Advanced Pressure Relief Construction Method for Ultra-Deep Shafts in Metal Mines

Abstract

The present invention relates to the technical field of the construction of ultra-deep vertical shafts in metal mines, and relates to a construction method for pre-relieving pressure in ultra-deep vertical shafts of metal mines. Its aim is to solve the problems that it is difficult to ensure the construction safety of deep shafts and the construction difficulty is great. It is used for large-diameter vertical shafts with a well depth exceeding 1500 m. By adopting methods such as vertical shaft core logging, surrounding rock joint and crack investigation, and rock mechanics tests, the lithology and physical and mechanical parameters of the shaft surrounding rock are obtained; then, the mechanical behavior of the shaft surrounding rock is analyzed to obtain the distribution characteristics of the excavation disturbance stress field of the shaft surrounding rock; the support timing and support thickness of the shaft wall concrete lining are determined, and the high stress accumulated inside the rock mass is released through pre-relieving pressure blasting, so as to actively control the stress state of the shaft surrounding rock in the unlined section, weaken the interaction between the shaft surrounding rock and the subsequent shaft wall concrete lining, and effectively reduce the construction difficulty; a variety of means such as transparent analysis of the shaft formation and prevention and control warning of ground pressure disasters are adopted to ensure the safety and high efficiency of the excavation and support construction of ultra-deep vertical shafts.

Description

Technical Field

[0001] The present invention relates to the technical field of construction of ultra-deep vertical shafts in metal mines, and particularly to a construction method for advanced pressure relief in ultra-deep vertical shafts of metal mines. Background Art

[0002] With the development of China's mining industry, many mines have successively entered deep mining, and the development of deep mineral resources has become an inevitable trend in the future development of the world's mining industry. The depth of vertical shafts has increased from the initial 1200m - 1500m to the current 1500m - 2000m, and is approaching 2000m. As the throat of mine construction and production, the vertical shaft project is the most difficult basic project in the mine infrastructure process. Therefore, the construction of ultra-deep vertical shafts (deeper than 1500m) will become the primary basic project for deep mine construction.

[0003] Traditional vertical shafts mostly adopt the construction technology of "excavating and lining one by one". Due to the spatial effect of the excavation working face of the vertical shaft, the surrounding rock stress and displacement are not fully released, resulting in an interaction between the surrounding rock of the shaft and the shaft wall. Most of the existing support methods are applied to shallow-buried vertical shafts (generally with a depth between 20 meters and 30 meters). Shallow-buried vertical shafts usually adopt the engineering analogy method, or according to the Rankine earth pressure theory, determine the lateral pressure of the vertical shaft through a plane retaining wall or a cylindrical retaining wall, then determine the lining support thickness of the shaft according to the Lame formula, and support the surrounding rock at a position close to the excavation face of the shaft. When applying the excavation and support technology of shallow-buried vertical shafts to deep vertical shafts, it will be found that due to the too high lateral pressure of deep vertical shafts, the support method of shallow-buried vertical shafts is extremely likely to result in a relatively large designed support thickness of the lining, low safety factor, and easy to cause a large amount of economic waste; and as the construction depth of the vertical shaft continues to deepen, it is also extremely likely to cause the in-situ stress in the surrounding rock mass to continuously increase; at the same time, after excavation unloading, due to the redistribution of internal stress in the surrounding rock of the shaft, the stress in the surrounding rock mass is highly concentrated, which is also likely to cause the brittle-ductile transformation of the rock mass, and even phenomena such as plastic dilation and rock burst, resulting in the occurrence of many shaft safety accidents.

[0004] Furthermore, the failure of the surrounding rock of the shaft is the result of the combined action of the geological characteristics of the excavation disturbance stress, the rock mass conditions, and the excavation method. Through research, it is found that the disaster-causing process of the excavation disturbance of the ultra-deep shaft is directly related to the failure response of the rock mass under high stress, especially the change in the displacement of the shaft after excavation and the high-strain energy storage state of the rock mass. The research also finds that there are significant differences in the geological conditions and stress states between ultra-deep shafts and shallow shafts. Especially under the strong excavation unloading effect, the stress state of the deep shaft is relatively complex, specifically manifested as: the surrounding rock of the deep shaft is affected by various forces, such as high in-situ stress, high confined water, and high rock temperature; under the action of high stress and strong excavation unloading, highly concentrated stress and deviatoric stress appear in the surrounding rock of the deep shaft, which is likely to cause significant changes in the deformation characteristics of the surrounding rock, that is, the transformation of the surrounding rock deformation from brittle to ductile-plastic, the rheology of the surrounding rock, and the prominent dilatancy. It can be seen that compared with shallow shafts, the construction of deep shafts is more difficult and the construction safety is lower.

[0005] Therefore, there is an urgent need for a construction method for the advanced pressure relief of ultra-deep shafts in metal mines to solve the above problems. Summary of the Invention

[0006] An object of the present invention is to provide a construction method for the advanced pressure relief of ultra-deep shafts in metal mines to solve the problems of difficult construction safety guarantee and large construction difficulty of deep shafts.

[0007] To achieve the above object, the present invention provides a construction method for the advanced pressure relief of ultra-deep shafts in metal mines, including:

[0008] Establish an engineering disaster model for ultra-deep shafts;

[0009] Carry out rock mechanics tests to determine the basic strength parameters of the rock;

[0010] According to the investigation of the joint fissures of the shaft surrounding rock and the basic strength parameters of the rock, divide the quality grade of the shaft surrounding rock and determine the rock mass mechanical parameters;

[0011] Excavate the shaft, analyze the mechanical behavior of the shaft surrounding rock based on the rock mass mechanical parameters and using the elastic-plastic theory analysis and numerical simulation methods, and then judge the rockburst tendency of the shaft surrounding rock at different depths;

[0012] Determine the support timing and support thickness of the ultra-deep shaft concrete lining;

[0013] Determine the support parameters, and carry out energy release support and advanced pressure relief blasting on the shaft surrounding rock in combination with the evaluation results of the rockburst tendency of the shaft surrounding rock at different depths.

[0014] Further, the steps of establishing the ultra-deep shaft engineering disaster model include: using the cores of the exploration boreholes for the ultra-deep shaft project to conduct core bottom layer information cataloging, dividing the rock mass quality grades according to the core characteristics and the development degree characteristics of joints and fissures, and establishing an engineering disaster model for the bedrock lithology and rock mass quality of the ultra-deep shaft; following the construction progress of the ultra-deep shaft, investigating the joints and fissures of the surrounding rock at different depths of the shaft, and comparing the investigation results of the shaft joints and fissures with the formation information revealed by the cores of the exploration boreholes to correct / update the ultra-deep shaft engineering disaster model.

