; in order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the accompanying drawings may be omitted.

[0033] Embodiment 1

[0034] like Figure 1-5As shown, tunnel engineering will inevitably encounter bad geological sections in goaf areas during construction, and due to national development, the demand for coal resources is increasing, and there are more and more goaf areas. There are situations where tunnel construction passes through multiple goaf areas. In order to avoid the huge impact force generated when the goaf area collapses, it will have a series of adverse effects on the tunnel. The present invention mentions a composite support structure for tunnel goaf areas that can be monitored in real time, which is composed of a tunnel primary lining 1, an energy dissipation anchor rod 2, and an advanced grouting conduit 3. Among them, the advance grouting conduit 3 is arranged outside the primary lining 1 of the tunnel, and the energy dissipation anchor rod 2 is arranged on the primary lining 1 of the tunnel. The advance grouting conduit 1 is located outside the primary lining 1 of the tunnel and is arranged in the surrounding rock above or near the face of the tunnel to prevent the surrounding rock and soil from collapsing and improve the stress of the tunnel support structure; the energy dissipation anchor rod 2 is arranged in a matrix along the radial and axial directions of the primary lining 1 of the tunnel, and the primary lining 1 of the tunnel includes a high-strength prestressed steel plate 11, a lightweight concrete 12 and a stress sensor 13. The high-strength prestressed steel plate 11 and the stress sensor 13 are both arranged in the lightweight concrete 12. The stress sensor 13 is used to monitor the tunnel. The stress condition of the primary lining 1 of the tunnel; one end of a single energy dissipation anchor rod 2 is used for fixed installation on the outer side of the primary lining 1 of the tunnel, and the other end is used for embedding in the surrounding rock of the tunnel goaf area, playing a supporting and energy dissipation effect, that is, when the surrounding rock of the tunnel goaf area suddenly collapses, the energy dissipation anchor rod 2 can buffer the large instantaneous load through its internal energy dissipation structure, thereby effectively playing the role of energy dissipation; specifically, the energy dissipation anchor rod 2 includes an anchoring section, an energy dissipation section and a supporting section, the supporting section is fixed on the primary lining 1 of the tunnel, and the supporting section is sequentially provided with an energy dissipation section and an anchoring section on the side away from the primary lining 1 of the tunnel, and the anchoring section adopts a threaded rod 2 1. Since the rod body of the threaded rod 21 adopts a threaded structure, the friction between the rod body and the surrounding rock of the tunnel goaf area is greatly increased, which can provide higher tensile strength and stability than ordinary plane support rods, and also improve the overall firmness of the anchor rod; an anchoring agent is arranged between the threaded rod 21 and the surrounding rock of the tunnel goaf area and wrapped outside the threaded rod 21, and the anchoring agent adopts a resin roll anchoring agent, that is, combined with the application of the resin roll anchoring agent, the overall performance of the anchoring section is significantly improved; and a displacement sensor 4 is arranged on the threaded rod 21 to monitor the working status of the threaded rod 21 in real time to ensure that the operating personnel can perform maintenance in time; the energy dissipation section is composed of an outer sleeve 22, a friction inner tube 23, a high-strength telescopic spring 25, and a first energy dissipation plate 26. The outer sleeve 22 is installed on the supporting section, which provides a stable supporting foundation. The side away from the supporting section is sleeved on the outside of the threaded rod 21. The inner wall of the outer sleeve 22 is fixed with a friction inner tube 23 for increasing the friction resistance between it and the T-shaped end at the lower part of the threaded rod 21. A high-strength telescopic spring 25 is arranged in the outer sleeve 22 and at the bottom of the threaded rod 21. The first energy dissipation plate 26 is located below the threaded rod 21 and is used to connect the high-strength telescopic spring 25. The first energy dissipation plate 26 is also arranged in the friction inner tube 23 and slides frictionally with it.The inner wall surface of the friction inner tube 23 is rough and uneven, and is used as friction energy dissipation in the entire energy dissipation structure, thereby absorbing and dissipating energy, that is, the threaded rod 21 and the first energy dissipation plate 26 both produce friction energy dissipation with the friction inner tube 23, and the high-strength telescopic spring 25 produces a buffering energy dissipation between the threaded rod 21 and the first energy dissipation plate 26, which can provide a buffering effect under sudden loads and further reduce the impact force. In this way, a high-efficiency energy dissipation structure is formed together. When the surrounding rock of the tunnel goaf suddenly collapses, the friction sliding and buffering deformation of the overall structure can be used to cooperate with energy dissipation, effectively disperse and reduce the instantaneous load acting on the support structure, and ensure the stability and safety of the structure. The health status of the support system is also monitored in real time through displacement sensors and stress sensors, which provides an important guarantee for the safe operation of tunnel engineering.

