Roadway supporting device and method

Abstract

The invention discloses a roadway supporting device and method, and belongs to the technical field of mine roadway supporting, and the method comprises the following steps: S1, laying a latticed distributed sensor network, and connecting the latticed distributed sensor network with a data analysis platform; s2, the data analysis platform receives data of the grid-shaped distributed sensor network and generates a three-dimensional strain cloud picture, and when it is monitored that a set threshold value or a specific evolution mode is exceeded, early warning is triggered; s3, based on the early warning information, performing partitioned active grouting reinforcement, and cooperatively installing an energy-absorbing anchor cable assembly; s4, then flexible anti-impact and anti-stripping net spraying layer construction is carried out; and S5, continuously monitoring internal data of the surrounding rock by using an optical fiber, dynamically evaluating the supporting effect and the stability state of the surrounding rock by a data analysis platform, and dynamically adjusting subsequent supporting parameters according to an evaluation result. According to the method, a closed-loop solution for'model damage 'is formed through an integrated prevention and control system of'sensing early warning, active reinforcement, collaborative energy absorption and flexible stripping resistance', and systematicness and initiative are high.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of mine roadway support, in particular to a roadway support device and a support method. BACKGROUND

[0002] At present, roadway support mainly adopts the combined form of anchor rod (cable), sprayed concrete, steel frame, metal net and the like. However, in the roadway with high stress, soft rock, joint development or affected by mining, large-area spalling of surrounding rock, roof separation and peeling off, and other "edition type damage" often occur.

[0003] In response, the support structure in the prior art plays a role only after the surrounding rock is deformed significantly or even damaged, and has weak perception ability for early micro-deformation and damage trend, and belongs to passive response. In monitoring, the traditional point monitoring such as roof separation instrument and surface convergence point is difficult to comprehensively and real-timely capture the deformation and damage signs of a large area, and the early warning is not timely. In terms of pertinence, the conventional support such as uniformly arranged anchor rod net has insufficient consideration for the surface constraint force, shear resistance and deformation coordination required for inhibiting "edition type damage".

[0004] Based on the above problems, a roadway support device and a support method are provided. SUMMARY

[0005] The purpose of the present application is to provide a roadway support device and a support method to solve the problems in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides a roadway support device and a support method, comprising the following steps:

[0007] S1, a grid-shaped distributed sensor network is arranged for the surrounding rock of the roadway, covering the areas prone to edition type damage, including the roof, the shoulder of the two sides and the soft interlayer area, and the distributed changes of the internal strain field and temperature field of the surrounding rock are monitored in real time, and the optical fiber demodulator is connected with the data analysis platform;

[0008] S2, the data analysis platform receives the data of the grid-shaped distributed sensor network and generates a three-dimensional strain cloud map, and through analyzing the spatial distribution form, evolution trend and rate of the strain concentration area and abnormal temperature area, early identification and early warning of the edition type damage are realized; when the set threshold or a specific evolution mode is monitored, the early warning is triggered;

[0009] S3, based on the early warning information, the risk area is determined, the grouting reinforcement range is demarcated, the partition active grouting reinforcement is carried out, and the energy-absorbing anchor cable assembly is installed in cooperation, and the optical fiber on the energy-absorbing anchor cable assembly is connected to the optical fiber demodulator;

[0010] S4, after the installation of the energy-absorbing anchor cable assembly is completed, the flexible anti-impact and anti-stripping net spraying layer construction is carried out;

[0011] S5, continuously monitoring the internal data of the surrounding rock by using the grid distributed sensor network and the optical fiber on the energy-absorbing anchor cable assembly, monitoring the spatial distribution and evolution of the internal strain, temperature, anchor cable stress and roadway surface convergence of the surrounding rock, the data analysis platform dynamically evaluating the supporting effect and the stability state of the surrounding rock according to the monitoring data, and dynamically adjusting the subsequent supporting parameters according to the evaluation results, including adjusting the parameters and region of the subsequent grouting reinforcement, supplementing the installation of anchor cables, and realizing the closed-loop optimization of the supporting strategy.

