Rock burst identification method, system and medium

Abstract

The present application relates to the technical field of geological exploration, and discloses a rock burst identification method, system and medium. The present application is based on a rock burst identification method proposed based on the stress characteristics and dynamic disturbance of the rock mass structure surface properties. Starting from the nature of the rock mass strength and the stress state, the present application uses mathematical space vector calculation to realize the identification of the location and potential scale of the strain type and structure surface type rock burst occurrence. The present application realizes the accurate calculation of the location and potential scale of the rock burst in the tunnel cavern, and is not limited by the rock properties and the type of the tunnel cavern. The present application can be continuously calculated during the tunnel excavation, and is not limited by the monitoring equipment. The calculation formula of the present application is simple and has a wide range of applications.

Description

Technical Field

[0001] This invention relates to the field of geological exploration technology, and in particular to a method, system and medium for identifying rockbursts. Background Technology

[0002] Rockburst is a dynamic phenomenon in which the elastic deformation potential energy accumulated in deep or highly tectonically stressed rock masses is suddenly released under conditions of tunnel excavation or other external disturbances, leading to the bursting and ejection of the surrounding rock. Rockburst is a typical geological hazard in deep underground engineering, characterized by its suddenness, randomness, and destructiveness; its occurrence often results in incalculable losses to tunnel construction personnel and equipment. Therefore, developing reasonable rockburst prediction methods and accurately identifying the location, scale, and size of rockbursts is of great significance for the prevention and control of rockburst hazards and for ensuring safe production in underground engineering.

[0003] Currently, there are four methods for predicting and forecasting rockbursts: ① Criterion-based method: This method identifies rockbursts based on rock characteristics, geostress features, elastic strain energy, etc. Its advantage lies in its simplicity and direct on-site measurement. However, whether it's a single-index or multi-index rockburst criterion is affected by various factors, limiting its predictive accuracy. ② Numerical index method: This method is based on the energy theory of rockburst occurrence and can predict potential rockburst locations. However, this method often simplifies on-site geological conditions and working conditions, and the acquisition of geostress and rock mass parameters may not be accurate, potentially leading to insufficient accuracy in the prediction results. ③ Applied mathematical methods: These include artificial neural networks, support vector machines, distance discriminant analysis, Bayesian discriminant analysis, fuzzy mathematics, extensions, and grey theory. Color system theory, attribute mathematics, efficacy coefficient method, ideal point method, approximation ideal solution method, evidence theory method, cloud model, etc. These methods reduce human intervention error and improve prediction effect by considering multiple influencing factors. However, their accuracy is seriously affected by the training sample. The representativeness of the training sample largely determines the accuracy of rockburst prediction. ④ Field monitoring method: such as microseismic monitoring, acoustic emission monitoring, infrared monitoring, microgravity monitoring, etc., can monitor rockburst risk in real time and are suitable for the construction stage. Among them, microseismic monitoring technology has been developed and can obtain microseismic information before the occurrence of rockburst 24 hours a day. By "interpreting" this information, rockburst can be predicted and warned in real time. However, the cost of using this field monitoring method is high and the monitoring range is small (only within 100m before and after the working face). Summary of the Invention

[0004] To overcome the problems of limited accuracy of prediction results, errors in training samples, and small monitoring range in existing rockburst identification methods, this invention provides a rockburst identification method, system, and medium.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a rockburst identification method, the method comprising:

[0007] Step 100: Obtain the identification parameters of the target tunnel chamber, including the tensile strength of the rock, the tensile strength of the rock mass, the attitude of the rock strata on the structural surface, and the first stress parameter at the measuring point;

[0008] Step 200: Determine the state of the rock mass in the target tunnel chamber. If the rock mass is dry, execute the identification process based on the identification parameters to obtain the rockburst parameters of the target tunnel chamber; otherwise, determine it as a rockburst-free area.

[0009] The identification process includes:

[0010] Step 201: Based on the fact that the first stress parameter is greater than the tensile strength of the rock, it is determined that a strain-type instantaneous rockburst is about to occur in the target tunnel chamber;

[0011] Step 202: Calculate the normal stress of the structural surface based on the first stress parameter and the attitude of the rock strata of the structural surface. Based on the fact that the normal stress of the structural surface is greater than the tensile strength of the rock mass, determine that an immediate rockburst of the structural surface type is about to occur in the target tunnel chamber.

[0012] Step 203: Calculate the spatial normal vector of the free face of the target tunnel chamber, obtain the first included angle based on the spatial normal vector and the direction vector of the first stress parameter, determine the position of the strain-type instantaneous rockburst based on the first included angle, and determine the volume of the strain-type instantaneous rockburst based on the first included angle and the preset tensile fracture position.

[0013] Step 204: Obtain the second included angle based on the spatial normal vector and the normal vector of the rock strata attitude of the structural plane; determine the location of the instantaneous rockburst of the structural plane type based on the second included angle; determine the volume of the instantaneous rockburst of the structural plane type based on the line connecting the intersection relationship of the rock strata attitude of the structural plane and the preset tension fracture location.

[0014] According to a specific implementation, in the above identification method, the first stress parameter includes the maximum principal stress, the intermediate principal stress, and the minimum principal stress; determining that a strain-type instantaneous rockburst has occurred in the target tunnel chamber includes:

[0015] Compare the maximum principal stress with the tensile strength of the rock. If the maximum principal stress is greater than the tensile strength of the rock, it is determined that a strain-type instantaneous rockburst has occurred in the target tunnel chamber, and the maximum principal stress is substituted into the subsequent identification process. If it is less than the tensile strength of the rock, the maximum principal stress is determined to be greater than the tensile strength of the rock.

[0016] Compare the intermediate principal stress with the tensile strength of the rock. If the intermediate principal stress is greater than the tensile strength of the rock, it is determined that a strain-type instantaneous rockburst has occurred in the target tunnel chamber, and the intermediate principal stress is substituted into the subsequent identification process; if it is less than...

[0017] The minimum principal stress is compared with the tensile strength of the rock. If the minimum principal stress is greater than the tensile strength of the rock, it is determined that a strain-type instantaneous rockburst has occurred in the target tunnel chamber, and the minimum principal stress is substituted into the subsequent identification process.

[0018] Wherein, the maximum principal stress is greater than the intermediate principal stress, and the intermediate principal stress is greater than the minimum principal stress; when the maximum principal stress, intermediate principal stress, and minimum principal stress are all less than the tensile strength of the rock, it is determined that strain-type instantaneous rockburst will not occur.

[0019] According to a specific implementation method, in the above identification method, the free face of the target tunnel chamber includes the tunnel face, the arch top face, the arch bottom face, and the arch waist sidewall face.

[0020] According to a specific implementation, in the above identification method, determining the location of the strain-type instantaneous rockburst based on the first included angle includes: when the first included angle is greater than... When the strain-type instantaneous rockburst occurs at the angle between the sidewalls of the target tunnel chamber; when the first included angle is less than or equal to When the minimum value of the first included angle is selected as the spatial normal vector of the rockburst location, the location of the rockburst occurrence is calculated based on the normal vector of the rockburst location; where σ tys σ is the tensile strength of the rock. i Let i be the first stress parameter, i equal to 1 / 2 / 3, σ1 represents the maximum principal stress, σ2 represents the intermediate principal stress, and σ3 represents the minimum principal stress.

[0021] According to a specific implementation, in the above identification method, determining the location of the instantaneous rockburst of the structural surface based on the second included angle includes:

[0022] When the second included angle is greater than When the instantaneous rockburst of the structural surface type occurs at the angle between the sidewalls of the target tunnel chamber; when the second included angle is less than or equal to When the second included angle is used as the spatial normal vector of the rockburst location, the location of the rockburst occurrence is calculated based on the normal vector of the rockburst location; where σ tys σ is the tensile strength of the rock. i Let i be the first stress parameter, i equal to 1 / 2 / 3, σ1 represents the maximum principal stress, σ2 represents the intermediate principal stress, and σ3 represents the minimum principal stress.

