Metal mine expansive rock roadway support parameter design method considering service time

Abstract

The invention discloses a metal mine expansive rock roadway support parameter design method considering service time. Rock strain and rock stress are determined by establishing a relative humidity distribution equation and a relative temperature distribution equation in rock; determining a tensile damage threshold and a shear damage threshold according to the uniaxial tensile strength, the compressive strength and the rock stress; obtaining volume force and total support strength, determining a first relation curve in combination with rock strain and rock stress, and determining a roadway limit convergence deformation standard value according to a roadway function failure limit width, a non-pedestrian side width, a mine car width and a pedestrian side width; and establishing a function relationship between the total support strength and the longest safe service life of the roadway in combination with the first relationship curve, and determining support parameters. According to the method, the timeliness of continuous strain accumulation of the rock in the service period is considered, the function relation between the total supporting strength and the service life is established, and the safety, rationality and economical efficiency of supporting design are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal mine support, and particularly relates to a method for designing support parameters for an expansive rock roadway in a metal mine considering the service time. Background Art

[0002] When driving a roadway in a metal mine in a deep or humid environment, it often passes through highly expansive rock strata. Due to its unique moisture absorption and expansion characteristics, such rocks will undergo volume expansion during long-term contact with groundwater or humid air, resulting in continuous deformation and shrinkage of the roadway section. As the service life of the roadway extends, the expansion effect gradually accumulates. If reasonable support measures are not taken in time, it is extremely easy to induce roadway instability, spalling, crown settlement, and even collapse accidents.

[0003] In addition, as the mining depth of the mine increases, the ambient temperature of the roadway also rises significantly. A large number of studies have shown that the high-temperature environment not only affects the mechanical properties of rocks but also exacerbates the moisture migration and moisture absorption and expansion rate, forming a "temperature-humidity combined excitation" effect. Traditional models often do not fully consider the superimposed effects of the temperature field on moisture migration and rock mass expansion-damage behavior, resulting in large model prediction errors and poor applicability.

[0004] In terms of support design, the current industry generally determines the bolt or shotcrete parameters under the initial stress state during excavation, ignoring the time-dependent effect of the continuous strain accumulation of expansive rock during the service period, and also not establishing a functional relationship between the support strength and the service life. The lack of a "service life"-oriented design concept leads to a dilemma in support design, often falling into "excessive redundancy" or "insufficient safety margin". In order to improve the safety, rationality, and economy of support design, there is an urgent need for a scientific, systematic, and practical engineering support design method. Summary of the Invention

[0005] Based on this, in view of the above problems, it is necessary to propose a method for designing support parameters for an expansive rock roadway in a metal mine considering the service time.

[0006] A method for designing support parameters for an expansive rock roadway in a metal mine considering the service time, the method comprising: Establishing an equation for the relative humidity distribution and an equation for the relative temperature distribution inside the rock; Determining the rock strain and rock stress according to the relative humidity distribution equation and the relative temperature distribution equation; Obtaining the uniaxial tensile strength and compressive strength, and determining the tensile damage threshold and shear damage threshold according to the uniaxial tensile strength, compressive strength, and the rock stress; Determining the damage variable according to the magnitudes of the tensile damage threshold and the shear damage threshold, and updating the rock strain according to the damage variable until the time ends; Obtain the volumetric force and the total support strength, and determine the first relationship curve in combination with the rock strain and the rock stress, where the first relationship curve is the relationship curve between the convergence deformation amount of the rock horizontal displacement and the total support strength; Obtain the limit width of roadway functional failure, the non - pedestrian side width, the mine car width, and the pedestrian side width, and determine the standard value of the limit convergence deformation of the roadway according to the limit width of roadway functional failure, the non - pedestrian side width, the mine car width, and the pedestrian side width; Establish a functional relationship between the total support strength and the longest safe service life of the roadway according to the first relationship curve and the standard value of the limit convergence deformation of the roadway; when the longest safe service life of the roadway is known, determine the total support strength; Determine the support parameters according to the total support strength, where the support parameters include: bolt spacing, bolt row spacing, and shotcrete thickness.

[0007] In one embodiment, the determining the rock strain and the rock stress according to the relative humidity distribution equation and the relative temperature distribution equation includes: Determine the rock relative humidity according to the relative humidity distribution equation; Determine the rock relative temperature according to the relative temperature distribution equation; Determine the rock strain according to the relative humidity increment corresponding to the rock relative humidity at different times, the relative temperature increment corresponding to the rock relative temperature at different times, and the rock mechanical state; Determine the rock stress according to the rock strain; The determining the tensile damage threshold and the shear damage threshold according to the uniaxial tensile strength, the compressive strength, and the rock stress includes: Determine the tensile damage threshold according to the uniaxial tensile strength and the maximum principal stress component in the rock stress; Determine the shear damage threshold according to the compressive strength, the minimum principal stress component, the maximum principal stress component in the rock stress, and the internal friction angle.

