Full-anchoring anchor rod structure for supporting mine laneway

Abstract

The invention discloses a full-anchoring anchor rod structure for mine roadway supporting, belongs to the technical field of roadway supporting, and aims to solve the problems that an anchor rod cannot be limited after being inserted into an anchor hole and is easy to move, and the stability of anchor rod supporting is influenced. Under the limiting action of a sliding groove, when the rotating pipe rotates, a fixing rod can be pushed to slide in the sliding groove under the action of a first hinge column, a second hinge column and a hinge rod, and the fixing rod slides towards the outer end of the sliding groove by controlling the rotating direction of the rotating pipe; at the moment, the three sets of fixing rods extrude the inner side wall of the anchor hole, the anchor rod can be stably fixed to the middle of the anchor hole, the anchor rod does not shift when grouting is conducted on the anchor rod, the stability of the anchor rod during grouting is improved, and the supporting quality of the anchor rod can be improved; meanwhile, the contact area between the anchor rod and the anchor hole can be increased through the fixing rod after follow-up grouting is completed, and the stability of the anchor rod for supporting the soft rock roadway is further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel support, and in particular relates to a fully anchored anchor rod structure for mine tunnel support. Background Art

[0002] Anchor bolts are a common form of support in coal mine tunnels. While they offer advantages such as quick installation and timely load-bearing, they also present numerous challenges. In recent years, full-length anchoring technology has gradually developed and gained widespread application in coal mines and tunnels, achieving significant results, particularly in weak and fractured surrounding rock.

[0003] After the existing anchor rods are inserted into the anchor holes of the tunnel, most of them cannot limit the anchor rods. During the grouting process, the anchor rods are easy to move, which in turn affects the stability of the anchor rod support. For this reason, we propose a fully anchored anchor rod structure for mine tunnel support. Summary of the Invention

[0004] The object of the present invention is to provide a fully anchored anchor rod structure for mine tunnel support, so as to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned object, the present invention provides the following technical solution: a fully anchored anchor rod structure for mine tunnel support, comprising an anchor rod, a connecting tube sleeved on the outer surface of the anchor rod, a rotating tube rotatably connected to the interior of the connecting tube, a plurality of grooves provided on the outer surface of the rotating tube, a fixed rod slidably connected to the interior of the groove, a sliding groove provided through the outer surface of the connecting tube, and the fixed rod slidably connected to the sliding groove, a plurality of hinge mechanisms provided at equal angular intervals in each group of grooves, and the plurality of hinge mechanisms are used to convert the rotational motion of the rotating tube into a linear displacement of the fixed rod;

[0006] When the rotating tube rotates, the fixing rod is driven to move radially in the sliding groove through the hinge mechanism until the inner wall of the anchor hole is evenly squeezed.

[0007] In the above implementation process, the anchor rod carrying the connecting tube and the rotating tube is placed into the drilled anchor hole, and then the rotating tube is rotated in the connecting tube. Since the fixed rod is slidably connected to the sliding groove, under the limiting action of the sliding groove, when the rotating tube rotates, the fixed rod is pushed to slide in the sliding groove under the action of the hinge mechanism, and by controlling the rotation direction of the rotating tube, the fixed rod slides toward the outer end of the sliding groove. At this time, the three groups of fixed rods are squeezed toward the inner wall of the anchor hole. At this time, the anchor rod can be stably fixed in the middle of the anchor hole, and the extrusion force is evenly transmitted, thereby avoiding local stress concentration in the anchor hole and improving the stability of the anchor rod during grouting.

[0008] In a specific embodiment, a socket is provided inside the top of the rotating tube through the slot, steel bars are inserted into the socket, and the steel bars are spaced apart from the hinge mechanism. The steel bars are used to strengthen the multi-directional alternating stress that the rotating tube can withstand under dynamic load conditions.

[0009] In the above implementation process, the addition of steel bars can significantly improve the torsional rigidity of the rotating tube, preventing twisting deformation under high torque loads, while also reducing local stress concentration and avoiding cracking of the rotating tube wall.

[0010] In a specific embodiment, the anchor rod is a hollow structure, and a protective sleeve is fixed inside the cavity of the anchor rod through a flexible bracket, and the protective sleeve is a detachable structure. A plurality of fiber optic Bragg grating sensors are arranged inside the protective sleeve, and the fiber optic Bragg grating sensor is used to reflect the axial strain, lateral shear force and torque of the anchor rod under dynamic load conditions in real time. A storage groove is provided on the outer surface of one side of the fixed rod, and a strain gauge is pasted inside the storage groove, and the strain gauge is used to monitor the development of cracks in the surrounding rock of the soft rock tunnel under dynamic load conditions and static load conditions. The strain gauge is electrically connected to the fiber optic Bragg grating sensor, and a sealing plate is embedded in the storage groove, and the sealing plate is used to isolate the strain gauge from humid air, water vapor and corrosive gas on the surrounding rock of the tunnel.