[0015] Further, the steps of conducting rock mechanics tests to determine the basic strength parameters of rocks include: sampling the rock masses at different tunneling depths of the ultra-deep shaft, processing the rock masses into standard rock specimens, and conducting uniaxial compressive strength tests, Brazilian splitting tests, and shear tests respectively to determine the basic strength parameters of the rocks; among them, the basic strength parameters of the rocks include: the average density of the rock specimens , the uniaxial compressive strength of the rock , the tensile strength of the rock , the elastic modulus E of the rock, the cohesion c of the rock, the Poisson's ratio μ of the rock, and the internal friction angle of the rock .

[0016] Further, the steps of dividing the quality grades of the shaft surrounding rock and determining the mechanical parameters of the rock mass according to the investigation of the joints and fissures of the shaft surrounding rock and the basic strength parameters of the rocks include: according to the situation of the joints and fissures of the ultra-deep shaft surrounding rock and the basic strength parameters of the rocks, using the Barton rock mass quality index Q classification, the rock mass geomechanics (RMR) classification, and the geological strength index GSI classification methods to classify the quality grades of the rock masses at different depths of the shaft; calculating according to the basic strength parameters of the rocks and the classification of the quality grades of the rock masses at different depths of the shaft to obtain the mechanical parameters of the rock masses at different depths (parts); among them, the mechanical parameters of the rock mass include the rock density , the compressive strength of the rock mass , the tensile strength of the rock mass , the elastic modulus E of the rock, the Poisson's ratio of the rock mass , and the shear strength of the rock mass .

[0017] Furthermore, for the excavated shaft, the steps of analyzing the mechanical behavior of the surrounding rock of the shaft based on rock mass mechanical parameters and using elastic-plastic theory analysis and numerical simulation methods, and then evaluating the rockburst tendency of the surrounding rock of the shaft at different depths include: After the shaft is excavated, the stress of the surrounding rock is redistributed. Using elastic-plastic theory analysis and numerical simulation methods to analyze the stress conditions of the surrounding rock of the shaft cross-section under hydrostatic pressure and non-hydrostatic pressure conditions respectively. According to the analysis results, the overall surrounding rock of the shaft is divided into three parts: the loosening zone, the surrounding rock bearing zone, and the initial stress zone; Using numerical simulation methods to analyze the spatial effect of the shaft excavation face, simulate the shaft excavation process, obtain the deformation characteristic curve of the shaft longitudinal section, and use elastic-plastic theory analysis methods to analyze the interaction between the surrounding rock of the shaft and the concrete lining of the shaft wall under uniform stress and non-uniform stress conditions respectively; Combining the rock type determination chart to determine the potential failure types of the surrounding rock of the shaft; Through comprehensive analysis and comparison of the brittle coefficient method, Barton method, and stress intensity method based on the rock physical and mechanical parameters, obtain the rockburst tendency evaluation.

[0018] Furthermore, the steps of using elastic-plastic theory analysis and numerical simulation methods to analyze the stress conditions of the surrounding rock of the shaft cross-section under hydrostatic pressure and non-hydrostatic pressure conditions respectively include: First, according to the formula , determine whether the surrounding rock of the shaft exceeds the elastic limit and is in a plastic state, and divide the surrounding rock state into an elastic state and a plastic state; When the tangential stress of the surrounding rock of the shaft satisfies the following formula, it is considered that plastic failure occurs in the surrounding rock of the shaft: , where is the maximum horizontal principal stress; Then calculate the elastic analysis solution under hydrostatic pressure: Using the polar coordinate system to calculate the following elastic analysis solutions of the surrounding rock stress and displacement, and the specific formulas are as follows: ,

[0019] , , , , where is the in-situ stress, is the radial stress, is the tangential stress, is the shear stress, is the radial displacement, is the tangential displacement, is the shear modulus, is the lateral pressure coefficient, , is the shaft radius, is the polar coordinate radius, is the angle of the polar coordinate, is the passive reaction coefficient; Finally, use numerical simulation methods to calculate the analytical solutions of the plastic zone and stress distribution of the surrounding rock of the shaft under non-static pressure conditions.

[0020] Further, the steps of determining the support timing and support thickness of the concrete lining for the ultra-deep shaft include: determining the unsupported self-stabilizing span and self-stabilizing time of the surrounding rock of the ultra-deep shaft through the RMR stability chart method according to the classification of the shaft rock mass quality and the excavation size of the ultra-deep shaft; based on the theory of sequential pre-relief pressure, comprehensively drawing the cross-sectional deformation characteristic curve and support characteristic curve of the surrounding rock to determine the support timing of the concrete lining of the shaft wall; and comprehensively judging the support thickness of the shaft wall lining according to the thick-walled cylinder theory and empirical method.

[0021] Further, the steps of comprehensively drawing the cross-sectional deformation characteristic curve and support characteristic curve of the surrounding rock include: analyzing the longitudinal profile deformation characteristic curve of the shaft and drawing the cross-sectional deformation characteristic curve of the surrounding rock according to the modified Fenner formula, and the formula is as follows: , where is the support resistance, is the internal friction angle of the rock, is the cohesion of the rock, , is the shaft radius, is the polar coordinate radius; drawing the support characteristic curve of the concrete lining according to the relationship formula between the support force and the structural stiffness, and the formula is as follows: , where is the support force, is the structural stiffness, is the radial displacement of the support.

[0022] Further, the steps of determining the support parameters and performing energy-releasing support and pre-relief blasting on the shaft surrounding rock in combination with the evaluation results of the rockburst proneness of the shaft surrounding rock at different depths include: designing support for the exposed surrounding rock section between the shaft wall and the working face by using a temporary support method in the form of bolt-net-shotcrete; determining the support parameters by comprehensively using the RMR rock mass geomechanics classification method and engineering analogy method; among them, the support parameters include: the diameter, length and row spacing of the bolts, the material, size and mesh shape of the metal mesh, and the length, diameter and spacing of the double rib strips; according to the evaluation results of the rockburst proneness of the shaft surrounding rock at different depths, adopting the pre-relief blasting method to release the local high stress of the shaft surrounding rock in the area where rockburst may occur and reduce the probability of rockburst occurrence in the shaft surrounding rock.

[0023] Based on the foregoing description, those skilled in the art can understand that in the foregoing technical solution of the present invention, a construction method for advanced pressure relief in ultra-deep vertical shafts of metal mines is provided, which is mainly used for pressure relief construction and ground pressure disaster prevention and control of large-diameter ultra-deep vertical shafts with a well depth exceeding 1500m. By adopting methods such as shaft core logging, surrounding rock joint fissure investigation, and rock mechanics tests, the lithology and physical and mechanical parameters of the shaft surrounding rock are obtained to achieve the purpose of transparent shaft construction and early warning; then, the mechanical behavior of the shaft surrounding rock is analyzed to obtain the distribution characteristics of the excavation disturbance stress field of the shaft surrounding rock; based on the theory of advanced sequential pressure relief, the support timing and support thickness of the shaft wall concrete lining are determined, and a certain distance is maintained between the shaft wall lining and the shaft excavation working face. The energy-releasing support structure is used to bear the deformation pressure generated by the stress redistribution of the shaft excavation surrounding rock, and the high stress accumulated inside the rock mass is released through advanced pressure relief blasting, so as to actively regulate the stress state of the unlined section of the shaft surrounding rock, weaken the interaction between the shaft surrounding rock and the subsequent shaft wall concrete lining, realize the pressure relief construction of the ultra-deep vertical shaft, and reduce the construction difficulty.

