A real-time inversion method and device for in-situ stress of a tunnel based on microseismic information

Abstract

The present invention discloses a method and device for real-time inversion of in-situ stress of a tunnel based on microseismic information, belonging to the technical field of tunnel safety monitoring. The method includes: constructing a spatial distribution model of each microseismic event in the tunnel area to be detected; determining the focal mechanism solution of each elastic wave according to the spatial distribution model of the microseismic event; solving the first in-situ stress tensor of the fault plane according to the focal mechanism solution of each elastic wave in the tunnel area to be detected; performing linear inversion of the in-situ stress on the P / T axis according to the azimuth and dip angle of the first in-situ stress tensor to determine the second in-situ stress tensor; and determining the principal stress in each direction of the fault plane according to the shape ratio of the second in-situ stress tensor. The problem of how to improve the detection accuracy of in-situ stress in the tunnel area and how to provide real-time feedback on the in-situ stress situation ahead is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel safety monitoring, and particularly relates to a method and device for real-time inversion of in-situ stress of a tunnel based on microseismic information. Background Art

[0002] With the development of tunnel engineering, in-situ stress, as data for determining the stability of a tunnel and providing important support for tunnel construction and support, the demand for its measurement has also increased rapidly.

[0003] Traditional in-situ stress measurement methods such as hydraulic fracturing and stress relief can only measure the magnitude and direction of stress at a single point, and cannot obtain the distribution of all in-situ stress fields in a certain area, resulting in low detection accuracy of in-situ stress in the tunnel area. At the same time, traditional in-situ stress measurement methods cannot provide real-time feedback on the in-situ stress situation ahead during construction. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and device for real-time inversion of in-situ stress of a tunnel based on microseismic information, so as to solve the problem of how to improve the detection accuracy of in-situ stress in the tunnel area and provide real-time feedback on the in-situ stress situation ahead.

[0005] The present invention adopts the following technical solutions:

[0006] The present invention provides a method for real-time inversion of in-situ stress of a tunnel based on microseismic information, including:

[0007] S101. Construct a spatial distribution model of each microseismic event in the tunnel area to be detected;

[0008] S102. Determine the focal mechanism solution of each elastic wave according to the spatial distribution model of microseismic events;

[0009] S103. Solve the first in-situ stress tensor of the fault plane according to the focal mechanism solution of each elastic wave in the tunnel area to be detected;

[0010] S104. Perform linear inversion of in-situ stress on the P / T axis according to the azimuth and dip angle of the first in-situ stress tensor to determine the second in-situ stress tensor;

[0011] S105. Determine the principal stress in each direction of the fault plane according to the shape ratio of the second in-situ stress tensor.

[0012] Optionally, constructing a spatial distribution model of each microseismic event in the tunnel area to be detected includes:

[0013] Obtain the position information and pressure magnitude of each microseismic event in the tunnel area to be detected through a microseismic monitoring system;

[0014] Construct a microseismic event spatial distribution model for each microseismic event based on the location information and pressure magnitude of each microseismic event.

[0015] Optionally, determining the focal mechanism solution of each elastic wave according to the microseismic event spatial distribution model includes:

[0016] Analyze the microseismic event spatial distribution model to determine the focal mechanism solution of each fault plane. The focal mechanism solution includes the strike, slip direction, and dip angle of the fault plane.

[0017] Optionally, determine the type of the fault plane according to the strike, slip direction, and dip angle of the fault plane in the focal mechanism solution.

[0018] Optionally, according to the focal mechanism solution of each elastic wave in the tunnel area to be detected, solving the first in-situ stress tensor of the fault plane includes:

[0019] According to the focal mechanism solution of each elastic wave in the tunnel area to be detected, first determine the normal vector, shear stress direction vector, and slip vector of the fault plane;

[0020] Then solve the first in-situ stress tensor of the fault plane according to the normal vector, shear stress direction vector, and slip vector of the fault plane.