[0035] In this embodiment, the friction resistance of the friction inner tube 23 increases from top to bottom. The friction coefficients of the inner wall surface of the friction inner tube 23 are different. For example, the friction coefficient of the lower part is twice the friction coefficient of the upper part. Different friction coefficient designs can ensure that each component can dissipate energy in an orderly manner, so that each component can play a role in an orderly manner when bearing loads. That is, when the surrounding rock of the tunnel collapses suddenly, the friction energy dissipation between the threaded rod 21 and the friction inner tube 23 begins to play a role first. Since the friction coefficient of the upper part of the friction inner tube 23 is low, the threaded rod 21 can move more flexibly, so that the initial impact force can be quickly consumed; then, when the load continues to act, the high-strength telescopic spring 25 begins to play a buffering role. Due to its elastic characteristics, the spring can absorb part of the kinetic energy and slow down the direct impact of the load on the anchor rod; finally, the friction energy dissipation between the first energy dissipation plate 26 and the friction inner tube 23 begins to play a role, because at this time the friction coefficient of the lower part is high, which can further consume the remaining energy and ensure the stability of the structure. This design not only improves the energy dissipation efficiency of the anchor rod, but also enhances its stability and reliability in various emergencies. The synergy between the various components enables the entire support structure to better cope with complex geological conditions and emergencies.

[0036] In this embodiment, a multi-layer support ring 24 is arranged on the friction inner tube 23 and between the threaded rod 21 and the first energy dissipation plate 26 to form a support structure, and the number and design of the support ring 24 can be adjusted according to specific engineering requirements to meet different impact resistance requirements. In this way, the design structure of the multi-layer support ring 24 can improve the impact resistance of the high-efficiency energy dissipation anchor rod 1 when the surrounding rock of the tunnel goaf suddenly collapses, and play a certain continuous destructive support effect in space and time, that is, the load can be transmitted layer by layer when it acts, reducing the direct impact of the instantaneous load on the anchor rod, thereby improving the impact resistance of the system, and helping the high-strength telescopic spring 25 to cooperate with the friction sliding of the first energy dissipation plate 26 during the buffering deformation process, so as to better assist in supporting the threaded rod 21.

[0037] In this embodiment, the energy dissipation section also includes a retractable bracket 27 and a high-strength laminated spring 28 disposed between the outer sleeve 22 and the support section. The high-strength laminated spring 28 is located in the retractable bracket 27. The design structure of the retractable bracket 27 allows the anchor rod to maintain a certain flexibility under different load conditions, thereby enhancing the adaptability of the overall structure; and the high-strength laminated spring 28 can produce compression deformation under load, absorb and mitigate the impact of instantaneous loads. Through the laminated design, the spring can provide a large deformation amount and efficient energy absorption capacity. The support section is composed of a second energy dissipation plate 29, a square tray 210, and a connecting rod 211. The second energy dissipation plate 29 is disposed on the square tray 210, and the two are tightened by the connecting rod 211. The retractable bracket 27 and the high-strength laminated spring 28 are disposed on the second energy dissipation plate 29. In this way, the compression energy dissipation composed of the retractable bracket 27, the high-strength laminated spring 28 and the second energy dissipation system working platform 29, to form a multi-stage energy dissipation structure, cooperates together to further improve the efficient energy dissipation of the energy dissipation anchor rod.