[0024] Furthermore, the construction method for advanced pressure relief in ultra-deep vertical shafts of metal mines provided by the present invention is applicable to complex environment strata such as deep high stress, strong compression, and strong excavation disturbance. Through the transparent analysis of the shaft strata and the early warning of ground pressure disaster prevention and control, multiple means are used to gradually solve the construction safety problems existing in the construction process of ultra-deep vertical shafts in sequence, changing the disaster hidden dangers brought by the conventional construction methods of traditional vertical shafts in the past, ensuring the safety and efficiency of the excavation and support construction of ultra-deep vertical shafts, as well as the long-term stability of the shaft construction and service period, and achieving the purpose of comprehensively improving the shaft ground pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To more clearly illustrate the technical solution of the present invention, some embodiments of the present invention will be described hereinafter with reference to the accompanying drawings. Those skilled in the art should understand that the components or parts indicated by the same reference numeral in different drawings are the same or similar; the drawings of the present invention are not necessarily drawn to scale. In the drawings:

[0026] Figure 1 is a flow chart of the construction method for advanced pressure relief in ultra-deep vertical shafts of metal mines in some embodiments of the present invention;

[0027] Figure 2 is a connection effect - surface quality trend chart between rock blocks;

[0028] Figure 3 is a rock mass geomechanics RMR stability chart;

[0029] Figure 4 is a comprehensive curve drawing;

[0030] Figure 5 is a schematic plan view of the temporary support design;

[0031] Figure 6 It is the top view of the temporary support design.

[0032] Description of the reference numerals in the drawings:

[0033] 1. Anchor bolt; 2. Metal mesh; 3. Double rib strips. Specific implementation manners

[0034] Those skilled in the art should understand that the embodiments described below are only a part of the embodiments of the present invention, rather than all the embodiments of the present invention. This part of the embodiments is intended to explain the technical principle of the present invention and is not intended to limit the protection scope of the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts should still fall within the protection scope of the present invention.

[0035] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "center", "upper", "lower", "top", "bottom", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0036] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can also be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0037] Next, with reference to Figures 1 to 6 , the advanced pressure relief construction method for ultra-deep vertical shafts in metal mines in some embodiments of the present invention will be described in detail. Among them, Figure 1 is the flow chart of the advanced pressure relief construction method for ultra-deep vertical shafts in metal mines in some embodiments of the present invention; Figure 2 is the connection effect - surface quality trend chart between rock blocks; Figure 3 is the RMR stability chart of rock mass geomechanics; Figure 4 is the comprehensive curve drawing; Figure 5 is the schematic plan view of the temporary support design; Figure 6 is the top view of the temporary support design.

[0038] Prior to this, it should be noted that for the convenience of description and to enable those skilled in the art to quickly understand the technical solution of the present invention, only the technical features that are strongly related (directly or indirectly) to the technical problems and / or technical concepts to be solved by the present invention will be described hereinafter. Technical features that are weakly related to the technical problems and / or technical concepts to be solved by the invention will not be elaborated. Since these weakly related technical features are common knowledge in the art, the present invention will not result in insufficient disclosure even if these weakly related features are not described.

[0039] The present invention is a construction technology method adopted in the construction of a vertical shaft under construction in a gold mine of Shandong Gold Group. The depth of this vertical shaft is expected to reach 2000 m, and the net diameter of the shaft is 10.5 m. This vertical shaft is a large-diameter ultra-deep vertical shaft. The deep formation of the ultra-deep vertical shaft is in a state of high stress and strong compression, with large rock hardness and high energy content. Under the disturbance of shaft construction, strong rock dynamic disasters are likely to occur, posing challenges to tunneling, support, etc. Using the traditional "excavate and line" vertical shaft construction method is extremely likely to cause the interaction between the shaft surrounding rock and the shaft wall, resulting in a low safety factor of the concrete shaft wall, and under the influence of high stress, the shaft wall structure is extremely likely to deform and fail.

[0040] Therefore, the present invention provides a construction method for pre-relieving pressure in a metal mine ultra-deep vertical shaft, which uses the pre-sequential pressure relief construction technology for the construction of ultra-deep vertical shafts. This method is applicable to the pressure relief construction and ground pressure disaster prevention and control of large-diameter ultra-deep vertical shafts with a depth exceeding 1500 m. Based on the results of vertical shaft core logging, the distribution of joint fissures in the shaft surrounding rock, and the physical and mechanical parameters of the rock as basic information, the vertical shaft formation is made transparent. Through the analysis of the mechanical behavior of the shaft surrounding rock, the pre-sequential pressure relief theory and method are adopted to achieve the pressure relief construction of the ultra-deep vertical shaft and ensure construction safety.

[0041] As Figure 1 shown, in some embodiments of the present invention, the construction method for pre-relieving pressure in a metal mine ultra-deep vertical shaft includes:

[0042] Step S110, establishing a disaster model for the ultra-deep shaft project. Step S110 includes:

[0043] Step S111: Using the core samples from the engineering investigation boreholes of the ultra-deep shaft, conduct core stratum information recording. Based on the core characteristics and the development degree characteristics of joints and fractures, divide the rock mass quality grades and establish an engineering disaster model for the bedrock lithology and rock mass quality of the ultra-deep shaft. Specifically, use the core samples from the engineering investigation boreholes of the ultra-deep shaft to conduct core recording. Core recording includes recording information such as shaft rock information, rock structural planes, and the filling materials of rock structural planes. Shaft rock information includes information such as rock color, weathering degree, rock structure, spacing of structural planes, hardness, bedrock lithology, and occurrence depth. Rock structural plane information includes information such as structural plane type, aperture, presence of filling materials, roughness, and attitude. The filling materials of rock structural planes include information such as water content, color, thickness, coherence, hardness, filling material type, and source. Among them, the structural plane types generally include fractures, tectonic joints, and general joints, etc.

[0044] In this embodiment, the lithology of the surrounding rock of the ultra-deep shaft is mainly granite, with a granite proportion of 90%. The average values of RQD (Rock Quality Designation, used to evaluate the integrity of the rock mass) at different levels are mostly above 70%. The joint and fracture angles are mostly above 60°, and the aperture is about 1 mm, belonging to high-inclination micro-fractures. According to the core characteristics and the development degree characteristics of joints and fractures, the rock mass is divided into four quality grades: relatively intact, fractures moderately developed, fractures developed, and fracture zone. Based on the above core recording information and the development degree characteristics of joints and fractures, establish an engineering disaster model reflecting the bedrock lithology and rock mass quality of the ultra-deep shaft.