[0008] In one embodiment, the determining the support parameters according to the total support strength includes: Determine the bolt support strength according to the total support strength; Obtain the bolt tensile strength and the bolt diameter, and determine the bolt spacing and the bolt row spacing according to the bolt support strength, the bolt tensile strength, and the bolt diameter; Obtain the bolt - mesh support strength, and determine the shotcrete support strength according to the total support strength, the bolt support strength, and the bolt - mesh support strength; Obtain the excavation radius of the circular roadway tunnel and the initial compressive strength of the shotcrete; determine the thickness of the shotcrete according to the excavation radius of the circular roadway tunnel with shotcrete support strength and the initial compressive strength of the shotcrete.

[0009] In one embodiment, The relative humidity distribution equation is as follows: where H RH is the relative humidity of the rock; is the gradient operator, representing the vector composed of the partial derivatives of the multivariate function in each coordinate direction; K h (T, D) is the humidity diffusion coefficient, which is a function related to temperature and damage, is the initial humidity diffusion coefficient. In the initial state, D is 0; is a constant; is the critical damage value, that is, when the damage is equal to or greater than , the humidity diffusion coefficient suddenly increases to a constant value ; t is time; x, y, and z are the coordinates of each point in the rock; T is the rock temperature; T0 is the reference temperature; is the temperature sensitivity coefficient; is the partial derivative of the relative humidity of the rock with respect to time; The relative temperature distribution equation is as follows: where T is the relative temperature of the rock, c is the specific heat capacity of the rock, k is the thermal conductivity of the rock, ρ is the density of the rock, t is time, is the gradient operator, is the partial derivative of the relative temperature of the rock with respect to time.

[0010] In one embodiment, the determination of the rock strain according to the relative humidity increment corresponding to the rock relative humidity at different times, the relative temperature increment corresponding to the rock relative temperature at different times, and the mechanical state of the rock is achieved through the following expression: (4) (5) , (7) where is the hygroscopic expansion coefficient, H RH is the relative humidity, L is the rock expansion rate during the water absorption expansion test, is the expansion strain caused by rock hygroscopicity, is the increment of relative humidity, is the Kronecker function, is the thermal expansion strain, is the coefficient of thermal expansion, is the increment of temperature, is the initial coefficient of thermal expansion, D is the damage variable, is the critical damage value, is a constant value; is the strain caused by mechanical load, is the rock strain.

[0011] In one embodiment, the determination of the rock stress based on the rock strain is achieved through the following expression: , i = 1, 2, 3, j = 1, 2, 3 = , i = j where, is the rock stress, which is a tensor; is the rock strain, is the volumetric strain, is the Lame elastic constant; G is the shear modulus, G = E / 2(1 + ), E is the elastic modulus, , and E are the elastic moduli of the undamaged material and the damaged material respectively, D is the damage variable, refers to the Poisson's ratio; is the Kronecker function; is the hygroscopic expansion coefficient; is the increment of relative humidity; H RH is the relative humidity of the rock; is the increment of relative temperature, T is the relative temperature of the rock, is the coefficient of thermal expansion.

[0012] In one embodiment, the determination of the tensile damage threshold based on the uniaxial tensile strength and the maximum principal stress component of the rock stress; the determination of the shear damage threshold based on the compressive strength, the minimum principal stress component, the maximum principal stress component of the rock stress and the internal friction angle is achieved through the following expression: where, is the tensile damage threshold; is the shear damage threshold; is the maximum principal stress component of the rock stress; is the minimum principal stress component of the rock stress; Uniaxial tensile strength; Compressive strength; is the internal friction angle; The determination of the damage variable according to the magnitudes of the tensile damage threshold and the shear damage threshold is achieved through the following expression: where D is the damage variable; is the maximum tensile strain; is the compressive principal strain; is the maximum principal strain; is the minimum principal strain.

[0013] In one embodiment, the acquisition of the body force and the total support strength, and the determination of the first relationship curve in combination with the rock strain and the rock stress are achieved through the following expression: (14) , i = 1, 2, 3, j = 1, 2, 3 = , i = j where, is the rock stress, which is a tensor; is the rock strain, is the volume strain, is the Lame elastic constant; G is the shear modulus, G = E / 2(1 + ), E is the elastic modulus, , and E are the elastic moduli of the undamaged material and the damaged material respectively, D is the damage variable, refers to the Poisson's ratio; is the Kronecker function; is the hygroscopic expansion coefficient; is the relative humidity increment; H RH is the relative humidity of the rock; is the relative temperature increment, T is the relative temperature of the rock, is the thermal expansion coefficient; is the displacement component in the i direction, is the displacement component in the j direction, x i and are the spatial coordinates, is the gradient operator, is the rock stress, f is the body force, is the total support strength.

[0014] In one embodiment, the standard value of the ultimate convergence deformation of the roadway is determined according to the ultimate width of the roadway function failure, the non-pedestrian side width, the mine car width, and the pedestrian side width, which is realized through the following expression: Wherein, is the standard value of the ultimate convergence deformation of the roadway; is the ultimate width of the roadway function failure; F s is the safety factor; a is the non-pedestrian side width; A1 is the mine car width; c is the pedestrian side width; The functional relationship between the total support strength and the longest safe service life of the roadway is as follows: Wherein, t d is the longest safe service life of the roadway; P is the total support strength, , , are constant coefficients.