[0023] According to a specific implementation, the above identification method further includes identifying time-delay rockbursts in the target tunnel chamber, wherein the time-delay rockburst identification includes:

[0024] The maximum, intermediate, and minimum principal stresses after time t are obtained by monitoring the in-situ stress of the target tunnel chamber.

[0025] The newly added maximum principal stress, newly added intermediate principal stress, and newly added minimum principal stress are summed with the first stress parameter along the X, Y, and Z axes to obtain the sum stress along the X, Y, and Z axes.

[0026] The second stress parameter is generated based on the sum of the stresses in the X, Y, and Z axes. The second stress parameter is then substituted into the identification process to obtain the rockburst parameters after time t, and it is determined that a time-delayed rockburst has occurred.

[0027] According to a specific implementation, the identification method described above further includes: monitoring the dynamic disturbance of the target tunnel chamber to obtain the vibration frequency, testing the rock mass of the target tunnel chamber to obtain the natural frequency, and determining whether a time-delayed rockburst has occurred at the location where an overstrain type instantaneous rockburst and / or a structural surface type instantaneous rockburst has occurred based on the vibration frequency and the natural frequency.

[0028] A rockburst identification method according to claim 1, characterized in that the rock strata attitude of the structural plane includes n sets of structural planes; determining the volume of the instantaneous rockburst of the structural plane type includes: selecting the structural plane with an extension length greater than or equal to 1m in the rock strata attitude of the structural plane as the dominant structural plane, and connecting the tangential relationship of the rock strata attitude of the dominant structural plane with the line of the preset tension fracture position; wherein, n is a positive integer, and for the dominant structural plane, n is less than or equal to 3.

[0029] Secondly, the present invention provides a rockburst identification system, the system comprising:

[0030] The acquisition module is used to obtain the identification parameters of the target tunnel chamber;

[0031] The identification module is used to execute a rockburst identification method as described in any of the above items, to identify rockbursts in the target tunnel chamber and obtain rockburst parameters.

[0032] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, causes the computer to perform the method as described in any of the preceding claims.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] This invention proposes a rockburst identification method based on the properties of rock mass structural surfaces and geostress characteristics. Starting from the essence of the rock mass's own strength and stress state, it uses mathematical spatial vector calculations to identify the location and potential scale of strain-type and structural surface-type instantaneous rockbursts. This invention improves the accuracy of rockburst identification through quantitative calculation, achieving a breakthrough in calculating the accurate location and potential scale of rockbursts in tunnel chambers. Furthermore, this invention is not limited by lithology or tunnel chamber type, enabling accurate calculations in all cases. It can also be continuously calculated during tunnel excavation, is not limited by monitoring equipment, and has a simple calculation formula with wide applicability. Attached Figure Description

[0035] Figure 1 This is a flowchart illustrating a rockburst identification method provided in an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram for calculating the scale of rockburst at the tunnel face, provided in an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram illustrating the calculation of rockburst volume on the flat floor of a tunnel chamber, provided in an embodiment of the present invention.

[0038] Figure 4 This is a schematic diagram for calculating the volume of rockburst at the arch waist of a tunnel, provided in an embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of the rockburst volume calculation model for an arc-shaped tunnel chamber provided in an embodiment of the present invention;

[0040] Figure 6 This is a schematic diagram of the rockburst volume calculation model for a group of dominant structural surfaces in an arc-shaped tunnel chamber provided in an embodiment of the present invention.

[0041] Figure 7 This is a schematic diagram of the rockburst volume calculation model for two sets of dominant structural surfaces of an arc-shaped tunnel chamber provided in an embodiment of the present invention;

[0042] Figure 8 This is a schematic diagram of the rockburst volume calculation model for the two dominant structural surfaces of the tunnel arch waist provided in an embodiment of the present invention;

[0043] Figure 9 This is a schematic diagram of the rockburst volume calculation model for two sets of dominant structural surfaces on the flat bottom plate of a tunnel chamber provided in an embodiment of the present invention;

[0044] Figure 10 This is a schematic diagram showing the calculation results of the angle between the free face of the tunnel and the stress provided in an embodiment of the present invention;

[0045] Figure 11This is a schematic diagram showing the direction and radius of the free face of the excavated tunnel chamber provided in an embodiment of the present invention;

[0046] Figure 12 This is a schematic diagram for calculating the rockburst volume of an arc-shaped tunnel chamber, provided in an embodiment of the present invention. Detailed Implementation

[0047] The present invention will be further described in detail below with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0048] The terms "first," "second," etc., used in the specification, embodiments, claims, and drawings of this invention are for distinguishing purposes only and should not be construed as indicating or implying relative importance or order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as including a series of steps or units. A method, system, product, or apparatus is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0049] Please refer to Figure 1 The diagram illustrates a flowchart of a rockburst identification method provided by an embodiment of the present invention, the method comprising:

[0050] Step 100: Obtain the identification parameters of the target tunnel chamber, including the tensile strength of the rock, the tensile strength of the rock mass, the attitude of the rock strata on the structural surface, and the first stress parameter at the measuring point.

[0051] Among these methods, the three-dimensional geostress state of the rock mass was measured in boreholes near potential rockburst tunnel chambers using geostress testing techniques such as hydraulic fracturing, viscoelasticity, and stress relief. This yielded the geostress component σ at the measuring points. x σ y σ z τ xy τ yz τ zx Given the maximum principal stress, intermediate principal stress, and minimum principal stress σ1, σ2, σ3 (where σ1 > σ2 > σ3), and the corresponding principal stress azimuth and inclination angles β1°∠α1°, β2°∠α2°, β3°∠α3°, calculate the normal vectors in the directions of the maximum principal stress, intermediate principal stress, and minimum principal stress σ1, σ2, σ3 as follows:

[0052]

[0053]

[0054]

[0055] Preferably, in areas with minimal topographic relief, the distance between ground stress measurement points should not exceed 1 km; while when tunnels traverse mountains or valleys, ground stress tests should preferably be conducted on both sides of the mountain or valley, with the distance between measurement points not exceeding 500 m.

[0056] Furthermore, the rock strata attitude θ of n sets of structural surfaces (in this embodiment, structural surfaces refer to relatively weak structural surfaces such as faults, bedding planes, quasi-bedding, dikes, and microfractures) in the potential rockburst tunnel chamber were measured using on-site compass and tape measurement, three-dimensional laser scanning, and in-well television. i °∠φ i ° (i = 1, 2, 3, ..., i ≤ n), obtain the structural surface spacing d and the extension length s, where θ i ° represents the dip direction of the rock strata, φ i ° is the dip angle of the rock strata; then the normal vector of the rock strata attitude of the i-th structural plane can be calculated:

[0057]

[0058] Furthermore, the tensile strength σ of the rock cores collected from boreholes or tunnel construction sites is measured using methods such as hydraulic fracturing, radial disc fracturing, and bending tests. tys Or the tensile strength value σ of the rock mass structural plane ti Or through the compressive strength value σ of the rock mass c And simply convert it to the tensile strength σ of the rock. tys Or the tensile strength value σ of the rock mass structural plane ti (i = 1, 2, 3, ..., i ≤ n) Perform a quick determination:

[0059] σ tys =σ ti =λσ c ,in

[0060] Step 200: Determine the state of the rock mass in the target tunnel chamber. If the rock mass is dry, execute the identification process based on the identification parameters to obtain the rockburst parameters of the target tunnel chamber; otherwise, determine it as a rockburst-free area. The identification process includes:

[0061] Step 201: Based on the fact that the first stress parameter is greater than the tensile strength of the rock, it is determined that a strain-type instantaneous rockburst has occurred in the target tunnel chamber. The specific determination process is as follows:

[0062] The first stress parameter σ iThe maximum principal stress σ1, intermediate principal stress σ2, and minimum principal stress σ3 are compared with the tensile strength of the rock. Specifically, when σ tys When σ < 1, a strain-type instantaneous rockburst is about to occur in the tunnel chamber; when σ tys When <σ1, σ should be judged simultaneously. tys With σ 2、 The size between σ3; if σ tys If σ < σ2, then σ2 should be substituted into the subsequent identification process for calculation, referring to σ1; if σ tys <σ2 and σ tys If σ < σ3, then σ3 should be substituted into the subsequent identification process for calculation, referring to σ1. When σ tys Given that σ1 > σ2 > σ3, strain-induced instantaneous rockbursts will not occur in the tunnel chamber. It is understood that the maximum principal stress is greater than the intermediate principal stress, and the intermediate principal stress is greater than the minimum principal stress.

