Crushed ore body stope roof stability and support parameter optimization method

Abstract

The invention relates to a broken ore body stope roof stability and support parameter optimization method, and belongs to the technical field of mine support methods. According to the technical scheme, a method of combining field testing and numerical simulation is adopted, and the proper length of the anchor rod is determined by testing the range of a pre-control top roadway loosening circle under the condition that the pre-control top roadway is not influenced by mining; on the basis of not changing an anchor rod design scheme, under different anchor cable support parameters of pre-control top roadways of stopes with different heights, deformation conditions of stope roofs in mining processes of excavation, filling and the like of ore bodies are simulated, the reduction amount of the maximum deformation amount is taken as a reference amount, and the effects of different support schemes of the pre-control top roadways are compared, so that the pre-control top roadways with different heights are obtained. And further determining anchor cable arrangement parameters. The method has the beneficial effects that by simulating the mining influence under frequent mining-filling of the chamber, the optimization result is more practical, the supporting work of the mine stope can be more effectively guided, and safe mining is guaranteed.

Description

Technical Field

[0001] The invention relates to a method for optimizing the stability of a broken ore body stope roof and supporting parameters, and belongs to the technical field of mine supporting methods. Background Art

[0002] In the process of underground metal mining, the stability of the stope roof is crucial and is the key to ensuring safe and efficient mining of high-stage filling stopes. Therefore, innovating the optimization method of the stability of the stope roof and support parameters of unstable ore bodies at high stages has a high practical significance for the safe and efficient mining of underground mines and improving mining production efficiency.

[0003] At present, the main technologies for pre-controlling roof support in underground mining areas of metal mines include advanced anchor (cable) support method, small pipe grouting reinforcement method, pipe shed method, horizontal high-pressure rotary spraying method, etc. Liu Xiaohui et al. proposed a mining scheme for pre-controlling roof segmentation and subsequent filling, and determined the anchor-spraying combined roof support scheme of resin anchor + wet shotcrete; Zang Chuanwei et al. determined the upward high-layer filling mining method through comparison, used FLAC3D simulation software to study the stability of the mining area under different mine room widths, and used anchor support method for pre-controlling roof; Wang Yang et al. studied the stability of the subsequent roof of the segmented empty field and its pre-controlling roof control technology through theoretical calculation and numerical simulation, and determined Reasonable roof support parameters; Su Hongrui tested the mining process of pre-controlled top downward medium-deep hole detonation, and determined the pre-controlled top mine room roof support method of pipe-seam anchor + shotcrete; Zhao Guoyan et al. implemented the long anchor cable pre-controlled top downward segmented rock drilling stage and subsequent filling mining method in view of the unstable rock fragmentation of Huangshaping Mine; Qin Kai et al. proposed a "one-hole, two-purpose" pre-protection roof anchor cable support technical solution for the mining process of pre-controlled top upward medium-deep hole empty field and subsequent filling method of Qianbi West Copper Mine.

[0004] In summary, bolt (cable) support is a commonly used support method for tunnel pre-reinforcement and initial support in underground mining. In terms of support parameter optimization, domestic and foreign scholars have done a lot of research work and made great progress. However, the existing technology mainly focuses on the optimization method of bolt support parameters, and there is little research on the optimization method of anchor cable support parameters. Summary of the invention

[0005] The purpose of the present invention is to provide a method for optimizing the stability and support parameters of a mining site of a broken ore body. The method adopts a combination of field testing and numerical simulation, and determines the appropriate anchor length by testing the range of the loose circle of a pre-controlled top tunnel without being affected by mining. On the basis of not changing the anchor design scheme, the deformation of the mining site roof during mining such as excavation and filling is simulated for pre-controlled top tunnels of mining sites at different heights under different anchor support parameters. The reduction in the maximum deformation is used as a reference, and the effects of different support schemes for the pre-controlled top tunnel are compared to determine the anchor arrangement parameters. Since the mining impact under frequent mining and filling of the mine room is simulated, the optimization result is more in line with reality, can more effectively guide the mine support work, ensure safe mining, and effectively solve the above-mentioned problems existing in the background technology.

