Rock burst roadway collaborative prevention control method

Abstract

The application provides a rock burst roadway collaborative control method, and the control method comprises the following steps: obtaining deep stress distribution characteristics, surrounding rock physical and mechanical parameters and rock burst risk level of a roadway, designing parameters based on survey results, the parameters comprising deep pressure relief drilling parameters, shallow backfill section parameters and anchorage pre-stress parameters, constructing deep pressure relief drilling according to the deep pressure relief drilling parameters to release deep high stress elastic energy, pre-evaluating pressure relief effect, determining that pressure relief reaches a standard when a stress drop reaches a preset proportion, after pressure relief reaches the standard, using expansion material to segmentally fill and backfill a shallow part of the drilling, strengthening shallow anchorage area strength, implementing anchorage support, and forming a rock burst resistant structure in cooperation with the backfill body, and through real-time monitoring and dynamic adjustment, rock burst prevention and control and roadway stability are ensured. The control method can strengthen the shallow anchorage area strength, form a collaborative rock burst resistant structure, and realize rock burst prevention and control and roadway stability.

Description

Technical Field

[0001] This invention relates to the field of underground engineering disaster prevention and control and roadway stability control technology, specifically, to a method for coordinated anti-rockburst control in roadways prone to rock bursts. Background Technology

[0002] In the fields of mineral resource extraction (especially deep coal mining) and underground engineering construction, rockburst, as a typical dynamic disaster, often leads to sudden failure of the surrounding rock in roadways, failure of support structures, and even casualties and equipment damage, severely restricting mining efficiency and engineering safety. With the increase in mining depth, the increase in coal seam hardness, and the complexity of geological conditions (such as thick coal seams and hard rock strata), the risk of roadway rockburst increases significantly, and the requirements for the stability and long-term effectiveness of rockburst prevention and control technologies become increasingly stringent.

[0003] In related technologies, although drilling and decompression technology in roadways can achieve deep stress release, drilling construction will damage the integrity of the shallow surrounding rock, resulting in gaps at the contact and anchoring interface between the anchor bolts / cables and the surrounding rock. The overall shear strength and bearing capacity of the shallow anchoring zone will be significantly reduced, which will not only fail to play the role of the support system in resisting impact, but will also make the shallow part a "weak link" in roadway instability, which is prone to cause the surrounding rock to collapse after anchoring failure.

[0004] Deep decompression (such as drilling and blasting) and shallow support (such as anchor bolts and grouting) are mostly separate procedures implemented in stages, without forming a synergistic mechanism of "energy control and rock stabilization": when only deep decompression is implemented, although deep energy can be released, the shallow surrounding rock is easily disturbed and unstable due to the lack of effective support; when only shallow support is strengthened, the root cause of high stress concentration in the deep cannot be eliminated, and the release of deep impact energy can easily penetrate the shallow support structure, resulting in the anti-impact technology being "one thing at the expense of another" and unable to meet the stability requirements of roadways with high impact risk. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] Therefore, embodiments of the present invention propose a collaborative rockburst prevention and control method for roadways, which strengthens the shallow anchorage zone to form a collaborative anti-rockburst structure, thereby achieving rockburst prevention and control and roadway stability.

[0007] The method for coordinated rockburst prevention and control in roadways according to an embodiment of the present invention includes the following steps:

[0008] To obtain the deep stress distribution characteristics, surrounding rock physical and mechanical parameters, and impact risk level of the tunnel;

[0009] The design parameters are based on the exploration results, including parameters for deep pressure relief drilling, parameters for shallow backfill sections, and parameters for anchor prestress.

[0010] Deep pressure relief drilling is carried out according to the aforementioned deep pressure relief drilling parameters in order to release the high-stress elastic energy in the deep environment.

[0011] A preliminary assessment of the pressure relief effect is conducted, and the pressure relief is deemed satisfactory when the stress reduction reaches a preset percentage.

[0012] After the pressure relief meets the standard, expansion material is used to fill and backfill the shallow part of the borehole in sections to strengthen the strength of the shallow anchoring zone.

[0013] Anchor supports are implemented and work in conjunction with the backfill to form an impact-resistant structure;

[0014] Real-time monitoring and dynamic adjustments are used to ensure rockburst control and roadway stability.

[0015] The rockburst-resistant roadway collaborative anti-rockburst control method of this invention can not only accurately eliminate the rockburst energy source through deep pressure relief, but also strengthen the integrity of the surrounding rock with the support structure formed by shallow backfilling, thus constructing a closed loop of "pressure relief-rock stabilization-rock resistance". At the same time, it is suitable for high-rockburst risk roadways under complex geological conditions such as deep wells, thick coal seams, and hard rock. It can maintain the stability of the surrounding rock for a long time, reduce the risk of roadway convergence deformation and secondary rockburst in the later stage, significantly reduce maintenance costs, extend the service life of the roadway, effectively release the elastic energy of deep high stress, strengthen the strength of the shallow anchoring zone, form a collaborative anti-rockburst structure, and achieve rockburst prevention and control and roadway stability.

[0016] In some embodiments, the deep stress relief drilling parameters include drilling depth, spacing, and borehole diameter, wherein the drilling depth extends beyond the shallow anchoring zone and covers the deep stress concentration area, and the drilling spacing and borehole diameter are adjusted according to the stress distribution to ensure full coverage of the stress concentration area.