[0012] Preferably, in S1, the grid spacing of the grid distributed sensor network is 1m*1m, and the laying method is:

[0013] 1) Within the range of 3-5m along the designed excavation contour line, a pneumatic drill is used to drill a hole, a sensing optical fiber is implanted in the hole, and the hole is plugged with an anchoring agent to form a pre-embedded optical fiber network;

[0014] 2) After the roadway is excavated and the slag is discharged, a surface layer optical fiber is additionally arranged on the surface of the surrounding rock before the initial support, a three-dimensional grid is formed with the pre-embedded optical fiber network, and the optical fiber is fixed with a steel nail to connect the optical fiber demodulator.

[0015] Preferably, in S2, the specific content of exceeding the set threshold or specific evolution mode is:

[0016] 1) The area of the strain concentration zone is greater than or equal to 5m 2 ;

[0017] 2) The strain rate of a single point is greater than or equal to 10με / h;

[0018] 3) The temperature anomaly zone continuously expands, and the temperature anomaly zone is a zone with a temperature difference of greater than or equal to 5℃ from the environment.

[0019] Preferably, in S3, the grouting uses chemical grout or cement-based composite grout, the chemical grout is modified epoxy resin, the cement-based composite grout is a mixed grout composed of cement, ultra-fine silica fume, nano calcium carbonate and water, the dosage of ultra-fine silica fume is 12-18%, the dosage of nano calcium carbonate is 2-4%, and the water-cement ratio is 0.5-0.8;

[0020] The grouting pressure is 1-5MPa.

[0021] Preferably, in S3, the specific steps of partitioned active grouting reinforcement are:

[0022] 1) Drilling holes in the reinforcement zone, installing grouting anchor rods with sealing devices in the holes, and inflating the sealing devices by compressed air;

[0023] 2) Connecting the grouting pipeline, first injecting clean water, and then grouting from outside to inside and from low to high;

[0024] 3) When the grouting pressure suddenly rises by 1MPa and the flow rate drops below 5L / min, the control valve is closed, the pressure is maintained for 3-8min, and then released to seal the outer leakage port of the anchor rod.

[0025] Preferably, the surrounding rock is filled in the crack area inside the rock mass by the active grouting reinforcement, the rock mass integrity is improved, the broken rock blocks are cemented, the'reinforced arch' is formed, the mechanical properties of the surrounding rock are improved, the shear and tensile strength thereof are improved, and the pressure stress is applied to the potential failure surface to inhibit the development thereof.

[0026] Preferably, in S3, the installation method of the energy-absorbing anchor cable assembly is as follows:

[0027] 1) A down-the-hole drill is used to drill a hole, an anchoring agent is injected at the bottom of the hole, and an anchor cable body with a constant resistor is inserted;

[0028] 2) After maintenance is completed, a buffer pad and a fan-shaped tray are installed, the anchor cable is pre-tightened by a tensioning jack, and is fixed by a lock;

[0029] 3) Flexible chains are used to connect adjacent trays to ensure smooth force transmission between the trays, and an optical fiber provided on the anchor cable is connected to an optical fiber demodulator.

[0030] Preferably, in S4, in the construction of the flexible impact-resistant and anti-stripping net spray layer, a flexible metal net or a composite fiber grid is first hung, and then high-performance fiber concrete is sprayed;

[0031] The flexible metal net or the composite fiber grid has a corrugated structure, the corrugated height is 15mm, and the spacing is 100mm; and the high-performance fiber concrete is doped with steel fibers or synthetic fibers.

[0032] Preferably, in S4, the construction method of the flexible impact-resistant and anti-stripping net spray layer is as follows:

[0033] 1) A flexible metal net or a composite fiber grid is first hung, and the net or the grid is locked at the lap joint by a clip to ensure that the gap between the net surface and the surrounding rock surface is less than or equal to 5cm;

[0034] 2) A first layer of high-performance fiber concrete is sprayed to ensure that the corrugated part of the flexible metal net or the composite fiber grid is embedded in the concrete;

[0035] 3) After the first layer of concrete is initially cured, a second layer of concrete is sprayed, and the thickness of the second layer of concrete is greater than that of the first layer of concrete; and a vibrating rod is used to assist in tamping in the corrugated dense area during the spraying process to avoid cavities.

[0036] The application further provides a roadway supporting device used in the supporting method.