[0063] It should be noted that the rock has a stress state before tunnel excavation. After excavation, this stress state changes. The surface rock mass of the tunnel surrounding rock changes from being subjected to the maximum principal stress σ1 to being zero. Therefore, the surface rock mass is subjected to an instantaneous tensile stress. When this tensile stress exceeds the tensile strength, failure will occur. Generally, in identifying rockbursts based on the ratio of the maximum principal stress to the rock's strength stress, only the maximum principal stress σ1 is considered. However, when the intermediate principal stress σ2 and the minimum principal stress σ3 coincide with the tunnel's free face and exceed the tensile strength, rockbursts can also occur on the rock surface. This invention, by considering multiple parameters, avoids the problem of inaccurate rockburst identification.

[0064] Step 202: Calculate the normal stress of the structural surface based on the first stress parameter and the attitude of the rock strata of the structural surface. Based on the fact that the normal stress of the structural surface is greater than the tensile strength of the rock mass, determine that the target tunnel chamber has experienced an instantaneous rockburst of the structural surface type.

[0065] The specific determination process is as follows:

[0066] The geostress component σ measured in boreholes near the rockburst tunnel chamber x σ y σ z τ xy τ yz τ zx The magnitude of the normal stress σ on the i-th structural surface is calculated using the Mohr stress circle. i :

[0067]

[0068] When σ ti <σ BiAt that time, an instantaneous rockburst of structural plane type is about to occur on the i-th group of structural planes in the tunnel, and the number k of the groups of instantaneous rockbursts of structural plane type and the normal vector of the corresponding i-th group of structural planes are determined. (a i b i c i )(i=1,2,3...,i≤n). When σ ti >σ Bi There will be no immediate structural rock bursts in the tunnel chambers.

[0069] It should be noted that when it is determined that neither strain-type instantaneous rockburst nor structural surface-type instantaneous rockburst will occur in the tunnel chamber, the tunnel will be determined not to experience rockburst, and the above identification process will terminate.

[0070] Step 203: Calculate the spatial normal vector of the free surface of the target tunnel chamber, obtain the first included angle based on the spatial normal vector and the direction vector of the first stress parameter, determine the position of the strain-type instantaneous rockburst based on the first included angle, and determine the volume of the strain-type instantaneous rockburst based on the first included angle and the preset tensile fracture position.

[0071] Specifically, based on the design drawings, select any section of the tunnel chamber to determine the dip and inclination angle ψ perpendicular to any point on the tunnel face, arch top, arch bottom, or arch waist sidewall. j °∠ω j °(j=1,2,3…), calculate its spatial normal vector. (l j m j n j (j=1,2,3…) is:

[0072]

[0073] Then calculate the principal stress direction vector. (i = 1, 2, 3) and vector The first included angle γ between them j When the first included angle At that time, a rock burst occurred at the corner of the tunnel chamber sidewalls; when the first included angle exists... At that time, determine (i=1,2,3) represents the stress normal phase vector of rockburst occurring in the tunnel chamber, within several γ... j Select the minimum value γ min corresponding vector (l min m min n minAs the normal vector of the free face of the tunnel where the rockburst occurred, the spatial position of the tunnel chamber corresponding to the spatial normal vector is the location of the rockburst, and the tensile stress on the vertical tunnel chamber sidewall is σ. b =σ1cos(γ min ),

[0074]

[0075] If the plane where the rockburst occurs in the tunnel chamber is not the tunnel face, then the location of the rockburst on the tunnel chamber sidewall needs to be determined; assuming the dip and inclination angle of the excavated tunnel face are ψ1°∠ω1° and pass through a point O1(0,0,0) in space, then its spatial normal vector... Then the plane equation and normal vector of the tunnel face are l1X+m1Y+n1Z=0.

[0076] Due to the plane normal vector of rockburst in the tunnel chamber Coordinates are (x k1 ,y k1 ,z k1 ), and from the origin to the point (x) k1 ,y k1 ,z k1 If the vector is A1, then the distance d1 from point A1 to the plane of the tunnel face is...

[0077]

[0078] Let A'1(x) k1 ',y k1 ',z k1 ') is point A1(x k1 ,y k1 ,z k1 The projected coordinates of the tunnel face to the working face plane. For vectors (x k1 ,y k1 ,z k1 Projection vector (x) to the tunnel face plane k1 ',y k1 ',z k1 '),but:

[0079]

[0080] Since the tunnel face is perpendicular to the XY horizontal plane, the vector Transforming it into two-dimensional vector coordinates on the plane of the tunnel face, then when y k1 When '>0, the two-dimensional vector of the location of the rockburst in the tunnel chamber is: When y k1 When '=0, the two-dimensional vector of the location of the rockburst in the tunnel chamber is: When y k1 When '<0, the two-dimensional vector of the location of rockburst in the tunnel chamber is: Will After vector normalization, a normalized unit vector is obtained. When y k1 When '>0, the two-dimensional vector of the location of the rockburst in the tunnel chamber is: When y k1 When '=0, the two-dimensional vector of the location of the rockburst in the tunnel chamber is: When y k1 When '<0, the two-dimensional vector of the location of rockburst in the tunnel chamber is: By unit vector Multiplying by the tunnel radius r1 yields the coordinates of the location of the strain-type instantaneous rockburst at the tunnel interface.

[0081] Furthermore, the stress field changes after tunnel excavation. Based on the above calculations, the tensile strength σ of a small rock element on the free surface of the tunnel chamber at the instant of stress release from the original rock is... tys When σ<1, strain-type rockburst will occur in the tunnel chamber; when the original rock stress is released, the tensile strength σ1*cos(γ) of a small rock element on the free face of the tunnel chamber is ≤σ1. tys When σ < 1, a minor rockburst will occur; the tensile strength σ of a small rock element on the free face of the tunnel chamber at the instant the original rock stress is released. tys When <σ1*cos(γ), a slight or greater rockburst will occur.

[0082] ① Calculation of rockburst volume at the tunnel face

[0083] When the direction of the maximum principal stress coincides with the tunnel axis, let the area of ​​the lower rectangular face of the tunnel face where rockburst occurs be S1, the area of ​​the upper semicircle be S2, and the total area of ​​the tunnel face be S. 合 Suppose that the tensile stress on the rock mass at a certain cross section outside the tunnel face is equal to the tensile strength σ of the rock mass. tys That is, the preset tension fracture location, the lower rectangular area of ​​the tunnel face is S2', the upper semicircular area is S4', and the total projected tunnel face area is S. 合 Please refer to '。 Figure 2 This diagram illustrates the calculation of rockburst scale at the tunnel face according to an embodiment of the present invention. Since the angle between the tunnel face and the bottom slab of the tunnel sidewall is a right angle, the tensile stress on the rock mass at a certain point due to the rotation of the free face is:

[0084] σ1*cos(γ)*cos(ε / 2)=σ tys .