[0011] In the above implementation process, the protective sleeve and the inner wall of the anchor rod are fixed by a flexible bracket to prevent the sleeve from being deformed by the grouting pressure. At the same time, the design of the flexible bracket allows the anchor rod to deform slightly when subjected to force, while maintaining the stability of the optical fiber path. Before use, the fiber optic Bragg grating sensor is installed from the detachable end of the protective sleeve. The multiple redundant designs enable data to be obtained through the remaining fiber optic Bragg grating sensors even when a single point is damaged, and the failed node is compensated by an algorithm. The layout of the fiber optic Bragg grating sensor is mainly to obtain the stress changes of the anchor rod, thereby identifying the risk of anchor rod failure. At the same time, after the anchor rod is fixed, the fixing rod can be fitted with the inner wall of the anchor hole under the action of the hinge mechanism, so that the strain gauge can detect the crack changes in the surrounding rock in the anchor hole, and cooperate with the fiber optic Bragg grating sensor to obtain the stress changes of the anchor rod, thereby obtaining the overall support condition of the tunnel and avoiding the phenomenon of surrounding rock collapse. The setting of the sealing plate can reduce the impact of environmental factors on the performance and measurement accuracy of the strain gauge, thereby improving the service life of the strain gauge.

[0012] In a specific embodiment, an anchor plate is sleeved on the outer surface of one end of the connecting tube close to the anchor rod opening, a worm gear is sleeved on the outer surface of the rotating tube, and the worm gear is located above the anchor plate, and symmetrically arranged slots are provided on the top of the anchor plate, and the interiors of the two groups of the slots are engaged and connected with a socket, and the surfaces of the two groups of sockets close to each other are rotatably connected with a worm, and the worm is meshed with the worm gear, and a rotating crank is installed on the outer wall of one side of one group of the sockets, and the rotating crank is used to drive the worm to rotate.

[0013] In the above implementation process, when the crank handle is rotated, the worm gear can be driven to rotate, and when the worm gear rotates, the rotating tube can be driven to rotate. Due to the connection method between the worm gear and the worm, that is, the worm can drive the worm gear to rotate, but the worm gear cannot drive the worm to rotate, there is no need to worry about the rotating tube being reversed. After the anchor rod grouting is completed and fixed, the holder can be pulled out of the slot for reuse to improve the utilization efficiency of the material.

[0014] In a specific embodiment, a silica gel damping material is filled between the fiber grating sensor and the protective sleeve, and the silica gel damping material is used to buffer grouting vibration.

[0015] In the above implementation process, silicone damping material is filled between the fiber Bragg grating sensor and the protective sleeve to buffer the grouting vibration, reduce the initial dynamic impact, and prevent the fiber Bragg grating sensor from being affected by the turbulent flow of the slurry.

[0016] In a specific embodiment, the outer surfaces of the anchor rod, the connecting pipe and the rotating pipe are all penetrated with evenly arranged slurry holes, and the slurry holes are designed to be gradually expanded to reduce the turbulence intensity of the slurry sprayed during grouting.

[0017] In the above implementation process, the slurry outlet hole is small inside and large outside, which is used to reduce the turbulence intensity when the slurry is ejected and reduce the disturbance to the internal structure and surrounding rock.

[0018] In a specific embodiment, the articulated mechanism is set into three groups, and the articulated mechanism includes a first articulated column, a articulated rod and a second articulated column. The upper surface of the fixed rod is provided with a first articulated column, the top wall of the groove is provided with a second articulated column, and a articulated rod is provided between the first articulated column and the second articulated column.

[0019] In the above implementation process, through the linkage of the first hinge column, the second hinge column and the hinge rod, the rotational motion of the rotating tube is converted into the linear displacement of the fixed rod, so that the fixed rod moves radially in the sliding groove on the connecting tube, evenly squeezing the inner wall of the anchor hole to achieve multi-point synchronous limiting.

[0020] In a specific embodiment, the fiber grating sensor also monitors the stress and strain data of the anchor rod during grouting based on a machine learning algorithm.