[0015] In one embodiment, the support parameters are determined according to the total support strength through the following expression: Wherein, P is the total support strength; P b is the bolt support strength; P m is the bolt-mesh support strength; P s is the shotcrete support strength; is the initial compressive strength of the shotcrete; R is the excavation radius of the circular roadway tunnel; is the shotcrete thickness; d is the bolt diameter; is the tensile strength of the bolt; L b,x is the bolt spacing; L b,y is the bolt row spacing.

[0016] This application establishes the relative humidity distribution equation and relative temperature distribution equation inside the rock; determines the rock strain and rock stress according to the relative humidity distribution equation and relative temperature distribution equation; obtains the uniaxial tensile strength and compressive strength, and determines the tensile damage threshold and shear damage threshold according to the uniaxial tensile strength, compressive strength and the rock stress; determines the damage variable according to the magnitudes of the tensile damage threshold and the shear damage threshold, and updates the rock strain according to the damage variable until the time deadline; obtains the body force and the total support strength, and determines the first relationship curve in combination with the rock strain and rock stress, where the first relationship curve is the relationship curve between the horizontal displacement convergence deformation amount of the rock and the total support strength; obtains the limit width, non-pedestrian side width, mine car width, and pedestrian side width of the roadway function failure, and determines the limit convergence deformation standard value of the roadway according to the limit width, non-pedestrian side width, mine car width, and pedestrian side width of the roadway function failure; establishes the functional relationship between the total support strength and the longest safe service life of the roadway according to the first relationship curve and the limit convergence deformation standard value of the roadway; determines the total support strength when the longest safe service life of the roadway is known; determines the support parameters according to the total support strength, and the support parameters include: bolt spacing, bolt row spacing, and shotcrete thickness. This application considers the timeliness of the continuous accumulation of rock strain during the service period in the swelling rock roadway, establishes the functional relationship between the support strength and the service life, and uses the design concept guided by "service life" to improve the safety, rationality, and economy of the support design. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Among them: Figure 1 FIG. is an application environment diagram of the support parameter design method for swelling rock roadways in metal mines considering the service time in an embodiment; Figure 2 FIG. is a flowchart of the support parameter design method for swelling rock roadways in metal mines considering the service time in an embodiment; Figure 3 FIG. is a numerical model diagram of a swelling rock roadway in a metal mine in an embodiment; Figure 4 FIG. is a relationship curve diagram of the water absorption rate and swelling rate of rock in an embodiment; Figure 5 FIG. is a first relationship curve diagram in an embodiment; Figure 6 It is a function relationship diagram between the total support strength and the longest safe service life of the roadway in an embodiment; Figure 7 It is a structural block diagram of a computer device in an embodiment. Specific implementation manners

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0020] When driving roadways in deep or humid environments in metal mines, high-swelling rock strata are often penetrated. Due to their unique moisture-absorbing and swelling characteristics, such rocks will expand in volume during long-term contact with groundwater or humid air, resulting in continuous deformation and shrinkage of the roadway section. As the service life of the roadway extends, the swelling effect gradually accumulates. If reasonable support measures are not taken in time, it is extremely easy to induce roadway instability, spalling, crown settlement, and even collapse accidents. In addition, as the mining depth of the mine increases, the environmental temperature of the roadway also increases significantly. A large number of studies have shown that the high-temperature environment not only affects the mechanical properties of rocks, but also exacerbates the moisture migration and moisture-absorbing and swelling rate, forming a "temperature-humidity composite excitation" effect. Traditional models often do not fully consider the superimposed effects of the temperature field on moisture migration and rock mass swelling-damage behavior, resulting in large model prediction errors and poor applicability. In terms of support design, the current industry generally determines the bolt or shotcrete parameters under the initial stress state of excavation, ignoring the time effect of the continuous strain accumulation of swelling rock during the service period, and not establishing the function relationship between the support strength and the service life. The lack of a "service life"-oriented design concept leads to a dilemma in support design, often falling into "excessive redundancy" or "insufficient safety margin". In order to improve the safety, rationality, and economy of support design, there is an urgent need for a scientific, systematic, and practical engineering-suitable support design method. To solve the above technical problems, this application provides a support parameter design method for swelling rock roadways in metal mines considering the service time.

[0021] Figure 1 It is an application environment diagram of the support parameter design method for swelling rock roadways in metal mines considering the service time in an embodiment. Refer to Figure 1, the design method for support parameters of swelling rock roadways in metal mines considering service time is applied to the design system for support parameters of swelling rock roadways in metal mines considering service time. The design system for support parameters of swelling rock roadways in metal mines considering service time includes a terminal 110 and a server 120. The terminal 110 and the server 120 are connected through a network. The terminal 110 can specifically be a desktop terminal or a mobile terminal, and the mobile terminal can specifically be at least one of a mobile phone, a tablet computer, a laptop computer, etc. The server 120 can be implemented by an independent server or a server cluster composed of multiple servers. The terminal 110 is used to establish the relative humidity distribution equation and the relative temperature distribution equation inside the rock; the server 120 is used to determine the rock strain and the rock stress according to the relative humidity distribution equation and the relative temperature distribution equation; obtain the uniaxial tensile strength and the compressive strength, and determine the tensile damage threshold and the shear damage threshold according to the uniaxial tensile strength, the compressive strength, and the rock stress; determine the damage variable according to the magnitudes of the tensile damage threshold and the shear damage threshold, and update the rock strain according to the damage variable until the time deadline; obtain the body force and the total support strength, and determine the first relationship curve in combination with the rock strain and the rock stress, where the first relationship curve is the relationship curve between the horizontal displacement convergence deformation amount of the rock and the total support strength; obtain the limit width of roadway functional failure, the non-pedestrian side width, the tram width, and the pedestrian side width, and determine the standard value of roadway limit convergence deformation according to the limit width of roadway functional failure, the non-pedestrian side width, the tram width, and the pedestrian side width; establish the functional relationship between the total support strength and the longest safe service life of the roadway according to the first relationship curve and the standard value of roadway limit convergence deformation; determine the total support strength when the longest safe service life of the roadway is known; and determine the support parameters according to the total support strength.