[0085] As a simplified assumption, a point at the location of the rock burst on the tunnel's free face, extending along the tunnel excavation direction to the stress equilibrium point outside the tunnel, is considered a single rod. According to Saint-Venant's principle, F1 = F2, s1 = ah. Therefore, σ1cos(γ)S 合 =σ1cos(γ)(S1+S2)=σ tys S' 合 Therefore

[0086] because: but:

[0087] The depth of the rock burst at the working face is: The volume of the rockburst is:

[0088] ② Calculation of rockburst volume on straight floor of tunnel chamber

[0089] For a straight tunnel floor, when the direction of the maximum principal stress is perpendicular to the tunnel floor, let the width of the tunnel floor be a, the length of the tunnel floor in the rockburst section be b, and the area of ​​the tunnel floor in the rockburst section be S. 合 Assume that the tensile stress on the rock mass at a certain cross-section outside the tunnel floor is equal to the tensile strength σ of the rock mass. tys That is, the preset tension fracture location, with a bottom slab width of a', a rockburst section tunnel floor slab length of b', and a rockburst section tunnel floor area of ​​S. 合 Please refer to '. Figure 3 This diagram illustrates the calculation of rockburst volume on the flat floor of a tunnel chamber according to an embodiment of the present invention. Since the angle between the tunnel chamber floor and the tunnel chamber sidewall floor is a right angle, the tensile stress on the rock mass at a certain point due to the rotation of the free surface is: σ1*cos(γ)*cos(ε / 2)=σ tys

[0090] Due to the simplified assumption that a point on the outer side of the tunnel floor where the rock burst occurs is the stress limit equilibrium point, a member is considered. According to Saint-Venant's principle, F1 = F2, S 合 =ab,σ1cos(γ)S 合 =σ tys S' 合 Therefore because: but: The depth of the rock burst at the working face is: The volume of the rockburst is:

[0091] ③ Calculation of rockburst volume in tunnel arch sidewalls

[0092] For the arch waist sidewall of a tunnel chamber, when the direction of the maximum principal stress is perpendicular to the arch waist sidewall, let the radius of the tunnel chamber be r1, the height of the arch waist sidewall be h, and the area of ​​the arch waist sidewall in the rockburst section be S. 合 Assume that the tensile stress on the rock mass at a certain cross-section outside the tunnel floor is equal to the tensile strength σ of the rock mass. tys That is, the predetermined tension fracture location, the distance of this section from the tunnel centerline is l, and the tunnel floor area of ​​the rockburst section is S. 合 Please refer to '. Figure 4 The diagram illustrates the calculation of rockburst volume in the tunnel arch waist according to an embodiment of the present invention.

[0093] For simplification, consider a member extending radially and horizontally from the point where a rock burst occurs on the exposed sidewall of the tunnel arch to the stress equilibrium point outside the tunnel. According to Saint-Venant's principle, F1 = F2. σ1cos(γ)S 合 =σ tys S' 合 ,

[0094] The volume of the rockburst is

[0095] ④ Calculation of rockburst volume in arc-shaped tunnel chambers

[0096] Let A be the center of the arc-shaped tunnel chamber, r1 be the radius of the tunnel chamber, and B be the location where the rockburst occurs on the free face. The direction is consistent with the principal stress σ1*cos(γ); let C, D, and F be the stress limit equilibrium points extending radially from the center A of the tunnel cavity surface to the outside of the cavity. The tensile stress at these three points is approximately equal to the tensile strength σ of the rock mass. tys That is, the preset tension fracture position, the distance from the center of the circle to point C is l; let the vector The first angle between the vector and the X-axis is ω1. and The first included angle between them is ε; based on the three points C, D, and F on the circumcircle, a small circle with radius r2 and center O(x6, y6) can be drawn, and the vector... The first included angle between them is ω2, please refer to... Figure 5 The diagram illustrates a schematic of the rockburst volume calculation model for an arc-shaped tunnel chamber provided in an embodiment of the present invention.

[0097] Simplifying, we assume a rod extending radially from the point of rock eruption on the tunnel's free face to the stress equilibrium point outside the tunnel. According to Saint-Venant's principle, the different ways forces act on the rod's ends only affect a range no greater than the rod's lateral dimension. Let the axial forces and areas at points B and C in the micro-rock element be F1, F2, A1, and A2, respectively, and the first included angle of the sector be ε1 (°). Therefore... According to Saint-Venant's principle, F1 = F2, therefore the calculation yields:

[0098]

[0099]

[0100]

[0101] Taking a rockburst location in the first quadrant of the coordinate system as an example, according to the determination of the instantaneous rockburst location based on strain type, the unit vector of the rockburst occurrence location is...

[0102]

[0103]

[0104] Then vector The first angle between the x-axis and the x-axis is vector The first angle between the x-axis and the x-axis is Then the coordinates of points F and D can be obtained as follows:

[0105]

[0106]

[0107] Based on the coordinates of the three points C(x3,y3), D(x4,y4), and F(x5,y5) on the small circle, the center of the small circle can be calculated to be O(x6,y6).

[0108] Then vector They are (x5-x6, y5-y6) and (x4-x6, y4-y6) respectively.

[0109]

[0110] Find the area of ​​the shaded region in the rockburst area:

[0111] S 阴影 =S 扇OFCD -S 扇OFBD =S 扇OFCD -(S 扇AFBD -S AFO -SADO )

[0112] Due to S AFO =S ADO ,so:

[0113]

[0114] The volume of the rockburst is

[0115] In addition to the manual calculation method mentioned above, the rockburst area can also be drawn in CAD software based on design parameters and rock mass parameters, and the rockburst shadow area can be obtained through the query function, and the rockburst volume can be calculated in the end.

[0116] Step 204: Obtain the second included angle based on the spatial normal vector and the normal vector of the rock strata attitude of the structural plane; determine the location of the instantaneous rockburst of the structural plane type based on the second included angle; determine the volume of the instantaneous rockburst of the structural plane type based on the line connecting the intersection relationship of the rock strata attitude of the structural plane and the preset tension fracture location.

[0117] Specifically, based on the design drawings, determine the spatial normal vectors perpendicular to the tunnel face, arch crown, arch bottom, and arch waist sidewalls. (l j m j n j (j = 1, 2, 3…), calculate the normal vector. (a i b i c i ) and vector (l j m j n j The second included angle γ between ); when the second included angle At that time, a rock burst occurred at the corner of the tunnel chamber sidewalls; when the second angle... At that time, determine (l j m j n j Let σ be the normal vector of the plane where a rockburst occurs in the tunnel chamber. The spatial location of this normal vector in the tunnel chamber is the location where the rockburst occurs, and the tensile stress perpendicular to the structural surface is σ. j =σ i cos(γ).

[0118]

[0119] If the plane where the rockburst occurs in the tunnel chamber is not the tunnel face, then the location of the rockburst on the tunnel chamber sidewall needs to be determined; assuming the dip and inclination angle of the excavated tunnel face are ψ1°∠ω1° and pass through a point O1(0,0,0) in space, then its spatial normal vector... The plane equation and normal vector of the tunnel face are:

[0120] l1X+m1Y+n1Z=0,

[0121] The plane normal vector for a rockburst occurring in a tunnel chamber is: (l j m j n j ),because and Let these be vectors on the same cross-section of the tunnel chamber, and all perpendicular to the XY horizontal plane. Transforming it into two-dimensional vector coordinates on the plane of the tunnel face, then when m j When the value is greater than 0, the two-dimensional vector representing the location of the rockburst in the tunnel chamber is: When m j When = 0, the two-dimensional vector of the location of the rockburst in the tunnel chamber is: When m j When <0, the two-dimensional vector of the location of the rockburst in the tunnel chamber is: Will After vector normalization, a normalized unit vector is obtained. When y k1 When '>0, the two-dimensional vector of the location of the rockburst in the tunnel chamber is: When y k1 When '=0, the two-dimensional vector of the location of the rockburst in the tunnel chamber is: When y k1 When '<0, the two-dimensional vector of the location of rockburst in the tunnel chamber is: By unit vector Multiplying by the tunnel radius r1 gives the coordinates of the location of the rockburst at the tunnel interface.

[0122] Furthermore, regarding the volume of instantaneous rockbursts caused by structural planes, in this embodiment of the invention, structural planes with an extension length greater than or equal to 1m in the occurrence of the structural plane rock strata are selected as dominant structural planes. Typically, there are only three sets of dominant structural planes. Structural planes are a general term for various geological interfaces that cut through rock masses. Since the spatial states of dominant structural planes cutting through rock masses in nature are highly diverse, if there are more than three sets of joints cutting through the rock, the three sets of structural planes with the longest extension lengths are selected as dominant structural planes for calculating the volume of instantaneous rockbursts caused by structural planes. The following provides a detailed explanation of determining the scale and volume of instantaneous rockbursts caused by structural planes based on three sets of dominant structural planes.