[0017] The parameters of the shallow backfill section include the backfill range from the borehole opening to the end of the shallow anchoring zone, the filling material having reserved expansion space, and the material injection volume meeting the filling requirements of the borehole.

[0018] The anchor prestress parameters include using the anchor to provide initial preload to reduce initial deformation of the shallow surrounding rock in the roadway.

[0019] In some embodiments, the deep pressure relief drilling is carried out using a mining drilling rig, with the drilling angle at 0 to 3° along both sides of the roadway. The diameter of the borehole is in the range of 100 mm to 250 mm, and the depth is not less than 20 m. The drilling angle avoids penetrating the roof or floor of the coal seam.

[0020] In some embodiments, the stress inside the borehole is monitored in real time during the drilling process. If a sudden increase in stress is encountered, the drilling depth is adjusted to ensure thorough pressure relief. After the drilling is completed, rock cuttings inside the borehole are cleaned to prevent blockage.

[0021] In some embodiments, the pre-assessment of the pressure relief effect includes monitoring stress changes around the hole using a stress sensor after drilling is completed. When the deep stress reduction reaches the expected proportion, the pressure relief is deemed satisfactory. If it does not meet the standard, additional drilling is performed and the drilling spacing is reduced.

[0022] In some embodiments, the evaluation of the anchor support effect includes installing a hydraulic jack to monitor the preload in real time and taking remedial measures based on the preload loss.

[0023] In some embodiments, the segmented backfilling includes: bottoming the hole, inserting the grouting pipe into the bottom of the shallow backfilling section of the borehole, injecting material to a suitable proportion of the hole depth, and allowing it to stand until the material initially expands to form bottom support;

[0024] The material is filled in layers to ensure a dense filling. The remaining space is filled in multiple times, and after each filling, the material is gently vibrated with a vibrator to remove air from the hole. The final filling is done to the area where expansion space is reserved from the hole opening, and then covered with a dust cover.

[0025] In some embodiments, the expansion effect monitoring includes measuring the expansion pressure inside the borehole in stages using a pressure sensor. When the pressure stabilizes within a preset range that can compress the surrounding rock without damaging the borehole wall, the backfill is deemed qualified; if the pressure is insufficient, additional material is injected.

[0026] In some embodiments, the rockburst roadway collaborative rockburst prevention and control method of the present invention further includes the following steps:

[0027] After the deep drilling is completed and the pressure relief meets the standards, shallow backfilling is completed within a preset time to avoid prolonged exposure and instability of the shallow surrounding rock after pressure relief. Subsequent tunneling or mining operations are carried out only after the backfilling is completed and the material has fully set.

[0028] And / or,

[0029] After shallow backfilling is completed, the roadway anchors are pre-tightened a second time according to the design requirements to ensure that the anchors are in close contact with the backfill and surrounding rock to form an anti-scour structure.

[0030] In some embodiments, the real-time monitoring includes at least one of the following monitoring methods: anchor stress state monitoring, roadway surface displacement monitoring, regional dynamic load monitoring, local dynamic load monitoring, local static load monitoring, and distributed optical fiber monitoring. Attached Figure Description

[0031] Figure 1 This is a diagram showing the layout of borehole locations and monitoring locations in the rockburst roadway collaborative anti-rockburst control method according to an embodiment of the present invention.

[0032] Figure label:

[0033] 100. Coal seam

[0034] 1. Drilling,

[0035] 2. Anchors,

[0036] 3. Hydraulic pillow force gauge. Detailed Implementation

[0037] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0038] The method for coordinated rockburst prevention and control in roadways according to an embodiment of the present invention includes the following steps:

[0039] To obtain the deep stress distribution characteristics, surrounding rock physical and mechanical parameters, and impact risk level of the tunnel.

[0040] Understandably, equipment such as borehole stress gauges and sonic detectors are used to investigate the strata at the tunnel face and sides, collecting data on deep stress distribution characteristics, surrounding rock physical and mechanical parameters (such as compressive strength and fracture density), and impact risk levels. This provides a scientific basis for subsequent parameter design, ensuring the targetedness and effectiveness of anti-scour measures, identifying high-risk areas, optimizing resource allocation, and improving the efficiency of anti-scour control.

[0041] The design parameters are based on the exploration results. The parameters include the parameters of the deep pressure relief borehole 1, the parameters of the shallow backfill section, and the prestress parameters of the anchor 2.

[0042] Understandably, the parameters of the deep stress relief borehole 1 (including borehole depth, spacing and diameter) are designed based on the characteristics of deep stress distribution, the parameters of the shallow backfill section (including backfill range, performance requirements of expansion materials, etc.) are designed, and the prestress parameters of the anchor 2 (such as the preload of anchor rods and anchor cables) are determined.

[0043] Reasonable parameter design ensures that the deep pressure relief borehole 1 effectively releases the high stress elastic energy in the deep part and avoids damage to the shallow surrounding rock due to the construction of borehole 1; the shallow backfill section design strengthens the strength of the shallow anchoring zone; the high prestressed support provides sufficient initial preload to reduce the initial deformation of the shallow surrounding rock.

[0044] The deep pressure relief borehole 1 was constructed according to the parameters of the deep pressure relief borehole 1 to release the high-stress elastic energy in the deep environment.

