An aging collaborative control method based on the selection of different target points before and after the peak of roadway surrounding rock

Abstract

The present invention relates to the field of engineering rock mass technology, and specifically discloses a time-effective coordinated control method based on the selection of differential targets before and after the peak of tunnel surrounding rock. Based on ground stress conditions and coal rock mechanical parameters, combined with the FDEM method, the process of incubation-initiation-extension of elastic deformation before the peak of surrounding rock and tension-shear fracture after the peak after tunnel excavation is simulated, the development characteristics of the tension-shear fracture network of surrounding rock are predicted in advance, and the tension and shear control targets within the plastic zone of surrounding rock are determined; through the two-stage control method of "pre-peak prediction" targeted strengthening and "post-peak prediction + observation" targeted control, the time-effective coordinated control of differential targets before and after the peak of surrounding rock is realized. The method uses FDEM and borehole imaging, based on the evolution characteristics of the tunnel tension-shear fracture network, to identify and distinguish tension control targets, shear control targets and grouting targets in the tension-shear fracture network of surrounding rock on a microscopic scale, specifically adjust the anchor (cable) structure and grouting parameters, and realize the targeted time-effective strengthening control of surrounding rock throughout the life cycle of the tunnel.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering rock masses, and in particular to a time-effect collaborative control method based on the selection of different target points before and after the peak of roadway surrounding rock. Background Art

[0002] As the mesoscopic structure of the excavation damage zone (EDZ) of underground roadways, the mesoscopic tensile-shear fracture network of surrounding rock has a significant process of gestation-germination-expansion under the action of roadway excavation unloading. Affected by factors such as the working face layout, lithology, and in-situ stress direction, its development range and expansion direction have strong regularity and predictability. The existing support strategies based on elastic theory for controlling the macroscopic plastic zone of roadways have low timeliness and lack consideration of the mesoscopic structure and evolution law of the excavation damage zone (EDZ) of roadways. Most of the existing surrounding rock control theories tend to suspend, combine, and compress the macroscopic damage zone, or improve and explain the macroscopic mechanical parameters of the anchored body, without clearly discussing the fracture mechanism and mesoscopic fracture network morphology in the excavation damage zone, and to a certain extent ignoring the pre-peak inhibition effect of bolt (cable) components on the potential fracture germination and development within the loosening damage zone; currently, the design of the secondary support scheme of roadway surrounding rock bolts (cables) under different geological conditions or mining states is mostly based on the macroscopic loosening circle range of the surrounding rock, strengthening the bearing capacity of the post-peak fractured surrounding rock by increasing the number of bolts (cables) or changing the length of bolts (cables), lacking consideration of the synergistic effect of pre-peak control and post-peak regulation of surrounding rock during the whole life cycle of the roadway, and not clarifying the time-effect synergistic relationship between the pre-peak and post-peak control methods and control effects of the surrounding rock. Summary of the Invention

[0003] The purpose of the present invention is to address the above problems and provide a time-effect collaborative control method based on the selection of different target points before and after the peak of roadway surrounding rock. To solve the above technical problems, the present invention adopts the following technical solutions:

[0004] A time-effect collaborative control method based on the selection of different target points before and after the peak of roadway surrounding rock involves the following stages and steps:

[0005] Pre-peak stage:

[0006] (1) Based on the mine geological data and mining data, determine the position, driving direction of the roadway to be excavated, and the distribution state of in-situ stress around it, and clarify the types and mechanical parameters of the coal and rock masses near the roadway;

[0007] (2) Based on the mining state, in-situ stress parameters, and mechanical parameters of coal and rock masses near the roadway to be excavated, construct an FDEM numerical model of roadway excavation, obtain the evolution process of the tensile-shear fracture network of the surrounding rock after roadway excavation through numerical calculation, and combine the mine mining data to predict the stress transfer process, deformation and failure law of the surrounding rock, and the expansion range and development direction of the tensile-shear fracture network;

[0008] (3) Classify the anchoring target points for the anchoring range of bolts and cables according to the development characteristics of the tensile-shear fracture network predicted by FDEM simulation; take the widely developed positions of tensile cracks in the shallow surrounding rock within the anchoring range of bolts and cables as the tensile control target points, and take the intersection areas of shear strain zones in the deep surrounding rock within the anchoring range of bolts and cables as the shear control target points;