[0123] ① Cut by a set of dominant structural planes

[0124] When there is one dominant structural plane (the structural plane extends for more than 1m), and according to the above calculations, the second angle between the structural plane and the normal vector of the tunnel chamber's free face is... The dominant structural surface normal vector at that time (a1, b1, c1), based on the measured structural plane spacing d and extension length s, plot the structural planes on the strain-type instantaneous rockburst calculation model diagram. Please refer to... Figure 6 This document illustrates a schematic diagram of a rockburst volume calculation model for a group of advantageous structural surfaces in an arc-shaped tunnel chamber, provided in an embodiment of the present invention. By drawing the rockburst volume calculation model in a CAD drawing and using the area query function, the S-value on the tunnel cross-section can be obtained. 阴影 The area.

[0125] The volume of the rockburst is: V 岩爆 =bS 阴影 .

[0126] ② Cut by two sets of dominant structural planes

[0127] When there are two sets of dominant structural surfaces (the structural surface extension length is greater than 1m), and according to the above calculations, the second angle γ1 between the surface and the normal vector of the tunnel chamber's free face is... Sometimes and Advantageous structural surface normal vector (a1, b1, c1) (a2, b2, c2), based on the measured structural surface spacing d and extension length s, the structural surfaces are plotted on the strain-type instantaneous rockburst calculation model diagram; by plotting the rockburst volume calculation model diagram in the CAD drawing, the area S on the tunnel section is obtained through the area query function. 阴影 The area.

[0128] When it is an arc-shaped tunnel chamber, such as Figure 7 As shown, the volume of the rockburst is V. 岩爆 =bS 阴影 When it is the arch of a tunnel chamber, such as Figure 8 As shown, the volume of the rockburst is When it is a flat floor slab of a tunnel chamber, such as Figure 9 As shown, the volume of the rockburst is

[0129] ③ Cut by 3 sets of dominant structural planes

[0130] When there are 3 sets of dominant structural surfaces (the structural surface extension length is greater than 1m), and based on the above calculations, the normal vector to the free face of the tunnel chamber is obtained. (l1, m1, n1) Second included angles γ1, γ2 Sometimes and and Advantageous structural surface normal vector (a1, b1, c1) (a2, b2, c2) Given points P1(x1,y1,z1), P2(x2,y2,z2), and P3(x3,y3,z3) on three sets of structural surfaces (a3, b3, c3), the plane equations S of the three sets of structural surfaces can be calculated. J1 S J2 S J3 :

[0131] S J1 : a1x + b1y + c1z + d1 = 0; S J2 a²x + b²y + c²z + d² = 0; S J3 a3x+b3y+c3z+d3=0.

[0132] Obtain a point on the free surface of the tunnel, that is, the preset tension fracture location, and calculate the free surface vector of the tunnel. The plane equation S of (l1, m1, n1) c :

[0133] Solve S separately J1 S J2 S J3 The intersection point coordinates p(x1,y1,z1), the structural surface S J1 S J2 S c The intersection point coordinates c(x2,y2,z2), the structure surface S J1 S J3 S c The intersection point coordinates b(x3,y3,z3), the structural surface S J2 S J3 S c The coordinates of the intersection point a(x4,y4,z4) need to be solved using Cramer's rule to obtain the three plane intersection points by solving the non-homogeneous linear equation system.

[0134] With structural surface S J1 S J2 S J3 Taking the intersection point coordinates p(x1, y1, z1) as an example, the specific calculation process is as follows:

[0135] SP = D, where...

[0136] Then P = S -1Given S and D, we can find the coordinates p(x1,y1,z1). Similarly, we can find c(x2,y2,z2), b(x3,y3,z3), and a(x4,y4,z4). Therefore, we obtain: Therefore, the volume of the rockburst cut by the three sets of structures is:

[0137]

[0138] According to a specific implementation, the above identification method further includes time-delay rockburst identification of the target tunnel chamber, wherein the time-delay rockburst identification includes:

[0139] The maximum, intermediate, and minimum principal stresses after time t are obtained by monitoring the in-situ stress of the target tunnel chamber.

[0140] The newly added maximum principal stress, newly added intermediate principal stress, and newly added minimum principal stress are summed with the first stress parameter along the X, Y, and Z axes to obtain the sum stress along the X, Y, and Z axes.

[0141] The second stress parameter is generated based on the sum of the stresses in the X, Y, and Z axes. The second stress parameter is then substituted into the identification process to obtain the rockburst parameters after time t, and it is determined that a time-delayed rockburst has occurred.

[0142] Specifically, in tectonically active regions, the maximum principal stress σ increasing over time is obtained by monitoring in-situ stress. 1z Intermediate principal stress σ 2z Minimum principal stress σ 3z (where: σ) z1 >σ z2 >σ z3 The corresponding principal stress azimuth and dip angle are β. 1z °∠α 1z °、β 2z °∠α 2z °、β 3z °∠α 3z °; Based on the initial maximum principal stress σ1, intermediate principal stress σ2, and minimum principal stress σ3 (where: σ1>σ2>σ3), the corresponding principal stress azimuth angles and inclination angles β1°∠α1°, β2°∠α2°, and β3°∠α3°.

[0143]

[0144]

[0145]

[0146] Let the direction vectors of the X, Y, and Z axes be respectively (1, 0, 0), (0, 1, 0), (0, 0, 1), then the initial maximum principal stress σ1, the initial intermediate principal stress σ2, the initial minimum principal stress σ3, the new maximum principal stress σ z1 , the new intermediate principal stress σ z2 , and the new minimum principal stress σ z3 (where: σ1 > σ2 > σ3, σ z1 > σ z2 > σ z3 ) are decomposed in the X, Y, and Z axis directions and the stress is summed:

[0147] σ x合 = σ1cos(η x1 ) + σ2cos(η x2 ) + σ3cos(η x3 ) + σ 1z cos(η x1z ) + σ 2z cos(η x2z ) + σ 3z cos(η x3z ),

[0148] σ y合 = σ1cos(η[[ID=4%]] y1 ) + σ2cos(η y2 ) + σ3cos(η y3 ) + σ 1z cos(η y1z ) + σ z2 cos(η y2z ) + σ z3 cos(η y3z ),

[0149] σ z合 = σ1cos(η z1 ) + σ2cos(η z2 ) + σ3cos(η z3 ) + σ 1z cos(η z1z ) + σ 2z cos(η z2z ) + σ 3z cos(η z3z ),

[0150] where

[0151] Finally, the sum of stresses σ in the X, Y, and Z axes is obtained. x合 σ y合 σ z合 , and τ xy合 τ yz合 τ zx合 It is 0. Compare σ. x合 σ y合 σ z合 The values ​​among the three are used to determine the maximum principal stress σ. 1合 The minimum value among the three is set as the minimum principal stress σ. 3合 The intermediate value among the three is set as the intermediate principal stress σ. 2合 The σ 1合 σ 2合 σ 3合 The second stress parameter is substituted into the identification process for calculation and judgment. If the requirements are met, it indicates that a time-delayed rockburst will occur at time t under the condition of no support.

[0152] Furthermore, the time-delayed rockburst identification also includes: monitoring the dynamic disturbance of the target tunnel chamber to obtain the vibration frequency, testing the rock mass of the target tunnel chamber to obtain the natural frequency, and judging whether a time-delayed rockburst has occurred at the location where an overstrain type instantaneous rockburst and / or a structural surface type instantaneous rockburst has occurred based on the vibration frequency and the natural frequency.

