Temporary support optimization method, system and device based on stress diffusion model

Abstract

The invention relates to the technical field of mining and tunneling support, in particular to a temporary support optimization method, system and device based on a stress diffusion model. Obtaining the distribution characteristics of a temporary support stress field in the roadway surrounding rock unsupported area based on the temporary support stress diffusion model, analyzing the characteristics of the stress field generated by the temporary support in the roadway surrounding rock unsupported area through a numerical simulation experiment, verifying the temporary support stress diffusion model, and obtaining factors influencing the stability of the surrounding rock in the roadway surrounding rock unsupported area; according to the method, the linear relation between the optimal temporary supporting force and the non-supporting distance is determined, the optimal temporary supporting force is derived, the maximum non-supporting distance and the sum of the length of a temporary supporting area and the non-supporting distance are determined based on the attenuation degree of the temporary supporting stress, and therefore cutting parameters and temporary supporting parameters are designed and optimized. According to the method, efficient development of coal resources can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of mine mining and tunneling support, and more specifically to a temporary support optimization method, system and device based on a stress diffusion model. Background Art

[0002] A key bottleneck facing the efficient development of coal resources is the imbalance between tunneling and mining activities. The core problem of the slow progress of tunneling operations is that tunneling and permanent support operations are difficult to implement in parallel. This limitation significantly restricts production efficiency. To solve this problem, temporary support is seen as a potential breakthrough. However, there is currently a lack of clear understanding of the mechanism of how temporary support specifically affects the stability of the surrounding rock of the tunnel in the unsupported area. This technical gap not only hinders the effective guarantee of the stability of the unsupported area, but also makes it a major challenge to reasonably set the unsupported span. Therefore, in-depth exploration of the mechanism of temporary support is crucial to improving tunneling efficiency and ensuring the overall safety of mining operations. Summary of the invention

[0003] The purpose of the present invention is to provide a temporary support optimization method based on a stress diffusion model, which is used to provide a stress diffusion model for tunnel excavation in a coal mine fully mechanized mining face, so as to analyze the stress diffusion effect of temporary support and determine its reasonable span and strength, thereby optimizing construction parameters, improving support design, and providing effective technical support for the rapid exploitation of coal resources.

[0004] In order to achieve the above object, the present invention is implemented by the following steps:

[0005] Step S1: establishing a temporary support stress diffusion model, and obtaining the distribution characteristics of the temporary support stress field in the unsupported area of ​​the tunnel surrounding rock based on the temporary support stress diffusion model;

[0006] Step S2: analyzing the characteristics of the stress field generated by the temporary support in the unsupported area of ​​the tunnel surrounding rock through numerical simulation experiments, and verifying the temporary support stress diffusion model;

[0007] Step S3: Based on the temporary support stress diffusion model and the characteristics of the stress field generated by the temporary support in the unsupported area of ​​the tunnel surrounding rock, the factors affecting the stability of the unsupported area of ​​the tunnel surrounding rock are analyzed, wherein the factors include the size of the temporary support force, the length of the temporary support area and the unsupported distance;

[0008] Step S4: Based on the factors that affect the stability of the surrounding rock in the unsupported area of ​​the tunnel surrounding rock, determine the linear relationship between the optimal temporary support force and the unsupported distance, and derive the optimal temporary support force required for the unsupported area. Based on the attenuation degree of the temporary support stress, determine the maximum unsupported distance. Based on the top plate stress, determine the sum of the temporary support area length and the unsupported distance. Based on the temporary support stress diffusion model, design and optimize the cutting parameters and temporary support parameters, arrange equipment, and design and optimize the tunnel excavation process.

[0009] As a preferred technical solution of the present invention, in step S1, establishing a temporary support stress diffusion model includes:

[0010] Step S11: dividing the tunnel into a waiting excavation area, an empty top area, a temporary support area and a permanent support area, and considering the tunnel surrounding rock as an infinite beam, and considering the effect of the temporary support force on the tunnel surrounding rock as a uniform normal force acting on the infinite beam plane;

[0011] Step S12: Integrate the first radial stress on the temporary support area to obtain the second radial stress caused by the temporary support force at any given point. The first radial stress is expressed by Formula 1, and the second radial stress is expressed by Formula 2:

[0012]

[0013] Step S13: Integrate the second radial stress on the empty top area to obtain the diffusion stress of the temporary support force in the top plate space, which is expressed by Formula 3;

[0014]

[0015] Step S14: obtaining the diffusion law of the temporary support force in the surrounding rock of the tunnel based on Formula 3;

[0016] Among them, F represents the temporary support force, σ1 represents any radial stress, σ2 represents the radial stress caused by the temporary support force F at any point, σ3 represents the stress of the temporary support force F in the empty top area, x is the excavation direction along the tunnel, z is the height direction along the tunnel, L1 is the length of the empty top area, L2 is the length of the temporary support area, ζ represents the micro-segment at the x-axis ζ, and x1, x2, and x3 are the coordinates on the x-axis.

