A method for controlling rock burst in stages
By installing a prestressed anchor cable system and stress monitoring devices in the surrounding rock, stress changes can be monitored in real time, and the prestressed tendons of the anchor cables can be compensated in stages, thus solving the problem of rockburst control and ensuring construction safety and rock mass stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ANHUI UNIVERSITY OF ARCHITECTURE
- Filing Date
- 2024-01-12
- Publication Date
- 2026-06-02
AI Technical Summary
Existing technologies are insufficient to effectively control and prevent rockburst disasters, especially in deep underground engineering projects. Rockbursts are highly random, sudden, and destructive, threatening construction safety and causing equipment damage.
By sampling the surrounding rock and conducting indoor experiments, a prestressed anchor cable system was installed. Combined with stress monitoring devices, stress changes were monitored in real time. The prestressed tendons of the anchor cables were tensioned in stages to balance the rock mass stress and prevent rock bursts.
Effective control of rockbursts was achieved, ensuring construction safety and avoiding the hazards caused by rockbursts. Stress monitoring and staged compensation tensioning maintained the stability and balance of the rock mass.
Smart Images
Figure CN117704912B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of geotechnical engineering technology, specifically to a method for phased compensation control of rockburst damage. Background Technology
[0002] With economic and social development, rockbursts have become a major and unavoidable problem for large-scale underground engineering projects in hydropower, transportation, mining, and national defense as they extend deeper into the earth. The mechanism of rockbursts is closely related to regional tectonics, stratigraphic lithology, groundwater activity, and the degree of development of structural planes. Under high ground stress conditions, the accumulated elastic deformation potential energy within deep rock masses is suddenly released due to excavation, mining, or other external disturbances, leading to dynamic phenomena such as rock bursting, peeling, ejection, and even throwing. It is a complex dynamic instability geological hazard. Because rockburst disasters are increasingly frequent and possess strong randomness, suddenness, and destructiveness, large-scale, multi-point rockbursts ranging from minor to severe can occur during excavation, directly threatening the safety of personnel and equipment, causing catastrophic consequences such as damage to construction equipment or even the abandonment of underground projects. Therefore, rockbursts are one of the key problems that must be solved in future large-scale underground geotechnical engineering projects.
[0003] Based on past rockburst engineering examples, many factors contributing to rockbursts manifest as influences on the stress distribution of the surrounding rock, or dynamic disturbances causing instability when the surrounding rock is at critical equilibrium. Existing publicly available technologies for controlling and managing rockbursts primarily employ temporary protective measures, such as water jetting to reduce stress, implementing pre-emptive stress release, and rockburst monitoring and prediction. In these approaches, the construction process damages the original rock mass structure, causing the rock strata to lose their temporary equilibrium. The potential energy accumulated in the rock strata is then rapidly converted into kinetic energy or other forms of energy and released through rockburst. The work done by altering the position, volume, and shape of the rock strata is stored within the rock strata as a significant amount of potential energy, existing as a state of hidden stress. These problems urgently need to be addressed. Therefore, a phased compensation control method for rockburst damage is proposed. Summary of the Invention
[0004] The technical problem this invention aims to solve is how to address the hazards caused by rockbursts. It provides a phased compensation control method for rockburst damage. This method first involves sampling the surrounding rock mass and conducting indoor rock experiments to obtain stress-related quantities. Next, it involves the construction of a prestressed anchor cable system to compensate for stress release losses caused by rock excavation. Pre-embedding stress monitoring devices is used to reflect the stress state of the rock mass. After the anchor cables and stress monitoring devices are completed, the initial prestressing of the anchor cables is applied to pre-excavation stress. Stress monitoring data is acquired during construction, and stress values at different stages are collected, analyzed, and fed back. Based on the feedback of stress results, the anchor cables are compensated and tensioned in stages and segments.
[0005] The present invention solves the above-mentioned technical problems through the following technical solution, and the present invention includes the following steps:
[0006] S1: Geological Exploration
[0007] After sampling the surrounding rock mass, indoor rock tests were conducted on the rock samples, and the severity of rockburst was determined by theoretical criteria.
[0008] S2: Construction of prestressed anchor cable system
[0009] Select the type of prestressed anchor cable and construct the duct;
[0010] S3: Placement and fixation of stress monitoring components
[0011] The stress monitoring element is placed at the tensioning end of the prestressed anchor cable. The end of the duct is enlarged using a hole enlarging machine to obtain an enlarged hole position. The stress monitoring element is placed in the enlarged hole position and fixed in the duct with strong adhesive. The stress monitoring element is used to monitor the stress change of the anchor cable prestress.
