Layered surrounding rock tunnel beam arch structure determination method, equipment, medium and product

Abstract

The invention discloses a stratified surrounding rock tunnel beam arch structure determining method and device, a medium and a product, and relates to the technical field of tunnel engineering.The method comprises the steps that obtained stratified surrounding rock physical and mechanical parameters and tunnel parameters are input into numerical simulation software; obtaining stratified surrounding rock stress state data output by the software before and after tunnel excavation; according to the stratified surrounding rock stress state data before and after tunnel excavation, determining a stress change data set corresponding to a stress unit at any point of the stratified surrounding rock; determining the maximum pressure stress increase ratio according to the stress change data set, and determining the inner boundary of the stratified surrounding rock beam arch based on the maximum pressure stress increase ratio; and according to the stress change data set, determining a pressure stress increase ratio spatial distribution condition, and based on the pressure stress increase ratio spatial distribution condition, determining the stratified surrounding rock beam arch outer boundary. According to the method, the layered surrounding rock beam arch structure characterization and the boundary quantitative determination are realized.

Description

Technical Field

[0001] The present application relates to the technical field of tunnel engineering, and in particular to a method, equipment, medium and product for determining a beam-arch structure of a layered surrounding rock tunnel. Background Art

[0002] With the large-scale construction of transportation infrastructure, tunnels and underground projects are gradually developing towards deep burial depths, complex surrounding rock conditions and high geostress environments. Especially for layered surrounding rocks with significant anisotropy, the interweaving of bedding conditions and complex geostresses makes the mechanical response of the surrounding rock extremely complex. At present, tunnel support design based on engineering experience is often accompanied by repeated adjustments and replacements of the structure. Designers often need to explore control strategies for surrounding rock stability in an empirical trial-and-error process, during which they may encounter serious problems such as large deformation of the surrounding rock and tunnel collapse. Therefore, in-depth analysis of the bearing mechanism of layered surrounding rocks, clarifying the bearing characteristics and quantitative determination methods of beam-arch boundaries are of great significance for ensuring the safety of tunnel construction and promoting the scientific and reliable development of tunnel design theory.

[0003] During tunnel excavation, the surrounding rock will show the characteristics of progressive destruction from the inside to the outside, showing the form of an arch structure. The arch structure has good compressive resistance and stability when bearing loads. However, the layered surrounding rock can be regarded as a composite beam structure, in which the interlayer contact effect is equivalent to the boundary condition of a single beam. Therefore, the beam-arch structure of the layered surrounding rock must have the mechanical characteristics of both the arch structure and the beam structure, and the bearing structure characteristics of the beam-arch are the key to maintaining the stability of the layered surrounding rock.

[0004] Due to the existence of various weak interlayers in the layered surrounding rock, the thickness, position, shape and mechanical properties of these interlayers are different in different engineering geological environments. At the same time, under different tunnel burial depths, lateral pressure coefficients and tunnel cross-sectional shapes, the stress state of the surrounding rock changes extremely complexly, involving changes in stress magnitude and direction. This makes the characterization basis of the main load-bearing structure beam arch of the layered surrounding rock and the quantitative description method of the internal and external boundaries complex and vague, which is a difficult problem that plagues the engineering and academic communities. Summary of the invention

[0005] The purpose of this application is to provide a method, equipment, medium and product for determining the beam-arch structure of a layered surrounding rock tunnel, which can realize the characterization of the layered surrounding rock beam-arch structure and the quantitative determination of the boundaries.

[0006] To achieve the above objectives, this application provides the following solutions:

[0007] In a first aspect, the present application provides a method for determining a beam-arch structure of a layered surrounding rock tunnel, comprising:

[0008] Obtaining physical and mechanical parameters of layered surrounding rock and tunnel parameters; the physical and mechanical parameters of layered surrounding rock are determined based on existing geological survey data and empirical formulas, and the physical and mechanical parameters of layered surrounding rock include rock physical and mechanical parameters of layered surrounding rock and interlayer contact physical and mechanical parameters, and the interlayer contact physical and mechanical parameters need to be calibrated based on the rock physical and mechanical parameters, the rock mass strength conversion empirical formula in the empirical formula, and the rock mass uniaxial compression test; the tunnel parameters are determined based on actual engineering conditions and design requirements;

[0009] Inputting the physical and mechanical parameters of the layered surrounding rock and the tunnel parameters into numerical simulation software, obtaining the layered surrounding rock stress state data before tunnel excavation and the layered surrounding rock stress state data after tunnel excavation output by the numerical simulation software; the layered surrounding rock stress state data includes the magnitude and direction of stress;

[0010] Determine a stress change data set corresponding to a stress unit at any point of the layered surrounding rock according to the stress state data of the layered surrounding rock before the tunnel excavation and the stress state data of the layered surrounding rock after the tunnel excavation; the stress change data set includes stress change data of the stress unit in any direction; the stress change data is a compressive stress increase ratio, and the compressive stress increase ratio is a compressive stress difference between the stress unit after being disturbed and before being disturbed;

[0011] Determine the maximum compressive stress increase ratio corresponding to the stress unit at any point of the layered surrounding rock according to the stress change data set, and determine the inner boundary of the layered surrounding rock beam arch based on the maximum compressive stress increase ratio corresponding to the stress unit at any point of the layered surrounding rock;

[0012] According to the stress change data set, the spatial distribution of the compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock is determined, and based on the spatial distribution of the compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock, the outer boundary of the layered surrounding rock beam arch is determined.