[0009] (4) Based on the distribution of tensile-shear control target points within the anchoring range of bolts and cables, adjust the material, structure, and layout parameters of bolts and cables in the primary support plan; for the distribution area of tensile control target points within the anchoring range, change the material to improve the tensile strength of the bolt and cable body or increase the installation pre-tightening force; for the shear control target points within the anchoring range, increase the radius of bolts and cables at the corresponding positions, install shear-resistant devices, or increase the anchoring force;

[0010] (5) Use the modified specific bolts and cables to carry out the primary support for the surrounding rock, adjust the laying length and laying angle of bolts and cables, so that the length of bolts and cables is greater than the plastic zone radius of the surrounding rock in this direction, and at the same time, the bolt and cable body is perpendicular to the predicted tensile-shear fractures;

[0011] Post-peak stage:

[0012] (6) Conduct real-time monitoring on the excavated roadway, monitor the deformation of the surrounding rock through the GWL300 intrinsically safe displacement sensor, and for the positions where significant large deformations occur or the surrounding rock is severely broken during the service period of the roadway, carry out full-section borehole imaging through the ZLJ350 roadway drill in cooperation with the ZKXG100 mine intrinsically safe borehole peep detector;

[0013] (7) Compare the borehole imaging with the FDEM numerical simulation results of the roadway section in the corresponding section to determine the development state of the tensile-shear fracture network of the surrounding rock in the roadway section in the corresponding section, and judge the development range of the tensile-shear fracture network of the surrounding rock, the development depth of tensile fractures, and the development positions of shear strain zones;

[0014] (8) Based on the comparison results of observation and simulation, use the target discrimination criteria in step (4) to judge the positions of tensile and shear control target points of the surrounding rock, carry out specific modifications to the reinforcement bolts and cables, and at the same time adjust the length, laying direction, laying density, and layout position of bolts and cables according to the development range of the fracture network to determine the secondary support plan for the large deformation area of the roadway;

[0015] (9) According to the comparison results of borehole imaging and simulation, divide the grouting control target points in the surrounding rock into shallow grouting control target points and deep grouting control target points; among them, the shallow grouting control target points are mainly based on the developed positions of tensile fractures or tensile-shear mixed fractures in the surrounding rock. The borehole imaging results are mainly characterized by shallow target positions, short fracture interval distances, and high surrounding rock fragmentation degrees. Adopt targeted one-round grouting to bond the fragmented rock mass into a whole to construct the shallow pressure-bearing shell of the roadway and control the dilatation deformation of the post-peak fractured surrounding rock;

[0016] (10)The main control target of deep grouting is mainly the slip position of the surrounding rock shear strain band. The main characteristics in the borehole imaging results are that the target position is deep, the fracture interval distance is long, and the surrounding rock is intact. Targeted secondary grouting is carried out to construct a deep pressure-bearing shell by increasing the grouting pressure and grouting range, and control the slip deformation of the surrounding rock after peak fracture.

[0017] (11)Targeted reinforcement control is carried out on the surrounding rock in the large deformation area of the roadway through local specific bolt and cable reinforcement of the surrounding rock and targeted grouting reinforcement.

[0018] (12)Through FDEM numerical simulation and borehole imaging observation methods, pre-peak prediction and post-peak observation of the evolution characteristics of the roadway tensile-shear fracture network are carried out. Combining the discrimination of the tensile-shear fracture network target of the roadway surrounding rock at the mesoscopic scale, the bolt and cable materials, structures, layout parameters are specifically modified, and the surrounding rock grouting parameters are specifically adjusted to strengthen the targeted aging control of the roadway surrounding rock throughout the life cycle.