[0153] Preferably, when the vibration frequency of low-frequency vibration (<40Hz) or dynamic disturbance is close to or basically consistent with the natural frequency of the rock mass of the target tunnel chamber, a time-delayed rockburst will occur at the location where strain-type instantaneous rockburst and / or structural plane-type instantaneous rockburst has occurred before.

[0154] In summary, this invention proposes a rockburst identification method based on the properties of rock mass structural surfaces and geostress characteristics. Starting from the essence of the rock mass's own strength and stress state, it uses mathematical spatial vector calculations to identify the location and potential scale of strain-type and structural surface-type instantaneous rockbursts. This invention improves the accuracy of rockburst identification through quantitative calculation, achieving a breakthrough in calculating the accurate location and potential scale of rockbursts in tunnel chambers. Furthermore, this invention is not limited by lithology or tunnel chamber type, enabling accurate calculations in all cases. It can also be continuously calculated during tunnel excavation, is not limited by monitoring equipment, and has a simple calculation formula with wide applicability.

[0155] The present invention will be further described and explained below with reference to specific embodiments.

[0156] For a specific target tunnel chamber, as described in step 100 above, the three-dimensional in-situ stress state of the rock mass within the borehole of the potential rockburst tunnel chamber section is measured using the stress relief method to obtain the in-situ stress component σ at the measuring point. x σ y σ z τ xy τ yz τ zx The pressures are 14.21 MPa, 13.31 MPa, 11.07 MPa, 1.99 MPa, 0.62 MPa, and -1.09 MPa, respectively. The maximum principal stress σ1, intermediate principal stress σ2, and minimum principal stress σ3 are obtained as 16.11 MPa, 11.76 MPa, and 10.73 MPa, respectively, along with the corresponding principal stress azimuth and inclination angles of 52°∠13.9°, 324.6°∠10.4°, and 90.2°∠72.5°. The normal vectors in the directions of the maximum principal stress, intermediate principal stress, and minimum principal stress σ1, σ2, and σ3 are calculated as follows:

[0157]

[0158]

[0159]

[0160] Furthermore, using a compass and measuring tape, the attitudes of five groups of rock strata in the potential rockburst tunnel section were obtained: 299°∠86°, 312°∠82°, 96°∠82°, 279°∠73°, and 259°∠80°. The normal vectors for the attitudes of the five structural planes can then be calculated as follows:

[0161]

[0162]

[0163]

[0164]

[0165]

[0166] Furthermore, the tensile strength σ of the rock was measured using the Brazilian disk radial fracturing method. tys The uniaxial compressive strength of the rock ranged from 7.45 to 9.46 MPa, and the uniaxial compressive strength measured by uniaxial compression tests was 91.7 to 139.38 MPa. The compressive strength value σ of the rock mass... c And simply convert it into the tensile strength value σ of the rock mass structural plane. ti A rapid determination can be performed on (i = 1, 2, 3, ..., i ≤ n) to obtain the tensile strength characteristic value σ.t1 ≈4.59MPa, σ t2 ≈6.97MPa, σ t3 ≈9.17MPa, σ t4 ≈13.94MPa.

[0167] Furthermore, as described in step 200 above, the tunnel rock mass is in a dry state after excavation, so the identification process is executed based on the above identification parameters.

[0168] Specifically, as described in step 201 above, the rock tensile strength σ obtained by the Brazilian disk radial fracturing method... tys and σ estimated by the uniaxial compressive strength of rock t1 σ t2 σ t3 σ t4 The values ​​are compared with the maximum principal stress σ1, the intermediate principal stress σ2, and the minimum principal stress σ3, respectively. Except for σ... t4 In addition, all of them are less than the maximum principal stress σ1, intermediate principal stress σ2, and minimum principal stress σ3, which indicates that strain-type instantaneous rockburst will occur in the tunnel chamber. The maximum principal stress σ1, intermediate principal stress σ2, and minimum principal stress σ3 are then substituted into the subsequent identification process for calculation.

[0169] As described in step 202 above, the geostress component σ measured in the borehole near the rockburst tunnel chamber... x σ y σ z τ xy τ yz τ zx The corresponding values ​​are 14.21 MPa, 13.31 MPa, 11.07 MPa, 1.99 MPa, 0.62 MPa, and -1.09 MPa, respectively. The normal stresses of the five structural surfaces were calculated using the Mohr stress circle, and are as follows:

[0170] σ B1 =11.15 MPa, σ B2 =11.25MPa, σ B3 =10.99MPa, σ B4 =11.66MPa, σ B5 =11.34MPa.

[0171] The normal stress on all structural surfaces is greater than the tensile strength σ. tys (7.45~9.46MPa), which is also greater than σ. t4 Based on the estimated tensile strength of the external rock layers, it was determined that all five rock strata would experience instantaneous structural rockbursts.

[0172] As described in step 203 above, specifically, based on the design drawings, any section of the tunnel chamber was selected to determine the inclination and dip angle ψ of 13 free faces perpendicular to the tunnel face, arch top, arch bottom, and arch waist sidewall. j °∠ω j °(j=1,2,3…12,13), calculate the spatial normal vectors corresponding to the dip and tilt angles of the 13 free planes, as well as the first angle γ between the vectors and the maximum principal stress σ1, intermediate principal stress σ2, and minimum principal stress σ3. ij (Where i = 1, 2, 3, j = 1, 2, 3…12, 13), the specific calculation results are as follows: Figure 10 As shown, the direction of the free face of the excavated tunnel chamber relative to the tunnel radius is illustrated in the diagram. Figure 11 As shown.

[0173] To ensure the accuracy of rockburst location calculation, this embodiment selects the rock tensile strength σ measured by the Brazilian disk radial fracturing method. tys Using the minimum and maximum values ​​of 7.45 MPa and 9.46 MPa as parameters for tensile strength calculation, and the maximum principal stress σ1 = 16.11 MPa, intermediate principal stress σ2 = 11.76 MPa, and minimum principal stress σ3 = 10.73 MPa obtained by the stress relief method as stress parameters for calculating the stress circle range, we can obtain:

[0174] according to Figure 10 The calculations shown indicate that the dip angles of the left arch waist (262°∠-70°~10°) all satisfy the conditions for rock burst initiation and are controlled by the maximum principal stress σ1. The first angle between the tunnel free face and the direction of the maximum principal stress is smallest when the dip angles of the left and right arch waists are -16° and 16°, respectively. This determines the direction vector. The normal vector of the free surface of the rockburst cavern controlled by the maximum principal stress is σ1*cos(γ). 1min =16.11*cos(29.04°) = 14.08MPa; When the dip angle of the face is 352°∠3°, the rock burst initiation condition is met, and it is controlled by the intermediate principal stress σ2. Among them, only the first angle between the face and the direction of the intermediate principal stress is the smallest, thus determining the direction vector. The normal vector of the free surface of the rockburst cavern controlled by the intermediate principal stress is σ2*cos(γ). 2min =11.76*cos(28.18°) = 10.37MPa; When the dip angles of the arch crown and arch base are 252°∠-87°, and the dip angle of the left arch waist is 262°∠-72.7°~50°, the rock burst initiation conditions are met, and it is controlled by the minimum principal stress σ3. Among them, the first angle between the left arch waist dip angle and the direction of the minimum principal stress is the smallest when it is -72.7°. Determine the direction vector. The normal vector of the free surface of the rockburst cavern controlled by the intermediate principal stress is σ3*cos(γ). 3min =10.73*cos(2.46°) =10.72MPa. Therefore, rock bursts will occur in this section of the tunnel from the arch to the bottom of the left arch and the working face.

[0175] If the plane where the rockburst occurs in the tunnel chamber is not the tunnel face, then the location of the rockburst on the tunnel chamber sidewall needs to be determined; assuming the dip and inclination angle of the excavated tunnel face are 352°∠3° and pass through a point O1(0,0,0) in space, then its spatial normal vector... (l1, m1, n1) = (-0.138982473, -0.988910926, 0.052335955), then the plane equation and normal vector of the tunnel face are: -0.138982473X - 0.988910926Y + 0.052335955Z = 0.