[0013] In a second aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described method for determining the beam-arch structure of a layered surrounding rock tunnel.

[0014] In a third aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for determining the beam-arch structure of a layered surrounding rock tunnel.

[0015] In a fourth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the above-mentioned method for determining the beam-arch structure of a layered surrounding rock tunnel.

[0016] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0017] The present application provides a method, device, medium and product for determining the beam-arch structure of a layered surrounding rock tunnel. The method includes obtaining physical and mechanical parameters of layered surrounding rock and tunnel parameters; the physical and mechanical parameters of layered surrounding rock are determined based on existing geological survey data and empirical formulas, the physical and mechanical parameters of layered surrounding rock include rock physical and mechanical parameters of layered surrounding rock and physical and mechanical parameters of interlayer contact, and the physical and mechanical parameters of interlayer contact need to be calibrated based on the rock physical and mechanical parameters, the empirical formula for rock mass strength conversion in the empirical formula and the uniaxial compression test of rock mass; the tunnel parameters are determined based on actual engineering conditions and design requirements; the physical and mechanical parameters of layered surrounding rock and tunnel parameters are input into numerical simulation software to obtain the stress state data of layered surrounding rock before tunnel excavation and the stress state data of layered surrounding rock after tunnel excavation output by the numerical simulation software state data; the stress state data of layered surrounding rock includes the magnitude and direction of stress; according to the stress state data of layered surrounding rock before tunnel excavation and the stress state data of layered surrounding rock after tunnel excavation, the stress change data set corresponding to the stress unit at any point of the layered surrounding rock is determined; the stress change data set includes the stress change data of the stress unit in any direction; the stress change data is the compressive stress increase ratio, and the compressive stress increase ratio is the compressive stress difference between the stress unit after being disturbed and before being disturbed; according to the stress change data set, the maximum compressive stress increase ratio corresponding to the stress unit at any point of the layered surrounding rock is determined, and the inner boundary of the layered surrounding rock beam arch is determined based on it; according to the stress change data set, the spatial distribution of the compressive stress increase ratio corresponding to the stress unit at any point of the layered surrounding rock is determined, and the outer boundary of the layered surrounding rock beam arch is determined based on it. By analyzing the stress state data before and after tunnel excavation, the present application can obtain the stress changes of the surrounding rock during the excavation process, especially the compressive stress increase ratio on the stress unit at any point, and based on the maximum compressive stress increase ratio and the spatial distribution of the compressive stress increase ratio, the inner and outer boundaries of the beam arch of the layered surrounding rock can be accurately determined. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1This is an application environment diagram of a method for determining a beam-arch structure of a layered surrounding rock tunnel in one embodiment of the present application;

[0020] Figure 2 A schematic flow chart of a method for determining a beam-arch structure of a layered surrounding rock tunnel provided in one embodiment of the present application;

[0021] Figure 3 A schematic flow chart of a method for determining a beam-arch structure of a layered surrounding rock tunnel provided in another embodiment of the present application;

[0022] Figure 4 A schematic diagram of a tunnel cross-section model provided in another embodiment of the present application;

[0023] Figure 5 A schematic diagram of layered surrounding rock stress values ​​after tunnel excavation is provided for another embodiment of the present application;

[0024] Figure 6 A schematic diagram of the stress direction of layered surrounding rock after tunnel excavation is provided for another embodiment of the present application;

[0025] Figure 7a A schematic diagram of the stress state of layered surrounding rock in any direction before disturbance provided by another embodiment of the present application;

[0026] Figure 7b A schematic diagram of the stress state of layered surrounding rock in any direction after disturbance provided by another embodiment of the present application;

[0027] Figure 8 A schematic flow chart of a numerical analysis algorithm for characterizing the compressive stress increase ratio provided in another embodiment of the present application;

[0028] Fig. 9 A schematic diagram of the inner boundary of a layered surrounding rock beam arch provided in another embodiment of the present application;

[0029] Fig.10 A schematic diagram of an arch structure area and a beam structure area of ​​layered surrounding rock provided in another embodiment of the present application;