[0019] Furthermore, the in-situ stress distribution state includes the direction 、 、 and magnitude 、 、 ;

[0020] Furthermore, the mechanical parameters include the elastic modulus E d 、tensile strength 、compressive strength 、cohesion C 、internal friction angle Φ 、Poisson's ratio v 。

[0021] Due to the adoption of the above technical solutions, the present invention has remarkable technical effects: (1) By means of FDEM numerical simulation and borehole imaging technology, this method fully combines the mesoscopic evolution characteristics of the tensile-shear fracture network of roadway surrounding rock. Based on the mesoscopic differences in the fracture types, development ranges, and propagation laws of the surrounding rock, it realizes the differential selection and targeted control of the tensile control target points, shear control target points, and grouting target points of the roadway surrounding rock, and improves the refined strategy selection of the surrounding rock control plan. (2) This method fully considers the evolution characteristics of the tensile-shear fracture network structure of the roadway surrounding rock, and combines the advanced inhibition effect of bolt (cable) components on the initiation and development of potential fractures in the loosened and damaged area, realizing the discrimination of differential target points for roadway surrounding rock control, pre-peak prediction and prevention, and post-peak coordinated control. (3) Based on the evolution law of the tensile-shear fracture network of the roadway surrounding rock, by distinguishing the effective mechanisms of different surrounding rock control means, differentially selecting the surrounding rock control target points, and establishing a time-effect coordinated control system for the pre-peak and post-peak of the surrounding rock, this method significantly reduces the cost of roadway stability control and realizes the targeted time-effect strengthening control of the surrounding rock throughout the life cycle of the roadway. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 FIG. is a technical roadmap of the time-effect coordinated control method based on the differential target selection before and after the peak of the roadway surrounding rock in the present invention;

[0023] Figure 2 FIG. is a schematic diagram of target selection based on the mesoscopic tensile-shear fracture network of the roadway surrounding rock in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "vertical", "upper", "lower", "horizontal", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, "first", "second", "third", "fourth" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0026] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "couple" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or a connection through an intermediate medium; it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] As Figure 1-2 shown, a time-effect collaborative control method based on the selection of different target points before and after the peak of roadway surrounding rock in the present invention involves the following stages and steps:

[0028] Before-peak stage:

[0029] (1) Based on the mine geological data and mining data, determine the position of the roadway to be excavated in advance, the driving direction, and the distribution state of in-situ stress around it, and clarify the types and mechanical parameters of the coal and rock masses near the roadway.

[0030] (2) Based on the mining state, in-situ stress parameters, and mechanical parameters of coal and rock masses near the roadway to be excavated in advance, construct an FDEM numerical model for roadway excavation, and obtain the evolution process of the tensile-shear fracture network of the surrounding rock after roadway excavation through numerical calculation. Combine the mine mining data to predict the stress transfer process, deformation and failure law of the surrounding rock, and the expansion range and development direction of the tensile-shear fracture network.

[0031] (3) Classify the anchoring target points for the anchoring range of bolts (cables) according to the development characteristics of the tensile-shear fracture network predicted by FDEM simulation. Take the position where tensile cracks widely develop in the shallow surrounding rock within the anchoring range of bolts (cables) as the tensile control target point (the main deformation failure characteristic of the bolts within the area is tensile stress along the bolt axis), and take the intersection area of the shear strain zones in the deep surrounding rock within the anchoring range of bolts (cables) as the shear control target point (the main deformation failure characteristic of the bolts within the area is shear stress along the slip direction of the shear strain zone).

[0032] (4) Based on the distribution of tensile-shear control target points within the anchoring range of bolts (cables), adjust the material, structure, and layout parameters of bolts (cables) in the primary support plan. In the area where the tensile control target points are distributed within the anchoring range, improve the tensile strength of the bolt (cable) body or increase the installation pre-tightening force by changing the material to further improve the anchoring force of the bolt (cable) and inhibit the development of tensile cracks in the shallow surrounding rock. For the shear control target points within the anchoring range, increase the radius of the bolts (cables) at the corresponding positions, install shear-resistant devices, or increase the anchoring force (normal stress) to specifically improve the shear strength of the bolts (cables) and the overall shear resistance of the rock to control the slip and dislocation of the surrounding rock.