[0021] Optionally, perform P / T axis linear inversion of in-situ stress according to the azimuth and dip angle of the first in-situ stress tensor to determine the second in-situ stress tensor, including:

[0022] According to the azimuth and dip angle of each component of the first in-situ stress tensor, map each component of the first in-situ stress tensor to the beach ball to form each corresponding mapping point;

[0023] Then, according to the position relationship between each mapping point and the known observation P point and observation T point on the beach ball, determine the effective components of the first in-situ stress tensor;

[0024] Finally, form the second in-situ stress tensor according to the effective components.

[0025] Optionally, determine the principal stresses in each direction of the fault plane according to the shape ratio of the second in-situ stress tensor, including:

[0026] First, calculate the first difference between the maximum principal stress and the intermediate principal stress in the second in-situ stress tensor;

[0027] Then calculate the second difference between the maximum principal stress and the minimum principal stress;

[0028] Then calculate the ratio of the first difference to the second difference to obtain the shape ratio;

[0029] Finally, select a set of stresses with a shape ratio not equal to 1 as the stresses corresponding to each direction of the fault plane.

[0030] The present invention also provides a device for real-time inversion of in-situ stress in a tunnel based on microseismic information, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned method for real-time inversion of in-situ stress in a tunnel based on microseismic information is realized.

[0031] The beneficial effects of the present invention are as follows: By detecting and analyzing all microseismic events in the entire tunnel area to be detected, through P-wave inversion, multiple elastic wave equations related to each microseismic event are established, and all source mechanism solutions with unknowns less than the number of equations are solved; further, based on the source mechanism solutions, through P / T analysis and shape ratio analysis respectively, accurate in-situ stress tensors are determined. The method provided by the present invention solves the problem of how to improve the detection accuracy of in-situ stress and achieves the technical effect of real-time feedback of the in-situ stress situation ahead. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a flowchart of a method for real-time inversion of in-situ stress in a tunnel based on microseismic information provided by the present invention;

[0033] Figure 2 is a schematic diagram of a spatial distribution model of tunnel microseismic events provided by the present invention;

[0034] Figure 3 is a schematic diagram of a microseismic source mechanism solution provided by the present invention, wherein:

[0035] (a) Normal-slip, (b) Normal fault, (c) Normal-slip, (d) Reverse fault, (e) Reverse fault, (f) Normal fault, (g) Normal fault, and (h) Strike-slip fault;

[0036] Figure 4 is a rose diagram of a source mechanism provided by the present invention, wherein:

[0037] (a), (b), and (c) are respectively rose diagrams of fault plane 1 with respect to azimuth, dip angle, and slip angle, and (d), (e), and (f) are respectively rose diagrams of fault plane 2 with respect to azimuth, dip angle, and slip angle;

[0038] Figure 5 is a schematic diagram of multiple solutions of principal stress provided by the present invention;

[0039] Figure 6 is a schematic diagram of the relationship between the P / T axis and the principal stress provided by the present invention;

[0040] Figure 7 is a linear in-situ stress inversion rose diagram provided by the present invention, wherein:

[0041] (a) Rose diagram of the maximum principal stress of fault plane 1, (b) Rose diagram of the intermediate principal stress of fault plane 1, and (c) Rose diagram of the minimum principal stress of fault plane 1;

[0042] Figure 8 Schematic diagram of a real-time ground stress inversion device for tunnels based on microseismic information provided by the present invention. Detailed implementation manners

[0043] The present invention will be described in detail below with reference to the accompanying drawings and specific implementation manners.

[0044] The present invention provides a real-time ground stress inversion method for tunnels based on microseismic information. As Figure 1 shown, the method includes:

[0045] Step 101, constructing a spatial distribution model of each microseismic event in the tunnel area to be detected.