[0030] Fig.11 A schematic diagram of the outer boundary of a layered surrounding rock beam arch provided in another embodiment of the present application;

[0031] Fig.12 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] At present, there is a lack of systematic and in-depth research and understanding of the bearing mechanism of layered tunnel surrounding rock, and there is no complete calculation process and method that can objectively and quantitatively characterize the main bearing structure of layered surrounding rock, the beam arch. The existing technology does not fully consider the complexity of layered surrounding rock, such as the anisotropy, heterogeneity and interlayer shear characteristics of the rock strata. At the same time, the analysis and research on the influence of disturbances during the construction process, such as excavation sequence, support timing and method, on the formation of beam arches is not comprehensive and specific. Methods that can quantitatively describe the characteristics and properties of the range, thickness, position and shape of layered surrounding rock beam arches are still in the exploratory stage. At the same time, there is a lack of quantitative methods for the inner and outer boundaries of beam arches with practical engineering significance.

[0034] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0035] The method for determining the beam-arch structure of a layered surrounding rock tunnel provided in the embodiment of the present application can be applied to Figure 1In the application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be set up separately, integrated on the server 104, or placed on the cloud or other servers. The terminal 102 can send the physical and mechanical parameters of the layered surrounding rock and the tunnel parameters to the server 104, and the server 104 inputs the physical and mechanical parameters of the layered surrounding rock and the tunnel parameters into the numerical simulation software to obtain the layered surrounding rock stress state data before and after tunnel excavation output by the software; according to the layered surrounding rock stress state data before and after tunnel excavation, determine the stress change data set corresponding to the stress unit at any point in the layered surrounding rock; according to the stress change data set, determine the maximum compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock, and determine the inner boundary of the layered surrounding rock beam arch based on this; according to the stress change data set, determine the spatial distribution of the compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock, and determine the outer boundary of the layered surrounding rock beam arch based on this. The server 104 can feed back the obtained inner boundary and outer boundary of the layered surrounding rock beam-type arch to the terminal 102. In addition, in some embodiments, the layered surrounding rock tunnel beam-type arch structure determination method can also be implemented by the server 104 or the terminal 102 alone, such as being directly processed by the terminal 102, or the server 104 can obtain the layered surrounding rock physical and mechanical parameters and tunnel parameters from the data storage system and process them.

[0036] The terminal 102 may be, but is not limited to, various desktop computers, laptop computers, and IoT devices, and the server 104 may be implemented as an independent server or a server cluster consisting of multiple servers, or may be a cloud server.

[0037] In an exemplary embodiment, Figure 2 As shown, a method for determining the beam-arch structure of a layered surrounding rock tunnel is provided. The method is executed by a computer device, and specifically can be executed by a computer device such as a terminal or a server alone, or can be executed by a terminal and a server together. In the embodiment of the present application, the method is applied to Figure 1 The server 104 in the example is used as an example to illustrate, including the following steps 201 to 205. Among them:

[0038] Step 201, obtain the physical and mechanical parameters of layered surrounding rock and tunnel parameters; the physical and mechanical parameters of layered surrounding rock are determined based on existing geological survey data and empirical formulas, and the physical and mechanical parameters of layered surrounding rock include the physical and mechanical parameters of rock and interlayer contact of layered surrounding rock, and the interlayer contact physical and mechanical parameters need to be calibrated based on the physical and mechanical parameters of rock, the empirical formula for rock mass strength conversion in the empirical formula, and the uniaxial compression test of rock mass; the tunnel parameters are determined based on actual engineering conditions and design requirements. Step 202, input the physical and mechanical parameters of layered surrounding rock and tunnel parameters into the numerical simulation software, and obtain the stress state data of layered surrounding rock before tunnel excavation and the stress state data of layered surrounding rock after tunnel excavation output by the numerical simulation software; the stress state data of layered surrounding rock includes the magnitude and direction of stress.

[0039] Step 203, determining a stress change data set corresponding to a stress unit at any point in the layered surrounding rock according to the stress state data of the layered surrounding rock before tunnel excavation and the stress state data of the layered surrounding rock after tunnel excavation; the stress change data set includes stress change data of the stress unit in any direction; the stress change data is a compressive stress increase ratio, and the compressive stress increase ratio is a compressive stress difference between the stress unit after being disturbed and before being disturbed;

[0040] Step 204, determining the maximum compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock according to the stress change data set, and determining the inner boundary of the layered surrounding rock beam arch based on the maximum compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock.

[0041] Step 205, determining the spatial distribution of the compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock according to the stress change data set, and determining the outer boundary of the layered surrounding rock beam arch based on the spatial distribution of the compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock.