[0017] As a preferred technical solution of the present invention, in step S11, the area to be excavated refers to an area where excavation has not yet been carried out, the empty top area refers to an area where excavation has been completed but lacks temporary support, the temporary support area refers to an area directly supported by temporary support, and the permanent support area refers to a stable area where anchoring work has been completed and the surrounding rock of the tunnel has been formed.

[0018] As a preferred technical solution of the present invention, in step S14, after obtaining the diffusion law of the temporary support force in the surrounding rock of the tunnel:

[0019] Based on the diffusion law of the temporary support force in the surrounding rock of the tunnel, when the temporary support force increases from the roof in the empty top area along the height direction of the tunnel, the stress diffusion of the temporary support force in the empty top area first increases and then decreases, reaching a peak value at a first value;

[0020] The stress diffusion of the temporary support force in the empty top area along the tunnel excavation direction is divided into three continuous areas: a stress diffusion area, a stress attenuation area and a non-diffusion area, wherein the stress diffusion area refers to an area in which the temporary support force has almost no attenuation, the stress attenuation area refers to an area in which the temporary support force attenuates faster, and the non-diffusion area refers to an area in which the temporary support force does not work.

[0021] As a preferred technical solution of the present invention, in step S1, obtaining the distribution characteristics of the temporary support stress field in the unsupported area of ​​the tunnel surrounding rock includes:

[0022] Mathematical modeling is performed on the tunnel surrounding rock, and the temporary support is presupposed to exert a uniform normal force on a semi-infinite plane, and the diffusion law of the temporary support stress in the tunnel surrounding rock along the tunnel height and excavation direction is derived through integral deduction.

[0023] As a preferred technical solution of the present invention, analyzing the stress field generated by the temporary support in the unsupported area includes:

[0024] Simulation experiment A and experiment B are set, wherein experiment A simulates the situation where no temporary support is applied after the tunnel is excavated, and the stress distribution state of the tunnel surrounding rock is recorded as a first distribution state, and experiment B simulates the situation where temporary support is applied after the tunnel is excavated, and the stress distribution state of the tunnel surrounding rock is recorded as a second distribution state;

[0025] A tunnel model is established using numerical model software, and first parameters of the experiment A and the experiment B are input into the tunnel model. For the experiment B, second parameters of the experiment B are also input into the tunnel model, wherein the first parameters are common to the experiments A and B, including tunnel dimensions and rock mechanics, and the second parameters include the support force and support position of the temporary support;

[0026] Based on the tunnel model, running the experiment A and the experiment B, and recording the stress and displacement change data of the tunnel surrounding rock during the simulation of the experiment A and the experiment B as simulation results;

[0027] Compare the simulation results of the experiment A and the experiment B, analyze the influence of the temporary support on the stress field of the surrounding rock of the tunnel, and determine the stress concentration area and stress reduction area caused by the temporary support;

[0028] The stress difference between the experiment A and the experiment B at the same position is calculated to obtain the change value of the stress at different heights, and the distribution and change value of the stress along the excavation direction are also obtained, and the stress diffusion area, stress attenuation area and stress-free diffusion area are determined based on the stress distribution and the change value.

[0029] As a preferred technical solution of the present invention, step S3 further includes:

[0030] Based on Experiment A and Experiment B, it can be seen that as the temporary support force increases, the strain of the tunnel roof in the unsupported area decreases and the stress increases. When the strain of the tunnel roof in the unsupported area is equal to zero, the temporary support force is obtained and used as the optimal temporary support force. At the same time, the linear relationship between the unsupported distance and the optimal temporary support force is obtained.

[0031] As a preferred technical solution of the present invention, the step S4 further includes:

[0032] Based on the linear relationship between the unsupported distance and the optimal temporary support force, the unsupported distance is adjusted, and based on the length of the temporary support area, the combined length of the temporary support area and the unsupported area is defined, and the combined length of the temporary support area and the unsupported area is less than a second value. Temporary support equipment is also designed, and the length of the temporary support equipment is less than a third value.

[0033] The present invention also provides a temporary support optimization system based on the stress diffusion model as described above, comprising the following modules:

[0034] A model building unit, used to build a temporary support stress diffusion model, and obtain the distribution characteristics of the temporary support stress field in the unsupported area of ​​the tunnel surrounding rock based on the temporary support stress diffusion model;

[0035] A model verification unit, used to analyze the characteristics of the stress field generated by the temporary support in the unsupported area of ​​the tunnel surrounding rock through numerical simulation experiments, and verify the temporary support stress diffusion model;

[0036] A factor analysis unit, for analyzing factors affecting the stability of the surrounding rock in the unsupported area of ​​the tunnel surrounding rock based on the temporary support stress diffusion model and the characteristics of the stress field generated by the temporary support in the unsupported area of ​​the tunnel surrounding rock, wherein the factors include the magnitude of the temporary support force, the length of the temporary support area and the unsupported distance;

[0037] The parameter optimization unit is used to determine the linear relationship between the optimal temporary support force and the unsupported distance based on the factors affecting the stability of the surrounding rock in the unsupported area of ​​the tunnel surrounding rock, and derive the optimal temporary support force required for the unsupported area, determine the maximum unsupported distance based on the attenuation degree of the temporary support stress, and determine the sum of the temporary support area length and the unsupported distance based on the top plate stress, and design and optimize the cutting parameters and temporary support parameters based on the temporary support stress diffusion model, arrange equipment, and design and optimize the tunnel excavation process.