[0022] As Figure 2 shown, in one embodiment, a design method for support parameters of swelling rock roadways in metal mines considering service time is provided. This method can be applied to both the terminal and the server. In this embodiment, it is exemplified by being applied to the terminal. According to Figure 1 shown, this embodiment provides a design method for support parameters of swelling rock roadways in metal mines considering service life. In this embodiment, the support design is carried out for a typical swelling rock roadway at the -480 level of a certain metal mine. The designed shape of the roadway is a three-centered arch, with a width of 3.3 meters and a height of 3.3 meters, as Figure 3 shown; the design method for support parameters of swelling rock roadways in metal mines considering service time provided by this application specifically includes the following steps: S10: Establish the relative humidity distribution equation and the relative temperature distribution equation inside the rock; S20: Determine the rock strain and rock stress according to the relative humidity distribution equation and the relative temperature distribution equation; S30: Obtain the uniaxial tensile strength and compressive strength, and determine the tensile damage threshold and shear damage threshold according to the uniaxial tensile strength, compressive strength and the rock stress; S40: Determine the damage variable according to the magnitudes of the tensile damage threshold and the shear damage threshold, and update the rock strain according to the damage variable until the time deadline; S50: Obtain the body force and the total support strength, and determine the first relationship curve in combination with the rock strain and rock stress, where the first relationship curve is the relationship curve between the rock horizontal displacement convergence deformation amount and the total support strength; S60: Obtain the limit width of roadway functional failure, the non - pedestrian side width, the mine car width, and the pedestrian side width, and determine the standard value of roadway limit convergence deformation according to the limit width of roadway functional failure, the non - pedestrian side width, the mine car width, and the pedestrian side width; S70: Establish the functional relationship between the total support strength and the longest safe service life of the roadway according to the first relationship curve and the standard value of roadway limit convergence deformation; when the longest safe service life of the roadway is known, determine the total support strength; S80: Determine the support parameters according to the total support strength, where the support parameters include: bolt spacing, bolt row spacing, and shotcrete thickness.

[0023] This application takes into account the time - effect of continuous strain accumulation of rocks in the swelling rock roadway during the service period, establishes the functional relationship between the support strength and the service life, and improves the safety, rationality and economy of the support design with the design concept oriented by "service life".

[0024] In one embodiment, for the determining the rock strain and rock stress according to the relative humidity distribution equation and the relative temperature distribution equation in step S20, it includes: S201: Determine the rock relative humidity according to the relative humidity distribution equation; S202: Determine the rock relative temperature according to the relative temperature distribution equation; S203: Determine the rock strain according to the relative humidity increment corresponding to the rock relative humidity at different times, the relative temperature increment corresponding to the rock relative temperature at different times, and the rock mechanical state; S204: Determine the rock stress according to the rock strain; For the determining the tensile damage threshold and the shear damage threshold according to the uniaxial tensile strength, compressive strength and the rock stress in step S30, it includes: S301: Determine the tensile damage threshold based on the uniaxial tensile strength and the maximum principal stress component in the rock stress; S302: Determine the shear damage threshold based on the compressive strength, the minimum principal stress component, the maximum principal stress component, and the internal friction angle in the rock stress.

[0025] In one embodiment, for the step of determining the support parameters according to the total support strength in step S80, it includes: S801: Determine the bolt support strength according to the total support strength; S802: Obtain the bolt tensile strength and the bolt diameter, and determine the bolt spacing and bolt row spacing according to the bolt support strength, the bolt tensile strength, and the bolt diameter; S803: Obtain the mesh support strength, and determine the shotcrete support strength according to the total support strength, the bolt support strength, and the mesh support strength; S804: Obtain the excavation radius of the circular roadway tunnel and the initial compressive strength of the shotcrete; determine the shotcrete thickness according to the shotcrete support strength, the excavation radius of the circular roadway tunnel, and the initial compressive strength of the shotcrete.

[0026] In one embodiment, a multi-field coupling numerical model of rock temperature-humidity-stress is established to describe the swelling deformation and mechanical damage behavior of expansive rock in metal mines caused by environmental temperature-humidity changes during service. By combining unsteady heat conduction, humidity diffusion under the influence of temperature, temperature-humidity induced strain, and damage evolution process, this model accurately simulates the multi-physical field linkage behavior during the long-term service of roadway surrounding rock.

