An anisotropic rock mass evaluation method and system based on a directional structure index

Abstract

The application provides an anisotropic rock mass evaluation method and system based on a directional structure index, and belongs to the technical field of geological engineering, and comprises the following steps: obtaining internal strength factor data, structure strength factor data and boundary condition factor data of a rock mass to be evaluated; calculating internal strength factor rating Ri; constructing a directional weight function W(θ); calculating structure surface comprehensive condition rating Jc, and directionally correcting the rock quality designation RQD value of a drill hole to obtain a directional structure strength index DSSI(θ) through coupling calculation; calculating boundary condition factor rating Bc; calculating a directional rock mass quality comprehensive index D-RMR(θ) and calibrating the original value of D-RMR(θ); generating a visual representation map by taking the calibrated D-RMR(θ) value corresponding to different direction angles θ; and evaluating the quality grade of the rock mass to be evaluated. The application can accurately and quantitatively reveal the directional characteristics of anisotropic rock mass, effectively avoid distortion of key parameters, and has the advantages of high accuracy, strong practicability and intuitive results.

Description

Technical Field

[0001] This invention belongs to the field of geological engineering technology, and more specifically, it relates to an anisotropic rock mass evaluation method and system based on directional structure index. Background Technology

[0002] In geological engineering practice, rock mass quality classification is the foundation for engineering design and construction. Currently, internationally accepted rock mass classification methods mainly include Rock Mass Quality Index (RMR), Tunnel Quality Index (Q system), and Geological Strength Index (GSI). These classic methods have been proven effective in long-term engineering practice, but their core theories are mostly based on the assumption that the rock mass is isotropic or approximately isotropic.

[0003] However, most rock masses encountered in engineering, such as slate, schist, phyllite, shale, and interbedded sedimentary rocks, exhibit significant anisotropy. Their mechanical properties (such as strength and deformation modulus) vary greatly depending on the relationship between the direction of force and the orientation of the dominant structural planes of the rock mass (such as bedding, foliation, and joints).

[0004] Existing technologies have made some attempts to address the evaluation of anisotropic rock masses, mainly including:

[0005] Empirical correction methods: Some scholars have attempted to consider the directional influence of structural surfaces within the RMR or Q system framework by introducing empirical correction coefficients or additional terms. However, these corrections often lack a unified theoretical basis, have poor universality, and do not provide a sufficiently detailed description of the complex relationship between structural surface attitude and engineering orientation.

[0006] Complex constitutive model method: Some studies have established complex mechanical models that consider the influence of structural planes or bedding directions based on the constitutive relations of anisotropic materials (such as transversely isotropic models, Drucker-Prager model modifications, etc.). These models are theoretically rigorous, but obtaining parameters often requires extensive indoor mechanical tests from multiple angles (such as triaxial tests, true triaxial tests), resulting in high data acquisition costs, cumbersome calculation processes, and the need for specialized numerical simulation software support, making it difficult to rapidly promote and apply them within the survey and design cycle of conventional engineering projects.

[0007] Tensor theory or extreme value analysis: This method introduces tensor descriptions of rock mass mechanical properties or analyzes based on extreme strength values ​​in different directions. These methods are conceptually abstract, and their understanding and application by engineers are relatively difficult.

[0008] Existing technologies generally suffer from the following technical shortcomings when dealing with anisotropic rock masses:

[0009] The "non-directionality" of the evaluation results: Traditional methods usually give a single, non-directional comprehensive score, which cannot quantify the directional risk of engineering excavation (such as tunnel excavation direction, slope excavation face orientation) relative to the rock mass structure. This leads to either overly conservative designs, resulting in unnecessary economic waste, or unidentified directional risks that endanger engineering safety.

[0010] Distortion of key parameters: For example, the value of the Rock Quality Degree (RQD) is heavily dependent on the angle between the borehole direction and the structural plane. When the borehole direction is nearly parallel to the structural plane, the RQD value will be artificially high and cannot truly reflect the degree of rock fragmentation. Existing methods typically do not provide directional correction for this.