[0176] Due to the plane normal vector of rockburst in the tunnel chamber Given coordinates (0.764935018, -0.597632754, 0.240228038) and (0.300703988, 0.001049651, 0.953716944), and vectors from the origin to point (0.764935018, -0.597632754, 0.240228038), the distances d1 and d2 from points A1 and A2 to the tunnel face plane are respectively:

[0177]

[0178] Let A'1(x) k1 ',y k1 ',z k1 '), A'3(x k3 ',y k3 ',z k3 ') is point A1(x k1 ,y k1 ,z k1 ), A3(x k3 ,y k3 ,z k3 The projected coordinates of the tunnel face to the working face plane. For vectors (0.764935018, -0.597632754, 0.240228038) The projection vector (x) from (0.300703988, 0.001049651, 0.953716944) onto the tunnel face plane is given by the vector. k1 ',y k1',z k1 '), (x k3 ',y k3 ',z k3 '),but:

[0179]

[0180]

[0181] We can obtain,

[0182] Due to the tunnel cross-section The corresponding radius r 1、 r3 is 7.29m and 4.38m respectively. The coordinates of the rockburst location relative to the center point of the arc of the tunnel wall are (-7.00, 2.00) and (-4.18, 1.32).

[0183] Furthermore, based on the fact that strain-type rockbursts can occur in tunnel chambers; according to the test results, due to σ tys The values ​​ranged from 7.45 to 9.46 MPa, with an average value of σ1*cos(γ 1min )>σ3*cos(γ 3min )>σ2*cos(γ 2min )>σ tys Minor or more severe rock bursts are expected to occur in this section of the tunnel, from the arch to the bottom of the left arch and at the working face.

[0184] ① Calculation of rockburst volume at the tunnel face

[0185] Since the direction of the intermediate principal stress σ2 is consistent with the direction of the tunnel axis, let's assume that the tensile stress on the rock mass at a certain cross section outside the tunnel face is equal to the tensile strength σ of the rock mass. tys =8.18MPa, which is the preset tensile fracture location. According to the design drawings, the area of ​​the tunnel face where rockburst occurs is S1 = 62.6438m². 2 Since the angle between the tunnel face and the tunnel diameter is a right angle, as the free face rotates, the tensile stress on the rock mass at a certain point is σ²*cos(γ)*cos(ε / 2)=σ tys ,

[0186] As a simplified assumption, a point at the location of the rock burst on the tunnel's free face, extending along the tunnel excavation direction to the stress limit equilibrium point outside the tunnel, is considered a single rod. According to Saint-Venant's principle, F1 = F2, therefore σ2cos(γ)S1 = σ tys S'1,

[0187] Because the tunnel chamber in this embodiment has an irregular cross-section composed of multiple arcs, the offset command is used in CAD to... At that time, the tunnel chamber area was 79.415m². 2 .

[0188] The depth of the rock burst at the working face is: The volume of the rockburst is:

[0189] ② Calculation of rockburst volume on straight floor of tunnel chamber

[0190] For a straight tunnel floor, since the direction of the minimum principal stress σ3 is consistent with the tunnel axis, let's assume that the tensile stress on the rock mass at a certain cross-section outside the floor is equal to the tensile strength σ of the rock mass. tys = 8.18MPa. According to the design drawings, the width 'a' of the tunnel chamber floor slab is 9m. Taking a tunnel floor slab with a length 'b' along the tunnel axis of 3m as an example, the area S1 is 27m². 2 The angle between the working face and the tunnel diameter is a right angle. As the free face rotates, the tensile stress on the rock mass at a certain point is σ³*cos(γ). 3min )*cos(ε / 2)=σ tys ,

[0191] Due to the simplified assumption that a point at the location of the rock burst on the tunnel's free face extends along the tunnel excavation direction to the stress limit equilibrium point outside the tunnel chamber as a single rod, according to Saint-Venant's principle, F1 = F2, therefore σ3cos(γ)S1 = σ tys S'1, because: but The depth of the rock burst at the working face is:

[0192] The volume of the rockburst is:

[0193] ④ Calculation of rockburst volume in arc-shaped tunnel chambers

[0194] Based on the calculation results of the location of instantaneous rockbursts caused by strain, rockbursts will occur along the arc-shaped sidewalls from the bottom of the left arch waist to the arch crown of the tunnel chamber. Specifically, the rockburst at the left arch waist is controlled by the maximum principal stress, while the rockburst at the arch crown is controlled by the minimum principal stress. Based on the above calculations, σ1*cos(γ) 1min )=16.11*cos(29.04°)=14.08MPa、σ3*cos(γ 3min=10.73*cos(2.46°) =10.72MPa. Therefore, let the locations of rockbursts on the free face be B and E. According to the design drawings, the design radius r1 of the left arch waist and the design radius r3 of the arch top chamber are 7.29m and 4.38m, respectively, with centers O1 and O3. Let the tensile stress at the stress limit equilibrium points C, D, and F extending radially from the center O1 of the curved surface of the left arch waist of the tunnel chamber to the outside of the chamber be approximately equal to the tensile strength σ of the rock mass. tys Let G, H, and I be the stress limit equilibrium points extending radially from the center O3 of the tunnel arch surface to the outside of the tunnel. The tensile stress at these three points is equal to the tensile strength σ of the rock mass. tys ;like Figure 12 As shown. Let the distance from the center O1 to point C be l. σ1 Let the distance from the center O2 to point H be l. σ3 Let vector The first angle between the x-axis and the x-axis is ω. σ1 Let vector The first angle between the x-axis and the x-axis is ω. σ3 Let vector and The first included angle between them is ε σ1 Let vector and The first included angle between them is ε σ3 .

[0195] For simplification, consider a rod extending radially from the point where a rock eruption occurs on the free face of the tunnel chamber to the stress limit equilibrium point outside the chamber. According to Saint-Venant's principle, the different ways forces act on the rod end only affect a range no greater than the rod's lateral dimension. Let the axial forces and areas at points B and C in the micro-rock element be F1, F2, A1, and A2, respectively; and let the axial forces and areas at points H and E in the micro-rock element be F3, F4, A3, and A4, respectively.

[0196] Therefore, regarding the rock burst on the left arch waist of the tunnel chamber:

[0197]

[0198] According to Saint-Venant's principle, F1 = F2, therefore the calculation yields...

[0199] Therefore, for rock bursts in the tunnel vault... According to Saint-Venant's principle, F1 = F2, therefore the calculation yields...

[0200] The rockburst location is in the second quadrant. Based on the determination of the location of strain-type instantaneous rockbursts, the unit vectors of the rockbursts occurring at the left arch waist and the tunnel arch roof are respectively:

[0201]

[0202]

[0203] Due to the tunnel cross-section The corresponding radius r 1、 r3 is 7.29m and 4.38m respectively. The coordinates of the rockburst location relative to the center point of the arc of the tunnel wall are (-7.00, 2.00) and (-4.18, 1.32).

[0204] Then vector The first angle between the x-axis and the x-axis is: vector The first angle between the x-axis and the x-axis is: vector The first angle between the x-axis and the x-axis is: vector The first angle between the x-axis and the x-axis is:

[0205] Then the coordinates of points D(x4,y4), F(x5,y5), G(x6,y6), and I(x7,y7) can be obtained as follows:

[0206]

[0207]

[0208]

[0209]

[0210] Due to vectors The angular offset range has exceeded the arc shape of the tunnel design with center O1 as the center and r1 as the radius. To determine the scale of the rockburst, it is necessary to calculate the stress limit equilibrium point on the outside of the tunnel from the center O1 of the left arch waist curved surface of the tunnel along the radial direction.

[0211] According to the design drawings, the normal vector from the bottom of the left arch of the tunnel to the center O1 has a dip angle of 262°∠16°. Its first angle γ with the direction of maximum principal stress 拱腰底 =42.10°, then

[0212] Centered on circle O1, Extending in direction l 拱腰底 The length extends to point K, and point K is determined as the critical point of the rockburst boundary. Let there be a point J on the arc centered at O3 with radius r3 such that σ tys =σ1cos(γ 1min cos(γ) J ),but The coordinates of point J relative to the center O3 can be calculated as I(2.54, 3.57).