[0045] A mining drilling rig is used to drill borehole 1 along both sides of the roadway at a suitable inclination angle, controlling the inclination angle of borehole 1 between 0 and 3°. A suitable borehole diameter (e.g., 100mm, 150mm, etc.) is selected, and the borehole depth is generally 20m. During construction, the stress inside the borehole is monitored in real time, and the depth of borehole 1 is adjusted to ensure thorough pressure relief. After construction, rock cuttings are cleaned from the borehole to prevent blockage. This effectively releases the elastic energy of high stress in the deep layers, reduces stress concentration in the deep layers, and reduces the occurrence of rockbursts. Reasonable borehole 1 parameter design avoids excessive damage to the shallow surrounding rock and maintains the integrity of the shallow surrounding rock. A pre-evaluation of the pressure relief effect is conducted; when the stress reduction reaches a preset proportion, the pressure relief is deemed satisfactory.

[0046] After the pressure relief meets the standard, expansion material is used to fill and backfill the shallow part of borehole 1 in sections to strengthen the shallow anchorage zone.

[0047] After depressurization is completed, stress sensors are used to monitor stress changes around the borehole. When the deep stress reduction reaches the expected proportion (compared to the initial value), the depressurization is deemed successful. If it does not, additional borehole 1 is drilled or the spacing between boreholes 1 is reduced. This ensures the depressurization effect meets expectations and avoids the risk of rockburst due to insufficient depressurization; dynamic adjustment of depressurization parameters improves the reliability of the depressurization effect.

[0048] The expansion material is prepared by mixing silicate cement as the base material with an expansion agent, ultrafine silica fume, and a retarder in a reasonable ratio. After thorough mixing, it is injected in sections into the shallow backfill section of borehole 1. After the bottom of the hole is prepared, it is filled in layers with dense compaction. After each injection, a vibratory tool is used to gently vibrate and remove air from the hole. The final filling extends to a point where an appropriate expansion space is left from the borehole opening, and a dust cover is then placed over it.

[0049] The expansion material fills the shallow voids in borehole 1, strengthens the shallow anchorage zone, and improves the impact resistance of the support system; segmented filling and vibration ensure uniform material distribution, avoid voids and holes, and improve the compaction and bearing capacity of the backfill.

[0050] Two anchors were installed for support, and together with the backfill, they formed an impact-resistant structure.

[0051] High-strength anchor cables and anchor bolts are installed to provide high initial preload. Secondary preload is applied to the shallow portion of borehole 1 after backfilling to ensure tight contact between the anchor bolts / cables and the backfill and surrounding rock, forming a three-in-one anti-scour structure of "anchor bolt-backfill-surrounding rock".

[0052] High prestressed support provides sufficient initial prestress to reduce initial deformation of shallow surrounding rock; anchor 2 works in synergy with backfill to form a stable and impact-resistant structure, improving the overall stability of the roadway.

[0053] Real-time monitoring and dynamic adjustments are used to ensure rockburst control and roadway stability.

[0054] Real-time monitoring of indicators such as anchor bolt (cable) preload, roadway surface displacement, regional dynamic load, local dynamic load, and local static load. Based on changes in monitoring data, dynamic adjustments to support parameters and anti-scour measures are made to ensure roadway stability and safety.

[0055] Real-time monitoring can promptly detect potential rockburst risks and support failures, providing a basis for dynamic adjustments; dynamic adjustments can optimize rockburst prevention measures, improving the efficiency and effectiveness of rockburst control.

[0056] In other words, the rockburst-resistant roadway collaborative anti-rockburst control method of this invention can not only accurately eliminate the rockburst energy source through deep pressure relief, but also strengthen the integrity of the surrounding rock with the support structure formed by shallow backfilling, thus constructing a closed loop of "pressure relief-rock stabilization-rock resistance". At the same time, it is suitable for high-rockburst risk roadways under complex geological conditions such as deep wells, 100mm thick coal seams, and hard rock. It can maintain the stability of the surrounding rock for a long time, reduce the risk of roadway convergence deformation and secondary rockburst in the later stage, significantly reduce maintenance costs, extend the service life of the roadway, effectively release the elastic energy of deep high stress, strengthen the strength of the shallow anchoring zone, form a collaborative anti-rockburst structure, and achieve rockburst prevention and control and roadway stability.

[0057] In some embodiments, the parameters of the deep stress relief borehole 1 include the borehole 1 depth, spacing, and diameter, wherein the borehole 1 depth extends beyond the shallow anchoring zone and covers the deep stress concentration area, and the borehole 1 spacing and diameter are adjusted according to the stress distribution to ensure full coverage of the stress concentration area; the parameters of the shallow backfill section include the backfill range from the borehole 1 opening to the end of the shallow anchoring zone, the filling material having reserved expansion space, and the material injection volume meeting the filling requirements of the borehole; the prestress parameters of the anchor 2 include using the anchor 2 to provide initial preload to reduce the initial deformation of the shallow surrounding rock of the roadway.

[0058] The depth of borehole 1 is designed to extend beyond the shallow anchoring zone and cover the deep stress concentration area. The specific depth is determined based on geological survey results and stress distribution characteristics, typically around 20 meters. Through observation of the side stress of the coal pillar at the working face, the peak location of the lateral support pressure is determined to be approximately 10 to 15 meters. Therefore, the depth of borehole 1 is optimized to ensure effective release of deep high stress. In other words, it releases the elastic energy of deep high stress, reduces deep stress concentration, decreases the probability of rockbursts, and ensures that the end of borehole 1 covers the deep stress concentration area, avoiding substandard pressure relief due to insufficient borehole 1 depth.