[0011] The “fuzziness” of qualitative descriptions: For example, the GSI system’s description of layered and platy rock masses is rather general, making it difficult to distinguish the huge differences between tightly cemented and weakly muddy structural surfaces, which makes the evaluation results highly subjective and unreliable.

[0012] The "low practicality" of complex models: The aforementioned theoretical models or correction methods that consider directionality are difficult to promote and apply within the conventional engineering survey and design cycle due to their complexity, high cost and cumbersome calculation process.

[0013] Therefore, there is an urgent need in this field for a new method and system that can accurately, quantitatively, and efficiently evaluate anisotropic rock masses and intuitively reflect their directional characteristics, so as to guide the optimized design and safe construction of engineering projects. Summary of the Invention

[0014] The purpose of this invention is to provide an anisotropic rock mass evaluation method and system based on directional structure index. This invention can comprehensively consider the inherent anisotropy of the rock, the directionality of the structural plane and the boundary conditions, and output the rock mass quality evaluation results that vary with direction in a quantitative manner. It solves the technical problems of traditional methods such as inability to perform directional evaluation, distortion of key parameters and poor practicality.

[0015] To achieve the above objectives, a first aspect of the present invention provides a method for evaluating anisotropic rock masses based on a directional structure index, comprising the following steps:

[0016] S1. Obtain the intrinsic strength factor data, structural strength factor data, and boundary condition factor data of the rock mass to be evaluated; the intrinsic strength factor data includes the intact uniaxial compressive strength (UCS) of the rock mass in at least two directions.

[0017] S2. Calculate the intrinsic strength factor rating based on the intrinsic strength factor data. The intrinsic anisotropy coefficient is introduced here. and correction function Based on the structural strength factor data, the spatial angle between the engineering axis and the normal to the dominant structural surface of the rock mass is defined as the direction angle. Construct a directional weighting function that allows the engineering properties of rock mass to vary periodically with the engineering direction and the angle between the orientations of structural planes. ; Calculate the comprehensive condition rating of structural surfaces And the rock quality index RQD value of the borehole was directionally corrected to obtain The correction function takes into account the angle between the drilling direction and the structure surface itself. The directional structural strength index was obtained through coupled calculation. RQD baseline The baseline RQD value is used; the boundary condition factor rating is calculated based on the boundary condition factor data. ;

[0018] S3. Calculate the comprehensive quality index of directional rock mass. W1, W2, and W3 are the weight coefficients of each factor, and W1 + W2 + W3 = 1; The original value is calibrated to obtain the calibrated value. Value; different engineering direction angles After corresponding calibration The value is used to generate a visual characterization map; based on the visual characterization map, the quality grade of the rock mass to be evaluated is assessed.

[0019] Furthermore, the intrinsic strength factor data includes strength values ​​σp parallel to the dominant structural plane of the rock mass and strength values ​​σv perpendicular to the dominant structural plane of the rock mass, Ri=UCS score ×f(Ia), Among them, UCS score UCS score, a traditional rock mass quality indicator. Ia is the rock brittleness sensitivity coefficient, where Ia = σv / σp.

[0020] Furthermore, K1 takes a value of 0.6-0.95, K2 takes a value of 0.05-0.4; and / or W2 takes a value of 0.5-0.7, and W1 and W3 take a value of 0.15-0.3.

[0021] Furthermore, the RQD directionality correction adopts a sinusoidal function form: Among them, RQD raw The original borehole rock quality indicators, It is the angle between the engineering axis and the structural surface itself.

[0022] Furthermore, the structural strength factor data includes the occurrence, average spacing, and surface characteristics of the dominant structural planes of the rock mass, as well as the rock quality index (RQD) value of at least one borehole.

[0023] Furthermore, considering the spacing between rock mass structural surfaces and surface characteristics, Jc is obtained according to a preset scoring criterion, which refers to rock mass quality indicators or tunnel quality indicators for scoring; and / or,

[0024] Based on the groundwater conditions and referring to the rock mass quality indicators, a boundary condition factor rating Bc is obtained.