[0046] In an embodiment, by selecting a tunnel area to be detected in the surrounding rock of the tunnel, this area can be a cubic tunnel area about 15 meters away from the tunnel entrance, for example: a 5*5 cubic tunnel area. The geological structure data of each tunnel area is shown in Table 1. Install one (or more) microseismic monitoring systems in this area. Any rock mass generally generates many fine microfractures before macroscopic failure. These microfractures generate elastic waves in the form of elastic wave performance release, which are monitored in real time by the microseismic system installed on the rock mass. The occurrence time, location, and nature of the microfractures of the rock mass are obtained through the inversion method. And multiple elastic waves emitted by all seismic sources in this area can be captured, and the effective elastic waves are screened out by comparing with the microseismic waveforms in the database. According to the screened effective elastic waves, a spatial distribution model of microseismic events is constructed. This spatial distribution model of microseismic events can reflect the position information of each seismic source and the distribution of each seismic source. As Figure 2 shown, each ball in the figure represents a seismic source. The correlation between the seismic sources with relatively dense distribution is larger, and the correlation between the seismic sources with a relatively long distance is smaller.

[0047] Table 1 Geological structure data of the tunnel area

[0048]

[0049] Step 102, determining the focal mechanism solution of each elastic wave according to the spatial distribution model of microseismic events.

[0050] In one embodiment, the physical process of earthquake occurrence or the source physics process, known as the source mechanism, can be determined through the seismograms of multiple seismic stations or microseismic systems. Some characteristic quantities at the earthquake source or some physical quantities of the source physics process during an earthquake are called source parameters. Source parameters include the strike, dip, and rake of the source fault plane, the direction and amplitude of the displacement of both sides of the source fault, the length and width of the source fault, the propagation speed of fault fracture, the state of the source principal stress, etc., which can be obtained through methods such as solving the source mechanism solution in combination with macroscopic earthquake measurement and analysis of the spatial distribution model of microseismic events. Therefore, by analyzing macroscopic earthquake measurement, the spatial distribution model of microseismic events, and elastic waves, the source mechanism solution of the fault plane is determined. The source mechanism solution includes the source mechanism and source parameters. It should be noted that the type of the fault plane can be judged through the strike, dip, and rake of the fault plane in the source parameters of the source mechanism solution.

[0051] Step 103: According to the source mechanism solutions of each elastic wave in the tunnel area to be detected, solve the first in-situ stress tensor of the fault plane.

[0052] In one embodiment, according to the relevant geological structure information of the fault plane analyzed from macroscopic earthquake measurement, the spatial distribution model of microseismic events, and elastic waves, such as the type of the fault plane, it can be a normal strike-slip, normal fault, etc. Taking the normal fault as an example, by determining the fault plane where the microseismic event is located, measuring the normal vector of the fault plane, the shear stress direction vector of the fault plane, the slip vector of the fault plane, and the stress tensor of the fault plane, establish equations regarding the normal vector of the fault plane, the shear stress direction vector of the fault plane, the slip vector of the fault plane, and the stress tensor of the normal fault plane to solve the equation of the first in-situ stress tensor of the fault plane. The specific equations established are shown in formulas (1)-(3) to solve the first in-situ stress tensor of the fault plane.

[0053] It should be noted that the first in-situ stress tensor solved here is the resultant force of the principal stresses in each direction of the fault plane. At this time, there are multiple sets of solutions for the source mechanism solution, and different sets of solutions correspond to an in-situ stress tensor. This equation establishes a joint equation for multiple earthquake sources in the tunnel area to be monitored, establishing a system of equations with the number of equations greater than the number of unknowns, and multiple sets of source mechanism solutions can be solved. On the one hand, when considering more earthquake sources in the tunnel area to be detected, the solved source mechanism solution is more accurate, and the first in-situ stress tensor of the solved fault plane is also more accurate; on the other hand, by solving the source mechanism solutions of all microseismic events in the tunnel area, compared with the traditional method of solving the source mechanism solution of a single microseismic event at a certain point, the efficiency of judging each fault plane in this area is improved.

[0054] Step 104: Perform linear inversion of the in-situ stress of the P / T axis according to the azimuth and dip of the first in-situ stress tensor to determine the second in-situ stress tensor.