[0006] The technical solution of the present invention is: a method for optimizing the stability and support parameters of a broken ore body stope roof, comprising the following steps: The first step is to conduct on-site testing of the loosening zone of the surrounding rock of the pre-controlled top tunnel and design a support scheme. The loosening zone test is carried out on the pre-controlled top tunnel that is not affected by mining, and the appropriate anchor length is determined based on the existing loosening zone support theory. Based on the loosening zone test results and combined with experience, a preliminary design of a combined support scheme of anchors and anchor cables is made for the pre-controlled top tunnel in the mining area. The second step is to construct a three-dimensional numerical model of the stope support, using software to model it according to the actual layout of the stope; The third step is to determine the numerical simulation scheme. Rock destruction is a gradual process that takes a certain amount of time. It is a macroscopic manifestation of damage evolution and the gradual development, expansion and connection of new cracks. On the basis of not changing the anchor design scheme, numerical simulation software is used to perform numerical simulation under different anchor support parameters for pre-controlled top lanes at different heights of mining areas, and the stability of the roof surrounding rock is compared to determine reasonable anchor support parameters. The fourth step is to analyze the effect of mining support. On the basis of not changing the anchor design scheme, for the different anchor support parameters of the pre-controlled top tunnels in mining fields at different heights, the reduction in the maximum deformation is used as a reference. The deformation of the arch position of each pre-controlled top tunnel is used to compare the effects of different support schemes for the pre-controlled top tunnel.

[0007] In the first step, for the broken and unstable ore body, due to the limitation of anchor rod length, the entire fractured area cannot be anchored and controlled by anchor rods after the tunnel is affected by mining. Therefore, a joint support method of anchor rods and anchor cables is adopted to form a shallow anchoring area and a deep anchoring area to ensure the stability of the anchored surrounding rock of the top tunnel before and after the mining, and prevent large-scale collapse and roof fall. The 30m high mining area pre-controlled top tunnel adopts a combined support scheme of anchor rods and anchor cables, with 3-5 anchor rods set on the top plate, 2-4 anchor rods set on each side of the side, and the spacing between rows is 800 mm×800 mm; the anchor cables are arranged at intervals, 4-6 anchor rods are arranged in each row, and the spacing is 1.0-2.0 m; the 60m high mining area pre-controlled top tunnel adopts a combined support scheme of anchor rods and anchor cables, with 7-9 anchor rods set on the top plate, 2-4 anchor rods set on each side of the side, and the spacing is 800 mm×800 mm; the anchor cables are arranged at intervals, 7-9 anchor rods are arranged in each row, and the spacing is 1.0-2.0 m.

[0008] In the second step, in the 30 m high mining area model, 2 through-vein tunnels and 4 bottom-pulling tunnels are arranged in the horizontal rock layer at the top of the mining area, and 6 exit routes are arranged between the adjacent bottom-pulling tunnels and through-vein tunnels, among which the bottom plate of the bottom structure tunnel to the top plate of the pre-controlled top tunnel, as well as the left and right sides of the mine room are boundaries, within which there is ore, and the other areas are rocks; in the 60 m high mining area, 2 through-vein tunnels and 4 bottom-pulling tunnels are also arranged in the horizontal rock layer at the top of the mining area, and 6 exit routes are arranged between the adjacent bottom-pulling tunnels and through-vein tunnels, among which the bottom plate of the bottom structure tunnel to the top plate of the pre-controlled top tunnel, as well as the left and right sides of the mine room are boundaries, within which there is ore, and the other areas are rocks.

[0009] In the third step, the ore bodies in the numerical model are first numbered from left to right as ①, ②, ③ and ④. The thickness of the ore body excavated in a single time is 6.0 m, that is, a single ore body can be excavated 5-10 times respectively. Combined with the commonly used anchor cable spacing on site, the numerical calculation process and the anchor cable support scheme are generally as follows: 1) the bottom structure and pre-controlled top tunnel excavation and support corresponding to the ore body ①; 2) the ore body ① is excavated in steps; 3) the filling of the area after the ore body ① is completely excavated; 4) the above process is repeated for ore bodies ②-④ until the filling of the area corresponding to the ore body ④ is completed.

[0010] In the fourth step, a pre-controlled top tunnel support model with different anchor cable spacing is constructed, and vertical displacement monitoring points are respectively set in the numerical models with different anchor cable spacing. The vertical displacement monitoring points are respectively arranged at the center position of the arch of the pre-controlled top tunnel, and 3-5 working conditions with no anchor cable support and anchor cable spacing of 1.5-3.5 m are selected to simulate the deformation of the mine roof during mining processes such as excavation and filling, and a comparative analysis is performed to determine the appropriate anchor cable support parameters.