[0045] Step S112: Follow the construction progress of the ultra-deep shaft, investigate the joints and fractures of the surrounding rock at different depths of the shaft, and compare the investigation results of the shaft joints and fractures with the stratum information revealed by the core samples of the engineering investigation boreholes to correct / update the engineering disaster model of the ultra-deep shaft. Specifically, follow the construction progress of the ultra-deep shaft and continuously conduct investigations on the joints and fractures of the surrounding rock at different depths of the shaft. Focus on investigating the joints and tectonic structures exposed after the shaft excavation, including describing the strike, dip, dip angle, fracture density, aperture, fracture filling, etc. of the joints and tectonic structures. Then compare the investigation results of the shaft joints and fractures with the stratum information revealed by the core samples of the engineering investigation boreholes to correct / update the engineering disaster model of the ultra-deep shaft constructed through the core samples in Step S111.

[0046] Step S120: Conduct rock mechanics tests to determine the basic strength parameters of the rock. Step S120 includes:

[0047] Step S121: Take rock samples at different excavation depths of the ultra - deep shaft, process the rock masses into standard rock samples, and conduct uniaxial compressive strength tests, Brazilian splitting tests, and shear tests respectively to determine the basic rock strength parameters. Rock strength is an important index reflecting the engineering stability of rock masses and is an essential parameter for calculating the strength of engineering rock masses. Take samples of rock masses at different excavation depths of the ultra - deep shaft, process them into standard rock samples according to the requirements of the ISRM "Standard for Rock Mechanics Test Methods", and conduct uniaxial compressive strength tests, Brazilian splitting tests, and shear tests respectively to obtain the basic rock strength parameters.

[0048] The basic rock strength parameters include: the average density of the rock sample , the uniaxial compressive strength of the rock , the tensile strength of the rock , the elastic modulus E of the rock, the cohesion c of the rock, the Poisson's ratio μ of the rock, and the internal friction angle of the rock .

[0049] First, determine the specifications of the granite rock samples for the ultra - deep shaft according to the test content requirements and rock mechanics test standards, process the rock samples, then polish the processed rock samples, and measure the physical parameters such as the diameter, height, and mass of the polished rock samples. In this embodiment, the specifications of the granite rock samples are: the diameter of the uniaxial compression rock sample is 50 mm, and the height of the rock sample is 100 mm; the diameter of the rock sample for the shear test is 50 mm, and the height of the rock sample is 50 mm; the diameter of the Brazilian splitting rock sample is 50 mm, and the height of the rock sample is 25 mm. Calculate the average density of the rock sample according to the measurement results. In this embodiment, the average density of the rock sample is 2.52 g / cm 3 .

[0050] Start the experiment: Conduct basic parameter tests, uniaxial compression tests, Brazilian splitting tests, and shear tests on the rock samples respectively to obtain the rock mechanics parameter values at different depths. Specifically, in this embodiment, the rock density is 2.66 g / cm 3 , the uniaxial compressive strength of the rock is 150.36 MPa, the tensile strength of the rock is 13.08 MPa, the elastic modulus E of the rock is 47.61 MPa, the cohesion c of the rock is 18.95 MPa, and the internal friction angle of the rock is 35.71°.

[0051] Step S130: According to the investigation of the joint fissures of the shaft surrounding rock and the basic rock strength parameters, divide the quality grade of the shaft surrounding rock and determine the rock mass mechanical parameters. Step S130 includes:

[0052] Step S131: Based on the joint fissures of the surrounding rock of the ultra-deep shaft and the basic rock strength parameters, classify the rock mass quality at different depths of the shaft using the Barton Rock Mass Quality Index Q classification, Rock Mass Rating (RMR) classification, and Geological Strength Index (GSI) classification methods. Specifically, based on the joint fissures of the surrounding rock of the ultra-deep shaft and the results of rock mechanics tests (i.e., the basic rock strength parameters obtained from the experiments in Step S120), classify the rock mass quality at different depths of the shaft using the Barton Rock Mass Quality Index Q classification, Rock Mass Rating (RMR) classification, and Geological Strength Index (GSI) classification methods respectively to evaluate the stability of the surrounding rock mass of the shaft.

[0053] The Q classification method calculates the Q value through the Rock Mass Quality Index RQD, joint roughness coefficient , joint alteration coefficient , number of joint sets , joint water reduction coefficient and stress reduction coefficient SRF, and divides the rock mass into 9 grades according to the magnitude of the Q value.

[0054] The value of the Rock Mass Quality Index Q in the Q system classification index is determined by the following formula:

[0055] .

[0056] In this embodiment, using the Barton Rock Mass (Q) classification method, the calculated Q value ranges from 0.001 to 1000, representing the surrounding rock from extremely poor broken rock to extremely good hard and intact rock, and is divided into 5 quality grades.

[0057] The following classifies the surrounding rock with reference to Table 1 of the Barton Rock Mass (Q) classification method:

[0058] Table 1 Barton Rock Mass (Q) Surrounding Rock Classification

[0059]

[0060] The Rock Mass Rating (RMR) value of the Rock Mass Mechanics classification index is composed of 6 index parameters including rock block strength R 1 , RQD value R 2 , joint spacing R 3 , joint condition R 4 , groundwater R 5 and the correction parameter R for the influence of joint direction on the project 6 . During classification, score according to the values of various indicators according to the standards in Table 2 and sum to obtain the total RMR value. Finally, use the corrected total score to refer to Table 3 to obtain the category of the studied rock mass and the self-stabilization time of the unlined underground project and the rock mass strength index.

[0061] The calculation formula for the total RMR value is as follows:

[0062] .

[0063] The following are the classification parameters and scoring values of the RMR of the rock mass geological mechanics classification index in Table 2:

[0064] Table 2 RMR Classification Parameters and Their Scoring Values

[0065]

[0066] The following is Table 3, the rock mass quality evaluation and engineering characteristics table based on the total RMR score:

[0067] Table 3 Rock Mass Quality Evaluation and Engineering Characteristics Based on Total RMR Score

[0068]

[0069] The GSI value is selected based on the joint distribution characteristics and joint surface characteristics of the rock mass. The joint distribution characteristics of the rock mass include the number of joint sets, block shape, and degree of geological disturbance, and the joint surface characteristics are determined by joint surface roughness, joint weathering degree, and filling conditions. In this embodiment, the geological strength index GSI classification is as Figure 2 obtained in

[0070] Based on the above three different rock mass quality classification methods, the rock mass quality grades at different depths (partial) of the shaft are obtained, as shown in Table 4:

[0071] Table 4 Rock Mass Quality Classification Results

[0072]

[0073] Step S132, calculate according to the basic strength parameters of the rock and the grade division of the rock mass quality at different depths of the shaft to obtain the rock mass mechanical parameters at different depths (partial). Specifically, according to the Hoek-Brown strength criterion, evaluate the rock mass strength and deformation parameters, and determine the engineering rock mass mechanical parameters according to the "Standard for Classification of Engineering Rock Masses". Among them, the rock mass mechanical parameters include rock density ρ, rock mass compressive strength , rock mass tensile strength , rock elastic modulus E, rock mass Poisson's ratio and rock mass shear strength value and value. Step S132 includes:

[0074] Rock mass compressive strength Calculation process: Using the Hoek-Brown strength criterion, according to the geological strength index GSI, the geological strength index GSI is obtained by looking up the rock mass quality classification results in Table 4 in step S131, and then the rock mass characteristic constants s and a are valued according to the following formula:

[0075] ,

[0076] , where D is the disturbance coefficient, and the value range is 0 to 1;

[0077] Then, according to the rock mass characteristic constants s, a and the uniaxial compressive strength of the rock , the uniaxial compressive strength of the rock mass is calculated according to the following formula :

[0078] .