[0038] The present invention also provides a computing device, the device comprising:

[0039] Memory for storing computer programs;

[0040] A processor is used to implement the above-mentioned temporary support optimization method based on the stress diffusion model when executing the computer program.

[0041] Compared with the prior art, the beneficial effects of the present invention are at least as follows:

[0042] The technical solution of the present invention obtains the distribution law of temporary support force in the surrounding rock by establishing a temporary support stress diffusion model. The stress distribution characteristics of temporary support in the empty top area are obtained according to the stress difference when there is temporary support in the empty top area, and this distribution characteristic is similar to the law of the temporary support stress diffusion model, which can illustrate the correctness of the temporary support stress diffusion model. The influence of temporary support force, temporary support length and empty top distance on the stress and strain of the roof of the empty top area is also determined. The distribution of temporary support in the surrounding rock of the empty top area is along the height direction of the tunnel. With the increase of height, the stress first increases and then decreases, and reaches the maximum at a height of 3m from the roof. Along the tunnel excavation direction, the stress is almost unchanged within 3m, and drops sharply after exceeding 3m. Thereby obtaining an optimization scheme for temporary support parameters and realizing efficient development of coal resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0044] Figure 1 It is a flowchart of the steps of the temporary support optimization method based on the stress diffusion model in the present invention;

[0045] Figure 2 It is a structural diagram of the temporary support optimization system based on the stress diffusion model in the present invention;

[0046] Figure 3 It is a schematic diagram of the underground support area of ​​a coal mine in the present invention;

[0047] Figure 4 is curve 1 in the present invention;

[0048] Figure 5 This is curve 2 in the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0050] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but unless otherwise specified, these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first xx script may be referred to as a second xx script, and similarly, a second xx script may be referred to as a first xx script.

[0051] A key bottleneck facing the efficient development of coal resources is the imbalance between excavation and mining activities. In other words, excavation and permanent support operations are difficult to carry out in parallel. This limitation significantly restricts production efficiency.

[0052] In view of the above technical problems, the present invention proposes Figure 1 The temporary support optimization method based on the stress diffusion model shown in FIG. 1 includes the following steps:

[0053] Step S1: Establish a temporary support stress diffusion model, and obtain the distribution characteristics of the temporary support stress field in the unsupported area of ​​the tunnel surrounding rock based on the temporary support stress diffusion model.

[0054] Specifically, a temporary support stress diffusion model is first established. This model assumes that the temporary support exerts a uniform normal force on a semi-infinite plane, and derives the diffusion law of the temporary support force along the tunnel height and excavation direction through two integrals. The model regards the tunnel surrounding rock as an infinite beam to meet the assumption of stress diffusion.

[0055] Step S2: Analyze the characteristics of the stress field generated by the temporary support in the unsupported area of ​​the tunnel surrounding rock through numerical simulation experiments, and verify the temporary support stress diffusion model.

[0056] Specifically, numerical simulation experiments were conducted to compare the stress fields with and without temporary support. Two groups of simulation experiments (experiment A and experiment B) were conducted using FLAC3D software. Experiment A simulated the situation without temporary support, and experiment B simulated the situation with temporary support. By comparing the stress differences between the two groups of experiments, the temporary support stress diffusion model was verified, and the distribution characteristics of the temporary support stress in the unsupported area were determined.

[0057] Step S3: Based on the verified temporary support stress diffusion model and the characteristics of the stress field generated by the temporary support in the unsupported area of ​​the tunnel surrounding rock, the factors affecting the stability of the unsupported area of ​​the tunnel surrounding rock are obtained, including the size of the temporary support force, the length of the temporary support area and the unsupported distance.

[0058] Specifically, the influence of the size of temporary support force, the length of temporary support area and the distance without support on the stability of surrounding rock in the unsupported area is analyzed. Through experimental data, it is found that with the increase of temporary support force, the roof strain decreases, indicating that the stress in the unsupported area increases. At the same time, it is found that the maximum unsupported distance should not exceed 3 meters, and the length of the temporary support area should not exceed 17 meters from the working face of the tunnel. Reasonable empty top distance can reduce the frequency of equipment displacement and improve work efficiency. At the same time, by determining the optimal temporary support force and maximum unsupported distance of the unsupported area, the stability of the surrounding rock can be ensured and the risk of tunnel collapse and rock shedding can be reduced.