[0038] The working principle of the energy dissipation anchor rod of the present invention is described below:

[0039] When encountering goaf collapse, first the threaded rod 21 is subjected to stress load to shrink and slide, and the sliding process occurs at the upper end of the friction inner tube 23, which is specifically manifested as friction energy dissipation. At the same time, the high-strength tension spring 25 will be compressed by pressure to perform buffering deformation and energy dissipation; at the same time, since the friction coefficient of the upper end of the friction inner tube 23 is smaller than that of the lower end, during the inward sliding process of the threaded rod 21 relative to the outer sleeve 22, the first energy dissipation plate 26 is kept stationary by the large friction coefficient of the friction inner tube 23; during this period, the threaded rod 21 gradually moves downward while the high-strength tension spring 25 is continuously compressed. When the T-shaped end of the lower part of the threaded rod 21 stops with the first layer of support plate 24, the support plate 24 at this time is not only impact-resistant, but also can be used as a supporting platform, and the first energy dissipation plate 26 connected to the lower part of the high-strength tension spring 25 will be subjected to the tension of the high-strength tension spring 25, and slide downward frictionally relative to the lower part of the friction inner tube 23. This process is friction energy dissipation, that is, the threaded rod 21 and the first energy dissipation plate 26 are connected to the lower part of the high-strength tension spring 25. The energy dissipation plate 26 generates a friction energy dissipation effect with the friction inner tube 23, and the high-strength telescopic spring 25 generates a buffering deformation energy dissipation effect between the threaded rod 21 and the first energy dissipation plate 26; if the downward pressure of the threaded rod 21 continues to increase and the first layer of support plate 24 is broken and the support fails, the threaded rod 21 and the friction inner tube 23 will be pushed to slide frictionally again, and the high-strength tensile spring 25 will be compressed again, and the first energy dissipation plate 26 and the friction inner tube 23 will be pushed to slide frictionally again, and the T-shaped end at the lower part of the threaded rod 21 will be stopped on the second layer of support plate 24 again, so that the first energy dissipation plate 26 is against the inner bottom of the outer sleeve 22; further, the previous friction sliding and buffering deformation energy dissipation residual stress is transferred to the second energy dissipation plate 29 through the telescopic bracket 27 and the high-strength laminated spring 28, and this part is mainly compressed and dissipated by the high-strength laminated spring 28, wherein the telescopic bracket 27 is used to protect the internal structure of the high-strength laminated spring 28 to ensure that the high-strength laminated spring 28 has a normal service environment. In this way, the energy dissipation anchor adopts a multi-level energy dissipation structure, which can dissipate energy through friction sliding, buffer deformation and compression deformation when the surrounding rock in the tunnel goaf area suddenly collapses, and the multi-level energy dissipation structure works together to effectively ensure the stability of the support structure.

[0040] Embodiment 2

[0041] For example Figure 6-7As shown, the present embodiment provides a composite support structure for tunnel goaf that can be monitored in real time, including an advance grouting conduit 3 arranged outside the primary lining 1 of the tunnel, and also including an energy dissipation anchor rod 2 arranged on the primary lining 1 of the tunnel, the energy dissipation anchor rod 2 including an anchoring section, an energy dissipation section and a supporting section, the supporting section is fixed on the primary lining 1 of the tunnel, and the supporting section is sequentially provided with an energy dissipation section and an anchoring section on the away side away from the primary lining 1 of the tunnel, wherein the anchoring section is a threaded rod 21, the rod body of the threaded rod 21 is provided with barbs 219 anchored into the surrounding rock, which can provide higher tensile strength and shear strength than ordinary plane rods, and the barb structure can provide stronger pull-out resistance under large impact force, effectively preventing the sliding and displacement of the anchor rod; the energy dissipation section is composed of an outer sleeve 22, a friction The outer sleeve 22 is provided on the supporting section, and a threaded rod 21 is provided on the side away from the supporting section. A telescopic joint 218 is provided in the axial direction of the outer sleeve 22. A friction inner sleeve 23 for increasing the friction resistance between the outer sleeve 22 and the tube cover 217 is fixed on the inner wall of the outer sleeve 22. The high-strength laminated spring 28 is provided on the tube cover 217. The telescopic joint 218 is located in the middle of the two sides of the outer sleeve 22. When the force is transmitted to the outer sleeve 22, the high-strength laminated spring 28 is compressed and deformed to dissipate energy initially, and the telescopic joint 218 is driven to expand and contract. When the impact force disappears, the high-strength laminated spring 28 can recover its deformation, and the telescopic joint 218 is restored to its original state. The tube cover 217 is provided with a displacement sensor 4; the tunnel primary lining 1 is provided with a stress sensor 13.