[0055] In one embodiment, according to the first in-situ stress tensor of the fault plane obtained by solving, in order to further detect whether the obtained first in-situ stress meets the azimuth requirement, by performing P-wave analysis on each microseismic source and depicting it on the P-wave first motion quadrant distribution map, which includes a P-axis (maximum principal stress axis) at the position bisecting the dilatation quadrant and a T-axis (minimum principal stress axis) at the position of the compression quadrant. By performing linear inversion of the in-situ stress with the P / T axis on the first in-situ stress and calculating and analyzing its dilatation and compression quadrants, and depicting the points on the P-wave first motion quadrant distribution map, it is determined whether the P point corresponding to the first in-situ stress tensor is between two actually measured P observation points, and whether the T point corresponding to the first in-situ stress tensor is between two actually measured T observation points. If the P point of the first in-situ stress tensor used for description is between two observed P points and the T point of the first in-situ stress tensor is between two observed T points, it indicates that the first in-situ stress tensor meets the azimuth requirement, thereby eliminating the first in-situ stress that does not meet the azimuth requirement in the focal mechanism solution; and the first in-situ stress tensor that is screened out and meets the P / T axis distribution is selected.

[0056] Step 105: Determine the principal stress in each direction of the fault plane according to the shape ratio of the second in-situ stress tensor.

[0057] In one embodiment, it should be noted that each component of the second in-situ stress tensor is the principal stress in each direction on the fault plane. They are sorted respectively according to the magnitude of the stress, and the maximum principal stress, intermediate principal stress, and minimum principal stress of the second in-situ stress are determined respectively. By calculating the first difference between the maximum principal stress and the intermediate principal stress, and the second difference between the maximum principal stress and the minimum principal stress, the ratio of the first difference and the second difference is obtained as the shape ratio of the second in-situ stress tensor. A group with a shape ratio not equal to 1, the maximum principal stress, intermediate principal stress, and minimum principal stress are selected from them. At this time, the selected maximum principal stress, intermediate principal stress, and minimum principal stress are the principal stresses in each direction with higher accuracy on the fault plane.

[0058] Optionally, constructing the spatial distribution model of each microseismic event in the tunnel area to be detected includes:

[0059] Obtain the position information and pressure magnitude of each microseismic event in the tunnel area to be detected through a microseismic monitoring system;

[0060] Construct the spatial distribution model of each microseismic event according to the position information and pressure magnitude of each microseismic event.

[0061] In one embodiment, by establishing a 3D model of the tunnel area to be detected, converting the position information of each microseismic event actually detected into the coordinate information of each point in the 3D model, and each point contains the pressure information of the microseismic event, a spatial distribution model of microseismic events is established by including the position information and pressure information of the microseismic event, as Figure 2 shown.

[0062] Optionally, determining the focal mechanism solution of each elastic wave according to the spatial distribution model of microseismic events includes:

[0063] Analyzing the spatial distribution model of microseismic events to determine the focal mechanism solution of each fault plane, and the focal mechanism solution includes strike, slip direction and dip angle.

[0064] Optionally, determining the type of the fault plane according to the strike, slip direction and dip angle of the fault plane in the focal mechanism solution.

[0065] In one embodiment, geological structure analysis is performed on each microseismic event through the spatial distribution model of microseismic events, the source parameters such as the strike, slip direction and dip angle of the source fault plane in the focal mechanism solution are solved, and a beach ball of the corresponding type of fault plane is drawn. As Figure 3 shown, the types of the analyzed fault planes generally include (a1) normal strike-slip, (b1) normal fault, (c1) normal strike-slip, (d1) reverse fault, (e1) reverse fault, (f1) normal fault, (g1) normal fault, and (h1) strike-slip fault.

[0066] It should be noted that in order to more clearly study the characteristics of elastic waves of each microseismic event in each focal mechanism, a rose diagram is used to statistically analyze the azimuth angle, dip angle and slip angle in the above-mentioned focal mechanism, as Figure 4 shown, Figure 4 Two rose diagrams related to fault plane 1 and fault plane 2 determined according to the analyzed focal mechanism are respectively described by rose diagrams. (a2), (b2) and (c2) respectively describe the azimuth angle, dip angle and slip angle of fault plane 1. The corresponding angle degrees and amplitudes can be read in each diagram. The descriptions of the rose diagrams of fault plane 2 in (d2), (e2) and (f2) are the same as those of the rose diagram of fault plane 1.