[0025] Furthermore, the calibration of the original D-RMR(θ) value is achieved by establishing a conversion function between the original D-RMR(θ) value and the traditional rock mass quality index value; and / or the visualization representation diagram is a "rock mass quality polar rose diagram", which displays the distribution of D-RMR(θ) value in the range of 0°-360° in polar coordinate form.

[0026] Furthermore, the calibration employs the theoretical boundary anchoring method, determining the linear calibration coefficients based on the theoretical maximum and minimum scores.

[0027] A second aspect of the present invention provides an anisotropic rock mass evaluation system based on a directional structure index, comprising:

[0028] The data input module is used to receive the intrinsic strength factor data, structural strength factor data, and boundary condition factor data of the rock mass to be evaluated input by the user; the intrinsic strength factor data includes the intact uniaxial compressive strength (UCS) of the rock in at least two directions;

[0029] A central processing module, connected to the data input module, is configured to execute steps S2 and S3 of the method described in any of the preceding embodiments, calculating and generating the directional rock mass quality composite index D-RMR(θ) and a visualization characterization map; and,

[0030] A visualization output module, connected to the central processing module, is used to display the visualization representation diagram on the user interface.

[0031] Furthermore, the central processing module includes:

[0032] The intrinsic strength factor calculation unit is used to calculate the intrinsic strength factor rating Ri.

[0033] The directional structural strength index calculation unit is used to couple the calculation of the directional structural strength index DSSI(θ). The coupled calculation includes the construction of the directional weight function W(θ), the calculation of the comprehensive condition rating Jc of the structural surface, and the RQD directional correction.

[0034] Boundary condition factor calculation unit, used to calculate boundary condition factor rating Bc; and,

[0035] The comprehensive evaluation unit is used to perform weighted summation of the output results of the intrinsic strength factor calculation unit, the directional structural strength index calculation unit, and the boundary condition factor calculation unit, and to calibrate the original value of D-RMR(θ) to obtain the calibrated D-RMR(θ).

[0036] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method as described in any of the preceding claims.

[0037] Compared with the prior art, the present invention has the following technical effects:

[0038] (1) Achieved directional quantitative evaluation: The present invention proposes a directional structural strength index DSSI(θ) for the first time based on the directional structural index, and introduces an innovative directional weight function W(θ)=K1+K2cos(2θ) and RQD directional correction, so that the rock mass quality evaluation result changes from a single value to a continuous function that varies with direction, which can accurately predict the risk of different excavation directions and provide a scientific basis for engineering line optimization and directional support design.

[0039] (2) Improved accuracy and objectivity of evaluation: The method of this invention introduces the intrinsic anisotropy coefficient Ia, the directional weight function (W(θ)) and the RQD directional correction, and couples multiple key geological parameters. It is more objective and accurate than the traditional qualitative or semi-quantitative GSI and RMR methods. Especially when dealing with complex anisotropic rock masses, it can effectively avoid the distortion of key parameters (such as the false high RQD) and the ambiguity of qualitative description in traditional methods.

[0040] (3) It has both engineering practicality and economy: The core data required by the method of the present invention can be obtained through conventional geological exploration methods (such as rock uniaxial compressive strength, structural surface occurrence, spacing, groundwater, etc.), without the need for expensive and time-consuming special tests. The calculation model is simplified and efficient, easy to implement through software and applied to engineering practice, effectively guiding the optimization design, avoiding excessive support, and generating significant economic benefits.

[0041] (4) Intuitive results and efficient decision-making: The unique "polar rose diagram of rock mass quality" in this invention transforms complex directional data into a clear and concise graphic, greatly improving engineers' efficiency in understanding rock mass characteristics and the accuracy and speed of decision-making. Compared with traditional complex constitutive models, this invention achieves an excellent balance between accuracy and efficiency, and is more in line with actual engineering needs. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 A flowchart illustrating an anisotropic rock mass evaluation method based on directional structure index, provided for an embodiment of the present invention;

[0044] Figure 2 A structural diagram of an anisotropic rock mass evaluation system based on directional structure index provided in an embodiment of the present invention;