[0021] During the above implementation process, the anchor rod will produce instantaneous stress mutations due to uneven slurry flow, surrounding rock deformation or external dynamic loads during the grouting process. The millisecond sampling frequency of the fiber grating sensor combined with the machine learning algorithm can identify abnormal signals in real time and provide early warning of the risk of anchor rod deviation or fracture. At the same time, by real-time monitoring of the anchor rod axial strain distribution, feedback is given to the grouting system to dynamically adjust the grouting pressure and flow rate to avoid secondary damage to the surrounding rock caused by excessive grouting pressure.

[0022] In a specific implementation scheme, the steel bars are formed into a skeleton-grid structure by arranging main bars axially along the inner surface of the rotating tube and circumferentially winding stirrups, wherein the axial main bars are 4 to 6 main bars equidistantly distributed along the axial direction of the rotating tube, with a diameter of 8 to 12 mm, welded or tied to the inner wall, and the circumferential stirrups are in the form of spiral winding or independent hoop, with a diameter of 6 to 8 mm, and the spacing between the bundles is 1 / 5 to 1 / 3 of the diameter of the rotating tube.

[0023] In the above implementation process, the steel bars arranged axially along the inner surface of the rotating tube are mainly used to improve the tensile strength and compressive stability of the structure, and avoid axial deformation or fracture when transmitting torque or bearing longitudinal loads. By adding steel bars to the rotating tube and designing a skeleton-grid structure, the torsional strength, fatigue resistance and environmental adaptability of the rotating tube are improved, which is used to solve the problem that traditional metal tubes are easily deformed and fractured under dynamic load conditions in mines.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a method for fixing the anchor rod in the anchor hole by inserting the anchor rod with the connecting tube and the rotating tube, and then rotating the tube in the connecting tube. Since the fixing rod is slidably connected with the sliding groove, under the limiting action of the sliding groove, when the rotating tube rotates, the fixing rod is pushed to slide in the sliding groove under the action of the hinge mechanism, and by controlling the rotation direction of the rotating tube, the fixing rod is made to slide toward the outer end of the sliding groove until the fixing rod is able to fit the inner wall of the anchor hole. At this time, the three sets of fixing rods are squeezed toward the inner wall of the anchor hole. At this time, the anchor rod can be stably fixed in the middle of the anchor hole, reducing the probability of anchor rod deviation during grouting. It can not only improve the stability of the anchor rod during grouting, but also improve the supporting quality of the anchor rod and reduce the probability of collapse of weak and broken surrounding rock. At the same time, under the action of the fixing rod, the contact area between the anchor rod and the anchor hole can be increased after subsequent grouting is completed, thereby further improving the stability of the anchor rod in supporting the tunnel.

[0026] 2. The present invention uses anchor rods as an active support means, which can apply prestress to the surrounding rock in time and limit the initial deformation of the surrounding rock. The subsequent grouting operation has the effect of sealing the surface of the surrounding rock, which can prevent the surrounding rock from being exposed and causing strength reduction due to factors such as weathering and deliquescence. At the same time, by adding steel bars in the rotating tube, not only the torsional stiffness of the rotating tube can be improved, but also the protection effect of the anchor rod can be improved, and the risk of anchor rod breakage due to lateral tension or longitudinal shear force under dynamic load conditions can be reduced, thereby improving the overall stability of the weak and broken surrounding rock. Moreover, through the reasonable design of the steel bar layout, the strength can be increased without significantly increasing the weight, thereby reducing material costs.

[0027] 3. The present invention obtains the stress changes of anchor rods, support conditions and crack development conditions of soft rock tunnels through the combination of fiber optic Bragg grating sensors and strain gauges. The fiber optic Bragg grating sensors monitor the stress and strain distribution of anchor rods under dynamic load conditions in real time at a millisecond frequency, and can also capture micro-strain fluctuations during the grouting process. After the anchor rods are fixed, the strain gauges can monitor the crack changes in the anchor hole through the sealing plate. When the strain gauges detect large fluctuations, the stress changes of the anchor rods are detected by the fiber optic Bragg grating sensor, and the risk of anchor rod failure is identified based on the machine learning algorithm. The health status of the soft rock tunnel is monitored, and whether there is unstable support in the soft rock tunnel and whether there is a risk of collapse of the weak and broken surrounding rock can be analyzed, which can reduce the roof fall accident rate to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0029] Figure 2 It is a schematic diagram of the cross-sectional three-dimensional structure of the present invention;

[0030] Figure 3 Schematic diagram of the three-dimensional structure of the rotating tube of the present invention;

[0031] Figure 4 It is a schematic diagram of the assembly structure of the hinge mechanism and the fixing rod of the present invention;

[0032] Figure 5 Schematic diagram of the assembly structure of the anchor rod and the protective sleeve of the present invention;

[0033] Figure 6 It is a schematic diagram of a cross-sectional three-dimensional structure of the assembly of the rotating tube and the skeleton-grid structure steel bars of the present invention;

[0034] Figure 7 A top view of the anchor disc and worm gear of the present invention;

[0035] Figure 8 It is a schematic diagram of the three-dimensional structure of the anchor plate and the slot.