[0037] Preferably, the distributed sensor network is composed of a plurality of sensing optical fibers, the sensing optical fiber is a single-mode optical fiber wrapped with a polyvinyl chloride protective layer, carbon fibers are mixed in the protective layer, the optical fiber joints are connected by a fusion process, the joints are sleeved with stainless steel protective sleeves and filled with epoxy resin for sealing;

[0038] The energy-absorbing anchor cable assembly comprises a plurality of energy-absorbing anchor cables, adjacent energy-absorbing anchor cables are connected by flexible connecting pieces, the energy-absorbing anchor cable comprises a tray and an anchor cable body installed on the tray by an anchor cable lock, the anchor cable body is a steel strand, a slippable constant resistor is installed on an inner anchoring section of the anchor cable body, a spring protection cover is sleeved outside the constant resistor, and an OFDR optical fiber is attached to a free section of the anchor cable body, and a stainless steel corrugated pipe is arranged outside the optical fiber;

[0039] The tray has a fan-shaped structure and is made of Q355 steel material, is provided with radial ribs on the surface, and is provided with an anchor cable hole in the center and a connecting hole at the edge.

[0040] The flexible connecting piece is a special chain or a high-strength fiber belt.

[0041] Preferably, a constant resistor is arranged at the end of the anchor cable, when the surrounding rock is deformed greatly, the structure can generate a constant resistance and allow a large amount of slippage, continuously provide supporting force and efficiently dissipate the deformation energy of the surrounding rock, and avoid brittle fracture of the anchor cable; the OFDR optical fiber is integrated along the length of the free section of the anchor cable, and is used for accurately monitoring the stress state and deformation distribution of each section of the anchor cable, and evaluating the supporting effect and the interaction between the surrounding rock and the support; the fan-shaped tray is used as the face-shaped tray, a large area of the tray covers the surface of the roadway, a uniform surface constraint force is provided, the tendency of flaky peeling of the surface of the surrounding rock is effectively inhibited, and a layer of flexible buffer pad is laid between the tray and the surface of the surrounding rock; the trays of a plurality of anchor cables are connected to each other by flexible connecting pieces with high strength, shear resistance and moderate tensile deformation, and form an integral net-shaped structure.

[0042] Preferably, the flexible impact-resistant and anti-stripping net spray layer assembly comprises a flexible metal net or a composite fiber grid with a diameter of 8 mm hung on the outside of the tray by round steel clips, the flexible metal net is a double-twisted steel wire net, and the composite fiber grid is a high-strength polyester fiber grid; periodic corrugations are stamped on the surface of the flexible metal net or the composite fiber grid.

[0043] The high-performance fiber concrete is composed of cement, river sand, gravel, water and fibers, the fibers are steel fibers or synthetic fibers, and the mixing amount is 1% to 2%.

[0044] The net material itself is designed with a regular distributed corrugated structure, the corrugation is 15 mm high and the interval is 100 mm, and the periodic undulation is formed by stamping, weaving or molding process; after the sprayed concrete is covered, the corrugations are not completely flattened, but form a network of micro "cavities" or "weak interfaces" inside the concrete layer.

[0045] The functions are as follows:

[0046] 1) Energy dissipation: When the surrounding rock deforms or has a local impact, the corrugated structure inside the concrete layer can induce micro-cracks to preferentially generate and expand at these "weak interfaces", effectively dissipating impact energy through the formation and friction of a large number of micro-cracks, preventing large-area, through brittle spalling of the concrete layer;

[0047] 2) Deformation coordination: The corrugated structure provides a certain compression / tension space, allowing the concrete layer to have greater coordinated deformation without overall failure; the net-concrete coordination, even if the concrete locally cracks and spalls, the flexible metal net / grid can effectively contain the broken concrete blocks and the back rock mass, preventing large-area falling, maintaining the integrity and safety of the support, and its high ductility can also adapt to the continuous deformation of the surrounding rock.

[0048] Preferably, the roadway support device further comprises an optical fiber demodulator for emitting optical signals, receiving return signals and interpreting strain / temperature information.

[0049] Therefore, the roadway support device and support method of the present application have the following beneficial effects:

[0050] (1) The present application uses a grid-shaped distributed optical fiber to capture large-area strain field anomalies and their spatial morphological evolution in real time, achieving early, accurate, and planar monitoring and early warning of the "pattern failure" incubation process, breaking through the limitations of traditional point monitoring.