[0045] Figure 3 The polar rose diagram of rock mass quality in a tunnel project is provided as an application example of the present invention. Detailed Implementation

[0046] To make the technical problems, technical solutions, and beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0047] Example 1

[0048] This invention provides a method for evaluating anisotropic rock masses based on directional structure index, the process of which is as follows: Figure 1 As shown, it includes the following steps:

[0049] S100, Multidimensional Factor Data Acquisition (i.e., Data Input):

[0050] Obtain three types of basic data for the rock mass to be evaluated, specifically including:

[0051] S110. Obtain the intrinsic strength factor data of the rock mass to be evaluated: including strength values ​​parallel to the dominant structural planes of the rock mass. Strength values ​​perpendicular to the dominant structural plane of the rock mass S120. Obtain structural strength factor data of the rock mass to be evaluated: including the attitude (dip, dip angle), average spacing, surface characteristics (roughness, weathering degree, infill condition) of the dominant structural planes of the rock mass, and the original rock quality indicators of at least one borehole. S130. Obtain boundary condition factor data of the rock mass to be evaluated, including groundwater conditions and stress state.

[0052] S200, multi-dimensional factor quantitative rating, specifically includes:

[0053] S210, Calculate the intrinsic strength factor rating : According to the information obtained in step S110 and Calculate the intrinsic anisotropy coefficient The traditional scoring method is corrected using an exponential decay function. .in, UCS scoring for traditional RMR. Correction function. Defined as: . in, This is the rock brittleness sensitivity coefficient, and the recommended value range is [value range missing]. For slates and schists with well-developed foliation, it is recommended to... .when (Isotropic) No reduction will be made; when As the score increases, it decreases exponentially.

[0054] S220, Calculate the directional structural strength index This step specifically includes the following sub-steps:

[0055] S221, Define the direction angle With engineering azimuth Mapping relationship: To achieve a comprehensive evaluation from 0-360°, this invention distinguishes between "engineering azimuth angle" and "calculated direction angle":

[0056] Engineering azimuth ( ): Refers to the azimuth angle of an engineering axis (such as the tunnel excavation direction) in a geographic coordinate system, with a range of values. This is used to draw the final rose diagram.

[0057] Direction angle ( ): In three-dimensional space, the spatial angle between the engineering axis vector and the normal vector of the dominant structural surface of the rock mass, with a range of values... It is used for mechanical calculations. During the calculation process, it traverses... (from arrive ), calculate each based on solid geometry relationships The corresponding unique Substitute the value into the subsequent formula.

[0058] S222, Constructing the Direction Weight Function Constructing the normalization function: .in, Reflecting the benchmark weight, Reflects the magnitude of anisotropy. Parameter value recommendations and sensitivity explanation:

[0059] Strongly anisotropic rock masses (such as slate and schist): Recommended , .at this time It fluctuates wildly depending on the direction.

[0060] Medium anisotropic rock mass: Recommended , .

[0061] Weakly anisotropic rock mass: Recommended , .

[0062] S223, RQD Directional Correction and Reference Value Determination:

[0063] Correction function: To eliminate the problem of artificial height in RQD when the drilling direction tends to be parallel to the structure surface, the angle between the engineering axis (assuming it is the same as the drilling direction) and the structure surface itself is defined as... Correction is achieved using a sine function: Revised .

[0064] when When (perpendicular to the structural plane), the coefficient approaches 1; when When (parallel to the structural plane), the coefficient approaches 0. (Note:) and (If there are geometric complementary or transformation relationships, they need to be calculated separately).

[0065] benchmark value Determination Method: To ensure reasonable normalization, it is recommended to determine the method according to the following priority. :

[0066] Method 1 (Optimal): Select a region that is approximately perpendicular to the structural plane. The average RQD of the borehole.

[0067] Method 2 (Empirical): Refer to the recommended values ​​in the standards for similar geological conditions.

[0068] Method 3 (Simplified): Take the arithmetic mean of the RQD of all boreholes within the project.