[0036] In the figure: 1. Anchor rod; 2. Connecting pipe; 3. Rotating pipe; 4. Cutting groove; 5. Fixing rod; 6. First hinged column; 7. Hinge rod; 8. Second hinged column; 9. Rebar; 10. Protective sleeve; 11. Fiber Bragg grating sensor; 12. Storage slot; 13. Strain gauge; 14. Sealing plate; 15. Anchor disc; 16. Worm gear; 17. Slot; 18. Holder; 19. Worm; 20. Rotating crank; 21. Slurry outlet. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] See also Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 7 and Figure 8 The present invention provides a fully anchored anchor structure for mine tunnel support, including an anchor rod 1, characterized in that a connecting tube 2 is sleeved on the outer surface of the anchor rod 1, a rotating tube 3 is rotatably connected inside the connecting tube 2, a plurality of groups of grooves 4 are provided on the outer surface of the rotating tube 3, a fixed rod 5 is slidably connected inside the groove 4, a sliding groove is provided through the outer surface of the connecting tube 2, and the fixed rod 5 is slidably connected to the sliding groove, a plurality of groups of hinge mechanisms are provided in each group of grooves 4 at equal angular intervals, and the plurality of hinge mechanisms are used to convert the rotational motion of the rotating tube 3 into the linear displacement of the fixed rod 5, when the rotating tube 3 rotates, the fixed rod 5 is driven by the hinge mechanism to move radially in the sliding groove until the inner wall of the anchor hole is evenly squeezed, and the hinge mechanism is provided in three groups, which include a first hinge column 6, The hinged rod 7 and the second hinged column 8, the upper surface of the fixed rod 5 is provided with a first hinged column 6, the top wall of the groove 4 is provided with a second hinged column 8, and a hinged rod 7 is provided between the first hinged column 6 and the second hinged column 8. The outer surface of the connecting tube 2 close to the opening of the anchor rod 1 is provided with an anchor plate 15, and the outer surface of the rotating tube 3 is provided with a worm gear 16, and the worm gear 16 is located above the anchor plate 15. The top of the anchor plate 15 is provided with symmetrically arranged card grooves 17, and the interior of the two groups of card grooves 17 are both engaged and connected with a card seat 18. The surfaces of the two groups of card seats 18 close to each other are rotatably connected with a worm 19, and the worm 19 is meshed with the worm wheel 16. A rotating crank 20 is installed on the outer wall of one side of one group of card seats 18, and the rotating crank 20 is used to drive the worm 19 to rotate.

[0039] Furthermore, before use, the holder 18 is first inserted into the slot 17 for fixation, and the worm 19 is meshed with the worm gear 16. Then, the anchor rod 1 is placed into the pre-drilled anchor hole with the connecting tube 2 and the rotating tube 3. At this time, the rotating crank 20 is rotated. When the crank 20 is rotated, the worm gear 16 can be driven to rotate by the worm 19. When the worm gear 16 rotates, the rotating tube 3 can be driven to rotate. Due to the connection mode between the worm gear 16 and the worm 19, that is, the worm 19 can drive the worm gear 16 to rotate, but the worm gear 16 cannot drive the worm 19 to rotate, there is no need to worry about the rotating tube 3 reversing. After the anchor rod 1 is grouting completed and fixed, the holder 18 can be pulled out from the slot 17 for reuse.

[0040] In the process of the rotating tube 3 being driven to rotate in the connecting tube 2 by the worm gear 16, since the fixing rod 5 is slidably connected with the sliding groove on the connecting tube 2, under the limiting action of the sliding groove, when the rotating tube 3 rotates, the fixing rod 5 can slide toward the outer end of the sliding groove under the action of the first hinge column 6, the second hinge column 8 and the hinge rod 7. At this time, the three groups of fixing rods 5 can all squeeze the inner wall of the anchor hole, which can not only stably fix the anchor rod 1 in the middle of the anchor hole, but also reduce the probability of the anchor rod 1 offset during grouting, improve the stability of grouting, and thus improve the quality of support. At the same time, under the action of the fixing rod 5, the contact area between the anchor rod 1 and the anchor hole can be increased after the subsequent grouting is completed, further improving the stability of the anchor rod 1 support, which is beneficial to improving the support effect of soft rock tunnels to a certain extent.