[0059] Based on the stress distribution, the spacing of borehole 1 should be set appropriately. In high-stress areas, the spacing of borehole 1 should be smaller to ensure that the end of borehole 1 fully covers the deep stress concentration area; in non-high-stress areas, the spacing of borehole 1 should be appropriately widened to reduce costs and construction complexity. Optimizing the spacing of borehole 1 ensures the uniformity and comprehensiveness of the pressure relief effect. It also avoids situations where stress concentration areas are not covered due to excessively large spacing of borehole 1, thus improving the reliability of the pressure relief effect.

[0060] Choosing the appropriate borehole diameter is typically 100 mm, 150 mm, 200 mm, or 250 mm, depending on the geological conditions and stress distribution. A larger borehole diameter can improve pressure relief, but it also increases construction costs and complexity. A well-chosen borehole diameter balances pressure relief effectiveness and construction costs; a larger diameter can more effectively release deep, high stress, thus improving pressure relief.

[0061] The backfill area extends from the borehole 1 opening to the end of the shallow anchorage zone, ensuring the integrity and strength of the shallow anchorage zone. The specific area is determined based on the anchorage zone design and geological conditions. Strengthening the shallow anchorage zone enhances the erosion resistance of the support system. Ensure the backfill material covers the entire shallow anchorage zone to prevent support failure due to insufficient backfill coverage.

[0062] A novel expansive material is used for backfilling. This material, based on silicate cement, is mixed with an expansive agent, ultrafine silica fume, and a retarder in a specific ratio. After thorough mixing, it is injected in stages into the shallow backfill section of borehole 1. The expansive material fills the voids in the shallow part of borehole 1, improving the density and load-bearing capacity of the backfill. Its expansive properties ensure uniform distribution of the material within the borehole, preventing voids and cavities and enhancing the support effect.

[0063] Based on the void conditions in the shallow part of borehole 1, determine the appropriate amount of filling material to ensure that the filling requirements of the borehole are met. Fill the borehole for the final time, leaving sufficient expansion space from the borehole opening, and then cover it with a dust cover. Ensure that the filling material fully fills the voids in the borehole, improving the density and load-bearing capacity of the backfill, and leaving expansion space to prevent borehole wall damage due to excessive material expansion.

[0064] High-strength anchor cables and bolts are used to provide high initial preload. The preload of the bolts is no less than 250 kN, and the preload of the roof anchor cables is no less than 300 kN. After installation, secondary preload is performed on the shallow part of borehole 1 after backfilling to ensure tight contact between the bolts, anchor cables, backfill, and surrounding rock. Sufficient initial preload reduces the initial deformation of the shallow surrounding rock in the roadway, forming a three-in-one anti-impact structure of "anchor bolt-backfill-surrounding rock" and improving the overall stability of the roadway.

[0065] Based on real-time monitoring data, the preload of anchor bolts (cables) is dynamically adjusted. When a loss of preload or an increase in surrounding rock deformation is detected, reinforcement support or adjustment of support parameters is carried out in a timely manner. Through dynamic adjustment, the support system is ensured to always be in optimal condition, improving the continuity and reliability of the anti-scour effect, promptly identifying and resolving support failures, and avoiding roadway instability caused by insufficient support.

[0066] In some embodiments, the deep pressure relief borehole 1 is constructed using a mining drilling rig, and is constructed along both sides of the roadway at an elevation angle of 0 to 3°. The diameter of the borehole 1 is in the range of 100 mm to 250 mm, the depth of the borehole is not less than 20 m, and the construction angle avoids penetrating the roof or floor of the coal seam 100.

[0067] Understandably, large-diameter pressure relief boreholes 1 were constructed on both sides of the roadway. The borehole 1 inclination angle was 0–3°, and the diameter was D (taken as 100, 150, 200, and 250 mm respectively). The borehole depth was 20 m (based on observations of the coal pillar side stress at the working face, the peak position of the lateral support pressure was approximately 10–15 m). Construction delays at the face in the strong, medium, and weak hazard zones were less than or equal to 5 m, 15 m, and 20 m respectively. The borehole height was 1.5 m from the roadway floor. The sealing lengths were less than 1 m and 3 m of the anchor bolt (cable) support range, approximately 5 m and 7 m of the anchoring range, and greater than 9 m from the anchoring range to the peak position of the lateral support pressure. The pressure relief effect was compared in the test section of the roadway, and the pressure relief parameters were optimized based on the actual site conditions.

[0068] The depth of borehole 1 must cover the deep stress concentration area. The spacing and diameter of borehole 1 should be adjusted according to the stress distribution to ensure complete coverage. The borehole depth is generally not less than 20 meters, and the diameter of borehole 1 is between 100 mm and 250 mm. The backfilling range extends from the borehole opening of borehole 1 to the end of the shallow anchoring zone, using expansive material and reserving expansion space to ensure that the material injection volume meets the filling requirements of the borehole. The preload of the anchor bolts should not be less than 250 kN, and the preload of the top plate anchor cables should not be less than 300 kN, providing sufficient initial preload to reduce initial deformation of the shallow surrounding rock.

[0069] In some embodiments, the stress inside the borehole is monitored in real time during the drilling process of borehole 1. If a stress surge occurs, the depth of borehole 1 is adjusted to ensure thorough pressure relief. After drilling, rock debris inside the borehole is cleaned to prevent blockage.