[0027] When the relative humidity outside the surrounding rock is greater than that inside, the formed humidity gradient will trigger the diffusion movement of water. This diffusion process is controlled by the humidity distribution and follows the unsteady diffusion mechanism described by Fick's second law. When the properties or temperature of the rock change, the humidity diffusion ability of the rock also changes, and the humidity migration behavior is no longer dominated by a constant diffusion coefficient. Instead, a temperature-damage coupling factor is introduced, and the relative humidity distribution equation inside the surrounding rock after correction is as follows: (1) (2) Among them, H RH is the relative humidity of the rock; is the gradient operator, representing the vector composed of partial derivatives of a multivariate function in each coordinate direction; K h (T, D) is the humidity diffusion coefficient, which is a function related to temperature and damage, is the initial humidity diffusion coefficient. In the initial state, D is 0; is a constant; is the critical damage value, that is, when the damage is equal to or greater than the humidity diffusion coefficient suddenly increases to a constant value ; t is time; x, y, and z are the coordinates of each point in the rock; T is the rock temperature; T0 is the reference temperature; is the temperature sensitivity coefficient; is the partial derivative of the relative humidity of the rock with respect to time; the relative humidity of the rock can be obtained through formulas (1) and (2); Similarly, when the temperature in the roadway is not stable, the temperature field inside the rock will also evolve dynamically with the diffusion of heat, and the relative temperature distribution equation inside the surrounding rock, that is, the relative temperature distribution equation, is as follows: (3) where T is the relative temperature of the rock, c is the specific heat capacity of the rock, k is the thermal conductivity of the rock, ρ is the density of the rock, t is time, is the gradient operator, is the partial derivative of the relative temperature of the rock with respect to time. Specifically, the relative temperature of the rock can be obtained through formula (3).

[0028] In one embodiment, when the temperature and humidity inside the rock change, the rock expands under the action of humidity and temperature, and the total strain of the rock can be decomposed into three parts: elastic strain increment, strain increment caused by humidity, and thermal expansion strain. For the determination of the rock strain according to the relative humidity increment corresponding to the relative humidity of the rock at different times, the relative temperature increment corresponding to the relative temperature of the rock at different times, and the mechanical state of the rock in step S203, it is realized through the following expression: (4) (5) , (6) (7) where, is the hygroscopic expansion coefficient, H RH is the relative humidity, L is the rock expansion rate during the water absorption expansion test, is the expansion strain caused by rock hygroscopicity, is the increment of the relative humidity, is the Kronecker function, is the thermal expansion strain, is the thermal expansion coefficient, is the increment of the temperature, is the initial thermal expansion coefficient, D is the damage variable, is the critical damage value, is a constant value; is the strain caused by the mechanical load, is the rock strain.

[0029] In one embodiment, when the thermal expansion and moisture absorption expansion properties of the rock are isotropic, for the determination of the rock stress according to the rock strain in step S204, it is achieved through the following expression: , i = 1, 2, 3, j = 1, 2, 3 (8) = , i = j (9) Wherein, is the rock stress, which is a tensor; is the rock strain, is the volumetric strain, is the Lame elastic constant; G is the shear modulus, G = E / 2(1 + ), E is the elastic modulus, , and E are the elastic moduli of the undamaged material and the damaged material respectively, D is the damage variable, refers to the Poisson's ratio; is the Kronecker function; is the moisture absorption expansion coefficient; is the relative humidity increment; H RH is the rock relative humidity; is the relative temperature increment, T is the rock relative temperature, is the thermal expansion coefficient.

[0030] In one embodiment, for the determination of the tensile damage threshold according to the uniaxial tensile strength and the maximum principal stress component in the rock stress in step S301; and for the determination of the shear damage threshold according to the compressive strength, the minimum principal stress component, the maximum principal stress component and the internal friction angle in the rock stress in step S302, it is achieved through the following expressions: (10) (11) Wherein, is the tensile damage threshold; is the shear damage threshold; is the maximum principal stress component of the rock stress; is the minimum principal stress component of the rock stress; is the uniaxial tensile strength; is the compressive strength; is the internal friction angle; The determination of the damage variable based on the magnitudes of the tensile damage threshold and the shear damage threshold is achieved through the following expression: (12) where D is the damage variable; is the maximum tensile strain; is the compressive principal strain; is the maximum principal strain; is the minimum principal strain.

[0031] For the obtaining of the body force and the total support strength in step 50, and the determination of the first relationship curve in combination with the rock strain and the rock stress, it is achieved through the following expression: (13) (14) , i = 1, 2, 3, j = 1, 2, 3 (15) = , i = j (16) where, to simulate the common roadway support conditions in actual mine engineering, a support force term is further introduced into the model and participates in the stress equilibrium equation as a component of the external force field. Considering the support action provided by the support system (such as bolts, shotcrete layers, steel frames, etc.) to the surrounding rock, its influence can be regarded as an equivalent external force density. The modified stress equilibrium control equation is formula (14), is the rock stress, which is a tensor; is the rock strain, is the volume strain, is the Lame elastic constant; G is the shear modulus, G = E / 2(1 + ), E is the elastic modulus, , and E are the elastic moduli of the undamaged material and the damaged material respectively, D is the damage variable, refers to the Poisson's ratio; is the Kronecker function; is the hygroscopic expansion coefficient; is the relative humidity increment; H RH is the relative humidity of the rock; is the relative temperature increment, T is the relative temperature of the rock, is the thermal expansion coefficient; is the displacement component in the i direction, is the displacement component in the j direction, x i and are the spatial coordinates, is the gradient operator, is the rock stress, and f is the volume force, is the total support strength. For different total support strengths the deformation of the swelling rock roadway under the action is solved, and the time-dependent convergence deformation curves of the surrounding rock under different total support strengths are drawn, that is, through formulas (13)-(16), the following can be obtained Figure 5 multiple first relationship curves as shown, that is, the relationship curve between the horizontal displacement convergence deformation of the rock and the total support strength P.