[0041] See also Figure 3 and Figure 6 The present invention provides a fully anchored anchor rod structure for mine tunnel support, wherein the top of the rotating tube 3 is provided with an insertion hole through the inside of the cut groove 4, and the inside of the insertion hole is inserted with a steel bar 9, and the steel bar 9 is spaced apart from the hinge mechanism. The steel bar 9 is used to strengthen the multi-directional alternating stress borne by the rotating tube 3 under dynamic load conditions. The steel bar 9 is formed into a skeleton-grid structure by arranging main bars axially along the inner surface of the rotating tube 3 and winding stirrups circumferentially, wherein the axial main bars are 4 to 6 main bars equidistantly distributed along the axial direction of the rotating tube 3, with a diameter of 8 to 12 mm, and are welded or tied to the inner wall, and the circumferential stirrups are spirally wound or in the form of independent hoop, with a diameter of 6 to 8 mm, and the spacing between the bundled bars is 1 / 5 to 1 / 3 of the diameter of the rotating tube 3.

[0042] Furthermore, directly opening a socket on the rotating tube 3 and inserting the steel bar 9 can increase the torsional strength of the rotating tube 3, reduce local stress concentration, and avoid cracking of the inner wall of the rotating tube 3. In actual use, the steel bar 9 can also be used to construct a skeleton-network structure in the rotating tube 3 for the weak and broken surrounding rocks in the tunnel. When laying, for example, the rotating tube 3 with a diameter of 100 mm, the spacing between the stirrups is 20 to 30 mm. The main reinforcement arranged axially along the inner surface of the rotating tube 3 is mainly used to improve the tensile strength and compressive stability of the structure, and avoid axial deformation or fracture when transmitting torque or bearing longitudinal loads. The circumferentially wound stirrups limit radial displacement and enhance The torsional stiffness and shear resistance of the rotating tube 3 prevent cracking or local buckling of the tube wall under high torque or lateral impact. At the same time, the skeleton-grid structure forms a uniformly distributed force transmission network through the cross-connection of the main reinforcement and the stirrups, which disperses external loads such as the torque of the worm drive and the lateral force of the surrounding rock squeezing to the entire structure, reducing stress concentration. The circumferential stirrups limit the radial expansion of the tube wall through the hoop effect, and the axial main reinforcement resists longitudinal shear, together forming a torsional closed loop. Under frequent dynamic loads, the skeleton-grid structure can reduce the occurrence of local fatigue cracks by dispersing alternating stress, thereby improving the protection of the anchor rod 1 and increasing the service life of the anchor rod 1.

[0043] See also Figure 1 、 Figure 4 and Figure 5 The present invention provides a fully anchored anchor structure for mine tunnel support. The anchor 1 is a hollow structure. A protective sleeve 10 is fixed inside the cavity of the anchor 1 through a flexible bracket. The protective sleeve 10 is a detachable structure. A plurality of fiber grating sensors 11 are arranged inside the protective sleeve 10. The fiber grating sensors 11 are used to reflect the axial strain, lateral shear force and torque of the anchor 1 under dynamic load conditions in real time. A storage groove 12 is provided on the outer surface of one side of the fixing rod 5. A strain gauge 13 is pasted inside the storage groove 12, and the strain gauge 13 is used to monitor the The development of cracks in the surrounding rock of the soft rock tunnel under dynamic and static load conditions, the strain gauge 13 is electrically connected to the fiber optic Bragg grating sensor 11, and a sealing plate 14 is installed inside the storage groove 12, and the sealing plate 14 is used to isolate the strain gauge 13 from the humid air, water vapor and corrosive gas on the surrounding rock of the tunnel. Silicone damping material is filled between the fiber optic Bragg grating sensor 11 and the protective sleeve 10, and the silicone damping material is used to buffer grouting vibration. The fiber optic Bragg grating sensor 11 also monitors the stress and strain data of the anchor rod 1 during grouting based on the machine learning algorithm.