[0051] (2) The energy-absorbing anchor cable of the present application integrates a constant resistance / energy-absorbing inner anchor section, a distributed optical fiber monitoring free section, and a large-area planar tray, and forms a whole network through flexible connectors, simultaneously solving the problems of continuous support, energy dissipation, state monitoring, surface constraint, and cooperative bearing.

[0052] (3) In the flexible impact-resistant and spalling-resistant net structure of the present application, a flexible net material with a corrugated structure is designed, which forms an internal "weak interface" channel network after the shotcrete, actively inducing and utilizing micro-cracks to dissipate energy, and allowing greater coordinated deformation, improving the ability of the concrete spray layer to resist large-area spalling (pattern failure), while the flexible net plays a "bottom-holding" role in preventing falling.

[0053] The technical solutions of the present application will be further described in detail below with the aid of drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 The support flowchart of the present application is shown in the figure. DETAILED DESCRIPTION

[0055] The technical solutions of the present application will be further described in detail below with the aid of drawings and examples.

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0057] In this embodiment, all components are devices based on existing technologies.

[0058] Example

[0059] like Figure 1 As shown in the figure, this embodiment provides a support method based on a roadway support device, the support device being as follows:

[0060] 1) Distributed sensor networks:

[0061] The system uses BOTDA distributed optical fiber, specifically G.652D single-mode fiber with a diameter of 2mm. It is wrapped with a 3mm thick polyvinyl chloride (PVC) protective layer, and 2% carbon fiber is added inside the protective layer to enhance its shear resistance.

[0062] Deep optical fibers are pre-embedded 4m behind the tunnel excavation outline to form a 1m×1m three-dimensional grid; surface optical fibers are laid on the tunnel surface, intersecting with the deep optical fibers to form a "well" shape, and the grid nodes are fixed with stainless steel clips at 50cm intervals. The density in the roof area is increased to 0.8m×0.8m, and two reinforcing optical fibers parallel to the tunnel axis are added to the shoulders of both sides.

[0063] The fiber optic connector uses fusion splicing technology (fusion loss ≤0.1dB), and is fitted with a Φ5mm stainless steel protective sleeve. The sleeve is filled with epoxy resin for sealing to ensure waterproofing and moisture protection.

[0064] 2) Fiber optic demodulator:

[0065] It adopts an independently integrated mine-use explosion-proof demodulator (ExdⅠ), with a power of 50W, a sampling frequency of 1kHz, a strain measurement range of (-3000)~(+3000)με (accuracy ±5με), and a temperature measurement range of -20~80℃ (accuracy ±0.5℃).

[0066] The explosion-proof control cabinet is fixed at the entrance of the tunnel and is connected to the sensing fiber optic cable via an armored optical cable (Φ10mm). The optical cable is buried at a depth of 0.5m and protected by concrete.

[0067] 3) Data analysis platform:

[0068] An industrial computer with an Intel i7 processor and 16GB of memory is configured in the ground monitoring room, and a 10.1-inch intrinsically safe mining display screen with a resolution of 1920×1080 is installed in the tunnel.

[0069] The platform contains a strain field three-dimensional visualization module (refresh frequency 1 / 10 min), an abnormal identification algorithm based on machine learning, and an identification accuracy of ≥95%.

[0070] Early warning threshold setting: ① Strain concentration area ≥5m 2 ; ② Strain rate ≥10 με / h; ③ Temperature anomaly area (difference from ambient temperature ≥5℃) continues to expand for 30 min.

[0071] The early warning method is a field display screen sound and light alarm with a volume of 85 dB and a red light flashing frequency of 2 Hz. The warning report containing positioning information is pushed to the management personnel's mobile phone APP at the same time.

[0072] 4) Radial grouting anchor rod with sealing device:

[0073] The rod body is Φ25mm hollow threaded steel with Q355 material and a length of 3.5m. Φ8mm grouting holes are arranged every 30cm on the rod body in a quincunx pattern. The sealing device is located 1.2m from the rod tail and uses a double-layer rubber capsule with an outer layer of Shore hardness 60 and an inner layer of 40. After inflation, the diameter can reach Φ60mm, and the working pressure is 0.8MPa.