[0042] Furthermore, in step 201, the physical and mechanical parameters of the layered surrounding rock and the tunnel parameters are obtained, which specifically include:

[0043] According to the existing geological survey data, field test data and engineering experience database, the rock physical and mechanical parameters of the layered surrounding rock are obtained, including the uniaxial compressive strength of rock, rock deformation modulus, rock bulk modulus, rock shear modulus, rock cohesion and rock internal friction angle. The first rock mechanical parameters are obtained by converting the rock mass strength into the empirical formula in the empirical formula. At the same time, the second rock mechanical parameters are obtained by the uniaxial compression test of the rock in the numerical simulation software. When the first rock mechanical parameters obtained by converting the rock mass strength into the empirical formula in the empirical formula are consistent with the values ​​of the rock physical and mechanical parameters obtained by the uniaxial compression of the rock in the numerical simulation software, the corresponding interlayer contact surface physical and mechanical parameters are output as input parameters for subsequent calculations to complete the calibration of the interlayer contact physical and mechanical parameters.

[0044] Furthermore, in step 202, the physical and mechanical parameters of the layered surrounding rock and the tunnel parameters are input into the numerical simulation software to obtain the layered surrounding rock stress state data before tunnel excavation and the layered surrounding rock stress state data after tunnel excavation output by the numerical simulation software, which specifically include:

[0045] Based on actual engineering conditions, the tunnel cross-sectional shape, burial depth, support method, support timing, and the rock physical and mechanical parameters of the layered surrounding rock and the interlayer contact physical and mechanical parameters calculated according to geological survey data and engineering experience formulas are introduced. With the help of numerical simulation software, the surrounding rock tunnel excavation model and operation model are constructed to visualize the stress distribution before and after tunnel excavation, that is, the layered surrounding rock stress state data before tunnel excavation and the layered surrounding rock stress state data after tunnel excavation, with a focus on the increase in compressive stress before and after tunnel excavation and the change in direction.

[0046] Further, in step 203, according to the stress state data of the layered surrounding rock before tunnel excavation and the stress state data of the layered surrounding rock after tunnel excavation, a stress change data set corresponding to the stress unit at any point of the layered surrounding rock is determined, which specifically includes:

[0047] Step 2031, establishing a Cartesian coordinate system for the stress unit at any point of the layered surrounding rock.

[0048] Step 2032, obtaining the angle between the external normal line at any cross section of the stress unit and the x-axis of the Cartesian coordinate system, and marking it as the initial angle, where the x-axis of the Cartesian coordinate system is the horizontal direction of the plane.

[0049] Step 2033, calculating the stress before and after the disturbance at the cross section of the stress unit corresponding to the initial angle.

[0050] Step 2034, based on the preset rotation angle value, the initial angle is updated; specifically, the initial angle is rotated by the preset rotation angle value, so that the updated initial angle value is the sum of the initial angle value and the preset rotation angle value.

[0051] Step 2035, determine whether the updated initial angle is within the preset angle range, the preset angle range is 0 to 180 degrees. If the updated initial angle is within the preset angle range, the initial angle in the stress before and after the disturbance at the cross section of the stress unit corresponding to the initial angle is replaced with the updated initial angle, and return to the step of calculating the stress before and after the disturbance at the cross section of the stress unit corresponding to the initial angle; if the updated initial angle is not within the preset angle range, the stress change data is calculated based on the stress before and after the disturbance, and all the stress change data are output; all the stress change data constitute the stress change data set corresponding to the stress unit.

[0052] Furthermore, the calculation formula for the stress before the disturbance at the cross section of the stress unit corresponding to the initial angle is:

[0053]

[0054] The calculation formula for the stress after disturbance at the cross section of the stress unit corresponding to the initial angle is:

[0055]

[0056] Among them, σ α0 Represents the stress value before the disturbance at the cross section of the stress unit, σ x0 It represents the horizontal normal stress at any position (x, y) before the cross section of the stress unit is disturbed, σ y0 represents the vertical normal stress at any position (x, y) before the cross section of the stress unit is disturbed, α represents the initial angle, τ xy0 Represents the horizontal and vertical cross-sectional shear stress at any position (x, y) before the cross section of the stress unit is disturbed; σ αΔ It represents the stress value after the disturbance at the cross section of the stress unit, σ xΔ It represents the horizontal normal stress at any position (x, y) after the cross section of the stress unit is disturbed, σ yΔ It represents the vertical normal stress at any position (x, y) after the cross section of the stress unit is disturbed, τ xyΔ It represents the horizontal and vertical cross-sectional shear stress at any position (x, y) after the cross section of the stress unit is disturbed, where x is the coordinate value on the x-axis of the Cartesian coordinate system, and y is the coordinate value on the y-axis of the Cartesian coordinate system.