[0033] (5) Use the transformed specific bolt (cable) to carry out the primary support on the surrounding rock, adjust the layout length and layout angle of the bolt (cable), so that the length of the bolt (cable) is greater than the plastic zone radius of the surrounding rock in this direction, and at the same time, the rod (cable) body is perpendicular to the predicted tensile-shear fracture, so as to achieve the targeted strengthening of the surrounding rock in the pre-peak stage during the primary support process;

[0034] Post-peak stage:

[0035] (6) Conduct real-time monitoring on the excavated roadway, monitor the deformation of the surrounding rock through the GWL300 intrinsically safe displacement sensor, and for the positions where significant large deformations occur in the roadway during the service period or the surrounding rock is severely broken, carry out full-section borehole imaging through the ZLJ350 roadway drill in cooperation with the ZKXG100 mine intrinsically safe borehole peep detector;

[0036] (7) Compare the borehole imaging with the FDEM numerical simulation results of the roadway section in the corresponding section, determine the development state of the tensile-shear fracture network of the surrounding rock in the roadway section in the corresponding section, and judge the development range of the tensile-shear fracture network of the surrounding rock, the development depth of the tensile fracture, and the development position of the shear strain zone;

[0037] (8) Based on the comparison results of the observation and simulation, use the target discrimination criteria in step (4) to judge the positions of the tensile and shear control targets of the surrounding rock, carry out the specific transformation of the reinforcing bolt (cable), and at the same time adjust the length, layout direction, layout density and layout position of the bolt (cable) according to the development range of the fracture network, and determine the secondary support plan for the large deformation area of the roadway;

[0038] (9) According to the comparison results of the borehole imaging and the simulation, along the borehole direction, based on the regionality of the development of the tensile and shear fractures of the surrounding rock, it is stipulated that the relative position where the tensile and shear fractures develop close to the excavation free surface of the roadway is the shallow part, and the relative position where the tensile and shear fractures develop far from the excavation free surface of the roadway is the deep part. Divide the grouting control targets in the surrounding rock into shallow grouting control targets and deep grouting control targets. Among them, the shallow grouting control targets are mainly based on the development positions of the tensile fractures or tensile-shear mixed fractures of the surrounding rock. The main characteristics of the borehole imaging results are that the target position is shallow (close to the excavation free surface of the roadway), the fracture interval distance is short, and the degree of fragmentation of the surrounding rock is high. Carry out low-pressure targeted one-round grouting, and build a shallow pressure-bearing shell by bonding the broken rock mass into a whole to improve the swelling deformation of the shallow surrounding rock;

[0039] (10) The deep grouting control targets are mainly based on the slip positions of the shear strain zones of the surrounding rock. The main characteristics of the borehole imaging results are that the target position is deep (far from the excavation free surface of the roadway), the fracture interval distance is long, and the core blocks are complete. Carry out targeted two-round grouting, and build a deep pressure-bearing shell by increasing the grouting pressure and grouting range to control the slip deformation of the post-peak fractured surrounding rock;

[0040] (11) By strengthening the surrounding rock of the roadway through local specific bolts (cables) and targeted grouting reinforcement, targeted reinforcement control is carried out on the surrounding rock in the large deformation area of the roadway, inhibiting the continuous occurrence of structural instability and shear slip deformation of the surrounding rock after the peak, and realizing the targeted reinforcement and strengthening of the roadway surrounding rock;

[0041] (12) Through FDEM numerical simulation and borehole imaging observation methods, pre-peak prediction and post-peak observation of the evolution characteristics of the tensile-shear fracture network in the roadway are realized. Combining the discrimination of the target points of the tensile-shear fracture network of the roadway surrounding rock at the mesoscopic scale, by specifically modifying the bolt (cable) materials, structures, layout parameters and specifically adjusting the surrounding rock grouting parameters, targeted time-dependent strengthening control of the roadway surrounding rock throughout its life cycle is achieved.