[0042] In this embodiment, the anchoring section also includes a high-strength annular spring 216 arranged below the cylinder cover 217 and in a multi-layer overlapping structure. A horizontal plate 215 with balls 214 is arranged between two adjacent layers of high-strength annular springs 216. A plurality of balls 214 that slide and cooperate with the inner wall of the outer sleeve 22 are arranged on the edge of at most half of the outer circle of the horizontal plate 215. The horizontal plate 215 arranged at the bottom of the high-strength annular spring 216 of the bottom layer is fixedly installed on the supporting section through a stabilizing bracket 213. In this way, the horizontal plate 215 can rotate relative to the inner wall of the outer sleeve 22 through the balls 214. When subjected to impact force, the high-strength annular spring 216 can be driven by the horizontal plate 215 to undergo asymmetrical deformation. Through uneven deformation, the high-strength annular spring 216 can better cooperate with the parts in contact with it, reduce unnecessary friction and wear, and thus improve the efficiency and life of the overall system. The high-strength annular spring 216 with uneven deformation can disperse energy more evenly when absorbing energy, reducing the risk of damage caused by energy concentration. This is very beneficial for shock and vibration absorption and can improve the impact resistance of the system. The high-strength annular spring is made of polyurethane (PU), which has strong wear resistance, tensile strength, tear strength and impact resistance. When the anchor rod is subjected to impact force, the high-strength annular spring can undergo asymmetrical deformation to achieve the effect of energy dissipation.

[0043] In this embodiment, the support section is formed by stacking at least two layers of high-strength leaf springs 212. When the huge impact force generated by the collapse of the goaf is dissipated, the force is transmitted to the high-strength leaf spring 212. The high-strength leaf spring 212 is made of high-strength alloy steel and can withstand large loads and stresses without plastic deformation or fracture. The high-strength leaf spring 212 is arranged in an arch shape, and the geometric shape of the arch structure allows it to evenly distribute the force throughout the structure. This means that each part is subjected to a similar stress level, avoiding structural weaknesses or damage caused by stress concentration. The uniform stress distribution allows the arch structure to reduce the amount of material used while maintaining strength, thereby improving the economy of the structure.

[0044] In this embodiment, the primary lining 1 of the tunnel is composed of lightweight concrete 12, high-strength prestressed steel plate 11 and stress sensor 13. Among them, the high-strength prestressed steel plate 11 is made of ultra-high-strength steel S960QL steel, which has good toughness and weldability. On the premise of ensuring strength, thinner plates can be used to reduce weight. The lightweight concrete 12 can be prefabricated with foam concrete, which has light weight and good overall performance. It can also be mixed with industrial solid wastes such as fly ash, slag and active micro powder according to the specific project. The addition of fly ash can improve the impermeability of concrete, the addition of slag can improve the impermeability of concrete, and the addition of active micro powder can improve the strength, toughness and durability of concrete. Compared with traditional concrete support, it is more low-carbon and environmentally friendly, saving both materials and working hours. And foam concrete can effectively buffer the deformation caused by uneven settlement of the tunnel caused by the collapse of the goaf, ensuring that the tunnel can still operate safely and stably in the face of large settlement differences. The stress sensor 13 can monitor the stress condition of the primary lining in real time and set the maximum bearing capacity of the primary lining 1 of the tunnel as a threshold value. When the stress sensor 13 detects that the mechanical stress in the primary lining 1 of the tunnel is greater than its maximum bearing capacity (i.e., exceeds the threshold value), it will trigger the remote alarm system to inform the operating personnel that the stress of the primary lining 1 of the tunnel is abnormal, and take timely measures (such as temporary support, crack reinforcement, etc.) to ensure the stability of the overall structure.