[0044] Furthermore, a protective sleeve 10 is fixed inside the hollow anchor 1 by a flexible bracket, and 4 to 6 fiber grating sensors 11 are arranged axially at the detachable end of the protective sleeve 10, with a spacing of 50 cm, covering the entire length of the anchor 1. Each optical fiber is arranged with 2 to 3 redundant grating points. When a single point is damaged, the data is compensated by an interpolation algorithm to ensure monitoring continuity. A silicone damping material is filled between the fiber grating sensor 11 and the protective sleeve 10, and the outer layer is coated with a polyurethane buffer layer with a thickness of 1 mm to avoid grouting impact, reduce interference and damage to the fiber grating sensor, and ensure the accuracy and reliability of the monitoring data.

[0045] After the anchor rod 1 is fixed in the anchor hole, the strain gauge 13 in the storage groove 12 on the fixing rod 5 can monitor the development and change of cracks in the surrounding rock on the inner wall of the anchor hole in real time through the sealing plate 14. When the surrounding rock is deformed or cracks are generated and expanded, it will cause the rock mass at the location of the strain gauge 13 to undergo slight tensile or compressive deformation, resulting in a change in the resistance value of the strain gauge 13, thereby being able to infer the deformation of the surrounding rock and whether cracks are generated and expanded. When the strain gauge 13 detects cracks or severe deformation of the surrounding rock, the stress change of the anchor rod 1 is obtained by the fiber optic Bragg grating sensor 11, and the collected data is sorted and analyzed by the downhole edge server to draw a curve of strain change over time or with the progress of tunnel excavation. By observing the change trend, slope and mutation of the curve, it is judged whether cracks have appeared in the surrounding rock and the development trend of the cracks. For example, a sudden increase in the strain value and an accelerated rate of change may indicate that new cracks have appeared in the surrounding rock or that existing cracks are expanding.

[0046] The fiber Bragg grating sensor 11 can also obtain real-time stress and strain data of the anchor rod 1 during grouting and under dynamic load conditions, and transmit the collected data to the downhole edge server. The edge computing device performs filtering and normalization processing, extracts 20-dimensional features such as time domain features such as mean, variance, frequency domain features, and wavelet packet energy spectrum, and inputs them into the LSTM neural network for training. The training data set contains 100,000 samples of 10 working conditions such as normal grouting, dynamic load impact, and surrounding rock deformation. The accuracy rate is greater than 90%, and the risk level is output in real time. The risk levels include low risk, medium risk, high risk, and critical failure.

[0047] Low-risk judgment conditions: the slope of the strain curve is gentle, the rate of change is less than 0.01% / h, the crack length is less than 5mm, and there is no expansion trend. At the same time, the stress fluctuation range of anchor rod 1 is within the safety threshold. Countermeasures: routine inspection, no need to adjust support parameters.

[0048] Conditions for determining medium risk: the slope of the strain curve increases, the rate of change is 0.01% to 0.05% / h, the crack length is 5 to 10 mm, there is slight local expansion, and at the same time, the stress of anchor rod 1 is abnormal. Countermeasures: increase the monitoring frequency, update the real-time data to every minute, adjust the grouting pressure or strengthen the local area, such as adding steel arch support, and notify technical personnel to conduct on-site inspections.

[0049] High-risk judgment conditions: sudden change in strain curve, rate of change > 0.05% / h or instantaneous peak > 0.1% / ms, crack length > 10mm, and rapid expansion, rate > 1mm / h, at the same time, the stress of anchor rod 1 exceeds the limit. Countermeasures: immediately stop construction, evacuate the dangerous area and initiate emergency support plans, such as spraying concrete to seal the cracks. The system automatically triggers sound and light alarms and pushes information to management personnel.

[0050] Critical failure judgment conditions: the strain curve continues to rise sharply, the change rate is greater than 0.1% / h, the stress of anchor rod 1 reaches the material yield limit, and the fracture characteristics of anchor rod 1 are monitored, such as the interruption of fiber grating signal. Response measures: emergency evacuation of personnel, blockade of the roadway, and activation of the rescue robot to replace anchor rod 1 or reinforce the surrounding rock.

[0051] See also Figure 1 The present invention provides a fully anchored anchor rod structure for mine tunnel support. The outer surfaces of the anchor rod 1, the connecting pipe 2 and the rotating pipe 3 are all penetrated with evenly arranged slurry holes 21, and the slurry holes 21 adopt a gradually expanding design to reduce the turbulence intensity of the slurry sprayed during grouting.