[0012] S4: Anchor cable installation and grouting treatment of ducts
[0013] First, place the fixed end of the anchor cable prestressing tendon at the front end of the duct and install the fixed end compression anchor. Then, lead the tensioning end of the anchor cable prestressing tendon out from the rear end of the duct and install the tensioning end compression anchor. Fill the duct with grout through the grouting hole on the tensioning end compression anchor.
[0014] S5: Initial tensioning
[0015] After the grouting strength meets the requirements, the stress monitoring element is read for the first time to obtain the initial stress monitoring value. Combined with the uniaxial compressive strength stress index obtained from the rock sample in the indoor rock test, the pre-applied force is deduced by calculating the exposed area after excavation failure, and the anchor cable prestressing tendon is tensioned for the first time to compensate for the pre-added amount of the initial excavation failure.
[0016] S6: Excavation of the rockburst section
[0017] Preliminary excavation was carried out based on the initial tensioning compensation, while stress monitoring data was collected, analyzed, and fed back.
[0018] S7: Phased Compensation Tensioning
[0019] Based on the feedback from stress monitoring data, when a reversal point appears on the stress monitoring graph, it indicates that the tension is lower than the swelling inside the rock mass. Then, the prestressed anchor cable is tensioned again. When the stress monitoring curve shows a stable trend, it indicates that the surrounding rock mass is approaching a state of equilibrium.
[0020] S8: Excavation of the rockburst zone completed.
[0021] Multiple compensation tensioning operations were conducted until the excavation of this rockburst zone was completed.
[0022] Furthermore, in step S1, the likelihood of a rockburst is predicted by combining relevant tests on rock samples, and the severity of a rockburst is graded to distinguish key areas of concern, the number and extent of anchor cable arrangements.
[0023] Furthermore, in step S2, the prestressed anchor cable can meet the requirements of phased tensioning and release, including multiple anchor cable prestressing tendons, fixed end compression anchors, and tensioning end compression anchors. The fixed end compression anchors are set at the front end of the multiple anchor cable prestressing tendons, i.e., the front end of the duct, and the tensioning end compression anchors are set at the rear end of the multiple anchor cable prestressing tendons, i.e., the rear end of the duct.
[0024] Furthermore, the fixed-end extrusion anchor includes a fixed anchor plate, an extrusion sleeve, an extrusion spring, and steel strands. An extrusion spring is fitted onto one end of the steel strands, and the end fitted with the extrusion spring is pressed into the extrusion sleeve by an extrusion machine. The extrusion spring is completely embedded between the extrusion sleeve and the steel strands. The steel strands with the extrusion sleeve compressed are then sequentially threaded into the installation holes of the fixed anchor plate and fed into the front end of the channel as a whole.
[0025] Furthermore, the tensioning end compression anchor includes a tensioning end anchor plate, a working anchor, a tensioning end anchor ring clamp, and steel strands. After verifying the placement of the steel strands in the ducts and the steel strand numbers, the tensioning end anchor plate is placed at the rear end of the ducts. The steel strands are then passed through the holes on the working anchor in sequence and embedded in the tensioning end anchor ring clamp for fastening. Finally, tensioning operations are performed using a jack and a tool anchor.
[0026] Furthermore, in step S2, the process of duct construction is as follows: after the positioning and layout are completed, the drilling machine is positioned and drilling is performed at a preset inclination angle θ. After the drilling is completed, the hole quality is checked, and after the inspection is qualified, the duct is cleaned.
[0027] Furthermore, in step S7, the stress monitoring element collects the stress monitoring results of the prestressed anchor cable around the clock and throughout the entire process, and reflects the stress changes in real time through the computer backend; the stress change curve is obtained by analyzing the stress monitoring, that is, the stress monitoring diagram is obtained, and the feedback is sent to the construction operation surface to re-tension the anchor cable prestress.
[0028] Furthermore, in step S7, the following condition is met during the staged compensation tensioning:
[0029] Σ(σ i )dF i +ΣE p <ΣP i
[0030] Where, Σ(σi )dF i ΣE represents the total allowable stress resistance of the rock mass to prevent failure; p P represents the sum of active lateral pressures on the rock mass. i Let be the tension force during the i-th tensioning.
[0031] Furthermore, in step S8, when the stress monitoring chart shows a reversal point each time, it indicates that the surrounding rock is unstable. At this time, compensation tensioning is performed to make the surrounding rock tend to be flat. After the rockburst section is excavated, the excess anchor cable prestressing tendons are cut off and the permanent structure is constructed. For the segmented rockburst section, steps S1 to S8 are repeated until the permanent construction is completed, at which point the monitoring and tensioning work can be ended.