[0070] During the drilling of borehole 1, advanced stress sensors were used to monitor stress changes within the borehole in real time. These sensors were embedded in borehole 1 to collect stress data in real time and transmit the data to the monitoring center via a data transmission system. Real-time monitoring allowed for the timely detection of stress spikes, providing a scientific basis for subsequent adjustments to borehole 1, ensuring thorough pressure relief, and reducing the risk of rockbursts.

[0071] When a stress surge is detected, the depth of borehole 1 is immediately adjusted to extend it deep into the stress surge area, thus fully releasing the high stress in that region. The adjusted parameters of borehole 1 need to be re-optimized to ensure that the end of borehole 1 fully covers the deep stress concentration area. By adjusting the depth of borehole 1, the elastic energy of deep high stress can be effectively released, reducing deep stress concentration, decreasing the probability of rockbursts, and improving the stability of the roadway.

[0072] After drilling borehole 1 is completed, use specialized cuttings removal equipment, such as high-pressure water flushing or mechanical cleaning, to thoroughly remove the cuttings from the borehole. After cleaning, inspect the borehole to ensure that borehole 1 is unobstructed and free of blockages. Removing the cuttings from the borehole and ensuring its unobstructed flow provides favorable conditions for subsequent grouting or backfilling work and avoids construction problems caused by blockages.

[0073] In some embodiments, the pre-assessment of the pressure relief effect includes using a stress sensor to monitor the stress change around the hole after drilling 1 is completed. When the deep stress reduction reaches the expected proportion, it is determined that the pressure relief has met the standard. If it does not meet the standard, additional drilling 1 is performed and the spacing between drilling 1 is reduced.

[0074] Immediately after the completion of the deep pressure relief borehole 1, preparations for stress monitoring around the borehole were carried out. This included installing stress sensors, connecting data acquisition equipment, and setting monitoring parameters. Technical benefit: Ensuring the timely installation of monitoring equipment provides accurate data support for subsequent assessment of the pressure relief effect.

[0075] Immediately after drilling borehole 1 is completed, stress sensors are activated to monitor stress changes in key areas around the borehole in real time. These sensors can accurately measure the magnitude and trend of stress changes, and the data is transmitted to the monitoring center wirelessly or via wired connection. Real-time monitoring allows for timely understanding of the stress distribution after pressure relief in borehole 1, providing a scientific basis for evaluating the pressure relief effect.

[0076] The monitored deep stress values ​​are compared with the initial stress values ​​to calculate the stress reduction. When the stress reduction reaches a preset percentage (e.g., 50%), the pressure relief is deemed satisfactory. By setting clear standards, the reliability and consistency of the pressure relief effect are ensured, avoiding the risk of rockbursts due to insufficient pressure relief.

[0077] If monitoring results show that the deep stress reduction does not reach the expected proportion, remedial measures are required. These measures include: drilling additional borehole 1: drilling new deep stress-relief boreholes 1 in areas where the pressure relief effect has not been achieved, ensuring that the end of borehole 1 covers the deep stress concentration area; and reducing the spacing between boreholes 1: adjusting the spacing between boreholes 1 to make their distribution more dense, improving the uniformity and comprehensiveness of the pressure relief effect. Thus, by drilling additional boreholes 1 and reducing the spacing, the elastic energy of deep high stress is ensured to be fully released, reducing the probability of rockburst.

[0078] In some embodiments, the evaluation of the support effect of the anchor 2 includes installing a hydraulic bolster force gauge 3 to monitor the magnitude of the preload in real time and taking remedial measures based on the loss of preload.

[0079] Immediately after the anchor bolts (cables) are installed, hydraulic dynamometers 3 are installed on them. These dynamometers can monitor the preload of the anchor bolts (cables) in real time and transmit the data to the monitoring center. Through real-time monitoring, the changes in the preload of the anchor bolts (cables) can be grasped in a timely manner, providing a scientific basis for evaluating the support effect.

[0080] Activate hydraulic jacking gauge 3 to monitor the preload of the anchor bolts (cables) in real time. This data reflects the stress state of the anchor bolts (cables) and helps determine the effectiveness of the support. Real-time monitoring allows for timely detection of preload loss, providing a basis for subsequent support adjustments and ensuring the effectiveness of the support system.

[0081] Regularly analyze monitoring data to assess the preload loss. If the preload loss exceeds a set threshold, the support effect is deemed substandard, requiring remedial measures. Analyzing preload loss allows for timely detection of support failures, preventing roadway instability caused by insufficient support.

[0082] When the preload loss exceeds the set threshold, remedial measures should be taken immediately. These include: secondary preload: performing secondary preload on the anchor bolts (cables) to restore the preload to the design value; strengthening the support: in areas where the support effect is substandard, increasing the number of anchor bolts (cables) or replacing them with higher-strength anchor bolts (cables); adjusting support parameters: based on monitoring data, adjusting parameters such as the spacing and length of the anchor bolts (cables) to optimize the support effect. By taking timely remedial measures, the effectiveness of the support system is restored, ensuring the stability of the roadway.

[0083] In some embodiments, segmented backfilling includes: bottoming the hole, inserting the grouting pipe into the bottom of the shallow backfilling section of the borehole 1, injecting material to a suitable ratio of hole depth, and allowing it to stand until the material initially expands to form bottom support; layered compaction filling, injecting material into the remaining space multiple times, and using a vibrating tool to gently vibrate after each injection to expel air from the hole, and finally filling to the reserved expansion space from the hole opening and covering it with a dust cover.