[0032] Based on the rock temperature-humidity-stress-damage multi-field coupling numerical model, the following numerical model is established Figure 3 as shown. The geometric size of the model is 30m×30m, and the discrete grid is 17,472 units. A vertical stress of 13.36 MPa (equivalent to a burial depth of 509 m) is applied to the top boundary to represent the self-weight of the overburden, and the support pressure is applied to the roadway surface. The mechanical parameters of the model are that the elastic modulus E is taken as 0.3 GPa, the compressive strength f c0 is taken as 24 MPa, the internal friction angle is taken as 33°, the Poisson's ratio v is taken as 0.3, the homogeneity index m is taken as 4, the density ρ is taken as 2680 kg / m 3 , and the humidity diffusion coefficient K h (T,D) is 2×10 -10 m 2 / s, is the temperature sensitivity coefficient is 0.05 / K, the specific heat capacity c is 950 J / (kg·K), the thermal conductivity k is 0.6 W / (m·K), and the initial thermal expansion coefficient is 9×10 -6 K -1 The moisture absorption and expansion coefficient of the rock is determined through experiments The relationship with the water content w is as Figure 4 shown. The different support strengths are determined to be 0 MPa, 0.3 MPa, 0.6 MPa, 0.9 MPa, 1.2 MPa, and 1.5 MPa. Through numerical simulation, the deformation of the roadway under different support strengths is obtained ( Figure 5 the curves in it can reflect), indicating that in the case of no support, the horizontal convergence deformation of the roadway is 2.29 m; while under a higher support strength (such as 1.5 MPa), the horizontal convergence deformation of the roadway is effectively limited to less than 1.27 m.

[0033] For expansive rock tunnels, since the surrounding rock has obvious plastic expansion characteristics, sudden damage such as roof falls and spalling is usually not likely to occur. Large deformation of the surrounding rock becomes the most common and most engineering-impactful form of ground pressure. Therefore, when evaluating the stability of the tunnel, the convergence deformation of the tunnel can be used as an indicator to determine whether the tunnel function has failed. The tunnel cross-section is mainly composed of the width of the mine car passage, the width of the pedestrian passage, and the width of the non-pedestrian side. In order to ensure that the operating function of the tunnel is not affected during its long-term service, the "limit width of tunnel function failure" can be defined as On this basis, by introducing the safety factor F s , the maximum deformation allowed by the tunnel can be calculated, that is, the tunnel limit convergence deformation standard The determination of the tunnel limit convergence deformation standard value according to the tunnel function failure limit width, non-pedestrian side width, mine car width, and pedestrian side width in step S301 is implemented by the following expression: in, is the standard value of the tunnel limit convergence deformation; F is the limit width of the tunnel function failure; s is the safety factor, the commonly used range is 1.5<F s <2.0; a is the width on the non-pedestrian side; A1 is the width of the mine car; c is the width on the pedestrian side; Figure 5 As shown in the figure, the functional failure rebellion standard is the tunnel limit convergence deformation standard value ; By combining formula (17) and formula (14), the maximum safe service life of the tunnel is determined , the longest safe service life of the tunnel The total support strength P is obtained, and the longest safe service life t of the known tunnel is d Under the condition of , determine the total support strength P; the non-ferrous metal mine tunnel engineering design specification GB 50915-2013 requires that the width of the tunnel on the non-pedestrian side should not be less than 0.3m, and the width on the pedestrian side should not be less than 0.8m. The width of the mine car currently used in the mine is 1.1m, so the minimum width required for the mine car to pass is 2.2m. The tunnel section width is 3.3m. When the shrinkage deformation on both sides of the tunnel reaches 1.1m, the tunnel function fails. Considering the safety factor F s is 1.5, and the criterion for tunnel function failure is determined to be 0.73m.

[0034] The obtained time-dependent convergence deformation curve is compared with the roadway limit convergence deformation standard. When the convergence deformation value of the roadway calculated by the numerical model is equal to the roadway limit convergence deformation standard, the corresponding time is the service life of the roadway. The time-dependent convergence deformation curve under different support strengths is compared with the roadway limit convergence deformation standard.Figure 6 As shown in the figure, a functional relationship between the total support strength and the longest safe service life of the roadway is established as follows: (18) where t d is the longest safe service life of the roadway; P is the total support strength, the specific value of which is 23.80, the specific value is 3.23, the specific value is 0.41.

[0035] In one embodiment, for the determination of the support parameters according to the total support strength in step S80, it is achieved through the following expression: (19) (20) (21) where P is the total support strength; P b is the bolt support strength; P m is the bolt-mesh support strength; P s is the shotcrete support strength; is the initial compressive strength of the shotcrete; R is the excavation radius of the circular roadway tunnel; is the shotcrete thickness; d is the bolt diameter; is the tensile strength of the bolt; L b,x is the bolt spacing; L b,y is the bolt row spacing.