[0067] Optionally, according to the focal mechanism solution of each elastic wave in the tunnel area to be detected, solving the first in-situ stress tensor of the fault plane includes:

[0068] According to the focal mechanism solution of each elastic wave in the tunnel area to be detected, first determine the normal vector, shear stress direction vector and slip vector of the fault plane;

[0069] Then, according to the fault plane normal vector, the shear stress direction vector, and the slip vector, the first in-situ stress tensor of the fault plane is solved.

[0070] In one embodiment, according to the analyzed focal mechanism, an in-situ stress tensor equation corresponding to the type of fault plane is established, and each component of the first in-situ stress tensor is represented by δ i , where i = 1, 2, 3…, and i represents the component serial number.

[0071] Assume that the principal stresses on the fault plane are as shown in formula (1):

[0072] δ i = τ ij n i n j (1)

[0073] Where, δ i is the principal stress of the first stress tensor, n i is the normal vector of the i-th fault plane, and n j is the normal vector of the j-th fault plane.

[0074] τN i = T i - δ i (2)

[0075] In the formula, T i is the first stress tensor of the fault plane, N i is the direction vector of the shear stress on the fault plane, and τ is the shear stress of the fault plane.

[0076] Assume that the slip vector s of the fault plane is consistent with and the same as the direction of the shear stress on the fault plane, and then after normalization, the following formula is obtained:

[0077] At = S (3)

[0078] In the formula, t is the vector of the first in-situ stress tensor, and each component of t satisfies σ1 + σ2 + σ3 = 0. The coefficient matrix A is a 3X5 matrix:

[0079]

[0080] s is the unit vector of the slip vector of the fault plane. When there are M sets of focal mechanism solutions, formula (3) becomes 3M equations with 5 unknowns regarding the in-situ stress, and the solution of the required first in-situ stress can be obtained according to the generalized linear inversion of the L2 norm.

[0081] Based on the above formulas (1) - (3), the vector of the first in-situ stress tensor is solved as t = [σ 11 σ 12 σ 13 σ 22 σ23 .

[0082] At this time, there are multiple solutions for t. The specific multiple solutions for the first in-situ stress inversion are shown in Table 2 as follows:

[0083] Table 2 Stress inversion results

[0084]

[0085] Among them, σ1 is the maximum principal stress of the first in-situ stress, σ2 is the intermediate principal stress of the first in-situ stress, and σ3 is the minimum principal stress of the first in-situ stress. As Figure 5 shown, due to the analysis of each component of the first in-situ stress from different orientations, and because the interior angles are complementary, the first in-situ stress has multiple solutions. σ1 can be 30° or 70°. According to Table 2, the multiple solutions of the first in-situ stress are as follows: One set of solutions is σ1, azimuth N89.87°E, dip angle 3.01°; σ2, azimuth N4.77°W, dip angle 7.59°; σ3 azimuth N14.21°W, dip angle 6.93°; Another set of solutions is σ1, azimuth N89.87°E, dip angle 85.86°; σ2, azimuth N4.77°W, dip angle 7.59°; σ3 azimuth N14.21°W, dip angle 46.11°, etc.

[0086] Optionally, according to the azimuth and dip angle of the first in-situ stress tensor, performing a linear inversion of the in-situ stress for the P / T axis to determine the second in-situ stress tensor includes:

[0087] First, map each component of the first in-situ stress tensor to the beach ball according to the azimuth and dip angle of each component of the first in-situ stress tensor to form each corresponding mapping point;

[0088] Then, according to the positional relationship between each mapping point and the known observation P point and observation T point on the beach ball, determine the effective components of the first in-situ stress tensor;

[0089] Finally, form the second in-situ stress tensor according to the effective components.

[0090] In one embodiment, based on the solution of the focal mechanism, the first in-situ stress has the property of multiple solutions. In order to determine each more accurate component in the first in-situ stress, a linear inversion of the in-situ stress for the P / T axis is performed on the first in-situ stress. The multiple solutions are mapped to the beach ball in the form of points according to the azimuth and dip angle for each component of the first in-situ stress, and the positional relationship with the known observation P point and observation T point on the beach ball is analyzed. As Figure 6As shown, on the beach ball, the position where one component of the first principal stress is the maximum principal stress σ1 is between the positions of two preset observation points P, indicating that σ1 is located in the dilatation wave quadrant, and the observation point P is the point corresponding to the macroseismic measurement; similarly, the minimum σ3 is between the positions of two preset observation points T, indicating that σ3 is located in the compression wave quadrant, and the observation point T is also the point corresponding to the macroseismic measurement.