[0011] The beneficial effects of the present invention are as follows: a method combining field testing and numerical simulation is adopted to determine the appropriate anchor length by testing the range of the loose circle of the pre-controlled top tunnel without the influence of mining; on the basis of not changing the anchor design scheme, for the pre-controlled top tunnels of mining fields at different heights, different anchor cable support parameters are used to simulate the deformation of the mining field roof during mining processes such as excavation and filling, and the reduction in the maximum deformation is used as a reference to compare the effects of different support schemes for the pre-controlled top tunnel, so as to determine the anchor cable arrangement parameters; since the mining influence under frequent mining and filling of the mine room is simulated, the optimization result is more in line with reality, and can more effectively guide the mine support work and ensure safe mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic flow chart of the method of the present invention; Figure 2 It is a three-dimensional numerical model of a stope at a height of 30 m in an embodiment of the present invention; Figure 3 It is a three-dimensional numerical model of a stope at a height of 60 m in an embodiment of the present invention; Figure 4 It is a three-dimensional numerical model of anchor cable support in a stope with a height of 30 m under the condition of an anchor cable spacing of 1.5 m in an embodiment of the present invention; Figure 5 It is a cloud diagram of vertical displacement change of a stope at a height of 30 m under the condition of no support in the embodiment of the present invention (initial excavation of ore body ①); Figure 6 It is a cloud diagram of vertical displacement change of a stope at a height of 30 m under the condition of no support in the embodiment of the present invention (the ore body ① area is completely excavated and then filled); Figure 7 It is a cloud diagram of vertical displacement change of a stope at a height of 30 m under unsupported conditions in an embodiment of the present invention (initial excavation of ore body ②); Figure 8 It is a cloud diagram of vertical displacement change of a stope at a height of 30 m under the condition of no support in the embodiment of the present invention (the ore body ② area is completely excavated and filled); Fig. 9 It is a cloud diagram of vertical displacement change of a stope at a height of 30 m under the condition of no support in the embodiment of the present invention (initial excavation of ore body ③); Fig.10 It is a cloud diagram of vertical displacement change of a stope at a height of 30 m under the condition of no support in the embodiment of the present invention (the ore body ③ area is completely excavated and filled); Fig.11 It is a cloud diagram of vertical displacement change of a stope at a height of 30 m under the condition of no support in the embodiment of the present invention (initial excavation of ore body ④); Fig.12 It is a cloud diagram of vertical displacement change of a stope at a height of 30 m under the condition of no support in the embodiment of the present invention (the ore body ④ area is completely excavated and filled); Fig.13 This is a deformation curve diagram of the 1# vertical displacement monitoring point in the stope at a height of 30m in the embodiment of the present invention; Fig.14 This is a deformation curve diagram of the 3# vertical displacement monitoring point in the 30m height stope in the embodiment of the present invention; Fig.15 It is a three-dimensional numerical model of cable anchor support in a stope at a height of 60 m under the condition of cable anchor spacing of 1.5 m in an embodiment of the present invention; Fig.16 It is a cloud diagram of vertical displacement change of a stope at a height of 60 m under the condition of no support in the embodiment of the present invention (initial excavation of ore body ①); Fig.17 It is a cloud diagram of vertical displacement change of a stope at a height of 60 m under the condition of no support in the embodiment of the present invention (the ore body ① area is completely excavated and then filled); Fig.18 It is a cloud diagram of vertical displacement change of a stope at a height of 60 m under unsupported conditions in an embodiment of the present invention (initial excavation of ore body ②); Fig.19 It is a cloud diagram of vertical displacement change of a stope at a height of 60 m under the condition of no support in the embodiment of the present invention (the ore body ② area is completely excavated and filled); Fig. 20 It is a cloud diagram of vertical displacement change of a stope at a height of 60 m under the condition of no support in the embodiment of the present invention (initial excavation of ore body ③); Fig.21 It is a cloud diagram of vertical displacement change of a stope at a height of 60 m under the condition of no support in the embodiment of the present invention (the ore body ③ area is completely excavated and filled); Fig. 22 It is a cloud diagram of vertical displacement change of a stope at a height of 60 m under the condition of no support in the embodiment of the present invention (initial excavation of ore body ④); Fig.23 It is a cloud diagram of vertical displacement change of a stope at a height of 60 m under the condition of no support in the embodiment of the present invention (the ore body ④ area is completely excavated and filled); Fig.24 This is a deformation curve diagram of the 5# vertical displacement monitoring point in the 60m height stope in the embodiment of the present invention; Fig.25 It is a deformation curve diagram of the 7# vertical displacement monitoring point in the 60m height stope in an embodiment of the present invention. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solutions and advantages of the invention implementation cases clearer, the technical solutions in the implementation cases of the present invention will be clearly and completely described below in conjunction with the drawings in the implementation cases. Obviously, the implementation cases described are only a small part of the implementation cases of the present invention, rather than all the implementation cases. Based on the implementation cases in the present invention, all other implementation cases obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0014] A method for optimizing roof stability and support parameters of a broken ore body stope comprises the following steps: The first step is to conduct on-site testing of the loosening zone of the surrounding rock of the pre-controlled top tunnel and design a support scheme. The loosening zone test is carried out on the pre-controlled top tunnel that is not affected by mining, and the appropriate anchor length is determined based on the existing loosening zone support theory. Based on the loosening zone test results and combined with experience, a preliminary design of a combined support scheme of anchors and anchor cables is made for the pre-controlled top tunnel in the mining area. The second step is to construct a three-dimensional numerical model of the stope support, using software to model it according to the actual layout of the stope; The third step is to determine the numerical simulation scheme. Rock destruction is a gradual process that takes a certain amount of time. It is a macroscopic manifestation of damage evolution and the gradual development, expansion and connection of new cracks. On the basis of not changing the anchor design scheme, numerical simulation software is used to perform numerical simulation under different anchor support parameters for pre-controlled top lanes at different heights of mining areas, and the stability of the roof surrounding rock is compared to determine reasonable anchor support parameters. The fourth step is to analyze the effect of mining support. On the basis of not changing the anchor design scheme, for the different anchor support parameters of the pre-controlled top tunnels in mining fields at different heights, the reduction in the maximum deformation is used as a reference. The deformation of the arch position of each pre-controlled top tunnel is used to compare the effects of different support schemes for the pre-controlled top tunnel.