[0057] In this embodiment, when determining the characterization basis of the layered surrounding rock beam-type arch structure, the distribution of the compressive stress of the layered surrounding rock is analyzed with the help of numerical simulation software, and the most significant feature of the arch structure, the transformation of the compressive stress direction, is comprehensively considered. A characterization method for the layered surrounding rock beam-type arch is proposed, and the maximum compressive stress increase ratio is used as the quantitative characterization basis of the layered surrounding rock tunnel beam-type arch structure.

[0058] Further, in step 204, based on the maximum compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock, the inner boundary of the beam-type arch in the layered surrounding rock is determined, which specifically includes:

[0059] According to the stress distribution in the layered surrounding rock after tunnel excavation, the whole arch area and the partial arch area are divided, and the bearing effect of the arch structure is analyzed. When the maximum compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock is equal to 1.05, the position of the stress unit corresponding to the maximum compressive stress increase ratio is determined as the inner boundary of the layered surrounding rock structure.

[0060] Further, in step 205, based on the spatial distribution of the compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock, the outer boundary of the beam-type arch in the layered surrounding rock is determined, which specifically includes:

[0061] Based on the spatial distribution of the compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock, the beam structure area of ​​the layered surrounding rock is determined; the beam structure area is the compressive stress reduction area, and the compressive stress reduction area is the area with a negative compressive stress increase ratio; the boundary where the arch structure area transitions to the beam structure area is determined as the outer boundary of the beam-type arch of the layered surrounding rock.

[0062] By implementing the above-mentioned steps 201 to 205, the present application proposes a method for characterizing beam-type arches in layered surrounding rocks, combining the mechanical characteristics of the beam-type arch in exerting material compression resistance and the changes in compressive stress of the surrounding rock stress unit in different rotation angles before and after tunnel excavation. The maximum compressive stress increase ratio on the cross section in different directions at each point is used as the quantitative characterization basis for the beam-type arch effect of the layered surrounding rock; according to the value of the maximum compressive stress increase ratio of the layered surrounding rock under stress redistribution after tunnel excavation (i.e., 1.05), the bearing effect of the local arching area is comprehensively considered to achieve the quantitative determination of the inner boundary of the beam-type arch in the layered surrounding rock; at the same time, according to the spatial distribution of the maximum compressive stress increase ratio of the surrounding rock under stress redistribution after tunnel excavation, combined with the special arch structure area and beam structure area of ​​the layered surrounding rock, the quantitative determination of the outer boundary of the beam-type arch in the layered surrounding rock is achieved.

[0063] In another exemplary embodiment of the present application, a method for determining the beam-arch structure of a layered surrounding rock tunnel is illustrated by taking a double-track tunnel of a passenger dedicated railway as an example. Figure 3 The specific plan is as follows:

[0064] (1) The span of a double-track tunnel of a passenger dedicated railway is 12.52m, the height is 9.66m, the burial depth is 150m, and the lateral pressure coefficient is 0.8. The relevant physical and mechanical parameters are obtained based on the existing geological survey data, including the uniaxial compressive strength of rock, rock deformation modulus, rock bulk modulus, rock shear modulus, rock cohesion, rock internal friction angle, rock quality index, rock uniaxial compressive strength, and rock deformation modulus. If the geological survey data do not provide the physical and mechanical parameters of the rock mass, the uniaxial compressive strength and rock deformation modulus of the rock mass can be obtained by the following rock mass strength conversion empirical formula:

[0065]

[0066]

[0067] Among them, E c is the rock deformation modulus; E m is the deformation modulus of rock mass; σ c is the uniaxial compressive strength of rock; m The uniaxial compressive strength of the rock mass; RQD is the rock quality index, which is the percentage of intact drill core pieces exceeding 10 cm recovered during a single coring run; q is the conversion factor.

[0068] At the same time, the modeling also requires the normal stiffness k of the contact surface n and the tangential stiffness k of the contact surface s , can also be calculated using the empirical rule formula in the empirical formula:

[0069]

[0070] k s =0.4k n ;

[0071] Where factor is the multiplication factor (usually set to 10); K is the rock bulk modulus; G is the rock shear modulus; Δz min is the minimum width of the adjacent region in the normal direction.

[0072] At the beginning of modeling, it is necessary to calibrate the physical and mechanical parameters of the structural layer. The specific steps are as follows: first, the contact properties of the structural layer are set by considering the strength of the layered surrounding rock and the weakening effect of the layered plane parameters. At the same time, the rock physical and mechanical parameters obtained from the geological survey data are used to perform a numerical simulation experiment on the uniaxial compression of the rock mass to obtain the uniaxial compressive strength of the rock mass, which is then compared with the uniaxial compressive strength of the rock mass calculated based on the empirical formula for rock mass strength conversion. Only when the two are consistent can the rock mass contact properties for the subsequent construction of a specific tunnel model be determined. The detailed physical and mechanical parameters of the layered surrounding rock are shown in Table 1, where C is the cohesion of the contact surface, and C is the strength of the rock mass. r is the residual cohesion after the contact surface is destroyed, φ is the internal friction angle of the contact surface, σt is the extreme tensile strength of the contact surface, σ tr It is the residual strength after the contact surface is destroyed. These physical and mechanical parameters are obtained through geological survey data, field tests or field sampling and laboratory tests.