[0036] Specifically, when the support strength provided by the bolts, bolt-mesh and shotcrete is greater than or equal to the optimal support strength, the service time of the roadway meets the design requirements. The calculation formula for the total support strength is as formula (19). According to existing research, the bolt-mesh support strength P m provided by the bolt-mesh is a fixed value of 0.01 MPa, and the bolt support strength P b provided by the bolts accounts for 60% of the total support strength, and the remaining support strength is provided by the shotcrete.

[0037] In one embodiment, for the -480 horizontal swelling rock roadway, the bolt diameter used is 32 mm, the bolt tensile strength is 490 MPa, and the initial compressive strength of the C20 shotcrete is 10 MPa. According to the above formula, the final support parameters are: bolt spacing 810 mm, row spacing 810 mm, and shotcrete thickness 75 mm.

[0038] Figure 7The internal structure diagram of a computer device in an embodiment is shown. The computer device may specifically be a terminal or a server. As Figure 7 shown, the computer device includes a processor, a memory, and a network interface connected through a system bus. Among them, the memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor can implement the design method for the support parameters of the swelling rock roadway in a metal mine considering the service time. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can execute the design method for the support parameters of the swelling rock roadway in a metal mine considering the service time. Those skilled in the art can understand that Figure 7 the structure shown in

[0039] is only a block diagram of some structures related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0040] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0041] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A design method for the support parameters of the swelling rock roadway in a metal mine considering the service time, characterized in that, The method includes: Establishing the relative humidity distribution equation and the relative temperature distribution equation inside the rock; Determining the rock strain and the rock stress according to the relative humidity distribution equation and the relative temperature distribution equation; Obtaining the uniaxial tensile strength and the compressive strength, and determining the tensile damage threshold and the shear damage threshold according to the uniaxial tensile strength, the compressive strength and the rock stress; Determining the damage variable according to the magnitudes of the tensile damage threshold and the shear damage threshold, and updating the rock strain according to the damage variable until the time deadline; Obtaining the body force and the total support strength, and determining the first relationship curve in combination with the rock strain and the rock stress, where the first relationship curve is the relationship curve between the horizontal displacement convergence deformation amount of the rock and the total support strength; Obtaining the limit width of the roadway functional failure, the non - pedestrian side width, the mine car width, and the pedestrian side width, and determining the standard value of the limit convergence deformation of the roadway according to the limit width of the roadway functional failure, the non - pedestrian side width, the mine car width, and the pedestrian side width; Establishing the functional relationship between the total support strength and the longest safe service life of the roadway according to the first relationship curve and the standard value of the limit convergence deformation of the roadway; and determining the total support strength when the longest safe service life of the roadway is known; Determining the support parameters according to the total support strength, where the support parameters include: bolt spacing, bolt row spacing, and shotcrete thickness.

2. The design method of the support parameter for the swelling rock roadway in a metal mine considering the service time according to claim 1, characterized in that The determining the rock strain and the rock stress according to the relative humidity distribution equation and the relative temperature distribution equation includes: Determining the rock relative humidity according to the relative humidity distribution equation; Determining the rock relative temperature according to the relative temperature distribution equation; Determining the rock strain according to the relative humidity increment corresponding to the rock relative humidity at different times, the relative temperature increment corresponding to the rock relative temperature at different times, and the mechanical state of the rock; Determining the rock stress according to the rock strain; The determining the tensile damage threshold and the shear damage threshold according to the uniaxial tensile strength, the compressive strength and the rock stress includes: Determining the tensile damage threshold according to the uniaxial tensile strength and the maximum principal stress component in the rock stress; Determining the shear damage threshold according to the compressive strength, the minimum principal stress component and the maximum principal stress component in the rock stress, and the internal friction angle.

3. The design method of the support parameters for the swelling rock roadway in a metal mine considering the service time according to claim 1, characterized in that, The determining the support parameters according to the total support strength includes: Determining the bolt support strength according to the total support strength; Obtaining the bolt tensile strength and the bolt diameter, and determining the bolt spacing and the bolt row spacing according to the bolt support strength, the bolt tensile strength and the bolt diameter; Obtaining the bolt - mesh support strength, and determining the shotcrete support strength according to the total support strength, the bolt support strength and the bolt - mesh support strength; Obtaining the excavation radius of the circular roadway tunnel and the initial compressive strength of the shotcrete; and determining the shotcrete thickness according to the shotcrete support strength, the excavation radius of the circular roadway tunnel and the initial compressive strength of the shotcrete.