[0045] The operation steps of the embodiment are as follows:

[0046] Use a drilling machine or rock drill to determine the location and depth of the anchor according to the design drawings. Drill holes in the surrounding rock or lining of the tunnel according to the design requirements. The hole diameter is usually 10-20 mm larger than the anchor diameter for subsequent installation.

[0047] Then, according to the actual tunnel project outline, the number of sections and the length of each section of the tunnel's initial lining 1 are determined, and each section of the composite support structure is prefabricated in advance and transported to the site for installation. The installation sequence is to first install the composite support structure on the top of the tunnel, and then install it symmetrically on both sides of the tunnel surrounding rock.

[0048] When the tunnel generates a huge impact force due to the collapse of the goaf, the threaded rod 21 of the energy dissipation anchor 2 is stressed, and the force is transmitted to the energy dissipation section. At this time, the high-strength laminated spring 28 in the outer sleeve 22 is compressed, which will drive the telescopic joints 218 on both sides of the outer sleeve 22 to expand and contract. After the high-strength laminated spring 28 dissipates energy, the remaining force is transmitted to the high-strength annular spring 216 for energy dissipation, that is, when the force after the first-level energy dissipation is transmitted to the high-strength annular spring 216 through the cylinder cover 217, the cylinder cover 217 and the friction inner tube 23 on the inner wall of the outer sleeve 22 undergo friction and sliding energy dissipation. Further, after the high-strength annular spring 216 is stressed, it drives the cross plate 215 to rotate relative to the outer sleeve 22 using the ball 216, and dissipates energy through asymmetric deformation. Through uneven deformation, the high-strength annular spring 216 can better cooperate with the parts in contact with it, reduce unnecessary friction and wear, and thus improve the efficiency and life of the overall system.

[0049] After multiple levels of energy dissipation, the remaining force is transmitted to the high-strength leaf spring 212 through the connecting rod 211. The high-strength leaf spring 212 is an arched structure that can effectively disperse the transmitted pressure and evenly transfer the pressure to every part of the lining, thereby enhancing the stability and durability of the tunnel.

[0050] When the goaf collapses and generates impact force, the energy dissipation anchor rod 2 achieves the energy dissipation effect through structural deformation, thereby ensuring the stability of the tunnel and cooperating with the primary lining 1 of the tunnel to achieve a better support effect.

[0051] When considering the bearing capacity of the primary lining of the tunnel, only the maximum bearing capacity that the high-strength prestressed steel plate and foam concrete can provide is considered. That is, when the stress on the primary lining of the tunnel is greater than the maximum bearing capacity that the primary lining of the tunnel can provide, it means that the primary lining of the tunnel is in a dangerous state at this time and should be taken seriously and maintained in time. The composite stiffness that the primary lining of the tunnel can provide is the sum of the stiffness that the high-strength prestressed steel plate and foam concrete can provide, and the maximum bearing capacity that the primary lining of the tunnel can provide is the sum of the maximum bearing capacity that the high-strength prestressed steel plate and foam concrete can provide.

[0052] Specifically, the support stiffness of foam concrete is calculated by the following formula:

[0053]

[0054] In the formula, E C is the elastic modulus of foam concrete; ν c is the Poisson's ratio of foam concrete; R is the tunnel radius; t c is the thickness of foam concrete.

[0055] The maximum bearing capacity of foam concrete is calculated as follows:

[0056]

[0057] In the formula, σ c is the uniaxial compressive strength of foam concrete.