[0015] In the first step, for the broken and unstable ore body, due to the limitation of anchor rod length, the entire fractured area cannot be anchored and controlled by anchor rods after the tunnel is affected by mining. Therefore, a joint support method of anchor rods and anchor cables is adopted to form a shallow anchoring area and a deep anchoring area to ensure the stability of the anchored surrounding rock of the top tunnel before and after the mining, and prevent large-scale collapse and roof fall. The 30m high mining area pre-controlled top tunnel adopts a combined support scheme of anchor rods and anchor cables, with 3-5 anchor rods set on the top plate, 2-4 anchor rods set on each side of the side, and the spacing between rows is 800 mm×800 mm; the anchor cables are arranged at intervals, 4-6 anchor rods are arranged in each row, and the spacing is 1.0-2.0 m; the 60m high mining area pre-controlled top tunnel adopts a combined support scheme of anchor rods and anchor cables, with 7-9 anchor rods set on the top plate, 2-4 anchor rods set on each side of the side, and the spacing is 800 mm×800 mm; the anchor cables are arranged at intervals, 7-9 anchor rods are arranged in each row, and the spacing is 1.0-2.0 m.

[0016] In the second step, in the 30 m high mining area model, 2 through-vein tunnels and 4 bottom-pulling tunnels are arranged in the horizontal rock layer at the top of the mining area, and 6 exit routes are arranged between the adjacent bottom-pulling tunnels and through-vein tunnels, among which the bottom plate of the bottom structure tunnel to the top plate of the pre-controlled top tunnel, as well as the left and right sides of the mine room are boundaries, within which there is ore, and the other areas are rocks; in the 60 m high mining area, 2 through-vein tunnels and 4 bottom-pulling tunnels are also arranged in the horizontal rock layer at the top of the mining area, and 6 exit routes are arranged between the adjacent bottom-pulling tunnels and through-vein tunnels, among which the bottom plate of the bottom structure tunnel to the top plate of the pre-controlled top tunnel, as well as the left and right sides of the mine room are boundaries, within which there is ore, and the other areas are rocks.

[0017] In the third step, the ore bodies in the numerical model are first numbered from left to right as ①, ②, ③ and ④. The thickness of the ore body excavated in a single time is 6.0 m, that is, a single ore body can be excavated 5-10 times respectively. Combined with the commonly used anchor cable spacing on site, the numerical calculation process and the anchor cable support scheme are generally as follows: 1) the bottom structure and pre-controlled top tunnel excavation and support corresponding to the ore body ①; 2) the ore body ① is excavated in steps; 3) the filling of the area after the ore body ① is completely excavated; 4) the above process is repeated for ore bodies ②-④ until the filling of the area corresponding to the ore body ④ is completed.

[0018] In the fourth step, a pre-controlled top tunnel support model with different anchor cable spacing is constructed, and vertical displacement monitoring points are respectively set in the numerical models with different anchor cable spacing. The vertical displacement monitoring points are respectively arranged at the center position of the arch of the pre-controlled top tunnel, and 3-5 working conditions with no anchor cable support and anchor cable spacing of 1.5-3.5 m are selected to simulate the deformation of the mine roof during mining processes such as excavation and filling, and a comparative analysis is performed to determine the appropriate anchor cable support parameters. Example

[0019] (1) The Zhongguan Iron Mine of Hegang Mining mainly adopts the open-pit subsequent filling mining method for mining, and the mine room height is mainly designed into two categories: 30m and 60m. The 30m high mining area is arranged in the -230m level ~ -200m level, and its pre-controlled top roadway is arranged in the -200m level. The 60m high mining area is -230m level ~ -170m level, and its pre-controlled top roadway is arranged in the -170m level. The -230m level mainly arranges the vein-through roadway, bottom pull roadway and mine access road of the bottom structure. The pre-controlled top roadway of the 30m high mining area is designed as a pre-controlled top roadway in the middle area of ​​the top of a single mine room, and its cross-sectional size is 3.7m×3.6m. The cross-sectional size of the pre-controlled top roadway of the 60m high mining area is 6.0m×4.0m, and one pre-controlled top roadway is arranged on both sides of the top of a single mine room. In order to ensure mining safety, it is urgent to optimize the support parameters of the pre-controlled top roadway.