[0091] By screening out the first in-situ stress components that meet the dilatation wave quadrant and compression wave quadrant, the maximum principal stress σ1, the intermediate principal stress σ2, and the minimum principal stress σ3 are determined to form the second in-situ stress. By screening out the effective components of the first in-situ stress that meet the azimuth requirements and eliminating the data that do not meet the requirements, the geological characteristics of the fault plane are qualitatively measured, and the calculation accuracy of the first in-situ stress is improved.

[0092] Optionally, determining the principal stress in each direction of the fault plane according to the shape ratio of the second in-situ stress tensor includes:

[0093] First, calculate the first difference between the maximum principal stress and the intermediate principal stress in the second in-situ stress tensor;

[0094] Then, calculate the second difference between the maximum principal stress and the minimum principal stress;

[0095] Then, calculate the ratio of the first difference to the second difference to obtain the shape ratio;

[0096] Finally, screen out a set of stresses with a shape ratio not equal to 1 as the stresses corresponding to each direction of the fault plane.

[0097] In one embodiment, first, multiple parameters of the maximum principal stress σ1, the intermediate principal stress σ2, and the minimum principal stress σ3 are determined, and the shape ratio R is determined. The expression of R is shown in formula (4):

[0098] R = (σ1 - σ2) / (σ1 - σ3) (4)

[0099] Wherein, (σ1 - σ2) represents the first difference between the calculated maximum principal stress and the intermediate principal stress, (σ1 - σ3) represents the second difference between the calculated maximum principal stress and the minimum principal stress, and R is the shape ratio.

[0100] It should be noted that a large R indicates that the intermediate principal stress and the minimum principal stress are closer. Taking the limit R = 1, the tensional states of the minimum principal stress and the intermediate principal stress are the same; when R is relatively small, the maximum principal stress and the intermediate principal stress are close. Taking the limit case R = 0, the compressive state of the intermediate principal stress is the same as that of the maximum principal stress. When R is not equal to 1, it indicates that there is a fault in this area, and the determined maximum principal stress σ1, intermediate principal stress σ2, and minimum principal stress σ3 are important parameters for determining the geological characteristics of the fault plane.

[0101] InFigure 7 Among them, the maximum principal stress σ1 of section plane 1 is described by a rose diagram as shown in Fig. (a3), the intermediate principal stress σ2 of section plane 1 is shown in Fig. (b3), and the minimum principal stress σ3 of section plane 1 is shown in Fig. (c3). Each figure describes the distribution of the azimuth angle and dip angle of the corresponding principal stress.

[0102] Finally, the relatively accurate maximum principal stress σ1, intermediate principal stress σ2 and minimum principal stress σ3 are determined as shown in Table 3:

[0103] Table 3 Inversion results of principal stresses

[0104]

[0105] It should be noted that the geological characteristics of the fault plane can be quantitatively measured by the shape ratio, improving the detection accuracy of the fault plane.

[0106] The present invention also provides a real-time in-situ stress inversion device 800 for a tunnel based on microseismic information, as Figure 8 shown. The device 800 includes a memory 810, a processor 820, and a computer program 830 stored in the memory and executable on the processor. When the processor 820 executes the computer program 830, it implements a real-time in-situ stress inversion method for a tunnel based on microseismic information as described in any one of the above embodiments.

[0107] It should be noted that the real-time in-situ stress inversion method for a tunnel based on microseismic information that the device 800 can implement is consistent with the above method embodiments and will not be elaborated here.