[0059] Step S4: Based on the factors that affect the stability of the unsupported area of ​​the tunnel surrounding rock, determine the linear relationship between the optimal temporary support force and the unsupported distance, and derive the optimal temporary support force required for the unsupported area. Based on the attenuation degree of the temporary support stress, determine the maximum unsupported distance. Based on the roof stress of the tunnel surrounding rock, determine the sum of the length of the temporary support area and the unsupported distance. Based on the maximum unsupported distance, the length of the temporary support area and the unsupported distance, design and optimize the cutting parameters and temporary support parameters.

[0060] Specifically, based on experimental data, the linear relationship between the optimal temporary support force and the unsupported distance is determined. For example, for unsupported distances ranging from 1 meter to 5 meters, the optimal support forces are 13MPa, 17MPa, 20MPa, 23MPa, and 26MPa, respectively, showing a strong linear relationship. Based on this relationship, the optimal temporary support force required in the unsupported area is derived, and the cutting parameters and temporary support parameters are designed and optimized to improve the excavation efficiency.

[0061] Through the coordination of the above steps, tunnel excavation can ensure safety and efficiency while achieving efficient development of coal resources.

[0062] Furthermore, in the above step S1, establishing a temporary support stress diffusion model includes:

[0063] Step S11: the tunnel is divided into a waiting excavation area, an empty top area, a temporary support area and a permanent support area, and the tunnel surrounding rock is regarded as an infinite beam, and the effect of the temporary support force on the tunnel surrounding rock is regarded as a uniform normal force acting on the infinite beam plane;

[0064] Step S12: Integrate the first radial stress in the temporary support area to obtain the second radial stress caused by the temporary support force at any given point. The first radial stress is expressed by Formula 1, and the second radial stress is expressed by Formula 2:

[0065]

[0066] Step S13: Integrate the second radial stress in the empty top area to obtain the diffusion stress of the temporary support force in the top plate space, which is expressed by Formula 3;

[0067]

[0068] Step S14: obtaining the diffusion law of the temporary support force in the surrounding rock of the tunnel based on Formula 3;

[0069] Among them, F represents the temporary support force, σ1 represents any radial stress, σ2 represents the radial stress caused by the temporary support force F at any point, σ3 represents the stress of the temporary support force F in the empty top area, x is the excavation direction along the tunnel, z is the height direction along the tunnel, L1 is the length of the empty top area, L2 is the length of the temporary support area, ζ represents the micro-segment at the x-axis ζ, and x1, x2, and x3 are the coordinates on the x-axis.

[0070] Specifically, the diffusion law of temporary support force can be derived from the mathematical model formula 3. The diffusion of temporary support force F in the unsupported area (i.e., the empty top area) can be divided into three different stages. Figure 4 As shown, zone I is the stress diffusion zone, where the temporary support force is almost not attenuated; zone II is the stress attenuation zone, where the temporary support force attenuates rapidly; zone III is the non-diffusion zone, where the temporary support force does not work. Figure 5 It can be seen that the temporary support force increases first and then decreases as the distance from the top plate increases along the z-axis, reaching a peak at 3 meters. The stress diffusion along the excavation direction (x-axis) is divided into three continuous areas: stress diffusion area, stress attenuation area and stress-free diffusion area. During the excavation process, it should be ensured that the unsupported area is always in the stress diffusion area, which is the basis and prerequisite for achieving safe excavation operations.

[0071] Furthermore, in the above step S11, the area to be excavated refers to the area where excavation has not yet been carried out, the empty top area refers to the area where excavation has been completed but lacks temporary support, the temporary support area refers to the area directly supported by temporary support, and the permanent support area refers to a stable area where the anchoring work has been completed and the tunnel surrounding rock has been formed.

[0072] Specifically, the shield-based rapid excavation robot system consists of a cutting system, a temporary support system, a permanent support system, a ventilation and dust removal system, and an electro-hydraulic control platform. According to the spatial relationship between the equipment and the surrounding rock, the tunnel is divided into four areas: the area to be excavated, the empty top area, the temporary support area, and the permanent support area. Figure 3 As shown. Among them, the area to be excavated refers to the area where excavation has not yet been carried out; the empty top area refers to the area where excavation has been completed but lacks temporary support. The empty top area is also the unsupported area in the surrounding rock of the tunnel; the temporary support area is the area directly supported by temporary support; the permanent support area refers to the area where anchoring and other work have been completed and the surrounding rock has stabilized. Due to the existence of temporary support, excavation and permanent support can be carried out in parallel, thereby significantly improving excavation efficiency. Reasonable empty top distance can effectively reduce the frequency of equipment displacement, thereby further improving efficiency. While ensuring the stability of the surrounding rock, a larger empty top distance can achieve a longer excavation section and reduce the frequency of equipment movement. In addition, the empty top distance will also affect the temporary support force and the length of the temporary support area, which will be described in detail below. Among them, the empty top distance is also called the empty top area length or the unsupported distance, which refers to the length of the area where excavation has been completed but temporary support has not yet been carried out during the excavation of coal mine tunnels or tunnels.