[0084] By grouting at the bottom of the borehole, a solid foundation is ensured for the backfill material, preventing subsidence or uneven filling during subsequent filling. The initially expanded material forms bottom support, improving the stability of the backfill. Layered grouting and vibration ensure uniform material distribution, increasing the density and load-bearing capacity of the backfill. Expansion space is provided to prevent excessive expansion that could damage the borehole walls, and a dust cover is used to maintain the cleanliness and integrity of the backfill material.

[0085] That is to say, through bottom - hole priming and layered dense filling, it is ensured that the backfill material is evenly distributed in the shallow part of borehole 1, forming a solid foundation and a dense structure, and improving the stability of the backfill body. The segmented filling backfill strengthens the strength of the shallow anchorage area, and cooperates with the high - prestress support to form a stable anti - impact structure, improving the anti - impact capacity of the support system. The layered grouting and vibration ensure the uniform distribution of materials, expel the air in the hole, improve the density and bearing capacity of the backfill body, and avoid the failure of the support caused by uneven materials. The use of reserved expansion space and dust caps ensures that the backfill material will not be damaged due to excessive expansion or external factors during long - term use, and extends the service life of the backfill body.

[0086] It should be noted that appropriate expansion materials are selected according to geological conditions and backfill requirements to ensure that they have good expansibility and compressive strength. The initial setting time and expansion performance of the materials need to match the construction rhythm and geological conditions. Strictly control the grouting volume to ensure that the materials fully fill the voids in the hole, and avoid the backfill body being not dense due to insufficient grouting. The vibration force should be moderate to avoid uneven materials or structural damage caused by excessive vibration. According to the expansion performance of the materials and the diameter of borehole 1, reasonably reserve the expansion space to avoid the hole wall being damaged due to excessive expansion of the materials. After the filling is completed, promptly cover the dust cap to prevent dust and other sundries from entering the hole and keep the backfill material clean and intact.

[0087] In some embodiments, the expansion effect monitoring includes measuring the expansion pressure in the hole with a pressure sensor in stages. When the pressure stabilizes within a preset range that can compact the surrounding rock without damaging the hole wall, the backfill is judged to be qualified; if the pressure is insufficient, additional materials are injected.

[0088] After the segmented filling backfill is completed, pressure sensors are immediately installed in the shallow backfill section of borehole 1. These sensors can monitor the expansion pressure in the hole in real - time and transmit the data to the monitoring center. Through real - time monitoring, the change of the expansion pressure of the backfill material can be grasped in time, providing a scientific basis for the evaluation of the expansion effect.

[0089] After the backfill is completed, the expansion pressure in the hole is monitored with a pressure sensor in stages. The monitoring stages include the initial expansion stage, the stable stage, and the long - term monitoring stage. Through staged monitoring, the expansion process of the backfill material can be comprehensively understood to ensure that the expansion pressure is maintained within the preset range.

[0090] When the expansion pressure stabilizes within the preset range of "being able to compact the surrounding rock without damaging the hole wall", the backfill is judged to be qualified. The specific range is determined according to geological conditions and the performance of the backfill material. By setting clear qualification criteria, it is ensured that the backfill effect meets the design requirements and the anti - impact capacity of the support system is improved.

[0091] If monitoring results indicate insufficient expansion pressure, supplementary material injection is required. This includes: Material injection: In areas where the backfill material's expansion pressure is insufficient, inject expansion material to ensure the pressure within the borehole reaches the preset range; Adjusting grouting parameters: Based on monitoring data, adjust the grouting volume and pressure to optimize the backfilling effect. By injecting supplementary material and adjusting grouting parameters, the expansion pressure of the backfill material is maintained within the preset range, improving the erosion resistance of the support system.

[0092] In some embodiments, the rockburst roadway collaborative anti-rockburst control method of the present invention further includes the following steps: after the deep borehole 1 is completed and the pressure relief meets the standard, shallow backfilling is completed within a preset time to avoid prolonged exposure and instability of the shallow surrounding rock after pressure relief. After the backfilling is completed and the material has finally set, subsequent tunneling or mining operations are carried out; and / or, after the shallow backfilling is completed, the roadway anchor 2 is pre-tightened a second time according to the design requirements to ensure that the anchor 2 is in close contact with the backfill and the surrounding rock to form an anti-rockburst structure.

[0093] Specifically, after the deep borehole 1 is completed and the pressure relief is confirmed to be up to standard, shallow backfilling must be completed within a preset time. This preset time is usually determined based on geological conditions, the setting time of the backfill material, and construction efficiency to ensure that the shallow surrounding rock does not become unstable due to prolonged exposure.

[0094] Selection and preparation of backfill materials: A new type of expansive material is used, which is based on silicate cement and mixed with an expansive agent, ultrafine silica fume, and a retarder in a reasonable ratio. After thorough mixing, ensure that the material has suitable initial setting time, expansion performance, and later compressive strength.

[0095] Backfilling: Insert the grouting pipe into the bottom of the shallow backfill section of borehole 1, inject material to a suitable depth, and allow it to stand until the material initially expands and forms bottom support. Then, fill the remaining space in layers with dense compaction, gently vibrating after each injection to expel air from the borehole. For the final filling, leave sufficient expansion space from the borehole opening, and cover with a dust cover to protect the backfill material.