[0020] (2) On-site testing of the loosening zone of the surrounding rock of the pre-controlled top tunnel and design of support scheme.

[0021] The loosening zone test was carried out on the pre-controlled top tunnel that was not affected by mining, and the appropriate anchor length was determined based on the existing loosening zone support theory. The test areas were selected in the -170 level and -200 level pre-controlled top tunnels. The test results showed that the loosening zone in this area fluctuated greatly, the boundary line was relatively vague, about 1.4-2.3m, and joints and fissures were developed. The surrounding rock of the loosening zone was clearly broken, and the rock in some areas with a depth of 0.5-1.0m was relatively intact. The joints and fissures in some areas of the elastic zone were relatively developed.

[0022] For broken and unstable ore bodies, due to limitations such as anchor rod length, it is impossible to achieve anchor control of the entire fractured area after the tunnel is affected by mining. Therefore, a combined support method of anchor rods and anchor cables is required to jointly form shallow anchoring areas and deep anchoring areas to ensure the stability of the anchored surrounding rock of the top tunnel before and after the impact of mining, and prevent large-scale collapse and roof caving.

[0023] Preliminary design of support scheme. According to the test results of loosening circle and combined with experience, the preliminary design of the 30m high mining area pre-controlled top tunnel adopts the combined support scheme of anchor rods and anchor cables. Five anchor rods are set on the roof, and three anchor rods are set on each side of the side, with a spacing of 800mm×800mm; the anchor cables are arranged at intervals, with 6 anchor rods arranged in each row, and the spacing is 1.5m; the 60m high mining area pre-controlled top tunnel adopts the combined support scheme of anchor rods and anchor cables. Nine anchor rods are set on the roof, and three anchor rods are set on each side of the side, with a spacing of 800mm×800mm; the anchor cables are arranged at intervals, with 8 anchor rods arranged in each row, and the spacing is 2.0m. The anchor rods are φ20mm×2400mm left-handed non-longitudinal reinforcement threaded steel anchor rods, and the anchor cables are φ17.8mm×15000mm prestressed long anchor cables, which are used in conjunction with 1.0m×2.0m anchor nets, and finally shotcrete.

[0024] The following support schemes are proposed for different anchor cable spacings (Table 1), and numerical simulation is used to compare and analyze their control effects: Table 1 Anchor cable support scheme for pre-controlled top lanes at different heights

[0025] (3) Construct a three-dimensional numerical model of stope support.

[0026] According to the actual layout of the stope, Rhino software was used to model the site. Figure 2 As shown in the figure, the size of the 30m high stope model is length × width × height = 118m × 60m × 100m, and the size of a single mine room is length × width × height = 12m × 60m × 30m. In the -230 horizontal rock stratum, there are 2 vein-crossing tunnels and 4 bottom-pulling tunnels. There are 6 mine exit routes between adjacent bottom-pulling tunnels and vein-crossing tunnels. The bottom plate of the bottom structure tunnel to the roof of the pre-controlled top tunnel, as well as the left and right sides of the mine room are boundaries. The area is ore, and the other areas are rock.

[0027] 60 m high stope Figure 4 As shown in the figure, the size of the 60 m height stope model is length × width × height = 186 m × 60 m × 150 m, and the size of a single mine room is length × width × height = 15 m × 60 m × 60 m. In the -230 horizontal rock layer, there are also 2 vein-crossing tunnels and 4 bottom-pulling tunnels. There are 6 mine exit routes between adjacent bottom-pulling tunnels and vein-crossing tunnels. The bottom plate of the bottom structure tunnel to the roof of the pre-controlled top tunnel, as well as the left and right sides of the mine room are boundaries. There is ore in this area, and rock in other areas.

[0028] (4) Determine the numerical simulation scheme. Rock destruction is a gradual process that takes a certain amount of time. It is a macroscopic manifestation of damage evolution and the gradual development, expansion, and connection of new cracks. Without changing the anchor design scheme, numerical simulation software is used to perform numerical simulations under different anchor support parameters (Table 1) for pre-controlled top lanes at different heights of the mining area to compare the stability of the roof surrounding rock. In this way, reasonable anchor support parameters can be determined.