[0073] Furthermore, in the above step S14, after obtaining the diffusion law of the temporary support force in the surrounding rock of the tunnel:

[0074] Based on the diffusion law of temporary support force in the surrounding rock of the tunnel, when the temporary support force increases from the roof in the empty top area along the height direction of the tunnel, the stress diffusion of the temporary support force in the empty top area first increases and then decreases, reaching a peak value at the first value;

[0075] The stress diffusion of the temporary support force in the empty top area along the tunnel excavation direction is divided into three continuous areas: stress diffusion area, stress attenuation area and no diffusion area. Among them, the stress diffusion area refers to the area where the temporary support force has almost no attenuation, the stress attenuation area refers to the area where the temporary support force attenuates faster, and the no diffusion area refers to the area where the temporary support force does not work.

[0076] Specifically, at this time, the first value is the same as or close to the value corresponding to the maximum unsupported distance in the stress diffusion zone, that is, the maximum unsupported distance, that is, the safe and stable range.

[0077] Furthermore, the stress field generated by temporary support in the unsupported area is analyzed, including:

[0078] Simulation experiment A and experiment B are set up. Experiment A simulates the situation where no temporary support is applied after tunnel excavation, and records the stress distribution state of the tunnel surrounding rock as the first distribution state. Experiment B simulates the situation where temporary support is applied after tunnel excavation, and records the stress distribution state of the tunnel surrounding rock as the second distribution state.

[0079] A tunnel model is established using numerical model software, and the first parameters of Experiment A and Experiment B are input into the tunnel model. For Experiment B, the second parameters of Experiment B are also input into the tunnel model, wherein the first parameters are common to Experiment A and Experiment B, including tunnel dimensions and rock mechanics, and the second parameters include the support force and support position of the temporary support;

[0080] Based on the tunnel model, run experiments A and B, and record the stress and displacement change data of the tunnel surrounding rock during the simulation of experiments A and B as simulation results;

[0081] Compare the simulation results of Experiment A and Experiment B, analyze the influence of temporary support on the stress field of tunnel surrounding rock, and determine the stress concentration area and stress reduction area caused by temporary support;

[0082] The stress difference between Experiment A and Experiment B at the same position was calculated to obtain the stress change values ​​at different heights. The distribution and change values ​​of stress along the excavation direction were also obtained, and the stress diffusion zone, stress attenuation zone and stress-free diffusion zone were determined based on the stress distribution and change values.

[0083] Specifically, different forms of support induce different stress fields in the surrounding rock. As a slender rod-shaped element, the stress field caused by the anchor in the surrounding rock far exceeds its own size. In order to study the effect of temporary support on the unsupported area, it is first necessary to analyze the stress field generated by the temporary support in this area. However, the FLAC3D software cannot directly calculate the temporary support stress field that diffuses to the unsupported area. Therefore, two sets of simulation experiments A and B were carried out to simulate the excavation and support of the same tunnel. Experiment A represents the case without temporary support after excavation, and Experiment B represents the case with temporary support after excavation. By analyzing the stress difference between the two sets of experiments, the distribution characteristics of the temporary support stress in the unsupported area can be determined. The investigation of the distribution characteristics of the stress field in the surrounding rock of the unsupported area shows that although the temporary support does not directly support the unsupported area, it still generates significant stress fields in this area. The emergence of these stress fields in the unsupported area can be attributed to the diffusion of the temporary support force. By studying the variation law of the temporary support stress field on planes at different heights, it is observed that the stress first increases and then decreases with the increase of height. This change may be related to the difference in the diffusion capacity of temporary support forces at different heights. This change pattern is consistent with the rules obtained by our mathematical model, namely the stress diffusion model, and also verifies the accuracy of the mathematical model. In addition, there is a significant difference between the maximum stress at 3 meters and the stress at other heights, which will lead to an increased risk of separation of the roof (i.e., the roof of the tunnel) at 3 meters. Therefore, caution should be exercised when using temporary support at the location of the layered roof (roof of the tunnel). In addition, the stress field of the anchor support first decreases and then increases with the increase in height. Therefore, temporary support can effectively supplement anchor support and improve the stability of the surrounding rock before permanent support.

[0084] Furthermore, the above step S3 also includes:

[0085] Based on Experiment A and Experiment B, it can be seen that with the increase of temporary support force, the strain of the tunnel roof in the unsupported area decreases and the stress increases. When the strain of the tunnel roof in the unsupported area is equal to zero, the temporary support force is obtained and used as the optimal temporary support force. At the same time, the linear relationship between the unsupported distance and the optimal temporary support force is obtained.