[0052] Furthermore, after the anchor rod 1 is fixed in the anchor hole, grouting operation is carried out from the upper end opening of the anchor rod 1, and the slurry will be discharged from the slurry outlet hole 21 and filled into the anchor hole. The gradual expansion design gradually expands the cross-sectional area of the flow channel, so that the slurry flow rate decreases smoothly, reduces the turbulence and vortex caused by the high-speed jet, makes the slurry flow more stable, and avoids local scouring damage to the inner wall of the anchor hole and the surrounding rock. At the same time, the gradual expansion structure reduces the instantaneous pressure fluctuation of the grouting pump by slowing down the flow rate, which can not only make the grouting pressure more stable, but also improve the uniformity of slurry filling, reduce ineffective overflow, save material costs, and reduce the deposition of aggregates such as cement particles in the slurry and the risk of orifice blockage.

[0053] The working principle and usage process of the present invention are as follows: Before using the device, first, according to the different degrees of soft and broken surrounding rock in the tunnel, a socket is arranged in the rotating tube 3 to insert steel bars 9, or a skeleton-network structure is constructed in the rotating tube 3 using steel bars 9 to increase the torsional strength of the rotating tube 3, reduce stress concentration and improve support strength. A plurality of fiber grating sensors 11 are arranged axially at the detachable end of the protective sleeve 10, and the card holder 18 is inserted into the card slot 17 for fixation, and the worm 19 is meshed with the worm gear 16.

[0054] When using the device, the anchor rod 1 carrying the connecting tube 2 and the rotating tube 3 is placed into the drilled anchor hole, and then the rotating crank 20 is rotated to drive the worm gear 16 to rotate through the worm 19. Then, the rotating tube 3 can be driven to rotate in the connecting tube 2 under the action of the worm gear 16. Since the fixing rod 5 is slidably connected with the sliding groove on the connecting tube 2, under the limiting action of the sliding groove, when the rotating tube 3 rotates, the fixing rod 5 can move toward the outer end of the sliding groove under the action of the first hinge column 6, the second hinge column 8 and the hinge rod 7 until the fixing rod 5 can evenly squeeze the inner wall of the anchor hole. At this time, the anchor rod 1 can be stably fixed in the middle of the anchor hole, reducing the probability of deviation of the anchor rod 1 during grouting, improving the stability of the anchor rod 1 during grouting, and helping to improve the quality of soft rock tunnel support.

[0055] After the fixing rod 5 is fitted with the inner wall of the anchor hole, the strain gauge 13 in the storage groove 12 can detect the deformation and crack development of the soft rock tunnel in real time through the sealing plate 14. Under dynamic load conditions, when the strain gauge 13 detects cracks or severe deformation in the surrounding rock, the fiber grating sensor 11 obtains the stress change of the anchor rod 1, and the data collected by the strain gauge 13 and the fiber grating sensor 11 are transmitted to the underground edge server. The edge computing device draws a real-time curve of the strain change of the surrounding rock and the anchor rod 1 over time or with the progress of tunnel excavation. By observing the change trend, slope and mutation of the curve, it is determined whether there are cracks in the surrounding rock, the development trend of the cracks, and the use status and support status of the anchor rod 1, and outputs the corresponding risk level, which makes it convenient for relevant personnel to obtain the support status and stress change of the soft rock tunnel, as well as the long-term stress trend and potential failure modes of the anchor rod 1, such as shear fracture or fatigue accumulation. At the same time, it can also provide an early warning of the fracture risk of the anchor rod 1 10 to 15 minutes in advance, reducing the roof fall accident rate by more than 60%, and improving mine safety and support efficiency.

[0056] After the anchor rod 1 is fixed in the anchor hole, grouting is performed from the upper end opening of the anchor rod 1. The slurry will be discharged from the slurry outlet hole 21 and filled into the anchor hole. After the grouting is completed, the fixing rod 5 can also increase the contact area between the anchor rod 1 and the anchor hole, further improving the stability of the anchor rod 1 in supporting the tunnel.

[0057] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A fully anchored anchor rod structure for mine tunnel support, comprising an anchor rod (1), characterized in that: The outer surface of the anchor rod (1) is sleeved with a connecting tube (2), the interior of the connecting tube (2) is rotatably connected to a rotating tube (3), the outer surface of the rotating tube (3) is provided with multiple groups of grooves (4), the interior of the grooves (4) is slidably connected to a fixed rod (5), the outer surface of the connecting tube (2) is provided with sliding grooves, and the fixed rod (5) is slidably connected to the sliding grooves, and multiple groups of hinge mechanisms are evenly spaced in each group of grooves (4), and the multiple groups of hinge mechanisms are used to convert the rotational motion of the rotating tube (3) into the linear displacement of the fixed rod (5); When the rotating tube (3) rotates, the fixed rod (5) is driven to move radially in the sliding groove through the hinge mechanism until the inner wall of the anchor hole is evenly squeezed.