[0029] First, the ore bodies in the numerical model are numbered from left to right as ①, ②, ③, and ④. The thickness of the ore body for a single excavation is 6.0 m, that is, a single ore body can be excavated 10 times. Combined with the commonly used anchor cable spacing on site, the numerical calculation process and anchor cable support scheme are generally as follows: 1) The bottom structure and pre-controlled top tunnel excavation and support corresponding to the ore body ①; 2) The ore body ① is excavated in steps; 3) The area is filled after the ore body ① is completely excavated; 4) The above process is repeated for ore bodies ②-④ until the filling of the area corresponding to the ore body ④ is completed.

[0030] According to the mechanical test results of the ore body and filling body specimens, and the relevant parameters such as cohesion were calculated, the final mechanical parameters were determined and shown in Table 2.

[0031] Table 2 Rock mechanical parameters of three-dimensional numerical model

[0032] (4) Simulation and analysis of the support effect of the mining area. Without changing the anchor design scheme, the stability of the mining area roof surrounding rock was compared and analyzed under different anchor support parameters (Table 1) for the pre-controlled top tunnels at different heights. Vertical displacement monitoring points were set in the numerical models with different anchor cable spacings. The monitoring points were arranged at the center of the arch of the pre-controlled top tunnel. Three to five working conditions were selected, including no anchor cable support and anchor cable spacing of 1.5 to 3.5 m. The deformation of the mining area roof during the excavation and filling process of the ore body was simulated, and a comparative analysis was performed to determine the appropriate anchor cable support parameters.

[0033] 1) Simulation analysis of support effect of 30m high stope.

[0034] Figure 4 This is a three-dimensional numerical model of anchor cable support in a 30m high stope under the condition of an anchor cable spacing of 1.5m. Taking the anchor cable spacing of 1.5m in the figure as an example, 6 anchor cables are evenly set in the three-center arch area of ​​the pre-controlled top lane. Four vertical displacement monitoring points are set in the numerical models with different anchor cable spacings. The monitoring points are arranged at the center of the arch of the pre-controlled top lane, corresponding to ore bodies ①-④, and named 1-4# monitoring points. Taking the reduction in the maximum deformation as the reference, the deformation of the arch position of each pre-controlled top lane is used to compare the effects of different support schemes for the pre-controlled top lane.

[0035] Taking the whole rest and filling simulation process of the 30m height stope as an example, the vertical displacement cloud diagram without support is as follows: Figures 5 to 13 As shown in the figure, under the condition of no anchor cable and other support, after the first stage of ore body ① and the corresponding tunnel excavation, the maximum subsidence of the overburden stratum is about 0.096m, and the maximum subsidence area is relatively close to the top of ore body ①. With the continuous excavation and filling of the remaining ore bodies, the subsidence of the upper rock stratum in the stope gradually increases. After the excavation and filling of ore body ②, the maximum subsidence of the surrounding rock increases to 0.109m. After the excavation and filling of ore body ③, the maximum subsidence of the surrounding rock increases to 0.129m. After the excavation and filling of ore body ④ area, the displacement cloud map changes significantly, and the maximum subsidence increases to 0.145m.

[0036] The changes of monitoring point 1# under four working conditions: no anchor cable, anchor cable spacing of 1.5 m, 2.5 m, and 3.5 m are shown in the figure below. Fig.13As shown in the figure, under the condition of no support, the deformation growth trend is significantly higher than that under the condition of support such as anchor cables. The initial minimum deformation is about 0.065m, the maximum deformation is about 0.108m, and the change is 0.043m. When the cable spacing is 3.5m, the curve change trend slows down significantly, the initial minimum deformation is about 0.032m, the maximum deformation is about 0.055m, and the change is 0.027m. When the cable spacing is 2.5m, the curve change trend is smoother than that of the cable spacing of 3.5m, the initial minimum deformation is about 0.016m, the maximum deformation is about 0.031m, and the change is 0.015m. When the cable spacing is 1.5m, the curve change trend is close to the change trend of the cable spacing of 2.5m, the initial minimum deformation is about 0.012m, the maximum deformation is about 0.022m, and the change is 0.009m.

[0037] The changes of monitoring point 3# under four working conditions: no anchor cable, anchor cable spacing of 1.5 m, 2.5 m, and 3.5 m are shown in the figure. Fig.14 As shown in the figure, the overall deformation of monitoring point 3# is significantly higher than that of monitoring point 1#. Under the condition of no support, the initial minimum deformation is about 0.068m, the maximum deformation is about 0.127m, and the change is 0.059m; when the cable spacing is 3.5m, the initial minimum deformation is about 0.048m, the maximum deformation is about 0.095m, and the change is 0.047m; when the cable spacing is 2.5m, the initial minimum deformation is about 0.031m, the maximum deformation is about 0.068m, and the change is 0.037m; when the cable spacing is 1.5m, the initial minimum deformation is about 0.020m, the maximum deformation is about 0.052m, and the change is 0.032m.