[0086] Furthermore, the above step S4 also includes:

[0087] Based on the linear relationship between the unsupported distance and the optimal temporary support force, the unsupported distance is adjusted, and based on the length of the temporary support area, the combined length of the temporary support area and the unsupported area is defined, and the combined length of the temporary support area and the unsupported area is less than a second value. Temporary support equipment is also designed, and the length of the temporary support equipment is less than a third value.

[0088] Specifically, the key to safe and efficient excavation is to ensure the stability of the surrounding rock in the unsupported area, and changes in temporary support parameters will lead to changes in the stress-strain characteristics of the surrounding rock in the unsupported area. The main parameters of temporary support include the length of the temporary support area, the length of the unsupported area (the distance of the unsupported area), and the magnitude of the temporary support force. The length of the support area determines the equipment requirements, the temporary support force plays a key role in controlling the surrounding rock, and the unsupported distance determines the maximum spacing between excavation rows. First, the relationship between the temporary support force and the roof (roof of the roadway) strain in the unsupported area is studied. It is observed that with the increase of the temporary support force, the roof (roof of the roadway) strain decreases, indicating a corresponding increase in the stress in the unsupported area. This is similar to the behavior of permanent support (bolting support), where higher support forces enhance stress diffusion. The optimal temporary support force is defined as the force when the roof (roof of the roadway) strain is close to zero. Through investigation, it was found that the optimal support forces were 13MPa, 17MPa, 20MPa, 23MPa and 26MPa for the unsupported distance from 1m to 5m, respectively. A strong linear relationship was found between the unsupported distance and the optimal temporary support force, which can accurately predict the temporary support force required in the unsupported area and provide valuable guidance for the setting of temporary support force on site.

[0089] Secondly, the analysis of the roof (roof of the tunnel) strain in the temporary support area and the unsupported area at different unsupported distances showed that the roof (roof of the tunnel) strain in the temporary support area decreased with the increase of the unsupported distance. This reduction can be attributed to the stress diffusion from the unexcavated area to the temporary support area. In addition, when the unsupported distance is less than 3 meters, the roof (roof of the tunnel) strain in the unsupported area is lower than the roof (roof of the tunnel) strain in the temporary support area. When the unsupported distance is less than 3 meters, the roof (roof of the tunnel) strain in the unsupported area does not increase significantly. Compared with the maximum open top distance of 2 meters for permanent support, the use of temporary support can achieve a maximum open top distance of 3 meters, which is about 33% higher. This increase effectively improves the excavation efficiency.

[0090] Third, the study of the strain evolution of the roof (roof of the roadway) in the unsupported area focuses on the length of the temporary support area. It is observed that there is an inflection point in the strain variation in the unsupported area relative to the length of the temporary support. Specifically, before this inflection point, the increase in the length of the temporary support has no significant effect on the roof (roof of the roadway) strain. However, after reaching this inflection point, the roof (roof of the roadway) strain increases significantly with the further extension of the temporary support. The inflection points corresponding to the unsupported distance of 1 meter to 5 meters appear at temporary support area lengths of 16 meters, 15 meters, 14 meters, 13 meters, and 12 meters, respectively. The sum of the inflection point lengths corresponding to the length of the temporary support area and the unsupported distance is 17 meters, indicating that the combined length of the temporary support area and the unsupported area should not exceed 17 meters. In addition, based on the above conclusions, it can be inferred that the maximum allowable length of the temporary support area should not exceed 14 meters. The length of the existing temporary support equipment is less than 14 meters.

[0091] The present invention also provides a Figure 2 The temporary support optimization system based on the stress diffusion model shown in the figure includes the following modules:

[0092] A model building unit, used to build a temporary support stress diffusion model, and obtain the distribution characteristics of the temporary support stress field in the unsupported area of ​​the tunnel surrounding rock based on the temporary support stress diffusion model;

[0093] A model verification unit, used to analyze the characteristics of the stress field generated by the temporary support in the unsupported area of ​​the tunnel surrounding rock through numerical simulation experiments, and verify the temporary support stress diffusion model;

[0094] A factor analysis unit, for analyzing factors affecting the stability of the surrounding rock in the unsupported area of ​​the tunnel surrounding rock based on the temporary support stress diffusion model and the characteristics of the stress field generated by the temporary support in the unsupported area of ​​the tunnel surrounding rock, wherein the factors include the magnitude of the temporary support force, the length of the temporary support area and the unsupported distance;

[0095] The parameter optimization unit is used to determine the linear relationship between the optimal temporary support force and the unsupported distance based on the factors affecting the stability of the surrounding rock in the unsupported area of ​​the tunnel surrounding rock, and derive the optimal temporary support force required for the unsupported area, determine the maximum unsupported distance based on the attenuation degree of the temporary support stress, and determine the sum of the temporary support area length and the unsupported distance based on the top plate stress, and design and optimize the cutting parameters and temporary support parameters based on the temporary support stress diffusion model, arrange equipment, and design and optimize the tunnel excavation process.