[0042] The described in-situ stress distribution state includes the principal stress direction 、 、 and magnitude 、 、 ; The described mechanical parameters include the elastic modulus E d 、tensile strength 、compressive strength 、cohesion C 、internal friction angle Φ 、Poisson's ratio v ;

[0043] The present invention discloses a method for time-dependent collaborative control of differential target points before and after peak based on the evolution of mesoscopic tensile-shear fracture network in roadways. As the mesoscopic structure of the excavation damaged zone (EDZ) in underground roadways, the mesoscopic tensile-shear fracture network in surrounding rock has a significant process of gestation-initiation-propagation under the action of roadway excavation unloading. Affected by factors such as the working face layout, lithology, and in-situ stress direction, its development range and propagation direction have strong regularity and predictability. Based on the in-situ stress conditions and mechanical parameters of coal and rock masses of the pre-excavated roadway obtained through on-site investigation and laboratory tests, combined with the FDEM numerical simulation method, it is possible to numerically calculate and simulate the pre-peak elastic deformation of surrounding rock and the gestation-initiation-propagation process of post-peak tensile-shear fractures after roadway excavation, predict in advance the development range and propagation direction of the post-peak tensile-shear fracture network in surrounding rock, and determine the tensile and shear control target points within the plastic zone of the surrounding rock of the pre-excavated roadway; for the predicted target point types and positions where the target points are generated, transform the materials and structures of the corresponding sections of the bolt (cable) and adjust the layout direction of the bolt (cable) at the same time to achieve targeted strengthening of the surrounding rock in the pre-peak stage during the primary support process; for the significantly large deformation positions of the roadway under the primary support, use borehole imaging technology to observe the fracture evolution characteristics in the surrounding rock, and compare with the FDEM simulation results to determine the range of the tensile fracture zone and the development position of the shear strain band in the surrounding rock; take the development positions of the tensile fractures and shear strain bands within the grouting hole range as the grouting target points, and by adjusting grouting parameters such as grouting position, grouting radius, and grouting material, and adjusting the layout parameters of the secondary support bolts (cables) of the roadway at the same time, achieve targeted reinforcement of the surrounding rock in the post-peak stage of the large deformation area of the roadway; through the two-stage control methods of "pre-peak prediction" targeted strengthening and "post-peak prediction + observation" targeted control of the surrounding rock of the roadway, realize the time-dependent collaborative control of differential target points before and after peak of the surrounding rock of the roadway. This method, through the FDEM numerical simulation and borehole imaging methods, based on the evolution characteristics of the tensile-shear fracture network in the roadway, divides the tensile-shear fracture network in the surrounding rock of the roadway into tensile control target points, shear control target points, and grouting target points at the mesoscopic scale, and realizes the targeted time-dependent strengthening control of the surrounding rock of the roadway throughout its life cycle by specifically transforming the bolt (cable) structure and specifically adjusting the surrounding rock grouting parameters, improving the stability of the surrounding rock during the service period of the roadway.