[0038] In summary, as the anchor cable spacing decreases, the deformation of the overburden continues to decrease. Compared with the anchor cable spacing of 3.5 m, the control effect of the unsupported condition increases by about 49.1% and 25.2%; compared with the anchor cable spacing of 3.5 m and 2.5 m, the control effect increases by about 47.5% and 27.5%; compared with the anchor cable spacing of 2.5 m and 1.5 m, the control effect increases by about 29.0% and 23.5%. Comprehensively comparing, the average value of the control effect growth percentage is 37.15%, 37.50%, and 26.25%.

[0039] 2) Simulation analysis of the support effect of the 60m height stope.

[0040] Fig.15This is a three-dimensional numerical model of anchor cable support in a 30m high stope under the condition of an anchor cable spacing of 1.5m. Taking the anchor cable spacing of 1.5m in the figure as an example, 8 anchor cables are evenly set in the three-center arch area of ​​the pre-controlled top lane. In the numerical models with different anchor cable spacings, 8 vertical displacement monitoring points are set respectively. The monitoring points are arranged at the center of the arch of the pre-controlled top lane, corresponding to ore bodies ①-④ respectively, and named 1-8# monitoring points. One monitoring point is arranged in each pre-controlled top lane, and there are two monitoring points in each mine room. Taking the reduction of the maximum deformation as the reference, the deformation of the arch position of each pre-controlled top lane is used to compare the effects of different support schemes for the pre-controlled top lane.

[0041] Taking the whole rest and filling simulation process of the 60m height stope as an example, the vertical displacement cloud diagram without support is as follows: Figures 16 to 23 As shown in the figure, under the condition of no anchor cable and other support, after the first stage of ore body ① and the corresponding tunnel excavation, the maximum subsidence of the overburden stratum is about 0.117m, which is similar to the vertical displacement field distribution of the 30m height stope in the previous article, and the maximum subsidence area is relatively close to the top of ore body ①. With the continuous excavation and filling of the remaining ore bodies, the subsidence of the upper rock stratum in the stope gradually increases. After the excavation and filling of ore body ②, the maximum subsidence of the surrounding rock increases to about 0.127m. After the excavation and filling of ore body ③, the maximum subsidence of the surrounding rock increases to 0.144m. After the excavation and filling of ore body ④, the displacement cloud map changes significantly, and the maximum subsidence increases to 0.161m.

[0042] The changes of monitoring points 5# and 7# under four working conditions: no anchor cable, anchor cable spacing of 1.5m, 2.5m, and 3.5m. Figures 24 and 25 As shown in the figure, similar to the displacement field change of the 30m height mining area, the deformation of the overburden strata continues to decrease with the decrease of the anchor cable spacing. Similarly, the reduction of the maximum deformation is used as a reference, and the support control effect of the 5# and 7# monitoring points is compared. Compared with the unsupported condition and the anchor cable spacing of 5.0m, the control effect increases by about 33.9% and 39.4%; compared with the anchor cable spacing of 5.0m and 4.0m, the control effect increases by about 32.8% and 35.2%; compared with the anchor cable spacing of 4.0m and 3.0m, the control effect increases by about 23.4% and 37.3%. Comprehensively compared, the average value of the control effect growth percentage is 36.65%, 34.00%, and 30.35%.

[0043] 3) Optimization of anchor cable support parameters.

[0044] Since the pre-controlled top support technology also increases the complexity and time cycle of the process, the support cost is also an important factor in selecting the support scheme. In summary, considering the cost difference and construction intensity of anchor cable support, the anchor cable spacing in the pre-controlled top tunnel of the mining field at a height of 30m is determined to be 2.5m, and the anchor cable spacing in the pre-controlled top tunnel of the mining field at a height of 60m is determined to be 4.0m.

[0045] The present invention simulates the deformation of the mine roof during the mining process such as excavation and filling under different anchor cable support parameters of the pre-controlled top lanes in the mines at different heights, takes the reduction of the maximum deformation as a reference, compares the effects of different support schemes of the pre-controlled top lanes, and determines the anchor cable arrangement parameters. Since the mining impact under frequent mining and filling of the mine room is simulated, the optimization result is more in line with reality, and can more effectively guide the mine support work and ensure safe mining.