[0074] During installation, holes are drilled at an interval of 1.5m x 1.5m with a diameter of Φ40mm and a depth of 3.5m. After the anchor rod is inserted, the center hole is inflated, the pressure is maintained for 5min to confirm sealing, the exposed end is installed with a quick connector, and the quick connector is matched with the grouting pipe.

[0075] The grouting process uses a double-cylinder plunger pump with a working pressure of 10MPa and a displacement of 50L / min. A 500L stainless steel mixing tank is matched, and the mixing tank is equipped with a stirrer with a speed of 60r / min. The pipeline is Φ25mm high-pressure rubber pipe with a pressure resistance of 15MPa, and a pressure sensor and a flow control valve are installed at the end.

[0076] The chemical grout during grouting is modified epoxy resin with a viscosity of 150mPa·s, an initial setting time of 30min, and a micro-expansion rate of 2%, which is used for fracture development area;

[0077] The cement-based grout is P.O42.5 cement + 15% ultra-fine silica fume + 3% nano calcium carbonate with a water-cement ratio of 0.6, which is used for areas with good integrity.

[0078] The parameters of the grouting process are 2-3MPa for the fracture zone, 10-15L / min for the flow rate, 1-2MPa for the complete area, 20-25L / min for the flow rate, and the end criteria are a pressure surge of 1MPa and a flow rate of ≤5L / min, with a pressure maintaining time of 3min.

[0079] 5) Energy-absorbing anchor cable:

[0080] The anchor cable body is 7 strands of Φ5mm high-strength steel wire, with a breaking force of 200kN and a length of 8m. The free section is sheathed with a Φ30mm polyethylene protective tube.

[0081] The constant-resistance device is a Φ80mm seamless steel tube, 50cm in length, with a friction core inside, made of 45 steel, designed to have a constant resistance of 100±5kN, with a maximum slip of 800mm, achieved by adjusting the diameter of the friction core.

[0082] The OFDR optical fiber is Φ0.9mm, with a measurement accuracy of ±2με and a spatial resolution of 10cm. It is attached to the free section of the anchor cable using high-temperature glue (temperature-resistant 120℃) and is sheathed with a Φ3mm stainless steel corrugated tube.

[0083] The tray is a fan-shaped structure with a radius of 30cm and a thickness of 20mm, made of Q355 steel. The surface is stamped with 3 radial ribs, 10mm high. The central hole is Φ30mm in diameter, used for installing the lock, and the edge has 4 Φ12mm connecting holes for flexible connection.

[0084] The flexible connecting piece is a Φ10mm high-strength chain, with a breaking force of 80kN and a length of 5cm per section, allowing a 5% stretch. The two ends are matched with M12 bolts and the tray connecting holes.

[0085] The buffer pad layer is a 5mm thick neoprene plate with a Shore hardness of 50 and an elastic modulus of 2MPa. The surface is embossed with diamond patterns, 1mm deep.

[0086] 6) Flexible impact and stripping net spray layer assembly:

[0087] The flexible metal mesh is woven from 8mm diameter 65Mn steel wire, with internal diamond-shaped holes, 5cm in length. The mesh size is 2m x 1.5m, with a surface embossed with corrugations, 15mm high, 100mm long, and 5mm round at the peak. The corrugation direction is at a 45° angle to the axis of the tunnel.

[0088] When hanging, the corrugations face outward, with the mesh overlapping by 10cm. Φ8mm round steel clips (30cm apart) are used to fix the mesh to the anchor tray, with local wooden wedges to ensure that the mesh gap with the surrounding rock is ≤5cm.

[0089] The mix ratio (mass ratio) of high-performance fiber concrete is: cement: river sand: 5-10mm gravel: water: polypropylene fiber = 1:2:1.5:0.5:0.01. The fiber length is 12mm, the diameter is 38μm, and the tensile strength is 600MPa.

[0090] Its performance indicators are 28d compressive strength of 30MPa, flexural strength of 4MPa, and ultimate elongation of 1.5%.

[0091] The spraying equipment uses a wet sprayer, with a working pressure of 0.6MPa and a production rate of 8m 3 / h, matched automatic accelerator adding device (doping amount 3%, error ±0.2%), spray gun distance from working surface 1.5m spiral injection, circle diameter 30cm.