[0079] Uniaxial tensile strength of the rock mass Calculation process: First, according to the intact rock material constant , the geological strength index GSI and the disturbance coefficient D, the empirical parameter characteristic of the rock mass is calculated according to the following formula:

[0080] ,

[0081] Then, according to the uniaxial compressive strength of the rock , the empirical parameter characteristic of the rock mass and the rock mass characteristic constant s, the uniaxial tensile strength of the rock mass is calculated according to the following formula:

[0082] .

[0083] Elastic modulus E of the rock mass m Calculation process: According to the elastic modulus E of the rock, the geological strength index GSI and the disturbance coefficient D, the elastic modulus E of the rock mass is calculated according to the following formula m :

[0084] .

[0085] Poisson's ratio of the rock mass Calculation process: According to the elastic modulus E of the rock, the elastic modulus E m of the rock mass and the Poisson's ratio μ of the rock mass, the Poisson's ratio of the rock mass is determined:

[0086] .

[0087] Shear strength of the rock mass value and Value calculation process: First, according to the empirical parameters of rock mass characteristics and the rock mass characteristic constants s and a, calculate according to the following formula value:

[0088] ,

[0089] where, σ 3n = / , is the upper limit value of the restricted stress of the relationship between the Hoek-Brown criterion and the Mohr-Coulomb criterion;

[0090] Then, according to the uniaxial compressive strength of the rock , the rock mass characteristic constants s and a, the empirical parameters of rock mass characteristics and the upper limit value of the restricted stress of the relationship between the Hoek-Brown criterion and the Mohr-Coulomb criterion , calculate the value according to the following formula:

[0091] .

[0092] Finally, based on the rock mass compressive strength , rock mass tensile strength , rock mass elastic modulus E m , Poisson's ratio and rock mass shear strength values and values, combined with the rock mass position and rock density draw up a table of rock mass mechanical parameters, as shown in Table 5:

[0093] Table 5 Rock mass mechanical parameters

[0094]

[0095] Step S140, excavate the shaft, analyze the mechanical behavior of the surrounding rock of the shaft according to the rock mass mechanical parameters and using the elastoplastic theory analysis and numerical simulation methods, and then judge the rockburst tendency of the surrounding rock of the shaft at different depths. Step S140 includes:

[0096] Step S141, after excavating the shaft, the surrounding rock stress is redistributed. According to whether the magnitude of the redistributed stress of the surrounding rock exceeds the elastic limit of the rock mass, the surrounding rock state is divided into an elastic state and a plastic state; use the elastoplastic theory analysis and numerical simulation methods to analyze the stress conditions of the cross-section of the shaft surrounding rock under hydrostatic pressure and non-hydrostatic pressure conditions respectively, and divide the overall shaft surrounding rock into three parts: a loosening zone, a surrounding rock bearing zone, and an initial stress zone according to the analysis results. Step S141 includes:

[0097] Step S1411: First, according to the formula , determine whether the surrounding rock of the shaft has exceeded the elastic limit and is in a plastic state, so as to divide the surrounding rock state into an elastic state and a plastic state. When the tangential stress of the shaft surrounding rock satisfies the following formula, it is considered that the plastic failure of the shaft surrounding rock occurs:

[0098] ,

[0099] where is the maximum horizontal principal stress.

[0100] Step S1412: Under the hydrostatic pressure state, the elastic analysis solutions of the surrounding rock stress and displacement are calculated using the polar coordinate system, and the specific formulas are as follows:

[0101] ,

[0102] ,

[0103] ,

[0104] ,

[0105] ,

[0106] where is the virgin rock stress, is the radial stress, is the tangential stress, is the shear stress, is the radial displacement, is the tangential displacement, is the shear modulus, is the lateral pressure coefficient, , is the shaft radius, is the polar coordinate radius, is the angle of the polar coordinate, is the passive reaction coefficient.

[0107] Step S1413: Under the non-hydrostatic pressure state, the analytical solutions of the plastic zone and stress distribution of the shaft surrounding rock are obtained by using the numerical simulation method.

[0108] Step S1413: Through the elastic and plastic analysis of the shaft surrounding rock under the hydrostatic state and the non-hydrostatic state, the shaft surrounding rock is divided into three parts: the loosening zone, the surrounding rock bearing zone, and the initial stress zone.

[0109] Step S142: Analyze the spatial effect of the shaft excavation working face using numerical simulation methods, simulate the shaft excavation process, obtain the deformation characteristic curve of the shaft longitudinal section, and use the elastic-plastic theory analytical method to analyze the interaction between the shaft surrounding rock and the shaft wall concrete lining under uniform stress and non-uniform stress conditions respectively.

[0110] Affected by the excavation face, the stress redistribution state of the surrounding rock near the excavation face is significantly different from that of the surrounding rock far from the excavation face. The stress and displacement of the surrounding rock near the shaft excavation face cannot be fully released. The farther away from the excavation face, the more complete the stress release of the surrounding rock. Therefore, considering the spatial effect of the shaft excavation working face, assuming that the outer diameter of the lining is equal to the shaft excavation radius, it is found by analyzing the interaction between the shaft surrounding rock and the shaft wall concrete lining under uniform and non-uniform stress conditions through the elastic-plastic theory analytical method that the parameters affecting the maximum principal stress in the lining include the horizontal maximum principal stress, the lateral pressure coefficient, the lining thickness, and the lining shear modulus. Continuously increasing the strength and thickness of the lining concrete cannot effectively reduce the displacement and stress difference of the shaft surrounding rock. Therefore, it is concluded that the traditional shaft excavation and support technology is not applicable to the construction of ultra-deep vertical shafts.

[0111] Step S143: Combine the rock layer type determination chart to determine the potential failure types of the shaft surrounding rock.