Claims

1. A method for optimizing the stability and support parameters of the roof of a broken ore body stope, characterized in that The following steps are involved: The first step is to conduct on-site testing of the loosening zone of the surrounding rock of the pre-controlled top tunnel and design a support scheme. The loosening zone test is carried out on the pre-controlled top tunnel that is not affected by mining, and the appropriate anchor length is determined based on the existing loosening zone support theory. Based on the loosening zone test results and combined with experience, a preliminary design of a combined support scheme of anchors and anchor cables is made for the pre-controlled top tunnel in the mining area. The second step is to construct a three-dimensional numerical model of the stope support, using software to model it according to the actual layout of the stope; The third step is to determine the numerical simulation scheme. Rock destruction is a gradual process that takes a certain amount of time. It is a macroscopic manifestation of damage evolution and the gradual development, expansion and connection of new cracks. On the basis of not changing the anchor design scheme, numerical simulation software is used to perform numerical simulation under different anchor support parameters for pre-controlled top lanes at different heights of mining areas, and the stability of the roof surrounding rock is compared to determine reasonable anchor support parameters. The fourth step is to analyze the effect of mining support. On the basis of not changing the anchor design scheme, for the different anchor support parameters of the pre-controlled top tunnels in mining fields at different heights, the reduction in the maximum deformation is used as a reference. The deformation of the arch position of each pre-controlled top tunnel is used to compare the effects of different support schemes for the pre-controlled top tunnel.

2. A method for optimizing roof stability and support parameters of a broken ore body stope according to claim 1, characterized in that: In the first step, for the broken and unstable ore body, due to the limitation of anchor rod length, the entire fractured area cannot be anchored and controlled by anchor rods after the tunnel is affected by mining. Therefore, a joint support method of anchor rods and anchor cables is adopted to form a shallow anchoring area and a deep anchoring area to ensure the stability of the anchored surrounding rock of the top tunnel before and after the mining, and prevent large-scale collapse and roof fall. The 30m high mining area pre-controlled top tunnel adopts a combined support scheme of anchor rods and anchor cables, with 3-5 anchor rods set on the top plate, 2-4 anchor rods set on each side of the side, and the spacing between rows is 800 mm×800 mm; the anchor cables are arranged at intervals, 4-6 anchor rods are arranged in each row, and the spacing is 1.0-2.0 m; the 60m high mining area pre-controlled top tunnel adopts a combined support scheme of anchor rods and anchor cables, with 7-9 anchor rods set on the top plate, 2-4 anchor rods set on each side of the side, and the spacing is 800 mm×800 mm; the anchor cables are arranged at intervals, 7-9 anchor rods are arranged in each row, and the spacing is 1.0-2.0 m.

3. The method for optimizing the stability and support parameters of the roof of a broken ore body stope according to claim 1, characterized in that: In the second step, in the 30 m high mining area model, 2 through-vein tunnels and 4 bottom-pulling tunnels are arranged in the horizontal rock layer at the top of the mining area, and 6 exit routes are arranged between the adjacent bottom-pulling tunnels and through-vein tunnels, among which the bottom plate of the bottom structure tunnel to the top plate of the pre-controlled top tunnel, as well as the left and right sides of the mine room are boundaries, within which there is ore, and the other areas are rocks; in the 60 m high mining area, 2 through-vein tunnels and 4 bottom-pulling tunnels are also arranged in the horizontal rock layer at the top of the mining area, and 6 exit routes are arranged between the adjacent bottom-pulling tunnels and through-vein tunnels, among which the bottom plate of the bottom structure tunnel to the top plate of the pre-controlled top tunnel, as well as the left and right sides of the mine room are boundaries, within which there is ore, and the other areas are rocks.

4. The method for optimizing the stability and support parameters of a broken ore body stope roof according to claim 1, characterized in that: In the third step, the ore bodies in the numerical model are first numbered from left to right as ①, ②, ③ and ④. The thickness of the ore body excavated in a single time is 6.0 m, that is, a single ore body can be excavated 5-10 times respectively. Combined with the commonly used anchor cable spacing on site, the numerical calculation process and the anchor cable support scheme are generally as follows: 1) the bottom structure and pre-controlled top tunnel excavation and support corresponding to the ore body ①; 2) the ore body ① is excavated in steps; 3) the filling of the area after the ore body ① is completely excavated; 4) the above process is repeated for ore bodies ②-④ until the filling of the area corresponding to the ore body ④ is completed.

5. The method for optimizing the stability and support parameters of the roof of a broken ore body stope according to claim 1, characterized in that: In the fourth step, a pre-controlled top tunnel support model with different anchor cable spacing is constructed, and vertical displacement monitoring points are respectively set in the numerical models with different anchor cable spacing. The vertical displacement monitoring points are respectively arranged at the center position of the arch of the pre-controlled top tunnel, and 3-5 working conditions with no anchor cable support and anchor cable spacing of 1.5-3.5 m are selected to simulate the deformation of the mine roof during mining processes such as excavation and filling, and a comparative analysis is performed to determine the appropriate anchor cable support parameters.

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