[0069] S224. Coupled Calculation: Calculating the Comprehensive Condition Rating of Structural Surfaces (Based on RMR standards). Calculation index: .

[0070] S230. Calculate the boundary condition factor rating based on the boundary condition factor data. .

[0071] S300, Comprehensive evaluation and output of directional rock mass quality, specifically including:

[0072] S310, Calculate the comprehensive quality index of directional rock mass :

[0073] formula: Recommended weighting coefficients:

[0074] (Structural directionality) As the primary controlling factor.

[0075] (Internal strength) and (Boundary conditions) take .

[0076] If the project is greatly affected by groundwater, the elevation can be adjusted appropriately. If the rock itself is extremely soft, the height can be adjusted appropriately. .

[0077] S320, Result Calibration (Theoretical Boundary Anchoring Method): To map the original calculated values ​​to the standard RMR range of 0-100, a linear transformation is established: Steps to determine coefficients A and B:

[0078] Determine the full score boundary ( ): Set ideal working conditions ( Full marks Full marks and time (Full marks), calculate the original total score at this point. Set its corresponding standard score to 100.

[0079] Determine the zero boundary ( ): Set the worst working condition (all items are 0), and set its corresponding standard score to 0.

[0080] Solution: Solving the system of equations yields... and .generally , .

[0081] S330. Generate a visual representation map: Traverse the engineering azimuth angles. ( Repeat the calibration calculation Values ​​are used to plot the "polar rose diagram of rock mass quality".

[0082] Example 2

[0083] This invention provides an anisotropic rock mass evaluation system based on a directional structure index, the structure of which is as follows: Figure 2 As shown, it includes:

[0084] Data input module 311 is used to receive user-input intrinsic strength factor data, structural strength factor data, and boundary condition factor data of the rock mass to be evaluated; the intrinsic strength factor data includes the intact uniaxial compressive strength (UCS) of the rock in at least two directions;

[0085] Central processing module 321, connected to data input module 311, is configured to execute steps S200-S400 of the method described in Embodiment 1 above, calculating and generating the directional rock mass quality comprehensive index D-RMR(θ) and a visualization characterization map; and,

[0086] The visualization output module 312 is connected to the central processing module 321 and is used to display the visualization representation diagram on the user interface.

[0087] In one embodiment, the visualization output module 312 is used to generate and display a "rock mass quality polar rose diagram" and the corresponding rock mass quality grade and support recommendations.

[0088] Furthermore, the central processing module 321 in this embodiment of the invention includes:

[0089] Intrinsic strength factor calculation unit 321a is used to calculate intrinsic strength factor rating Ri;

[0090] Directional structural strength index calculation unit 321b is used for coupled calculation of directional structural strength index DSSI(θ). The coupled calculation includes the construction of directional weight function W(θ), calculation of structural surface comprehensive condition rating Jc, and RQD directional correction.

[0091] Boundary condition factor calculation unit 321c is used to calculate the boundary condition factor rating Bc; and,

[0092] The comprehensive evaluation unit 321d is used to perform weighted summation of the output results of the intrinsic strength factor calculation unit 321a, the directional structural strength index calculation unit 321b, and the boundary condition factor calculation unit 321c, and to calibrate the original value of D-RMR(θ) to obtain the calibrated D-RMR(θ).

[0093] The evaluation system of this invention adopts a hierarchical modular architecture design to realize the complete process of directional quantitative evaluation of rock mass quality. The system architecture includes: system boundary 300, user interface layer 310, core processing layer 320, and data storage layer 330. The data input module 311 and visualization output module 312 are located in the user interface layer 310. The user interface layer 310 is used to provide diverse interaction methods, supporting multimodal data input / output such as text and images to meet the usage habits of different users. At the same time, through the design of a visualization interface, the system's processing results are presented to the user in an intuitive and easy-to-understand way, such as generating charts, reports, and text summaries. The core processing layer 320 is the core of the system and contains a central processing module 321. The central processing module 321 is used to calculate the user-input data and generate visualization representation diagrams, such as calculating the intrinsic strength factor rating Ri, directional weight function W(θ), RQD directional correction RQD(θ), directional structural strength index DSSI(θ), directional rock mass quality comprehensive index D-RMR(θ), and its calibration. The data storage layer 330 includes a database or data file 331 for storing raw data, intermediate results generated during system operation, and scoring criteria.