[0092] The above supporting device is used for supporting a roadway with a buried depth of 800m in a coal mine, and the specific steps are as follows:

[0093] S1, 24h before roadway excavation, along the design excavation contour line outside the range of 3-5m, a pneumatic drill is used to drill a hole with a diameter of 50mm and a depth of 2m, a grid-shaped sensing optical fiber is implanted in the hole at an interval of 1m*1m, the orifice is plugged with anchoring agent, and the length is 50cm.

[0094] Immediately after the roadway excavation and the spoil, before the initial support, a surface optical fiber is additionally arranged on the surrounding rock surface to form a three-dimensional grid with the pre-embedded optical fiber, which is fixed with steel nails at an interval of 50cm, and the optical fiber joint is wrapped with 3 layers of waterproof tape for waterproof treatment.

[0095] The optical fiber is connected to an optical fiber demodulator and a data analysis platform, and is powered on for debugging, continuous monitoring for 2h, and ensuring that the signal is stable with a baseline error of ≤3με.

[0096] S2, the data analysis platform automatically collects strain / temperature data every 10min to generate a three-dimensional strain cloud image, and triggers an early warning when any of the following conditions is detected: ① the area of the strain concentration zone is ≥5m 2 ; ② the single-point strain rate is ≥10με / h; ③ the temperature abnormal zone (difference from the environment ≥5℃) continuously expands.

[0097] Within 15min after the early warning, the technician reviews the site, measures the surface convergence with a handheld laser range finder, confirms the risk area, and delineates the grouting reinforcement range along the strain concentration zone with an expansion of 1.5m.

[0098] S3, after 2h of early warning confirmation, based on the early warning information, the risk area is determined to delineate the grouting reinforcement range, holes are drilled in the reinforcement zone at an interval of 1.5m*1.5m, the hole diameter is Φ40mm, the depth is 3.5m, a grouting anchor rod with a self-sealing device is installed in the hole, 0.8MPa compressed air is introduced to make the sealing device expand, and the pressure is maintained for 5min to confirm the sealing;

[0099] Connect the grouting pipeline, first inject clean water, the water injection pressure is 1MPa, flush the hole for 5min, then grout in the order of “from outside to inside, from low to high”, in this embodiment, chemical grout is used for the fracture development zone, the grouting pressure is 2-3MPa, and the flow rate is 10-15L / min.

[0100] When the grouting pressure suddenly rises by 1MPa and the flow rate drops to below 5L / min, the control valve is closed, the pressure is maintained for 3min, and then the pressure is released, and the exposed end of the anchor rod is plugged with quick-setting cement.

[0101] After 12h of grouting, install the energy-absorbing anchor cable. Use a down-the-hole drill to drill holes at a spacing of 2m x 2m, with a hole diameter of Φ130mm and a depth of 8m. Inject anchoring agent (water-cement ratio 0.4) at the bottom of the hole, and insert the anchor cable body with a constant resistance device, slowly pushing it to the bottom of the hole to ensure that the constant resistance device fully enters the anchoring section.

[0102] After 24h of curing, install the buffer pad layer and the fan-shaped tray, and pre-tighten the anchor cable with a tensioning jack. The tensioning force is 80kN, and the load is held for 5min. The anchor cable is fixed by a lock.

[0103] Connect adjacent trays with flexible chains, and pre-tighten the chains to a slightly taut state to ensure smooth force transmission between the trays. At the same time, connect the optical fiber bonded to the free section of the anchor cable to an optical fiber demodulator.

[0104] S4. After 4h of anchor cable installation, construct a flexible impact-resistant and stripping-resistant net spray layer. Hang the flexible metal mesh, paying attention to the direction of the corrugations towards the outside of the roadway. Fasten the overlapping parts of the mesh with clips to ensure that the gap between the mesh and the surrounding rock surface is ≤5cm. Use wooden wedges to tightly secure the mesh in local areas.

[0105] Spray the first layer of fiber concrete, with a thickness of 5cm. During spraying, the spray gun should be 1.5m away from the working face, and the spiral movement should have a circle diameter of 30cm to ensure that the corrugated part of the metal mesh is embedded in the concrete, with an exposed corrugation height of 5mm.