[0032] Compared with the prior art, the present invention has the following advantages: the phased compensation control method for rockburst damage uses anchor cable prestressed tendons, combined with the real-time stress monitoring results of the rock mass, to obtain the stress change of the rock mass after stress release under the action of external force, and to perform phased compensation tensioning of the prestressed anchor cables according to the stress change, so as to meet the external force acting on the rock mass, achieve the balance when the rock mass is undisturbed, and avoid the occurrence of rockbursts and the resulting damage. Attached Figure Description
[0033] Figure 1 This is a flowchart illustrating the staged compensation control method for rockburst damage in an embodiment of the present invention.
[0034] Figure 2 This is a schematic diagram of the arrangement of anchor cable prestressing tendons on the surrounding rock in an embodiment of the present invention;
[0035] Figure 3 This is a schematic diagram (cross-section) showing the arrangement of stress monitoring elements, anchor cable prestressing tendons, etc. in an embodiment of the present invention.
[0036] Figure 4 This is a diagram of the initial tension stress in an embodiment of the present invention;
[0037] Figure 5 This is a diagram of the stress curve for staged compensation in an embodiment of the present invention.
[0038] Figure 2 , 3 In the middle section: 1. Surrounding rock, 2. Grouting, 3. Duct, 4. Fixed end extrusion anchor, 5. Fixed anchor plate, 6. Stress monitoring element, 7. Tensioning end anchor plate, 8. Tensioning end anchor ring wedge, 9. Tensioning end extrusion anchor, 10. Grouting hole, 11. Anchor cable prestressing tendon, 12. Enlarged hole position, 13. Fixed end, 14. Tensioning end. Detailed Implementation
[0039] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.
[0040] This embodiment provides a technical solution: a method for phased compensation control of rockburst damage, comprising: placing prestressed tendons 11 capable of phased tensioning through a duct 3 in the surrounding rock 1; simultaneously enlarging the end of the duct 3 to obtain an enlarged hole position 12; pre-embedding a stress monitoring element 6 in the enlarged hole position 12; then analyzing the stress monitoring data curve to reflect the monitoring process in real time; when an abnormal change in the inflection point appears in the stress monitoring data curve, feedback is given to the construction operation surface to perform phased tensioning of the prestressed tendons 11 to compensate for the stress, so that the surrounding rock 1 tends to be in a stable state.
[0041] like Figures 1 to 5 As shown, the staged compensation control method for rockburst damage in this embodiment specifically includes the following steps:
[0042] Step 1, Construction Preparation; The anchor cable prestressing tendon 11 is an unbonded prestressing tendon, with one end as the fixed end 13 and the other end as the tensioning end 14; the fixed end 13 is equipped with a fixed end compression anchor 4, including a fixed anchor plate 5, a compression sleeve, a compression spring, and steel strands. A compression spring is fitted onto one end of the steel strand, and the end with the compression spring is pressed into the compression sleeve using a compression machine. The compression spring is completely embedded between the compression sleeve and the steel strand. The steel strand with the compression sleeve fitted is then sequentially threaded into the installation holes of the fixed anchor plate 5 and fed into the front end of the duct 3 as a whole; the main... The function is to fix the steel strand inside the surrounding rock, so that the steel strand and the rock mass form a whole; the tensioning end compression anchor 9 includes tensioning end anchor plate 7, working anchor, tensioning end anchor ring clamp 8, and steel strand. Check the hole 3 where the steel strand is placed and the number of the steel strand. Place the tensioning end anchor plate 7 at the rear end of the hole 3. Pass the steel strand through the hole on the working anchor in sequence and embed it into the tensioning end anchor ring clamp 8 for fastening. Then, the tensioning operation is carried out by the jack and the tool anchor for fastening after the jack. The main function of the tensioning end is to provide sufficient prestress value to improve the tensile strength of the rock mass.
[0043] Step 2, duct construction; specifically, after the positioning and layout are completed, the drilling machine is positioned and drilling is carried out at a certain inclination angle θ. After the drilling is completed, the hole quality is checked. After the inspection is qualified, the duct 3 is cleaned.
[0044] Step 3, Placement and Fixing of Stress Monitoring Element 6: Specifically, the stress monitoring element 6 is placed at the tensioning end 14. The end of the channel 3 is enlarged using a hole enlarging machine to obtain the enlarged hole position 12. The stress monitoring element 6 is placed in the enlarged hole position 12 and fixed in the channel 3 with strong adhesive.