[0094] Figure 2 The embodiments of the present invention clearly demonstrate the complete implementation path from data acquisition and core algorithm processing to result visualization output. Each functional module has a clear responsibility and works together to form a complete and efficient technical solution.

[0095] Example 3

[0096] This invention provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the method described in Embodiment 1.

[0097] Application example: Rock mass quality evaluation of a tunnel project traversing a schistosic slate section, including the following steps:

[0098] Step 1: Data Acquisition

[0099] Data on the slate rock mass at section K10+500 of the tunnel were obtained through on-site geological surveys and laboratory tests:

[0100] 1) Intrinsic strength factor data: UCS perpendicular to foliation direction, σv=85MPa; UCS parallel to foliation direction, σp=40MPa.

[0101] 2) Structural strength factor data: The dominant structural plane (foliation) attitude is 270°∠30° (dip 270°, dip angle 30°); the average spacing is 8cm; the surface is flat and smooth with a small amount of mud filling; the average borehole RQD is 55% (assuming the borehole direction is consistent with the tunnel axis).

[0102] 3) Boundary condition factor data: The rock mass is in a moist state.

[0103] Step Two: Multi-dimensional Factor Quantitative Rating

[0104] 1) Calculate Ri:

[0105] The intrinsic anisotropy coefficient Ia = σv / σp = 85 / 40 = 2.125.

[0106] Based on the Ri score correction rule example, considering both rock strength (85 MPa) and moderately high anisotropy (Ia = 2.125), and referring to the RMR system UCS scoring standard (85 MPa corresponds to 15 points), and taking into account the Ia correction, the intrinsic strength factor rating is given as Ri = 15 × f(2.125). Assuming f(2.125) = 0.8 (Ia significantly reduces the score), then Ri = 15 × 0.8 = 12 (out of 15).

[0107] 2) Calculate DSSI(θ):

[0108] Assume the tunnel axis is due east (90°) and the tunnel is a horizontal tunnel.

[0109] ① Calculate the orientation angle θ: The normal direction of the foliation surface is: the dominant structural surface dips at 270°, and its normal direction's planar projection direction is 270° - 90° = 180° (i.e., due west), with a depression angle of 90° - 30° = 60°. The tunnel axis (due east, horizontal, i.e., 90°, dip angle 0°). The spatial angle between the tunnel axis (90°∠0°) and the normal direction of the foliation surface (180°∠60°) is calculated to be θ≈60°.

[0110] ② Construct the directional weight function W(θ): For slate, based on engineering experience, the empirical coefficients are set to K1=0.8 and K2=0.2.

[0111] Then W(60°) = K1 + K2 × cos(2θ) = 0.8 + 0.2 × cos(2 × 60°) =

[0112] 0.8 + 0.2 × cos(120°) = 0.8 + 0.2 × (-0.5) = 0.8 - 0.1 = 0.7.

[0113] ③ Calculate the overall structural condition rating Jc: Taking into account the spacing of 8cm (8 points according to the RMR system score) and the smooth surface with mud filling (15 points according to the RMR system score), the weighted result is Jc=8+15=23 (out of 45).

[0114] ④ RQD Directional Correction: RQD(θ) – The borehole direction is aligned with the tunnel axis (due east), and the angle (φ) between it and the dominant structural plane (270°∠30°) is approximately 30°. According to the RQD(θ) correction rule, when φ is close to 30°, the RQD value may be underestimated (because the borehole has an angle with the structural plane, potentially drilling through more intact rock). Here, we assume RQD… raw =55%, and the correction function f RQD(30°) =1.2 (Considering the angle between the borehole and the structural surface, the actual degree of fragmentation is worse than reflected by the original RQD, so the influence of RQD needs to be reduced).