[0044] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0045] The embodiments described above only represent the implementation modes of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A time-effective collaborative control method based on the selection of target points before and after the peak of surrounding rock in tunnels, characterized in that: The following stages and steps are involved: Pre-peak stage: (1) Based on the mine geological data and mining data, determine the location of the pre-excavation tunnel, the excavation direction and the surrounding ground stress distribution state, and clarify the type and mechanical parameters of the coal and rock mass near the tunnel; (2) Based on the mining status, ground stress parameters and coal rock mechanical parameters near the pre-excavated tunnel, a FDEM tunnel excavation numerical model was constructed. The evolution process of the tensile-shear fracture network of the surrounding rock after tunnel excavation was obtained through numerical calculation. Combined with the mining data of the mine, the stress transfer process of the surrounding rock, the deformation and failure law, and the extension range and development direction of the tensile-shear fracture network were predicted. (3) According to the development characteristics of the tensile shear fracture network predicted by FDEM simulation, the mesoscopic evolution characteristics of the tensile shear fracture network of the tunnel surrounding rock are fully combined. Based on the mesoscopic differences in the surrounding rock fracture types, development range, and expansion laws, the anchoring target points of the anchor bolt and cable anchoring range are classified; the locations where the tensile fractures of the surrounding rock within the anchor bolt and cable anchoring range are widely developed are taken as the tensile control targets, and the intersection areas of the shear strain zones of the surrounding rock within the anchor bolt and cable anchoring range are taken as the shear control targets; (4) Based on the distribution of tension-shear control target points within the anchoring range of anchor rods and cables, combined with the advanced inhibitory effect of anchor rod and cable components on the initiation and development of potential ruptures in the loosening and damage zone, adjust the material, structure and layout parameters of anchor rods and cables in the primary support plan; for the distribution area of ​​tension control target points within the anchoring range, change the material to improve the tensile strength of the anchor rod and cable body or increase the installation preload; for the shear control target points within the anchoring range, increase the radius of the anchor rod and cable at the corresponding position, install a shear device or increase the anchoring force; (5) Use the modified specific anchor bolts and cables to carry out primary support for the surrounding rock, adjust the length and angle of the anchor bolts and cables, make the length of the anchor bolts and cables greater than the plastic zone radius of the surrounding rock in that direction, and make the anchor bolts and cables perpendicular to the predicted tensile shear fracture, so as to achieve targeted strengthening of the surrounding rock in the pre-peak stage during the primary support process; Post-peak stage: (6) Real-time monitoring of the excavated tunnels, monitoring the deformation of the surrounding rock through the GWL300 intrinsically safe displacement sensor, and using the ZLJ350 tunnel drilling rig and the ZKXG100 mining intrinsically safe borehole peep detector to carry out full-section borehole imaging for locations where the tunnels have undergone significant deformation or severe surrounding rock crushing during the service period; (7) Compare the borehole imaging with the FDEM numerical simulation results of the corresponding section of the tunnel section to determine the development state of the surrounding rock tensile-shear fracture network of the corresponding section of the tunnel section, and judge the development range of the surrounding rock tensile-shear fracture network, the development depth of the tensile fracture, and the development location of the shear strain band; (8) Based on the observation and simulation comparison results, the target point identification criteria in step (4) are used to determine the position of the surrounding rock tension and shear control target points, and specific transformation of the reinforcement anchor bolts and cables is carried out. At the same time, the anchor bolt length, layout direction, layout density and layout position are adjusted according to the development range of the fracture network, and the secondary support plan for the large deformation area of ​​the tunnel is determined; (9) Based on the borehole imaging and simulation comparison results, the grouting control targets in the surrounding rock are divided into shallow grouting control targets and deep grouting control targets. The shallow grouting control targets are mainly composed of the locations where tensile fractures or tensile-shear mixed fractures of the surrounding rock are developed. The borehole imaging results are characterized by shallow target locations, short fracture intervals, and high degree of surrounding rock fragmentation. A targeted round of grouting is used to bond the broken rock mass into a whole to construct the shallow pressure-bearing shell of the tunnel, thereby controlling the crushing and expansion deformation of the post-peak fracture surrounding rock. (10) The control target of deep grouting is mainly the sliding position of the shear strain zone of the surrounding rock. The main features of the borehole imaging results are the deep target position, long fracture interval distance, and intact core block. A targeted second round of grouting is carried out to build a deep pressure shell by increasing the grouting pressure and grouting range to control the sliding deformation of the surrounding rock after the peak fracture. (11) Through local specific anchor bolt and cable reinforcement and targeted grouting reinforcement of the surrounding rock, targeted reinforcement control is carried out on the surrounding rock in the large deformation area of ​​the tunnel; (12) Through FDEM numerical simulation and borehole imaging observation methods, the pre-peak and post-peak prediction of the evolution characteristics of the tensile-shear fracture network of the tunnel is realized. Combined with the identification of the target points of the tensile-shear fracture network of the tunnel surrounding rock at the microscopic scale, the materials, structures, and layout parameters of the anchor rods and cables are modified in a targeted manner, and the grouting parameters of the surrounding rock are specifically adjusted to achieve targeted time-effective strengthening control of the surrounding rock throughout the life cycle of the tunnel.

2. The time-effective collaborative control method based on the selection of target points before and after the peak of surrounding rock in tunnel according to claim 1 is characterized by: The ground stress distribution state includes the principal stress directions θ1, θ2, θ3 and magnitudes σ1, σ2, σ3.

3. The time-effective collaborative control method based on the selection of target points before and after the peak of surrounding rock in tunnel according to claim 1 is characterized by: The mechanical parameters include elastic modulus E d , tensile strength σ t , compressive strengthσ c , cohesion C, internal friction angle Φ, Poisson's ratio v.

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