[0213] Based on the coordinates of points C, K, and J on the large circle, the large circle O1' can be drawn in the CAD drawing; based on points G, H, and I on the small circle, the small circle O3' can be drawn in the CAD drawing; finally, the shaded area S formed by the overlap of the large circle O1' and the small circle O3' is... 合 S is the rockburst area on the cross section. 合 =48.09m 2 .

[0214] Based on the on-site conditions, the rockburst length b is 10m, then the volume of the rockburst is V. 岩爆 =bS 合 =480.9m 3 .

[0215] In summary, this invention proposes a rockburst identification method based on the stress characteristics and dynamic disturbances of rock mass structural surfaces. Starting from the inherent strength and stress state of the rock mass itself, it uses mathematical vector calculations to identify the location and potential scale of various types of rockbursts. This invention achieves better accuracy through quantitative calculation, representing a breakthrough in accurately calculating the location and potential scale of rockbursts in tunnel chambers. Furthermore, this invention is not limited by lithology or tunnel type, enabling accurate calculations across all scenarios. It can also be continuously calculated during tunnel excavation, is not limited by monitoring equipment, and its calculation formulas are simple and widely applicable.

[0216] On the other hand, embodiments of the present invention also provide a rockburst identification system, the system comprising:

[0217] The acquisition module is used to obtain the identification parameters of the target tunnel chamber;

[0218] The identification module is used to execute a rockburst identification method as described in any of the above items, to identify rockbursts in the target tunnel chamber and obtain rockburst parameters.

[0219] In addition, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the computer performs the rockburst identification method as described in any of the preceding claims.

[0220] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for identifying rockbursts, characterized in that, The method includes: Step 100: Obtain the identification parameters of the target tunnel chamber, including the tensile strength of the rock, the tensile strength of the rock mass, the attitude of the rock strata on the structural surface, and the first stress parameter at the measuring point; Step 200: Determine the state of the rock mass in the target tunnel chamber. If the rock mass is dry, execute the identification process based on the identification parameters to obtain the rockburst parameters of the target tunnel chamber; otherwise, determine it as a rockburst-free area. The identification process includes: Step 201: Based on the fact that the first stress parameter is greater than the tensile strength of the rock, it is determined that a strain-type instantaneous rockburst is about to occur in the target tunnel chamber; Step 202: Calculate the normal stress of the structural surface based on the first stress parameter and the attitude of the rock strata of the structural surface. Based on the fact that the normal stress of the structural surface is greater than the tensile strength of the rock mass, determine that an immediate rockburst of the structural surface type is about to occur in the target tunnel chamber. Step 203: Calculate the spatial normal vector of the free face of the target tunnel chamber, obtain the first included angle based on the spatial normal vector and the direction vector of the first stress parameter, determine the position of the strain-type instantaneous rockburst based on the first included angle, and determine the volume of the strain-type instantaneous rockburst based on the first included angle and the preset tensile fracture position. Step 204: Obtain the second included angle based on the spatial normal vector and the normal vector of the rock strata attitude of the structural plane; determine the location of the instantaneous rockburst of the structural plane type based on the second included angle; determine the volume of the instantaneous rockburst of the structural plane type based on the line connecting the intersection relationship of the rock strata attitude of the structural plane and the preset tension fracture location. The first stress parameter includes the maximum principal stress, the intermediate principal stress, and the minimum principal stress. Determining that a strain-type instantaneous rockburst has occurred in the target tunnel chamber includes: The maximum principal stress is compared with the tensile strength of the rock. If the maximum principal stress is greater than the tensile strength of the rock, it is determined that a strain-type instantaneous rockburst has occurred in the target tunnel chamber, and the maximum principal stress is substituted into the subsequent identification process. Compare the intermediate principal stress with the tensile strength of the rock. If the intermediate principal stress is greater than the tensile strength of the rock, it is determined that a strain-type instantaneous rockburst has occurred in the target tunnel chamber, and the intermediate principal stress is substituted into the subsequent identification process. The minimum principal stress is compared with the tensile strength of the rock. If the minimum principal stress is greater than the tensile strength of the rock, it is determined that a strain-type instantaneous rockburst has occurred in the target tunnel chamber, and the minimum principal stress is substituted into the subsequent identification process. Wherein, the maximum principal stress is greater than the intermediate principal stress, and the intermediate principal stress is greater than the minimum principal stress; when the maximum principal stress, intermediate principal stress, and minimum principal stress are all less than the tensile strength of the rock, it is determined that strain-type instantaneous rockburst will not occur. Determining the location of the strain-type instantaneous rockburst based on the first included angle includes: when the first included angle is greater than... When the strain-type instantaneous rockburst occurs at the angle between the sidewalls of the target tunnel chamber; when the first included angle is less than or equal to When the minimum value of the first included angle is selected as the spatial normal vector of the rockburst location, the location of the rockburst occurrence is calculated based on the normal vector of the rockburst location; wherein, The tensile strength of the rock is given. Let i be the first stress parameter, where i equals 1 / 2 / 3. Indicates the maximum principal stress. Indicates the intermediate principal stress. Indicates the minimum principal stress; Determining the location of the instantaneous rockburst based on the second included angle includes: When the second included angle is greater than When the instantaneous rockburst of the structural surface type occurs at the angle between the sidewalls of the target tunnel chamber; when the second included angle is less than or equal to When the second included angle is used as the spatial normal vector of the rockburst location, the location of the rockburst is calculated based on the normal vector of the rockburst location; wherein, The tensile strength of the rock is given. Let i be the first stress parameter, where i equals 1 / 2 / 3. Indicates the maximum principal stress. Indicates the intermediate principal stress. This represents the minimum principal stress.

2. The rockburst identification method according to claim 1, characterized in that, The free face of the target tunnel chamber includes the working face, the arch top face, the arch bottom face, and the arch waist sidewalls.

3. The rockburst identification method according to claim 1, characterized in that, The method further includes time-delay rockburst identification of the target tunnel chamber, wherein the time-delay rockburst identification includes: The maximum, intermediate, and minimum principal stresses after time t are obtained by monitoring the in-situ stress of the target tunnel chamber. The newly added maximum principal stress, newly added intermediate principal stress, and newly added minimum principal stress are summed with the first stress parameter along the X, Y, and Z axes to obtain the sum stress along the X, Y, and Z axes. The second stress parameter is generated based on the sum of the stresses in the X, Y, and Z axes. The second stress parameter is then substituted into the identification process to obtain the rockburst parameters after time t, and it is determined that a time-delayed rockburst has occurred.

4. The rockburst identification method according to claim 3, characterized in that, The time-delayed rockburst identification also includes: monitoring the dynamic disturbance of the target tunnel chamber to obtain the vibration frequency, testing the rock mass of the target tunnel chamber to obtain the natural frequency, and judging whether a time-delayed rockburst has occurred at the location where an overstrain type instantaneous rockburst and / or a structural surface type instantaneous rockburst has occurred based on the vibration frequency and the natural frequency.

5. The rockburst identification method according to claim 1, characterized in that, The occurrence of the structural rock strata includes n sets of structural planes; Determining the volume of the instantaneous rockburst of the structural plane type includes: selecting a structural plane with an extension length greater than or equal to 1m in the attitude of the structural plane strata as the dominant structural plane, and connecting the tangential relationship of the attitude of the dominant structural plane strata with the line of the preset tension fracture position; wherein, n is a positive integer, and for the dominant structural plane, n is less than or equal to 3.

6. A rockburst detection system, characterized in that, The system includes: The acquisition module is used to obtain the identification parameters of the target tunnel chamber; The identification module is used to execute a rockburst identification method as described in any one of claims 1 to 5, to identify rockbursts in the target tunnel chamber, and to obtain rockburst parameters.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it causes the computer to perform the method as described in any one of claims 1 to 5.

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