[0045] It should be noted that the stress monitoring element 6 is used to monitor the stress change of the anchor cable (anchor cable prestressing tendon 11) prestress and to further tension the anchor cable prestress in stages.
[0046] Step 4, Anchor Cable Placement and Duct Grouting: After steps 1-3 are completed, specifically, the fixed end 13 of the anchor cable prestressing tendon 11 is placed at the front end of the duct 3, and the tensioning end 14 is equipped with the tensioning end anchor plate 7, the tensioning end working anchor 9, and the tensioning end anchor ring clamp 8. Grouting 2 is carried out through the grouting hole 10 on the anchor plate 7, and the quality of the grouting material is strictly controlled.
[0047] Step 5, Initial Tensioning Control: Specifically, after the strength of grouting 2 meets the requirements, the stress monitoring element 6 is read for the first time to obtain the initial stress monitoring value P0. Combined with the uniaxial compressive strength stress index obtained from the indoor rock test of the surrounding rock 1 sample, the pre-applied force is deduced by calculating the exposed area after excavation failure. The anchor cable prestressing tendon 11 is tensioned for the first time to compensate for the pre-added amount after the initial excavation failure. After completion, the stress monitoring value P1 after tensioning is read.
[0048] Step 6, Rockburst Section Excavation: Specifically, preliminary excavation is carried out based on the initial tensioning compensation, while stress monitoring data is collected, analyzed, and fed back.
[0049] Step 7, phased tensioning control: Specifically, based on the feedback from stress monitoring data, when a reversal point appears on the stress monitoring graph, it indicates that the tension amount is lower than the expansion amount inside the rock mass. Then, the anchor cable prestressing tendon 11 is tensioned again. When the stress monitoring curve shows a stable trend, it indicates that the surrounding rock mass 1 is approaching a state of equilibrium.
[0050] In this embodiment, the staged compensation tensioning is based on the law of conservation of energy. Where E represents the potential energy stored in the rock strata; A i P represents the work done by the deformation of rock strata under the action of external forces. i This represents the external force acting on the rock strata, i.e., the tension force in this embodiment; It indicates the change in position, shape, and volume of rock strata under the action of external forces.
[0051] The following conditions must be met when tensioning is performed in stages with compensation:
[0052] Σ(σ i )dF i +ΣE p <ΣP i
[0053] Where, Σ(σ i )dF i ΣE represents the total allowable stress resistance of the rock mass to prevent failure; pP represents the sum of active lateral pressures on the rock mass. i Let be the tension force during the i-th tensioning.
[0054] Step 8: Repeat step 7 until the rockburst zone is excavated. Specifically, each time a reversal point appears on the stress monitoring chart, it indicates that the surrounding rock is unstable. At this time, compensation tensioning is performed to make the surrounding rock 1 tend to be flat. After the rockburst zone is completed, the excess anchor cable prestressing tendons 11 are cut off and the permanent structure is constructed. For the segmented rockburst parts, repeat steps 1-8 until the permanent construction is completed, and then the monitoring and tensioning can be stopped.
[0055] In summary, the staged compensation control method for rockburst damage described in the above embodiments uses anchor cable prestressed tendons, combined with real-time stress monitoring results of the rock mass, to obtain the stress changes of the rock mass after stress release under external force. Based on the stress changes, the prestressed anchor cables are tensioned in stages to meet the external force acting on the rock mass, achieve equilibrium when the rock mass is undisturbed, and avoid the occurrence of rockbursts and the resulting damage.