[0058] Specifically, the support stiffness of the high-strength prestressed steel plate is calculated by the following formula:

[0059]

[0060] In the formula, E g is the equivalent elastic modulus of high-strength prestressed steel plate converted into foam concrete; ν g is the Poisson's ratio of high-strength prestressed steel plate.

[0061] The maximum bearing capacity calculation formula of high-strength prestressed steel plate is as follows:

[0062]

[0063] In the formula, σ s is the equivalent compressive strength of high-strength prestressed steel plate, calculated as follows:

[0064]

[0065] In the formula, A s is the cross-sectional area of ​​high-strength prestressed steel plate; s is the yield stress of high-strength prestressed steel plate.

[0066] The composite stiffness K that the tunnel primary lining can provide is F for:

[0067] K F =K c +K g

[0068] The maximum bearing capacity that the primary lining of the tunnel can provide max for:

[0069] p max =p max，c +p max，g

[0070] The stress sensors are arranged on both sides along the primary lining of the tunnel to monitor the stress of the primary lining of the tunnel. The left-right symmetrical arrangement can ensure that the stress conditions of multiple positions of the new primary lining can be monitored. The stress sensor described in the present invention is a piezoresistive flexible stress sensor, which is made of conductive polymer-based composite materials (CPCs). Conductive polymer-based composite materials (CPCs) are conductive fillers added to ordinary insulating polymer matrices. The present invention uses polyurethane (PU) as a substrate and adds conductive material graphene (GE). Graphene is a two-dimensional material composed of a single layer of carbon atoms and has extremely high electrical conductivity, which enables graphene to provide excellent electronic transmission performance when used as a conductive filler in the sensor, helping to achieve high-sensitivity electrical signal output, and has a large surface area, which helps to increase the contact area with the pressure-sensitive material, thereby enhancing the response speed and sensitivity of the resistance to strain changes, and is a very promising conductive and sensing material. Compared with traditional stress sensors prepared based on metal or semiconductor materials, flexible stress sensors have flexibility, high sensitivity, and a wide range of deformation and pressure testing capabilities.

[0071] The working principle of the piezoresistive flexible stress sensor of the present invention is as follows: when subjected to stress, the piezoresistive material converts the mechanical stress into resistance, and the diffused resistance is connected in the substrate in the form of a bridge. By changing the shape or relative position of the conductive filler to cause the change of resistance, the bridge will produce a corresponding unbalanced output. By applying a constant current or voltage, the bridge outputs an electrical signal proportional to the pressure, thereby realizing the pressure signal output of the sensor. The initial output resistance calculation formula is as follows:

[0072]

[0073] In the formula, R 0 is the resistor; ρ is the resistivity; L, ω, and t are the length, width, and thickness of the resistor, respectively.

[0074] The mechanical stress p applied to the sensor is converted into resistance using the following calculation formula:

[0075]

[0076] In the formula, R 0 is the initial output resistance; E is the elastic modulus of the conductive polymer-based composite material; G F is the strain gain factor.

[0077] Sensitivity is a key parameter for evaluating the sensing performance of pressure sensors. It reflects the sensor's response speed and accuracy to signals. It is defined as the ratio between the output signal and the input signal. The sensitivity S calculation formula is as follows:

[0078]

[0079] Where R is the output resistance when pressure p is applied to the sensor; R 0 is the initial output resistance; The pressure when the output resistance R is equal to the initial resistance R 0 The pressure difference when.

[0080] Specifically, the stress sensor transmits the converted resistance information to the remote monitoring center, and the remote center calculates the maximum bearing capacity P of the tunnel primary lining. max The corresponding resistance value is set as the threshold value. When the stress sensor detects that the mechanical stress in the primary lining of the tunnel is greater than its maximum bearing capacity P max When the stress on the tunnel lining is abnormal (i.e. exceeds the threshold), the remote alarm system will be triggered to inform the operating personnel that the initial lining stress in the tunnel is abnormal, and timely measures (such as temporary support, crack reinforcement, etc.) will be taken to ensure the overall stability of the structure.