[0073] Table 1 Physical and mechanical parameters of tunnel layered surrounding rock

[0074]

[0075] (2) Numerical simulation analysis of surrounding rock stress distribution

[0076] The numerical calculation model (i.e. tunnel section model) is established in the underground structure calculation software UDCE (Universal Distinct Element Code) as follows: Figure 4 As shown in the figure, the model is 120m wide and 120m high, and the center of the upper arch of the tunnel is located at the center of the model. Multiple different survey lines can be used to extract and analyze the data results, and the magnitude and direction of the layered surrounding rock stress after tunnel excavation are as follows: Figure 5 and Figure 6 shown.

[0077] (3) Characterization basis of layered surrounding rock beam-arch structure

[0078] In order to quantitatively analyze the beam-arch effect of layered surrounding rock after tunnel excavation, the quantitative characterization basis of the beam-arch effect of layered surrounding rock is first proposed. Since the stress redistribution of surrounding rock after tunnel excavation always occurs in the form of an arch structure in a single medium, and the directional transformation of compressive stress is the most significant feature of the arch structure, this embodiment uses the maximum compressive stress increase ratio before and after excavation at each point in the surrounding rock as the criterion for judging the range of the beam-arch.

[0079] (4) Establishing a numerical analysis algorithm for quantitative characterization of layered surrounding rock beam-arch structures

[0080] The present invention takes a stress unit at any point in the surrounding rock for analysis. The stress state of the layered surrounding rock in any direction before and after being disturbed (i.e. before and after excavation) is respectively as follows: Figure 7a and Figure 7b As shown, σ0 represents the normal stress at any position (x, y) before the cross section of the stress unit is disturbed, σ Δ It represents the normal stress at any position (x, y) after the cross section of the stress unit is disturbed.

[0081] Figure 7a and Figure 7bThe figure shows the stress state when the angle between the normal direction outside the cross section and the x-axis (horizontal direction) is α. In order to determine the maximum compressive stress increase ratio, the compressive stress changes in the cross sections in different directions at this point must be compared. On this basis, the stress units at different positions in the surrounding rock are rotated and calculated respectively, and the compressive stress values ​​of the cross sections in different directions within the range of 0-180° at the same position before and after the surrounding rock disturbance are dynamically compared. The stress distribution of a certain point in the Cartesian coordinate system is known, and the calculation formula for the stress of the cross section in any direction at this point before the surrounding rock disturbance is:

[0082]

[0083] The calculation formula for the stress of the cross section in any direction at this point after the surrounding rock is disturbed is:

[0084]

[0085] Among them, σ α0 Represents the stress value before the disturbance at the cross section of the stress unit, σ x0 It represents the horizontal normal stress at any position (x, y) before the cross section of the stress unit is disturbed, σ y0 represents the vertical normal stress at any position (x, y) before the cross section of the stress unit is disturbed, α represents the initial angle, τ xy0 Represents the horizontal and vertical cross-sectional shear stress at any position (x, y) before the cross section of the stress unit is disturbed; σ αΔ It represents the stress value after the disturbance at the cross section of the stress unit, σ xΔ It represents the horizontal normal stress at any position (x, y) after the cross section of the stress unit is disturbed, σ yΔ It represents the vertical normal stress at any position (x, y) after the cross section of the stress unit is disturbed, τ xyΔ Represents the horizontal and vertical cross-sectional shear stress at any position (x, y) after the cross section of the stress unit is disturbed.

[0086] Using the FISH language provided by UDEC software, a custom function is written to calculate the change of tunnel surrounding rock compressive stress before and after surrounding rock excavation to obtain the maximum compressive stress increase ratio, and to realize the embedded analysis of the beam-arch effect of layered surrounding rock. The specific numerical realization process is as follows: Figure 8 As shown, δ is the minimum rotation angle (i.e., the preset rotation angle value), and α is the initial angle (which is a variable value). Taking the stress unit as the research and calculation basis, the influence of the excavation boundary shape and the change of the formation conditions during the analysis process can be eliminated.

[0087] (5) Determination of the inner boundary of the beam-type arch in layered surrounding rock

[0088] The maximum compressive stress increase ratio of 1.05 is used as the basis for determining the inner boundary of the beam arch. The compressive stress increase ratio and the local arch area are combined to obtain the inner boundary of the beam arch as 0.88 meters. So far, the position of the inner boundary of the beam arch has been quantitatively determined, such as Fig. 9 shown.