[0056] 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 staged compensation control of rockburst damage, characterized in that, Includes the following steps: S1: Geological Exploration After sampling the surrounding rock mass, indoor rock tests were conducted on the rock samples, and the severity of rockburst was determined by theoretical criteria. S2: Construction of prestressed anchor cable system Select the type of prestressed anchor cable and construct the duct; S3: Placement and fixation of stress monitoring components The stress monitoring element is placed at the tensioning end of the prestressed anchor cable. The end of the duct is enlarged using a hole enlarging machine to obtain an enlarged hole position. The stress monitoring element is placed in the enlarged hole position and fixed in the duct with strong adhesive. The stress monitoring element is used to monitor the stress change of the anchor cable prestress. S4: Anchor cable installation and grouting treatment of ducts First, place the fixed end of the anchor cable prestressing tendon at the front end of the duct and install the fixed end compression anchor. Then, lead the tensioning end of the anchor cable prestressing tendon out from the rear end of the duct and install the tensioning end compression anchor. Fill the duct with grout through the grouting hole on the tensioning end compression anchor. S5: Initial tensioning After the grouting strength meets the requirements, the stress monitoring element is read for the first time to obtain the initial stress monitoring value. Combined with the uniaxial compressive strength stress index obtained from the rock sample in the indoor rock test, the pre-applied force is deduced by calculating the exposed area after excavation failure, and the anchor cable prestressing tendon is tensioned for the first time to compensate for the pre-added amount of the initial excavation failure. S6: Excavation of the rockburst section Preliminary excavation was carried out based on the initial tensioning compensation, while stress monitoring data was collected, analyzed, and fed back. S7: Phased Compensation Tensioning Based on the feedback from stress monitoring data, when a reversal point appears on the stress monitoring chart, it indicates that the tension is lower than the swelling inside the rock mass. Then, the prestressed anchor cable is tensioned again. When the stress monitoring chart shows a stable trend, it indicates that the surrounding rock mass is approaching a state of equilibrium. S8: Excavation of the rockburst zone completed. Multiple compensation tensioning operations were conducted until the excavation of this rockburst zone was completed.
2. The method for staged compensation control of rockburst damage according to claim 1, characterized in that, In step S1, the likelihood of rock bursts is predicted by combining indoor rock experiments with rock samples, and the severity of rock bursts is graded to distinguish key areas of concern, the number and range of anchor cables.
3. The method for staged compensation control of rockburst damage according to claim 1, characterized in that, In step S2, the prestressed anchor cable can meet the requirements of phased tensioning and release, including multiple anchor cable prestressing tendons, fixed end compression anchors, and tensioning end compression anchors. The fixed end compression anchors are set at the front end of the multiple anchor cable prestressing tendons, i.e., the front end of the duct, and the tensioning end compression anchors are set at the rear end of the multiple anchor cable prestressing tendons, i.e., the rear end of the duct.
4. The method for staged compensation control of rockburst damage according to claim 3, characterized in that, The fixed-end extrusion anchor includes a fixed anchor plate, an extrusion sleeve, an extrusion spring, and steel strands. An extrusion spring is fitted onto one end of the steel strands, and the end with the extrusion spring is pressed into the extrusion sleeve by an extrusion machine. The extrusion spring is fully embedded between the extrusion sleeve and the steel strands. The steel strands with the extrusion sleeve are then sequentially threaded into the installation holes of the fixed anchor plate and fed into the front end of the channel as a whole.
5. The method for staged compensation control of rockburst damage according to claim 3, characterized in that, The tensioning end compression anchor includes a tensioning end anchor plate, a working anchor, a tensioning end anchor ring clamp, and steel strands. After verifying the placement of the steel strands in the ducts and the steel strand numbers, the tensioning end anchor plate is placed at the rear end of the duct. The steel strands are then passed through the holes on the working anchor in sequence and embedded in the tensioning end anchor ring clamp for fastening. Then, the tensioning operation is carried out using a jack and a tool anchor.
6. The method for staged compensation control of rockburst damage according to claim 1, characterized in that, In step S2, the process of duct construction is as follows: after the positioning and layout are completed, the drilling machine is positioned and drilling is performed at a preset inclination angle θ. After the drilling is completed, the hole quality is checked. After the inspection is qualified, the duct is cleaned.
7. The method for staged compensation control of rockburst damage according to claim 3, characterized in that, In step S7, the stress monitoring element collects stress monitoring data of the prestressed anchor cable around the clock and throughout the entire process, and reflects the stress changes in real time through the computer backend. By analyzing the stress change curve through stress monitoring, a stress monitoring diagram is obtained, which is then fed back to the construction operation surface for re-tensioning of the anchor cable prestress.
8. The method for staged compensation control of rockburst damage according to claim 7, characterized in that, In step S7, the following conditions are met during the staged compensation tensioning: S(s i )dF i +SE p <ΣP i ; Where, Σ(σ i )dF i ΣE represents the total allowable stress resistance of the rock mass to prevent failure; p P represents the sum of active lateral pressures on the rock mass. i Let be the tension force during the i-th tensioning.
9. The method for staged compensation control of rockburst damage according to claim 8, characterized in that, In step S8, when a reversal point appears on the stress monitoring chart, it indicates that the surrounding rock is unstable. At this time, compensation tensioning is performed to make the surrounding rock tend to be flat. After the rockburst section is excavated, the excess anchor cable prestressing tendons are cut off and the permanent structure is constructed. For the segmented rockburst section, steps S1 to S8 are repeated until the permanent construction is completed, and then the monitoring and tensioning work can be ended.