[0096] The present invention also provides a computing device, comprising:

[0097] Memory for storing computer programs;

[0098] The processor is used to implement the above-mentioned temporary support optimization method based on the stress diffusion model when executing the computer program.

[0099] In summary, by establishing a temporary support stress diffusion model, the distribution law of temporary support force in the surrounding rock is obtained. According to the stress difference when there is temporary support in the empty top area, the stress distribution characteristics of temporary support in the empty top area are obtained, and this distribution characteristic is similar to the law of the temporary support stress diffusion model, which can explain the correctness of the temporary support stress diffusion model. The influence of temporary support force, temporary support length and empty top distance on the stress and strain of the empty top area roof is also determined. The distribution of temporary support in the surrounding rock of the empty top area is along the height direction of the tunnel. With the increase of height, the stress first increases and then decreases, and reaches the maximum at a height of 3m from the roof. Along the tunnel excavation direction, the stress is almost unchanged within 3m, and drops sharply after exceeding 3m. In this way, the optimization scheme of temporary support parameters is obtained to achieve efficient development of coal resources.

[0100] It should be understood that, although each step in the flow chart of each embodiment of the present invention is shown in sequence according to the indication of the arrow, these steps are not necessarily performed in sequence according to the order indicated by the arrow. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be performed in other orders. Moreover, at least a portion of the steps in each embodiment may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these sub-steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0101] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The above-mentioned program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0102] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

[0104] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A temporary support optimization method based on a stress diffusion model, characterized in that: The method comprises: Step S1: establishing a temporary support stress diffusion model, and obtaining the distribution characteristics of the temporary support stress field in the unsupported area of ​​the tunnel surrounding rock based on the temporary support stress diffusion model; Step S2: analyzing the characteristics of the stress field generated by the temporary support in the unsupported area of ​​the tunnel surrounding rock through numerical simulation experiments, and verifying the temporary support stress diffusion model; Step S3: Based on the temporary support stress diffusion model and the characteristics of the stress field generated by the temporary support in the unsupported area of ​​the tunnel surrounding rock, the factors affecting the stability of the unsupported area of ​​the tunnel surrounding rock are analyzed, wherein the factors include the size of the temporary support force, the length of the temporary support area and the unsupported distance; Step S4: Based on the factors that affect the stability of the surrounding rock in the unsupported area of ​​the tunnel surrounding rock, determine the linear relationship between the optimal temporary support force and the unsupported distance, and derive the optimal temporary support force required for the unsupported area. Based on the attenuation degree of the temporary support stress, determine the maximum unsupported distance. Based on the top plate stress, determine the sum of the temporary support area length and the unsupported distance. Based on the temporary support stress diffusion model, design and optimize the cutting parameters and temporary support parameters, arrange equipment, and design and optimize the tunnel excavation process.

2. The method according to claim 1, characterized in that In step S1, establishing a temporary support stress diffusion model includes: Step S11: dividing the tunnel into a waiting excavation area, an empty top area, a temporary support area and a permanent support area, and considering the tunnel surrounding rock as an infinite beam, and considering the effect of the temporary support force on the tunnel surrounding rock as a uniform normal force acting on the infinite beam plane; Step S12: Integrate the first radial stress on the temporary support area to obtain the second radial stress caused by the temporary support force at any given point. The first radial stress is expressed by Formula 1, and the second radial stress is expressed by Formula 2: σ1 = ∫Fz 3 (z 2 +(x - ξ) 2 ) -2 dξ = 0.5Farctan(ξz -1 - xz -1 ) + 0.5Fz(ξ - x)(z 2 +(ξ - x) 2 ) -1 (Formula 1) Step S13: Integrate the second radial stress on the empty top area to obtain the diffusion stress of the temporary support force in the top plate space, which is expressed by Formula 3; Step S14: obtaining the diffusion law of the temporary support force in the surrounding rock of the tunnel based on Formula 3; Among them, F represents the temporary support force, σ1 represents any radial stress, σ2 represents the radial stress caused by the temporary support force F at any point, σ3 represents the stress of the temporary support force F in the empty top area, x is the excavation direction along the tunnel, z is the height direction along the tunnel, L1 is the length of the empty top area, L2 is the length of the temporary support area, ζ represents the micro-segment at the x-axis ζ, and x1, x2, and x3 are the coordinates on the x-axis.

3. The method according to claim 2, characterized in that In step S11, the area to be excavated refers to an area where excavation has not yet been carried out, the empty top area refers to an area where excavation has been completed but lacks temporary support, the temporary support area refers to an area directly supported by temporary support, and the permanent support area refers to a stable area where anchoring work has been completed and the surrounding rock of the tunnel has been formed.