[0081] The displacement sensor 4 is a fiber grating displacement sensor. Due to its advantages of light weight, small size, corrosion resistance, high sensitivity, and fast response speed, it can be used to measure the displacement of the threaded rod 21 in the energy dissipation anchor and monitor the working status and health of the anchor. By manufacturing a grating structure with periodic refractive index changes in the optical fiber and utilizing the interaction between the incident light signal and the grating, when the optical fiber is displaced or strained, it causes the light signal to be scattered or reflected on the grating. This change will cause the intensity of the returned light signal to change. By measuring the intensity change of the reflected or scattered light signal, the sensor can accurately measure the tiny displacement or strain of the optical fiber and realize displacement monitoring and measurement. When the ambient temperature, pressure or strain changes, the central wavelength of the reflected light will change. The calculation formula is as follows:

[0082] λ B =2η eff ·Λ

[0083] In the formula, λ B is the central wavelength; η eff is the effective refractive index of the fiber propagation mode; Λ is the grating period.

[0084] Among them, the central wavelength offset Δλ B The relationship between the temperature change ΔT of the environment and the axial strain Δε produced by the grating is as follows:

[0085]

[0086] Where P e is the elastic-optical coefficient of the optical fiber, at room temperature, P e ≈0.22; α f is the thermal expansion coefficient of the optical fiber; ξ is the thermo-optical constant of the optical fiber.

[0087] The central wavelength can be offset by Δλ B Calculate the external displacement L, the calculation formula is as follows:

[0088]

[0089] Where, L is the external displacement; a, b, h are the length, width and thickness of the substrate respectively; E is the elastic modulus of the substrate; K 1 is the spring stiffness coefficient; the other parameters have the same meaning as above.

[0090] For example, the displacement sensor 5 is installed at the position of the threaded rod 21 or the barrel cover 217. When the energy dissipation anchor rod 2 is in the deformation and energy dissipation stage, it is used to monitor the movement distance of the threaded rod 21 or the barrel cover 217 along the outer sleeve 22, and transmit the data to the remote monitoring center. 5 cm is set as the threshold value. When the external displacement (i.e., relative to the displacement of the outer sleeve) reaching 5 cm is detected, the remote alarm system will be triggered to inform the operating personnel that the anchor rod here is working abnormally and the tunnel is subjected to impact loads, so that maintenance can be carried out in time to ensure the stability of the overall structure.

[0091] The composite support structure composed of the multi-stage energy dissipation anchor rods and the primary tunnel lining of the present invention can ensure the stability of the tunnel when there are a large number of goafs around the tunnel and when encountering a huge impact force caused by the collapse of the goafs.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A composite support structure for tunnel goaf that can be monitored in real time, comprising an advanced grouting conduit (3) arranged outside the primary lining (1) of the tunnel, characterized in that: The invention also comprises an energy dissipation anchor rod (2) arranged on the primary tunnel lining (1), wherein the energy dissipation anchor rod (2) comprises an anchoring section, an energy dissipation section and a supporting section, wherein the supporting section is fixedly arranged on the primary tunnel lining (1), and the energy dissipation section and the anchoring section are arranged in sequence on the side away from the primary tunnel lining (1), wherein the anchoring section is a threaded rod (21), and the energy dissipation section is composed of an outer sleeve (22), a friction inner tube (23), and a high-strength telescopic spring (25), wherein the outer sleeve (22 ) is arranged on the supporting section, and its side away from the supporting section is sleeved on the outside of the threaded rod (21); the inner wall of the outer sleeve (22) is fixedly provided with the friction inner tube (23) for increasing the friction resistance between it and the threaded rod (21); the high-strength telescopic spring (25) is arranged inside the outer sleeve (22) and at the bottom of the threaded rod (21); a displacement sensor (4) is arranged on the threaded rod (21); and a stress sensor (13) is arranged in the primary lining (1) of the tunnel.

2. The composite support structure for tunnel goaf that can be monitored in real time according to claim 1 is characterized in that: The energy dissipation section also includes a first energy dissipation plate (26) located below the threaded rod (21) and used to connect the high-strength telescopic spring (25). The first energy dissipation plate (26) is arranged in the friction inner tube (23) and slides frictionally therewith. The friction resistance of the friction inner tube (23) increases gradually from top to bottom.