[0089] (6) Determination of the outer boundary of the beam-type arch in layered surrounding rock

[0090] There are obvious beam structure stress areas above and below the excavation surface and at the top and bottom of the pressure arch. The compressive stress increase ratio in this area is close to 1, indicating that the stress before and after the excavation has not increased, and the compressive stress may even decrease after the excavation. The stress characteristics of the beam structure are that the middle part is under the maximum compression and bends downward, and the two sides are under tension. Therefore, the rock strata in the area where the compressive stress is reduced are all regarded as beam structure areas. At the same time, a complete arch area is formed between the inner and outer boundaries of the beam arch. Fig.10 The layered surrounding rock is regarded as a composite beam structure, the interlayer contact effect is the boundary condition of a single beam, and the boundary where the arch structure transitions to the beam structure is regarded as the outer boundary.

[0091] At this point, the quantitative characterization index of the beam-arch structure effect of the layered tunnel surrounding rock and the inner and outer boundaries of the beam-arch of the surrounding rock arch are 18.24m, and the outer boundary position of the beam-arch is quantitatively determined, such as Fig.11 As shown in the figure, a relatively systematic quantitative characterization method for tunnel surrounding rock beam-arch structure is finally formed, which has good engineering practical value.

[0092] The present application also provides an application scenario, which applies the above-mentioned method for determining the beam-arch structure of a layered surrounding rock tunnel. Specifically: The method for determining the beam-arch structure of a layered surrounding rock tunnel provided in this embodiment can be applied in the scenario of quantitatively determining the boundary of a beam-arch in layered surrounding rock. The scenario of quantitatively determining the boundary of a beam-arch in layered surrounding rock includes a link for generating inner and outer boundaries of a beam-arch and a link for displaying inner and outer boundaries of a beam-arch; the link for generating inner and outer boundaries of a beam-arch is used to determine the inner and outer boundaries of a beam-arch based on the stress distribution of the layered surrounding rock of the tunnel before and after excavation, and the mechanical characteristics of the arch structure and the beam structure in the layered surrounding rock; the link for displaying inner and outer boundaries of a beam-arch is used to visualize the inner and outer boundaries of a beam-arch; the method for determining the beam-arch structure of a layered surrounding rock tunnel belongs to the link for generating inner and outer boundaries of a beam-arch.

[0093] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Fig.12As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store processing data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for determining a beam-arch structure of a layered surrounding rock tunnel is implemented.

[0094] Those skilled in the art will understand that Fig.12 The structure shown in the figure is only a block diagram of a part of the structure 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 certain components, or have a different arrangement of components.

[0095] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0096] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0097] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0098] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0099] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0100] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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, they should be considered to be within the scope of this specification.

[0101] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for determining a beam-arch structure of a layered surrounding rock tunnel, characterized in that: The method for determining the beam-arch structure of a layered surrounding rock tunnel comprises: Obtaining physical and mechanical parameters of layered surrounding rock and tunnel parameters; the physical and mechanical parameters of layered surrounding rock are determined based on existing geological survey data and empirical formulas, and the physical and mechanical parameters of layered surrounding rock include rock physical and mechanical parameters of layered surrounding rock and interlayer contact physical and mechanical parameters, and the interlayer contact physical and mechanical parameters need to be calibrated based on the rock physical and mechanical parameters, the rock mass strength conversion empirical formula in the empirical formula, and the rock mass uniaxial compression test; the tunnel parameters are determined based on actual engineering conditions and design requirements; Inputting the physical and mechanical parameters of the layered surrounding rock and the tunnel parameters into numerical simulation software, obtaining the layered surrounding rock stress state data before tunnel excavation and the layered surrounding rock stress state data after tunnel excavation output by the numerical simulation software; the layered surrounding rock stress state data includes the magnitude and direction of stress; Determine a stress change data set corresponding to a stress unit at any point of the layered surrounding rock according to the stress state data of the layered surrounding rock before the tunnel excavation and the stress state data of the layered surrounding rock after the tunnel excavation; the stress change data set includes stress change data of the stress unit in any direction; the stress change data is a compressive stress increase ratio, and the compressive stress increase ratio is a compressive stress difference between the stress unit after being disturbed and before being disturbed; Determine the maximum compressive stress increase ratio corresponding to the stress unit at any point of the layered surrounding rock according to the stress change data set, and determine the inner boundary of the layered surrounding rock beam arch based on the maximum compressive stress increase ratio corresponding to the stress unit at any point of the layered surrounding rock; According to the stress change data set, the spatial distribution of the compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock is determined, and based on the spatial distribution of the compressive stress increase ratio corresponding to the stress unit at any point in the layered surrounding rock, the outer boundary of the layered surrounding rock beam arch is determined.