2. A fully anchored anchor structure for mine tunnel support according to claim 1, characterized in that: The top of the rotating tube (3) is provided with an insertion hole passing through the inside of the cut groove (4), and a steel bar (9) is inserted into the insertion hole. The steel bar (9) is spaced apart from the hinge mechanism, and the steel bar (9) is used to strengthen the multi-directional alternating stress borne by the rotating tube (3) under dynamic load conditions.

3. The fully anchored anchor structure for mine tunnel support according to claim 1, characterized in that: The anchor rod (1) is a hollow structure. A protective sleeve (10) is fixed inside the cavity of the anchor rod (1) through a flexible bracket, and the protective sleeve (10) is a detachable structure. A plurality of fiber optic Bragg grating sensors (11) are arranged inside the protective sleeve (10), and the fiber optic Bragg grating sensors (11) are used to reflect the axial strain, transverse shear force and torque of the anchor rod (1) under dynamic load conditions in real time. A storage groove (12) is provided on the outer surface of one side of the fixing rod (5). A strain gauge (13) is pasted inside the storage groove (12), and the strain gauge (13) is used to monitor the development of cracks in the surrounding rock of the soft rock tunnel under dynamic load conditions and static load conditions. The strain gauge (13) is electrically connected to the fiber optic Bragg grating sensor (11). A sealing plate (14) is embedded and installed inside the storage groove (12), and the sealing plate (14) is used to isolate the strain gauge (13) from moist air, water vapor and corrosive gas on the surrounding rock of the tunnel.

4. A fully anchored anchor structure for mine tunnel support according to claim 1, characterized in that: An anchor plate (15) is sleeved on the outer surface of one end of the connecting tube (2) close to the opening of the anchor rod (1), a worm gear (16) is sleeved on the outer surface of the rotating tube (3), and the worm gear (16) is located above the anchor plate (15), and the top of the anchor plate (15) is provided with symmetrically arranged slots (17), the interiors of the two groups of the slots (17) are both engaged and connected with a card seat (18), and the surfaces of the two groups of the card seats (18) close to each other are rotatably connected with a worm (19), and the worm (19) is meshed with the worm gear (16), and a rotating crank (20) is installed on the outer wall of one side of one group of the card seats (18), and the rotating crank (20) is used to drive the worm (19) to rotate.

5. The fully anchored anchor structure for mine tunnel support according to claim 3, characterized in that: A silica gel damping material is filled between the fiber optic Bragg grating sensor (11) and the protective sleeve (10), and the silica gel damping material is used to buffer grouting vibration.

6. A fully anchored anchor structure for mine tunnel support according to claim 1, characterized in that: The outer surfaces of the anchor rod (1), the connecting pipe (2) and the rotating pipe (3) are all penetrated by uniformly arranged slurry outlet holes (21), and the slurry outlet holes (21) are designed to be gradually expanded to reduce the turbulence intensity of the slurry sprayed during grouting.

7. The fully anchored anchor structure for mine tunnel support according to claim 1, characterized in that: The hinge mechanism is provided in three groups, and the hinge mechanism comprises a first hinge column (6), a hinge rod (7) and a second hinge column (8); the first hinge column (6) is provided on the upper surface of the fixing rod (5); the second hinge column (8) is provided on the top wall of the slot (4); and a hinge rod (7) is provided between the first hinge column (6) and the second hinge column (8).

8. The fully anchored anchor structure for mine tunnel support according to claim 3, characterized in that: The fiber grating sensor (11) also monitors stress and strain data of the anchor rod (1) during grouting based on a machine learning algorithm.

9. A fully anchored anchor structure for mine tunnel support according to claim 2, characterized in that: The steel bars (9) are formed into a skeleton-grid structure by arranging main bars axially along the inner surface of the rotating tube (3) and winding stirrups circumferentially, wherein the axial main bars are 4 to 6 main bars equidistantly distributed along the axial direction of the rotating tube (3), with a diameter of 8 to 12 mm, and are welded or tied to the inner wall, and the circumferential stirrups are spirally wound or in the form of independent hoop, with a diameter of 6 to 8 mm, and the spacing between the bars is 1 / 5 to 1 / 3 of the diameter of the rotating tube (3).

Images