[0106] After 2h of initial spraying or after the initial setting of the concrete, spray the second layer of concrete, with a thickness of 10cm. During the spraying process, use a vibrating rod with an insertion depth of 10cm to assist in compacting the dense areas of the corrugations and avoid cavities.

[0107] S5. Use the grid-shaped distributed sensor network and the optical fiber on the energy-absorbing anchor cable assembly to continuously monitor the internal data of the surrounding rock. The sensing system monitors in real time: ① the surrounding rock strain, which generates a trend report every day; ② the anchor cable stress, which is recorded every hour; and ③ the surface temperature of the spray layer, which identifies potential cracking areas.

[0108] When the stress of a certain section of the anchor cable exceeds 80kN, the constant resistance device activation threshold, or the surface strain of the spray layer is ≥1500με, supplement grouting in the corresponding area, increase the pressure by 20% compared to the first time, and increase the anchor cable density with a spacing of 1.5m x 1.5m.

[0109] Evaluate the support effect every month, use a sound wave detector to detect the integrity of the surrounding rock, and optimize the subsequent support parameters based on the evaluation results.

[0110] Through 6 months of monitoring:

[0111] The occurrence rate of "pattern failure" is reduced to 0, which is lower than the average of 1-2 times per month for traditional support.

[0112] The maximum deformation of surrounding rock is controlled within 150mm, and the traditional support is 300-500mm;

[0113] The response time of the support system is less than or equal to 30min (the traditional monitoring lag is greater than or equal to 24h), and the comprehensive maintenance cost is reduced by 40%.

[0114] Therefore, the roadway support device and the support method form a closed-loop solution for "panel type damage" through the integrated prevention and control system of "perception early warning-active reinforcement-cooperative energy absorption-flexible anti-stripping", and are strong in systematicness and initiative.

[0115] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that: the technical solutions of the present application can still be modified or replaced by equivalents, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A method of roadway support, characterised by, The method comprises the following steps: S1, a grid-shaped distributed sensor network is arranged for the surrounding rock of the roadway, and the grid-shaped distributed sensor network is connected with a data analysis platform through a fiber demodulator; S2, the data analysis platform receives data of the grid-shaped distributed sensor network and generates a three-dimensional strain cloud chart, and when a set threshold or a specific evolution mode is monitored, a warning is triggered; S3, based on the warning information, a risk area is determined, a grouting reinforcement range is demarcated, partitioned active grouting reinforcement is performed, and an energy-absorbing anchor cable assembly is installed in cooperation, the fiber on the energy-absorbing anchor cable assembly is connected to the fiber demodulator; S4, after the installation of the energy-absorbing anchor cable assembly is completed, a flexible impact-resistant and stripping-resistant net spraying layer is constructed; S5, the grid-shaped distributed sensor network and the fiber on the energy-absorbing anchor cable assembly are used to continuously monitor internal data of the surrounding rock, the data analysis platform dynamically evaluates the supporting effect and the stability state of the surrounding rock, and subsequent supporting parameters are dynamically adjusted according to the evaluation result.

2. A method of roadway support according to claim 1 wherein: In the S1, the grid distance of the grid-shaped distributed sensor network is 1m*1m, and the arrangement method is as follows: 1) within a range of 3-5m along the designed excavation contour line, a pneumatic drill is used to drill a hole, a sensing optical fiber is implanted in the hole, and the hole is plugged with an anchoring agent at the hole mouth to form a pre-embedded optical fiber network; 2) after the roadway is excavated and the slag is discharged, a surface layer optical fiber is additionally arranged on the surface of the surrounding rock before primary support, a three-dimensional grid is formed with the pre-embedded optical fiber network, and the optical fiber is fixed with a steel nail and connected with the fiber demodulator.

3. A method of roadway support according to claim 1 wherein: In the S2, the specific content of the set threshold or the specific evolution mode is as follows: 1) strain concentration area ≥ 5 m 2 ; 2) a single-point strain rate is greater than or equal to 10με / h; 3) a temperature anomaly area continuously expands, and the temperature anomaly area is an area with an environmental temperature difference greater than or equal to 5℃.