[0112] Based on on-site observations and laboratory tests, according to the failure mechanism of the surrounding rock, the failure types of the surrounding rock can be roughly divided into four categories: single rock or local instability failure, overall failure of the surrounding rock, rock burst failure, and deliquescence and swelling failure, as shown in Table 6. Through on-site investigations, the potential failure forms of the surrounding rock of the ultra-deep vertical shaft in this embodiment are mainly structure plane controlled failure, deep stress induced failure, rock burst, low confining pressure shear failure, spalling, and a combination of multiple failure types.

[0113] Table 6 Potential failure types of shaft surrounding rock

[0114]

[0115] Step S144: Through comprehensive analysis and comparison using three methods, namely the brittleness coefficient method, the Barton method, and the stress intensity method, based on the rock physical and mechanical parameters, obtain the rock burst tendency evaluation. Specifically, based on the rock physical and mechanical test results of the ultra-deep vertical shaft and the core logging data of the engineering exploration holes, use the brittleness coefficient method, the Barton method, and the stress intensity method for evaluation, and obtain the rock burst tendency evaluation results of the shaft surrounding rock at different depths in the deep part as shown in Table 7 below:

[0116] Table 7 Rock burst tendency evaluation results

[0117]

[0118] Step S150: Determine the support timing and thickness of the concrete lining for the ultra - deep vertical shaft according to the quality grade of the shaft surrounding rock. Step S150 includes:

[0119] Step S151: Determine the unsupported self - stabilizing span and self - stabilizing time of the ultra - deep vertical shaft surrounding rock by the RMR stability chart method based on the classification of the shaft rock mass quality and the excavation size of the ultra - deep vertical shaft. Specifically, based on the RMR rock mass classification results, it can be determined that the maximum unsupported self - stabilizing time interval of the shaft surrounding rock is between 1 week and 1 month, and the unsupported self - stabilizing span interval is between 10 m and 20 m.

[0120] Step S152: Based on the theory of advanced sequential pressure relief, comprehensively draw the cross - section deformation characteristic curve and support characteristic curve of the surrounding rock, and combine with the longitudinal - section deformation characteristic curve of the shaft obtained by numerical simulation analysis in Step S142 during the shaft excavation process to determine the support timing of the concrete lining of the ultra - deep vertical shaft wall. Establish the technology and method of the advanced sequential pressure relief theory based on the convergence - confinement method theory. Through the analysis of the longitudinal - section deformation curves of the shaft surrounding rock at different depths obtained in Step S142, as the shaft depth increases, the deformation of the shaft surrounding rock gradually increases, and at the position 10 m away from the shaft excavation face, the surrounding rock deformation tends to be stable. According to the modified Fenner formula, draw the cross - section deformation characteristic curve of the surrounding rock. Specifically, Step S152 includes:

[0121] Step S1521: Draw the cross - section deformation characteristic curve of the surrounding rock according to the modified Fenner formula. The formula is as follows:

[0122] ,

[0123] where is the support resistance.

[0124] Step S1522: Draw the support characteristic curve of the concrete lining according to the relationship formula between the support force and the structural stiffness. The formula is as follows:

[0125] ;

[0126] where is the support force, is the structural stiffness, is the radial displacement of the support.

[0127] By comprehensively drawing the longitudinal - section deformation characteristic curve, the cross - section deformation characteristic curve of the surrounding rock and the support characteristic curve, as Figure 4As shown in the figure, determine the timing of the concrete lining for the ultra-deep shaft. In this embodiment, the timing of the concrete lining is that the radial displacement of the shaft surrounding rock reaches 17.8 mm, and then the concrete lining can be poured. The distance between the lining support and the working face should be at least 5 m or more, and at the same time, it should be less than the self-stabilizing height of the unsupported surrounding rock. Finally, it is determined that the distance between the lining support and the shaft excavation face is 12 m, with an interval of three operation cycles.

[0128] Step S153: Comprehensively determine the lining support thickness of the ultra-deep shaft wall according to the thick-walled cylinder theory and the empirical method. Specifically, draw a graph of the unsupported self-stabilizing time / h - the unsupported self-stabilizing span / m according to the thick-walled cylinder theory and the empirical method, as Figure 3 shown, and determine the lining support thickness of the ultra-deep shaft wall according to Figure 3 and the empirical method. In this embodiment, the shaft wall thickness is 0.8 m to 1.0 m, which is obviously too large. By referring to the shaft wall support designs at home and abroad and comprehensively judging according to the empirical method, the lining thickness of the ultra-deep shaft wall is corrected to 0.5 m.

[0129] Step S160: Determine the support parameters, and carry out energy-releasing support and advance pressure-relief blasting on the shaft surrounding rock in combination with the evaluation results of the rockburst proneness of the shaft surrounding rock at different depths. Adopt the methods of energy-releasing support and advance pressure-relief blasting for the shaft surrounding rock to actively regulate the stress state and stress distribution characteristics of the surrounding rock. Step S160 includes:

[0130] Step S161: Design the support for the exposed surrounding rock section between the shaft wall and the working face by using a temporary support method in the form of bolt-net-shotcrete.

[0131] Step S162: Determine the support parameters by comprehensively using the RMR rock mass geomechanics classification method and the engineering analogy method. Combine the actual situation of the on-site project to carry out the design of the support parameters, and check the bolt support parameters by using the surrounding rock shear-slip theory.

[0132] Among them, the support parameters include: the diameter, length, and row and column spacing of the bolts, the density of the cable bolts, the material, size, and mesh shape of the wire mesh, the length, diameter, and spacing of the double reinforcing bars, and the tray specifications.

[0133] The design of the support parameters is shown in Tables 8 and 9:

[0134] Table 8 Design of Support Parameters Based on RMR Classification

[0135]

[0136] Table 9 Design of Support Parameters Based on Engineering Analogy Method

[0137]

[0138] Among them, the length of the bolts is determined according to Barton's empirical formula, and the formula is as follows:

[0139] ,

[0140] Among them, B is the distance between the lining support and the shaft excavation face, with the unit of meter; ESR is the excavation support ratio.

[0141] Based on the above analysis, a schematic diagram of the temporary support design is drawn. Combining with the thickness of the loosening zone of the shaft surrounding rock on site, the specifications of bolts, trays, wire meshes and double rib bars are finally determined.

[0142] As Figure 5 and Figure 6 shown, in this embodiment, the length L of the bolt 1 is 2.25 m, the row and interval distance S×A is 1.0 m×1.0 m, and the J energy-releasing bolt support is adopted. The tray specification is 120 mm×120 mm×8 mm. The wire mesh 2 is made of 8# wire diamond galvanized wire mesh. The double rib bar 3 is welded by two parallel Φ8 mm steel bars, the interval S of the double rib bar is 80 mm, and the length L of the double rib bar is 3 m. The safety factor of the bolt support is checked by using the surrounding rock shear slip theory, and the safety factor of the bolt support is 2.5, meeting the safety requirements. The specific support installation steps can be determined according to the actual operation of the staff, and the present invention does not limit it. The plan view after the support installation is as Figure 5 and Figure 6 shown, and details are not described herein again.