[0096] By completing shallow backfilling within a preset timeframe, structural instability caused by prolonged exposure of shallow surrounding rock was avoided, thus enhancing the stability of the tunnel. Layered grouting and vibration ensured uniform material distribution, improving the density and load-bearing capacity of the backfill. Excessive material expansion leading to borehole wall damage was prevented, ensuring the integrity of the backfill.

[0097] After shallow backfilling is completed and the material has fully set, the roadway anchors 2 (such as anchor bolts and anchor cables) are pre-tightened a second time. The timing of the second pre-tightening is usually after the backfill material has reached a certain strength, to ensure that the anchors 2 are in close contact with the backfill and surrounding rock.

[0098] According to design requirements, the preload of the anchor bolts and anchor cables is adjusted. The preload of the anchor bolts is not less than 250 kN, and the preload of the roof anchor cables is not less than 300 kN. Secondary preload ensures a stable bond between anchor 2 and the backfill and surrounding rock. After secondary preload, anchor 2, backfill, and surrounding rock form a synergistic anti-impact structure, improving the overall impact resistance of the roadway. Secondary preload ensures close contact between anchor 2 and the backfill and surrounding rock, forming a stable synergistic anti-impact structure and improving the impact resistance of the support system. After secondary preload, the preload of anchor 2 is maintained within the design range, reducing initial deformation of the shallow surrounding rock and improving the stability of the roadway. Dynamically adjusting the preload of anchor 2 optimizes the support effect and improves the targeting and effectiveness of anti-impact measures.

[0099] In some embodiments, real-time monitoring includes at least one of the following monitoring methods: anchor 2 stress state monitoring, roadway surface displacement monitoring, regional dynamic load monitoring, local dynamic load monitoring, local static load monitoring, and distributed optical fiber monitoring.

[0100] Hydraulic dynamometers 3 are installed on anchor bolts or cables to monitor the preload in real time. Data is transmitted to a monitoring center via wired or wireless means for real-time analysis to promptly detect preload loss and ensure the effectiveness of the anchor 2. This provides a basis for secondary preload and support optimization, improving the impact resistance of the support system.

[0101] Specifically, such as Figure 1 As shown, hydraulic pressure gauges 3 are installed on a row of anchor cables below borehole 1 on the slab side, and another row of pressure gauges is arranged on the anchor cables in the middle of the top plate for comparison. Monitoring of the anchor bolt stress state begins from the date of installation, with observations every 3 days, and the readings of the hydraulic pressure gauges are read and recorded. Based on the changes in the observed data, observations continue for one week after the pressure gauge readings tend to stabilize.

[0102] Laser rangefinders were used to set up measuring points within the roadway to monitor the displacement of the roadway roof and walls. Data from these measuring points were recorded regularly to analyze the deformation trend of the surrounding rock. The laser rangefinders were used to monitor the relative deformation of the roadway, with one measuring station positioned in the center of a borehole spacing and diameter scheme. A cross-point layout was used to arrange the measuring points. The distances between each measuring point were measured using the laser rangefinders, and the displacement of the roadway roof, floor, and walls was calculated. Observation profiles were immediately established after the roadway support was completed, and observations were conducted daily until the roadway deformation stabilized, continuing for one week.

[0103] The regional dynamic load monitoring scheme can adopt the microseismic method, that is, using no less than 4 microseismic probes arranged in the excavated area to monitor the activity envelope of the surrounding rock in the range of its excavation influence.

[0104] Local dynamic load monitoring can be performed using the ground sound method: During tunneling, two ground sound probes should be placed on the side of the tunnel facing away from the conveyor belt, with a probe spacing of 80m. When the tunnel has been excavated to 110m from the probe near the facing, the probe far from the facing should be moved to 30m behind the facing. This process of moving the ground sound probes should be repeated. Considering the influence of factors such as the chamber and support structure, the above-mentioned ground sound probe spacing is allowed to have an error of ±5m.

[0105] A local static load monitoring scheme can adopt the coal body stress method. The coal body stress method involves installing one stress gauge in a borehole behind the face during tunneling (the nearest stress gauge should be no more than 50m from the face), with a group spacing of 30m. Each group consists of one deep borehole (12m) + one shallow borehole (8m), with an intra-group spacing of 0.5–2.0m. The borehole diameter is approximately 42mm, ensuring coverage within 200m behind the face, and installation along the tunnel backfill side. The initial pressure is 4.5–5.0MPa. Tunneling is carried out using a roadheader for coal breaking. For online stress monitoring, if the stress is less than 12MPa at a measuring point depth of 9m or less than 14MPa at a measuring point depth of 15m, there is no risk of impact.

[0106] Distributed Fiber Optic Monitoring: Distributed fiber optic sensing technology is employed, based on the BOTDR principle and sensors, to establish a sensing fiber optic cable model. Distributed fiber optic monitoring holes are drilled in a 3m long × 2m wide × 2m high chamber excavated in the sidewall of the roadway. The hole opening is 1.4m from the coal wall and 1.2m from the floor. The fiber optic detection hole forms a 5° horizontal angle with the coal wall and a 1° upward vertical angle. Hole 1 has a diameter of 65mm and a depth of 60m. A metal-based cable-stayed strain sensing fiber optic cable is implanted into the monitoring hole using cement mortar. The fiber diameter is 5±0.2mm, the strain coefficient is 499.8MHz / %, and the maximum breaking force is 2350N.