4. A method of walling a roadway as claimed in claim 1 wherein: In the S3, the grouting uses chemical grout or cement-based composite grout, the chemical grout is modified epoxy resin, the cement-based composite grout is a mixed grout composed of cement, ultra-fine silica fume, nano calcium carbonate and water, the content of the ultra-fine silica fume is 12-18%, the content of the nano calcium carbonate is 2-4%, and the water-cement ratio is 0.5-0.8; The grouting pressure is 1-5MPa.

5. A method of walling a roadway as claimed in claim 1 wherein: In the S3, the installation method of the energy-absorbing anchor cable assembly is as follows: 1) a down-the-hole drill is used to drill a hole, an anchoring agent is injected at the bottom of the hole, and an anchor cable body with a constant resistor is inserted; 2) after curing, a buffer pad and a tray are installed, an anchor cable is pre-tightened by using a tension jack, and the anchor cable is fixed by using a lock; 3) adjacent trays are connected by using a flexible chain to ensure smooth force transmission between the trays, and the optical fiber on the anchor cable is connected to the fiber demodulator.

6. A method of walling a roadway as claimed in claim 1 wherein: In the S4, in the construction of the flexible impact-resistant and stripping-resistant net spraying layer, a flexible metal net or a composite fiber grid is first hung, and then high-performance fiber concrete is sprayed; The flexible metal net or the composite fiber grid has a corrugated structure, the corrugated height is 15mm, and the interval is 100mm; the high-performance fiber concrete is doped with steel fibers or synthetic fibers.

7. A method of wall-ribbing according to claim 1, characterised in that: In the S4, the construction method of the flexible impact-resistant and stripping-resistant net spraying layer is as follows: 1) a flexible metal net or a composite fiber grid is first hung, the net or the grid is locked at the lap joint by using a clip to ensure that the gap between the net or the grid and the surface of the surrounding rock is less than or equal to 5cm; 2) a first layer of high-performance fiber concrete is sprayed to embed the corrugated part of the flexible metal net or the composite fiber grid in the concrete. 3) After the first layer of concrete is cured, the second layer of concrete is sprayed, and the thickness of the second layer is greater than that of the first layer of concrete, and a vibrating rod is used to assist in guiding the second layer of concrete to be solid in the area where the corrugations are dense, so as to avoid cavities.

8. A roadway support device, characterized by: The roadway supporting device is used in the supporting method of any one of claims 1-7, and the roadway supporting device comprises a distributed sensor network, an energy-absorbing anchor cable assembly and a flexible impact-resistant and stripping-resistant net spraying layer assembly.

9. A means for roadway support according to claim 8, characterized in that: The distributed sensor network is composed of a plurality of sensing optical fibers, the sensing optical fiber is a single-mode optical fiber wrapped with a polyvinyl chloride protective layer, the protective layer is mixed with carbon fibers, the optical fiber joint is connected by a fusion process, and the joint is provided with a stainless steel protective sleeve and is injected with epoxy resin for sealing; The energy-absorbing anchor cable assembly is composed of a plurality of energy-absorbing anchor cables, adjacent energy-absorbing anchor cables are connected through flexible connecting pieces, the energy-absorbing anchor cable comprises a tray and an anchor cable body installed on the tray through an anchor cable lock, the anchor cable body is a steel strand, an internal anchoring section of the anchor cable body is provided with a constant resistor, the constant resistor is externally provided with a spring protection cover, and a free section of the anchor cable body is pasted with an OFDR optical fiber, and the optical fiber is externally provided with a stainless steel corrugated pipe; The tray has a fan-shaped structure and is made of Q355 steel material, an anchor cable hole is formed in the center of the tray, and connecting holes are arranged at the edges of the tray.

10. A gateway arrangement according to claim 9, characterised in that: The flexible impact-resistant and stripping-resistant net spraying layer assembly comprises a flexible metal net or a composite fiber grid hung on the outer side of the tray, the flexible metal net is a steel wire double-twisted net, and the composite fiber grid is a high-strength polyester fiber grid; periodic corrugations are stamped on the surface of the flexible metal net or the composite fiber grid. The high-performance fiber concrete is composed of cement, river sand, gravel, water and fibers, the fibers are steel fibers or synthetic fibers, and the fiber content is 1% to 2%.

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