Claims

1. A real-time inversion device for in-situ stress of a tunnel based on microseismic information, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, a real-time inversion method of in-situ stress of a tunnel based on microseismic information is implemented, including the following steps: S101. Construct a spatial distribution model of each microseismic event in the tunnel area to be detected; S102. Determine the focal mechanism solution of each elastic wave according to the spatial distribution model of the microseismic events; S103. Solve the first in-situ stress tensor of the fault plane according to the focal mechanism solutions of each elastic wave in the tunnel area to be detected; S104. Perform linear inversion of in-situ stress on the P / T axis according to the azimuth and dip angle of the first in-situ stress tensor to determine the second in-situ stress tensor; S105. Determine the principal stresses in each direction of the fault plane according to the shape ratio of the second in-situ stress tensor; Performing linear inversion of in-situ stress on the P / T axis according to the azimuth and dip angle of the first in-situ stress tensor to determine the second in-situ stress tensor includes: According to the azimuth and dip angle of each component of the first in-situ stress tensor, map each component of the first in-situ stress tensor to the beach ball first, forming each corresponding mapping point; Then, according to the positional relationship between each mapping point and the known observed P points and observed T points on the beach ball, determine the effective components of the first in-situ stress tensor; Finally, form the second in-situ stress tensor according to the effective components; The first in-situ stress tensor is the resultant force of the principal stresses in each direction of the fault plane; By performing P-wave analysis on each microseismic source and describing it on the P-wave first motion quadrant distribution map, the map includes the P axis, which is the maximum principal stress axis, at the position of the bisecting dilatation quadrant, and the T axis, which is the minimum principal stress axis, at the position of the compression quadrant. By performing linear inversion of in-situ stress on the P / T axis for the first in-situ stress and calculating and analyzing its dilatation and compression quadrants, and describing the points on the P-wave first motion quadrant distribution map, judge whether the P point corresponding to the first in-situ stress tensor is between the two actually measured P observation points, and whether the T point corresponding to the first in-situ stress tensor is between the two actually measured T observation points; if the P point of the first in-situ stress tensor used for description is between the two observed P points and the T point of the first in-situ stress tensor is between the two observed T points, it means that the first in-situ stress tensor meets the azimuth requirements, so as to eliminate the first in-situ stress that does not meet the azimuth requirements in the focal mechanism solution; and the second in-situ stress tensor is the one screened out to meet the P / T axis distribution; The observation point P and the observation point T are the points of the tunnel area to be detected measured according to macroscopic earthquakes; Solving the first in-situ stress tensor of the fault plane according to the focal mechanism solutions of each elastic wave in the tunnel area to be detected includes: According to the focal mechanism solutions of each elastic wave in the tunnel area to be detected, first determine the normal vector, shear stress direction vector, and slip vector of the fault plane; Then, solve the first in-situ stress tensor of the fault plane according to the normal vector, shear stress direction vector, and slip vector of the fault plane; Determining the principal stresses in each direction of the fault plane according to the shape ratio of the second in-situ stress tensor includes: First, calculate the first difference between the maximum principal stress and the intermediate principal stress in the second in-situ stress tensor; Next, calculate the second difference between the maximum principal stress and the minimum principal stress; Then, calculate the ratio of the first difference to the second difference to obtain the shape ratio; Finally, select a set of stresses for which the shape ratio is not 1 as the principal stresses corresponding to each direction of the fault plane.

2. The real-time in-situ stress inversion device for tunnels based on microseismic information according to claim 1, characterized in that, The construction of the spatial distribution model of each microseismic event in the tunnel area to be detected includes: Obtain the position information and pressure magnitude of each microseismic event in the tunnel area to be detected through a microseismic monitoring system; Construct a spatial distribution model of each microseismic event based on the position information and the pressure magnitude of each microseismic event.

3. The real-time in-situ stress inversion device for tunnels based on microseismic information according to claim 1, characterized in that, Determining the focal mechanism solution of each elastic wave according to the spatial distribution model of microseismic events includes: Analyze the spatial distribution model of microseismic events to determine the focal mechanism solution of each fault plane, and the focal mechanism solution includes the strike, slip direction, and dip angle of the fault plane.

4. The real-time ground stress inversion device for a tunnel based on microseismic information according to claim 3, wherein, Determine the type of the fault plane according to the strike, slip direction, and dip angle of the fault plane in the focal mechanism solution.

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