[0107] The above monitoring schemes can be implemented using one or more combinations, depending on the actual working conditions. Other detection methods, such as CT scan deployment schemes, can also be used.

[0108] Therefore, by combining multiple monitoring methods, a comprehensive understanding of the roadway's stress state, deformation, and stress distribution can be achieved, providing a scientific basis for optimizing anti-scour measures. Real-time monitoring can promptly detect potential risks such as preload loss, surrounding rock deformation, and stress concentration, providing valuable time for remedial measures. Based on monitoring data, the preload of anchor 2, support parameters, and pressure relief parameters are dynamically adjusted to optimize anti-scour measures and improve the sustainability and reliability of the anti-scour effect. Through real-time monitoring and dynamic adjustment, the effectiveness of the support system is ensured, roadway stability is improved, and the risk of surrounding rock damage and rockburst due to support failure is reduced. Based on monitoring data, support and pressure relief parameters are rationally adjusted to optimize resource allocation, reduce costs, and decrease construction complexity.

[0109] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0110] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0111] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0112] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0113] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0114] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for coordinated rockburst prevention and control in roadways, characterized in that, Includes the following steps: To obtain the deep stress distribution characteristics, surrounding rock physical and mechanical parameters, and impact risk level of the tunnel; Based on the exploration results, the design parameters include parameters for deep decompression boreholes, shallow backfill sections, and anchor prestress parameters. Deep pressure relief drilling is carried out according to the deep pressure relief drilling parameters to release the high stress elastic energy in the deep part. The deep pressure relief drilling parameters include drilling depth, spacing and diameter. The drilling depth extends beyond the shallow anchoring zone and covers the deep stress concentration area. The drilling spacing and diameter are adjusted according to the stress distribution to ensure full coverage of the stress concentration area. The parameters of the shallow backfill section include the backfill range from the borehole opening to the end of the shallow anchoring zone, the filling material having reserved expansion space, and the material injection volume meeting the filling requirements of the borehole. The anchor prestress parameters include using the anchor to provide initial preload to reduce initial deformation of the shallow surrounding rock in the roadway. During drilling, the stress inside the hole is monitored in real time. If a sudden increase in stress is encountered, the drilling depth is adjusted to ensure thorough pressure relief. After drilling, rock cuttings are cleaned from the hole to prevent blockage. A preliminary assessment of the pressure relief effect is conducted, and the pressure relief is deemed satisfactory when the stress reduction reaches a preset percentage. After the pressure relief meets the standard, the shallow part of the borehole is backfilled in sections using expansion material to strengthen the shallow anchoring zone. The section backfilling includes: drilling the bottom of the hole, inserting the grouting pipe into the bottom of the shallow backfilling section of the borehole, injecting material to 10% to 20% of the hole depth, letting it stand until the material initially expands to form bottom support, filling in layers and compacting, injecting material into the remaining space multiple times, and using a vibrating tool to gently vibrate after each injection to remove air from the hole, and finally filling to the reserved expansion space from the hole opening and covering with a dust cover. After the deep drilling is completed and the pressure relief meets the standards, shallow backfilling is completed within a preset time to avoid prolonged exposure and instability of the shallow surrounding rock after pressure relief. Subsequent tunneling or mining operations are carried out only after the backfilling is completed and the material has fully set. And / or, After the shallow backfill is completed, the roadway anchors are pre-tightened a second time according to the design requirements to ensure that the anchors are in close contact with the backfill and surrounding rock to form an anti-scouring structure. Anchor supports are implemented and work in conjunction with the backfill to form an impact-resistant structure; Real-time monitoring and dynamic adjustments are used to prevent rockbursts and ensure roadway stability.

2. The method for coordinated rockburst prevention and control in roadways according to claim 1, characterized in that, The deep pressure relief drilling is carried out using a mining drilling rig, with drilling at an elevation angle of 0 to 3° along both sides of the roadway. The borehole diameter is in the range of 100 mm to 250 mm, and the hole depth is not less than 20 m. The drilling angle should avoid penetrating the roof or floor of the coal seam.

3. The method for coordinated rockburst prevention and control in roadways according to claim 1, characterized in that, The pre-assessment of the pressure relief effect includes monitoring the stress change around the hole using a stress sensor after drilling is completed. When the deep stress reduction reaches a preset ratio, the pressure relief is deemed to be up to standard. If it is not up to standard, additional drilling is performed and the drilling spacing is reduced.

4. The method for coordinated rockburst prevention and control in roadways according to claim 1, characterized in that, The evaluation of the anchor support effect includes installing a hydraulic bolster force gauge to monitor the preload in real time and taking remedial measures based on the preload loss.

5. The method for coordinated rockburst prevention and control in roadways according to claim 1, characterized in that, The expansion effect monitoring includes measuring the expansion pressure inside the hole in stages using pressure sensors. When the pressure stabilizes within a preset range that can compact the surrounding rock without damaging the hole wall, the backfill is deemed qualified; if the pressure is insufficient, additional material is injected.

6. The method for coordinated rockburst prevention and control in roadways according to claim 1, characterized in that, The real-time monitoring includes at least one of the following monitoring methods: anchor stress state monitoring, roadway surface displacement monitoring, regional dynamic load monitoring, local dynamic load monitoring, local static load monitoring, and distributed optical fiber monitoring.

Images