4. The method according to claim 2, characterized in that: In the step S14, after obtaining the diffusion law of the temporary support force in the surrounding rock of the tunnel: Based on the diffusion law of the temporary support force in the surrounding rock of the tunnel, when the temporary support force increases from the roof in the empty top area along the height direction of the tunnel, the stress diffusion of the temporary support force in the empty top area first increases and then decreases, reaching a peak value at a first value; The stress diffusion of the temporary support force in the empty top area along the tunnel excavation direction is divided into three continuous areas: a stress diffusion area, a stress attenuation area and a non-diffusion area, wherein the stress diffusion area refers to an area in which the temporary support force has almost no attenuation, the stress attenuation area refers to an area in which the temporary support force attenuates faster, and the non-diffusion area refers to an area in which the temporary support force does not work.

5. The method according to claim 1, characterized in that In the step S1, the distribution characteristics of the temporary support stress field in the unsupported area of ​​the tunnel surrounding rock are obtained, including: Mathematical modeling is performed on the tunnel surrounding rock, and the temporary support is presupposed to exert a uniform normal force on a semi-infinite plane, and the diffusion law of the temporary support stress in the tunnel surrounding rock along the tunnel height and excavation direction is derived through integral deduction.

6. The method according to claim 1, characterized in that Analyzing the stress field generated by the temporary support in the unsupported area, including: Simulation experiment A and experiment B are set, wherein experiment A simulates the situation where no temporary support is applied after the tunnel is excavated, and the stress distribution state of the tunnel surrounding rock is recorded as a first distribution state, and experiment B simulates the situation where temporary support is applied after the tunnel is excavated, and the stress distribution state of the tunnel surrounding rock is recorded as a second distribution state; A tunnel model is established using numerical model software, and first parameters of the experiment A and the experiment B are input into the tunnel model. For the experiment B, second parameters of the experiment B are also input into the tunnel model, wherein the first parameters are common to the experiments A and B, including tunnel dimensions and rock mechanics, and the second parameters include the support force and support position of the temporary support; Based on the tunnel model, running the experiment A and the experiment B, and recording the stress and displacement change data of the tunnel surrounding rock during the simulation of the experiment A and the experiment B as simulation results; Compare the simulation results of the experiment A and the experiment B, analyze the influence of the temporary support on the stress field of the tunnel surrounding rock, and determine the stress concentration area and stress reduction area caused by the temporary support; The stress difference between the experiment A and the experiment B at the same position is calculated to obtain the change value of the stress at different heights, and the distribution and change value of the stress along the excavation direction are also obtained, and the stress diffusion area, stress attenuation area and stress-free diffusion area are determined based on the stress distribution and the change value.

7. The method according to claim 3, characterized in that The step S3 further comprises: Based on Experiment A and Experiment B, it can be seen that as the temporary support force increases, the strain of the tunnel roof in the unsupported area decreases and the stress increases. When the strain of the tunnel roof in the unsupported area is equal to zero, the temporary support force is obtained and used as the optimal temporary support force. At the same time, the linear relationship between the unsupported distance and the optimal temporary support force is obtained.

8. The method according to claim 3, characterized in that The step S4 further comprises: Based on the linear relationship between the unsupported distance and the optimal temporary support force, the unsupported distance is adjusted, and based on the length of the temporary support area, the combined length of the temporary support area and the unsupported area is defined, and the combined length of the temporary support area and the unsupported area is less than a second value. Temporary support equipment is also designed, and the length of the temporary support equipment is less than a third value.

9. A temporary support optimization system based on a stress diffusion model, used to implement the temporary support optimization method based on a stress diffusion model as claimed in any one of claims 1 to 8, characterized in that: The system includes the following modules: A model building unit, used to build a temporary support stress diffusion model, and obtain the distribution characteristics of the temporary support stress field in the unsupported area of ​​the tunnel surrounding rock based on the temporary support stress diffusion model; A model verification unit, used to analyze the characteristics of the stress field generated by the temporary support in the unsupported area of ​​the tunnel surrounding rock through numerical simulation experiments, and verify the temporary support stress diffusion model; A factor analysis unit, for analyzing factors affecting the stability of the surrounding rock in the unsupported area of ​​the tunnel surrounding rock based on the temporary support stress diffusion model and the characteristics of the stress field generated by the temporary support in the unsupported area of ​​the tunnel surrounding rock, wherein the factors include the magnitude of the temporary support force, the length of the temporary support area and the unsupported distance; The parameter optimization unit is used to determine the linear relationship between the optimal temporary support force and the unsupported distance based on the factors affecting the stability of the surrounding rock in the unsupported area of ​​the tunnel surrounding rock, and derive the optimal temporary support force required for the unsupported area, determine the maximum unsupported distance based on the attenuation degree of the temporary support stress, and determine the sum of the temporary support area length and the unsupported distance based on the top plate stress, and design and optimize the cutting parameters and temporary support parameters based on the temporary support stress diffusion model, arrange equipment, and design and optimize the tunnel excavation process.

10. A computing device, characterized in that: The device comprises a memory and a processor: The memory is used to store computer programs; The processor is used to implement the temporary support optimization method based on the stress diffusion model as described in any one of claims 1 to 8 when executing the computer program.

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