2. The method for determining the beam-arch structure of a layered surrounding rock tunnel according to claim 1, characterized in that: The rock physical and mechanical parameters include rock uniaxial compressive strength, rock deformation modulus, rock bulk modulus, rock shear modulus, rock cohesion and rock internal friction angle; the interlayer contact physical and mechanical parameters include the normal stiffness of the contact surface, the tangential stiffness of the contact surface, the cohesion of the contact surface, the residual cohesion after the contact surface is destroyed, the internal friction angle of the contact surface, the extreme value of the tensile strength of the contact surface and the residual strength after the contact surface is destroyed.

3. The method for determining the beam-arch structure of a layered surrounding rock tunnel according to claim 1, characterized in that: Determining a stress change data set corresponding to a stress unit at any point of the layered surrounding rock according to the layered surrounding rock stress state data before the tunnel excavation and the layered surrounding rock stress state data after the tunnel excavation, specifically includes: For the stress unit at any point of the layered surrounding rock, a Cartesian coordinate system is established; Obtaining the angle between the external normal line at any cross section of the stress unit and the x-axis of the Cartesian coordinate system, and marking it as the initial angle; Calculate the stress before and after the disturbance at the cross section of the stress unit corresponding to the initial angle; Based on a preset rotation angle value, updating the initial angle; Determining whether the updated initial angle is within a preset angle range; If the updated initial angle is within the preset angle range, the initial angle in the step of calculating the stress before and after the disturbance at the cross section of the stress unit corresponding to the initial angle is replaced with the updated initial angle, and the step of returning to calculating the stress before and after the disturbance at the cross section of the stress unit corresponding to the initial angle is returned; If the updated initial angle is not within the preset angle range, the stress change data is calculated based on the stress before the disturbance and the stress after the disturbance, and all stress change data are output; all stress change data constitute the stress change data set corresponding to the stress unit.

4. The method for determining the beam-arch structure of a layered surrounding rock tunnel according to claim 3, characterized in that: The calculation formula of the stress before the disturbance at the cross section of the stress unit corresponding to the initial angle is: The calculation formula for the stress after disturbance at the cross section of the stress unit corresponding to the initial angle is: Among them, σ α0 Represents the stress value before the disturbance at the cross section of the stress unit, σ x0 It represents the horizontal normal stress at any position (x, y) before the cross section of the stress unit is disturbed, σ y0 represents the vertical normal stress at any position (x, y) before the cross section of the stress unit is disturbed, α represents the initial angle, τ xy0 Represents the horizontal and vertical cross-sectional shear stress at any position (x, y) before the cross section of the stress unit is disturbed; σ αΔ It represents the stress value after the disturbance at the cross section of the stress unit, σ xΔ It represents the horizontal normal stress at any position (x, y) after the cross section of the stress unit is disturbed, σ yΔ It represents the vertical normal stress at any position (x, y) after the cross section of the stress unit is disturbed, τ xyΔ It represents the horizontal and vertical cross-sectional shear stress at any position (x, y) after the cross section of the stress unit is disturbed, where x is the coordinate value on the x-axis of the Cartesian coordinate system, and y is the coordinate value on the y-axis of the Cartesian coordinate system.

5. The method for determining the beam-arch structure of a layered surrounding rock tunnel according to claim 1, characterized in that: Based on the maximum compressive stress increase ratio corresponding to the stress unit at any point of the layered surrounding rock, the inner boundary of the layered surrounding rock beam arch is determined, specifically including: When the maximum compressive stress increase ratio corresponding to the stress unit at any point of the layered surrounding rock is equal to 1.05, the position of the stress unit corresponding to the maximum compressive stress increase ratio is determined as the inner boundary of the layered surrounding rock beam arch.

6. The method for determining the beam-arch structure of a layered surrounding rock tunnel according to claim 1, characterized in that: Based on the spatial distribution of the compressive stress increase ratio corresponding to the stress unit at any point of the layered surrounding rock, the outer boundary of the layered surrounding rock beam arch is determined, specifically including: Based on the spatial distribution of the compressive stress increase ratio corresponding to the stress unit at any point of the layered surrounding rock, the beam structure area of ​​the layered surrounding rock is determined; the beam structure area is a compressive stress reduction area, and the compressive stress reduction area is an area where the compressive stress increase ratio is negative; The boundary where the arch structure area transitions to the beam structure area is determined as the outer boundary of the layered surrounding rock beam-type arch.

7. The method for determining the beam-arch structure of a layered surrounding rock tunnel according to claim 3, characterized in that: The preset angle range is 0 to 180 degrees.

8. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method for determining the beam-arch structure of a layered surrounding rock tunnel according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for determining the beam-arch structure of a layered surrounding rock tunnel described in any one of claims 1 to 7 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method for determining the beam-arch structure of a layered surrounding rock tunnel described in any one of claims 1 to 7 is implemented.

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