[0143] Step S163: According to the evaluation results of the rockburst proneness of the shaft surrounding rock at different depths, in the areas where rockburst may occur, adopt energy-releasing support and advanced pressure-relief blasting methods to release the local high stress of the shaft surrounding rock and reduce the probability of rockburst occurrence in the shaft surrounding rock. Specifically, according to the analysis of the evaluation results of the rockburst proneness of the shaft surrounding rock at different depths in Table 6 in step S144, in the areas where rockburst may occur, adopt energy-releasing support and advanced pressure-relief blasting methods. By arranging horizontal and inclined blasting holes in the shaft surrounding rock respectively, cutting grooves and cutting fissures are formed by blasting to release the local high stress of the shaft surrounding rock and reduce the probability of rockburst occurrence in the shaft surrounding rock.

[0144] Those skilled in the art can understand that the present invention provides a construction method for advanced pressure relief in ultra-deep vertical shafts of metal mines, which is mainly used for the pressure relief construction of large-diameter ultra-deep vertical shafts with a well depth exceeding 1500 m and the prevention and control of ground pressure disasters. By adopting methods such as shaft core logging, surrounding rock joint fissure investigation, and rock mechanics tests, the lithology and physical and mechanical parameters of the shaft surrounding rock are obtained to achieve the purpose of transparent shaft construction and early warning; then, the mechanical behavior of the shaft surrounding rock is analyzed to obtain the distribution characteristics of the excavation disturbance stress field of the shaft surrounding rock; based on the advanced sequential pressure relief theory, the support timing and support thickness of the shaft wall concrete lining are determined, and a certain distance is maintained between the shaft wall lining and the shaft excavation working face. The energy-releasing support structure is used to bear the deformation pressure generated by the stress redistribution of the excavated surrounding rock of the shaft, and the high stress accumulated in the rock mass is released through advanced pressure relief blasting, so as to actively control the stress state of the shaft surrounding rock in the unlined section, weaken the interaction between the shaft surrounding rock and the subsequent shaft wall concrete lining, and realize the pressure relief construction of the ultra-deep vertical shaft.

[0145] Furthermore, the construction method for advanced pressure relief in ultra-deep vertical shafts of metal mines provided by the present invention is applicable to complex environment strata such as deep high stress, strong compression, and strong excavation disturbance. Through the transparent analysis of the shaft strata and the early warning of ground pressure disaster prevention and control, various means are used to gradually solve the construction safety problems existing in the construction process of ultra-deep vertical shafts in sequence, change the disaster hidden dangers brought by the traditional conventional construction methods of vertical shafts in the past, ensure the safety and efficiency of the excavation and support construction of ultra-deep vertical shafts, as well as the long-term stability of the shaft construction and service period, and achieve the purpose of comprehensively improving the shaft ground pressure.

[0146] So far, the technical solutions of the present invention have been described in combination with multiple foregoing embodiments. However, those skilled in the art can easily understand that the protection scope of the present invention is not limited to these specific embodiments. Without departing from the technical principle of the present invention, those skilled in the art can split and combine the technical solutions in the above-mentioned various embodiments, and can also make equivalent changes or replacements to the relevant technical features. Any changes, equivalent replacements, improvements, etc. made within the technical concept and / or technical principle of the present invention will fall within the protection scope of the present invention.

Claims

1. A method for advanced pressure relief construction of ultra-deep vertical shaft in metal mines, characterized in that: include: Establish an ultra-deep wellbore engineering disaster model; Conduct rock mechanics tests to determine basic rock strength parameters; According to the investigation of the joints and fissures of the surrounding rock of the wellbore and the basic strength parameters of the rock, the quality grade of the surrounding rock of the wellbore is divided and the mechanical parameters of the rock mass are determined; Excavate the shaft, analyze the mechanical properties of the surrounding rock of the shaft according to the rock mass mechanical parameters and use the elastic-plastic theory analysis and numerical simulation methods, and then judge the rock burst tendency of the surrounding rock of shafts at different depths; Determine the timing and thickness of concrete lining support for ultra-deep shafts; Determine the support parameters, and carry out energy release support and advance pressure relief blasting on the surrounding rock of the wellbore based on the rockburst tendency evaluation results of the wellbore surrounding rock at different depths.

2. The method for advanced pressure relief construction of ultra-deep vertical shaft in metal mines according to claim 1 is characterized in that: The steps of establishing the ultra-deep wellbore engineering disaster model include: Using the drill cores from ultra-deep shaft engineering surveys, the bottom layer information of the cores is catalogued, and the rock mass quality is graded according to the core characteristics and the degree of development of joints and fissures, and an engineering disaster model of the ultra-deep shaft bedrock lithology and rock mass quality is established; Following the progress of ultra-deep shaft construction, investigate the joints and fissures of the surrounding rocks at different depths of the shaft, and compare the shaft joint and fissure investigation results with the stratigraphic information revealed by the engineering survey drilling core to revise / update the ultra-deep shaft engineering disaster model.

3. The method for advanced pressure relief construction of ultra-deep vertical shaft in metal mines according to claim 1 is characterized in that: The steps of conducting rock mechanics tests and determining basic rock strength parameters include: Sampling the rock mass at different excavation depths of the ultra-deep shaft, processing the rock mass into standard rock samples, and conducting uniaxial compressive strength tests, Brazilian splitting tests and shear tests to determine the basic strength parameters of the rock; Among them, the basic strength parameters of rock include: the average density of rock samples , Uniaxial compressive strength of rock , rock tensile strength , rock elastic modulus E, rock cohesion c, rock Poisson's ratio μ and rock internal friction angle .

4. The method for advanced pressure relief construction of ultra-deep vertical shaft in metal mines according to claim 3 is characterized in that: The steps of classifying the quality grade of the surrounding rock of the wellbore and determining the mechanical parameters of the rock mass according to the investigation of the joints and fissures of the surrounding rock of the wellbore and the basic strength parameters of the rock include: According to the joints and fissures of the surrounding rock of the ultra-deep vertical shaft and the basic strength parameters of the rock, the rock quality at different depths of the shaft is graded using the Barton rock quality index Q classification, rock geomechanics RMR classification and geological strength index GSI classification methods; Calculate according to the basic strength parameters of the rock and the grade classification of the rock mass quality at different depths of the wellbore to obtain the mechanical parameters of the rock mass at different depths; Among them, rock mass mechanical parameters include rock density , rock mass compressive strength , rock mass tensile strength , rock mass elastic modulus E m , Poisson's ratio of rock mass and rock mass shear strength Value and value.