3. The composite support structure for tunnel goaf that can be monitored in real time according to claim 2 is characterized in that: A plurality of supporting rings (24) are arranged on the friction inner tube (23) and between the threaded rod (21) and the first energy dissipation plate (26).

4. The composite support structure for tunnel goaf that can be monitored in real time according to claim 2 is characterized in that: The energy dissipation section further comprises a telescopic bracket (27) and a high-strength laminated spring (28) arranged between the outer sleeve (22) and the supporting section, wherein the high-strength laminated spring (28) is located inside the telescopic bracket (27).

5. The composite supporting structure for tunnel goaf that can be monitored in real time according to claim 4 is characterized in that: The supporting section is composed of a second energy dissipation plate (29), a square tray (210), and a connecting rod (211); the second energy dissipation plate (29) is arranged on the square tray (210), and the two are tightened by the connecting rod (211); the retractable bracket (27) and the high-strength laminated spring (28) are arranged on the second energy dissipation plate (29).

6. A composite support structure for tunnel goaf that can be monitored in real time, comprising an advanced grouting conduit (3) arranged outside the primary lining (1) of the tunnel, characterized in that: The invention also comprises an energy dissipation anchor rod (2) arranged on the primary tunnel lining (1), wherein the energy dissipation anchor rod (2) comprises an anchoring section, an energy dissipation section and a supporting section, wherein the supporting section is fixedly arranged on the primary tunnel lining (1), and the energy dissipation section and the anchoring section are arranged in sequence on the side away from the primary tunnel lining (1), wherein the anchoring section is a threaded rod (21), and the energy dissipation section is composed of an outer sleeve (22), a friction inner tube (23), a high-strength laminated spring (28), and a sleeve cover (217), wherein the outer sleeve (22) The threaded rod (21) is arranged on the supporting section, and the side away from the supporting section is provided with the threaded rod (21). The outer sleeve (22) is provided with a telescopic joint (218) in the axial direction. The inner wall of the outer sleeve (22) is fixedly provided with the friction inner tube (23) for increasing the friction resistance between the outer sleeve and the cylinder cover (217). The high-strength laminated spring (28) is arranged on the cylinder cover (217); the cylinder cover (217) is provided with a displacement sensor (4); and the primary lining (1) of the tunnel is provided with a stress sensor (13).

7. The composite supporting structure for tunnel goaf that can be monitored in real time according to claim 6 is characterized in that: The anchoring section also includes a high-strength annular spring (216) arranged below the cylinder cover (217) and in a multi-layer overlapping structure, a transverse plate (215) with balls (214) is arranged between two adjacent layers of high-strength annular springs (216), and a plurality of the balls (214) that slide with the inner wall of the outer sleeve (22) are arranged along at most half of the outer circle of the transverse plate (215), and the transverse plate (215) arranged at the bottom of the bottom layer of high-strength annular springs (216) is fixedly installed on the supporting section through a stabilizing bracket (213).

8. The composite supporting structure for tunnel goaf that can be monitored in real time according to claim 7 is characterized in that: The support section is formed by stacking at least two layers of high-strength leaf springs (212).

9. The composite support structure for tunnel goaf capable of real-time monitoring according to any one of claims 1 to 8, characterized in that: The anchoring section also includes an anchoring agent wrapped around the outside of the threaded rod (21), wherein the anchoring agent is a resin roll anchoring agent, and a barb (219) is provided on the front end of the threaded rod (21).

10. The composite supporting structure for tunnel goaf capable of real-time monitoring according to claim 9, characterized in that: The primary tunnel lining (1) also includes a high-strength prestressed steel plate (11) and lightweight concrete (12); the high-strength prestressed steel plate (11) and the stress sensor (13) are both arranged in the lightweight concrete (12); and the displacement sensor (5) is a fiber grating displacement sensor.

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