4. The method for designing the support parameters of the expansive rock roadway in a metal mine considering the service time according to claim 1, characterized in that The relative humidity distribution equation is as follows: （1） where H RH is the relative humidity of the rock; is the gradient operator, representing the vector composed of the partial derivatives of a multivariate function in each coordinate direction; K h (T, D) is the humidity diffusion coefficient, which is a function related to temperature and damage, is the initial humidity diffusion coefficient. In the initial state, D is 0; is a constant; is the critical damage value, that is, when the damage is equal to or greater than , the humidity diffusion coefficient suddenly increases to a constant value ; t is time; x, y, and z are the coordinates of each point in the rock; T is the rock temperature; T0 is the reference temperature; is the temperature sensitivity coefficient; is the partial derivative of the relative humidity of the rock with respect to time; The relative temperature distribution equation is as follows: where T is the relative temperature of the rock, c is the specific heat capacity of the rock, k is the thermal conductivity of the rock, ρ is the density of the rock, t is time, is the gradient operator, is the partial derivative of the relative temperature of the rock with respect to time.

5. The design method of the support parameters for the expansive rock roadway in a metal mine considering the service time according to claim 2, characterized in that, Determining the rock strain based on the relative humidity increment corresponding to the relative humidity of the rock at different times, the relative temperature increment corresponding to the relative temperature of the rock at different times, and the mechanical state of the rock is achieved through the following expression: , Among them, is the hygroscopic expansion coefficient, H RH is the relative humidity, L is the rock expansion rate during the water absorption expansion test, is the expansion strain caused by rock hygroscopicity, is the increment of relative humidity, is the Kronecker function, is the thermal expansion strain, is the coefficient of thermal expansion, is the increment of temperature, is the initial coefficient of thermal expansion, D is the damage variable, is the critical damage value, is a constant value; is the strain caused by mechanical load, is the rock strain.

6. The design method of the support parameters for the expanding rock roadway in a metal mine considering the service time according to claim 5, characterized in that Determining the rock stress based on the rock strain is achieved through the following expression: , where i = 1, 2, 3 and j = 1, 2, 3 = , i = j Among them, is the rock stress, which is a tensor; is the rock strain, is the volumetric strain, is the Lame elastic constant; G is the shear modulus, G = E / 2(1 + ), E is the elastic modulus, , and E are the elastic moduli of the undamaged material and the damaged material respectively, D is the damage variable, refers to the Poisson's ratio; is the Kronecker function; is the hygroscopic expansion coefficient; is the relative humidity increment; H RH is the rock relative humidity; is the relative temperature increment, T is the rock relative temperature, is the thermal expansion coefficient.

7. The method for designing the support parameters of the expansive rock roadway in a metal mine considering the service time according to claim 2, wherein Determining the tensile damage threshold based on the uniaxial tensile strength and the maximum principal stress component in the rock stress; determining the shear damage threshold based on the compressive strength, the minimum principal stress component, the maximum principal stress component in the rock stress, and the internal friction angle is achieved through the following expression: Among them, is the tensile damage threshold; is the shear damage threshold; is the maximum principal stress component of the rock stress; is the minimum principal stress component of the rock stress; Uniaxial tensile strength; Compressive strength; is the internal friction angle; Determining the damage variable based on the magnitudes of the tensile damage threshold and the shear damage threshold is achieved through the following expression: Among them, D is the damage variable; is the maximum tensile strain; is the compressive principal strain; is the maximum principal strain; is the minimum principal strain.

8. The method for designing the support parameters of the expansive rock roadway in a metal mine considering the service time according to claim 7, characterized in that, Obtaining the body force and the total support strength, and determining the first relationship curve in combination with the rock strain and the rock stress is achieved through the following expression: , where i = 1, 2, 3 and j = 1, 2, 3 = , i = j Among them, is the rock stress, which is a tensor; is the rock strain, is the volumetric strain, is the Lame elastic constant; G is the shear modulus, G = E / 2(1 + ), E is the elastic modulus, , and E are the elastic moduli of the undamaged material and the damaged material respectively, D is the damage variable, refers to the Poisson's ratio; is the Kronecker function; is the hygroscopic expansion coefficient; is the relative humidity increment; H RH is the rock relative humidity; is the relative temperature increment, T is the rock relative temperature, is the thermal expansion coefficient; is the displacement component in the i direction, is the displacement component in the j direction, x i and are the spatial coordinates, is the gradient operator, is the rock stress, f is the body force, is the total support strength.

9. The method for designing the support parameters of the swelling rock roadway in a metal mine considering the service time according to claim 1, characterized in that Determining the standard value of the ultimate convergence deformation of the roadway based on the ultimate width of the roadway function failure, the non - pedestrian side width, the mine car width, and the pedestrian side width is achieved through the following expression: Among them, is the standard value of the ultimate convergence deformation of the roadway; is the ultimate width at which the roadway function fails; F s is the safety factor; a is the width of the non - pedestrian side; A1 is the width of the mine car; c is the width of the pedestrian side; The functional relationship between the total support strength and the longest safe service life of the roadway is as follows: Among them, t d is the longest safe service life of the roadway; P is the total support strength, , , are constant coefficients.

10. The design method of the support parameter of the expansive rock roadway in a metal mine considering the service time according to claim 3, characterized in that, Determining the support parameters based on the total support strength is achieved through the following expression: Among them, P is the total support strength; P b is the bolt support strength; P m is the bolt-net support strength; P s is the shotcrete support strength; is the initial compressive strength of the shotcrete; R is the excavation radius of the circular roadway tunnel; is the shotcrete thickness; d is the bolt diameter; is the tensile strength of the bolt; L b,x is the bolt spacing; L b,y is the bolt row spacing.

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