5. The method for advanced pressure relief construction of ultra-deep vertical shaft in metal mines according to claim 3 is characterized in that: The step of excavating a wellbore, analyzing the mechanical properties of the surrounding rock of the wellbore according to the rock mass mechanical parameters and using elastic-plastic theory analysis and numerical simulation methods, and then judging the rock burst tendency of the surrounding rock of the wellbore at different depths includes: After the wellbore is excavated, the surrounding rock stress is redistributed. The elastic-plastic theory analysis and numerical simulation methods are used to analyze the stress conditions of the wellbore cross-section surrounding rock under hydrostatic pressure and non-hydrostatic pressure conditions. According to the analysis results, the wellbore surrounding rock is divided into three parts: loose area, surrounding rock bearing area, and initial stress area. The numerical simulation method is used to analyze the spatial effect of the shaft excavation working face, simulate the shaft excavation process, obtain the shaft longitudinal section deformation characteristic curve, and use the elastic-plastic theory analytical method to analyze the interaction between the shaft surrounding rock and the shaft wall concrete lining under uniform stress and non-uniform stress conditions. Combined with the rock formation type determination chart, the potential damage type of the wellbore surrounding rock is determined; Based on the physical and mechanical parameters of rock, the rock burst tendency evaluation was obtained through comprehensive analysis and comparison of three methods: brittleness coefficient method, Barton method and stress intensity method.

6. The method for advanced pressure relief construction of ultra-deep vertical shaft in metal mines according to claim 5 is characterized in that: The steps of using elastic-plastic theory analysis and numerical simulation methods to analyze the stress conditions of the surrounding rock in the cross section of the wellbore under hydrostatic pressure and non-hydrostatic pressure conditions respectively include: First, according to the formula , judge whether the surrounding rock of the wellbore exceeds the elastic limit and is in a plastic state, and divide the surrounding rock state into elastic state and plastic state; when the tangential stress of the surrounding rock of the wellbore When the following formula is satisfied, it is considered that plastic failure occurs in the surrounding rock of the wellbore: ， in, is the maximum horizontal principal stress; Then calculate the elastic analysis solution under the hydrostatic pressure state: the following elastic analysis solution of surrounding rock stress and displacement is obtained by polar coordinate system calculation. The specific formula is as follows: ， ， ， ， ， in, is the original rock stress, is the radial stress, is the tangential stress, is the shear stress, is the radial displacement, is the tangential displacement, is the shear modulus, is the lateral pressure coefficient, , is the wellbore radius, is the polar coordinate radius, is the angle in polar coordinates, is the passive reaction coefficient; Finally, numerical simulation method is used to calculate the analytical solution of plastic zone and stress distribution of wellbore surrounding rock under non-static pressure state.

7. The method for advanced pressure relief construction of ultra-deep vertical shaft in metal mines according to claim 6, characterized in that: The step of determining the timing and thickness of the ultra-deep shaft concrete lining support comprises: According to the rock mass quality classification of the shaft and the excavation size of the ultra-deep shaft, the unsupported self-stabilizing span and self-stabilizing time of the surrounding rock of the ultra-deep shaft are determined by the RMR stability diagram method; Based on the theory of advanced sequential pressure release, the deformation characteristic curve and support characteristic curve of the surrounding rock cross section are comprehensively drawn to determine the timing of concrete lining support for the ultra-deep shaft wall; The thickness of the lining support for ultra-deep shafts is determined comprehensively based on thick-walled cylinder theory and empirical method.

8. The method for advanced pressure relief construction of ultra-deep vertical shaft in metal mines according to claim 7 is characterized in that: The step of comprehensively drawing the surrounding rock cross-section deformation characteristic curve and the support characteristic curve includes: The deformation characteristic curve of the surrounding rock cross section is drawn according to the modified Fenner formula, and the formula is as follows: ， in, To support resistance, is the internal friction angle of rock, is the rock cohesion; The concrete lining support characteristic curve is drawn based on the relationship between the support force and the structural stiffness. The formula is as follows: ， in, For the supporting force, is the structural stiffness, is the radial displacement of the support.

9. The method for advanced pressure relief construction of ultra-deep vertical shaft in metal mines according to claim 1, characterized in that: The step of determining support parameters and performing energy release support and advanced pressure relief blasting on the wellbore surrounding rock in combination with the rockburst tendency evaluation results of wellbore surrounding rock at different depths includes: A temporary support method in the form of anchor mesh spraying is used to design support for the exposed surrounding rock section between the shaft wall and the working face; The support parameters are determined by comprehensively adopting the RMR rock mass geomechanics classification method and engineering analogy method; the support parameters include: anchor diameter, length and spacing, metal mesh material, size and mesh shape, double reinforcement length, diameter and spacing; According to the rockburst tendency evaluation results of the surrounding rocks of wellbore at different depths, the advanced pressure relief blasting method is used in the area where rockburst may occur to release the local high stress of the surrounding rocks of the wellbore and reduce the probability of rockburst in the surrounding rocks of the wellbore.

10. The method for advanced pressure relief construction of ultra-deep vertical shaft in metal mines according to claim 4, characterized in that: The step of calculating according to the basic strength parameters of the rock and the grade classification of the rock mass quality at different depths of the wellbore to obtain the mechanical parameters of the rock mass at different depths includes: Rock mass compressive strength Calculation process: Using the Hoek-Brown strength criterion and according to the geological strength index GSI, firstly determine the rock mass characteristic constants s and a according to the following formula: ， , where D is the disturbance coefficient, ranging from 0 to 1; According to the rock mass characteristic constants s, a and the uniaxial compressive strength of rock , the compressive strength of rock mass is calculated according to the following formula : ； Rock mass tensile strength Calculation process: First, according to the complete rock material constant , geological strength index GSI and disturbance coefficient D, and the empirical parameters of rock mass characteristics are calculated according to the following formula : , According to the uniaxial compressive strength of rock , Empirical parameters of rock mass characteristics And the rock mass characteristic constant s, the rock mass tensile strength is calculated according to the following formula : ； Rock mass elastic modulus E m Calculation process: According to the rock elastic modulus E, geological strength index GSI and disturbance coefficient D, the rock elastic modulus E is calculated according to the following formula: m : ； Poisson's ratio of rock mass Calculation process: According to the rock elastic modulus E, rock mass elastic modulus E m and the rock Poisson's ratio μ, determine the rock mass Poisson's ratio : ； Rock mass shear strength Value and Value calculation process: First, according to the empirical parameters of rock mass characteristics and rock mass characteristic constants s and a, calculated according to the following formula value: ； Among them, σ 3n = / , The upper limit of the stress limit between the Hoek-Brown criterion and the Mohr-Coulomb criterion; According to the uniaxial compressive strength of rock , rock mass characteristic constants s and a, empirical parameters of rock mass characteristics And the upper limit of stress limited by the relationship between the Hoek-Brown criterion and the Mohr-Coulomb criterion , calculated according to the following formula value: ； Finally, the rock mass compressive strength calculated according to the above steps is , rock mass tensile strength , rock mass elastic modulus , Poisson's ratio of rock mass and rock mass shear strength Value and value, combined with the rock mass location and rock density Draw a table of rock mass mechanics parameters.

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