[0115] RQD(60°) = 55% × 1.2 = 66% (Note: Here, 60° in RQD(60°) refers to θ, i.e., the angle between the engineering direction and the normal to the structural surface, not φ). To simplify the example, assume RQD baseline =60%.

[0116] ⑤ Coupled calculation of DSSI(60°):

[0117] DSSI(60°)=Jc×W(60°)×(RQD(60°) / RQD baseline =23×0.7×(66 / 60)=16.1×1.1=17.71.

[0118] 3) Calculate Bc:

[0119] Based on the wet conditions and referring to the RMR system groundwater scoring standard, the boundary condition factor is rated Bc=10 (out of 15).

[0120] Step 3: Comprehensive Evaluation and Output of Directional Rock Mass Quality

[0121] 1) Calculate D-RMR (60°):

[0122] Let the weight coefficients of each factor be W1=0.2, W2=0.6, and W3=0.2 (ensuring that W1+W2+W3=1).

[0123] D-RMR raw(60°) = W1Ri + W2DSSI(60°) + W3Bc

[0124] =0.2×12+0.6×17.71+0.2×10=2.4+10.626+2=15.026.

[0125] D-RMR(θ) calibration: This is an example. Actual raw D-RMR values ​​need to be mapped to the traditional RMR range (0-100) using a calibration function to align with engineering experience. Assuming the D-RMR is calibrated using the calibration function... calibrated =3×D-RMRraw The overall rating after +3 is:

[0126] D-RMR_calibrated(60°)=3×15.026+3≈45+3=48.

[0127] 2) Generate a "polar rose diagram of rock mass quality":

[0128] By changing the tunnel axis direction and repeating the above calculations, a series of (θ, D-RMR) values ​​are obtained. calibrated(θ) Data points.

[0129] For example, when the tunnel axis is perpendicular to the foliation surface, θ = 0°, W(0°) = 0.8 + 0.2 × cos(0°) = 1.0. In this case, DSSI(0°) will change due to the RQD correction. Assuming RQD(0°) is 50%, DSSI(0°) = 23 × 1.0 × (50 / 60) = 19.17.

[0130] D-RMR raw(0°) =0.2×12+0.6×19.17+0.2×10=2.4+11.502+2=15.902. D-RMR after calibration calibrated(0°)= 3×15.902+3≈50.7+3=53.7.

[0131] When the tunnel axis is nearly parallel to the foliation surface (i.e., parallel to the structural surface normal), θ = 90°, W(90°) = 0.8 + 0.2 × cos(180°) = 0.6. In this case, DSSI(90°) will change due to RQD correction. Assuming RQD(90°) is 70%, DSSI(90°) = 23 × 0.6 × (70 / 60) = 16.1 × 1.167 = 18.78. (D-RMR) raw(90°) =0.2×12+0.6×18.78+0.2×10=2.4+11.268+2=15.668. D-RMR after calibration calibrated(90°) =3×15.668+3≈47.0+3=50.0.

[0132] (Note: This assumes the RQD correction function and calibration function; in actual applications, these need to be determined based on the specific data.)

[0133] Plot these data points as Figure 3 The rose diagram is shown. The diagram clearly shows that, under the current foliation orientation, the rock mass quality is better (relatively high rating) when excavating along the north-south trend (nearly parallel to the foliation strike); the rock mass quality is relatively worse when excavating along the east-west trend (nearly perpendicular to the foliation strike).

[0134] Step 4: Engineering Application Decision

[0135] Based on the calibrated D-RMR (48) rating, the corresponding support design table was consulted, and the rock mass in this direction was determined to be Class IV (poor). It is recommended to adopt a combined support form of "system anchor bolts + steel mesh shotcrete + steel arch frame". If the tunnel axis is adjusted to the north-south direction, the D-RMR rating may be improved to 65 (Class III, good), and the support form can be simplified to "system anchor bolts + shotcrete", thereby saving a lot of engineering costs.

[0136] The system structure of this invention embodiment is as follows: Figure 2 As shown, the user inputs geological data and engineering parameters through the data input module 311. The central processing module 321 calls the intrinsic strength factor calculation unit 321a, the directional structure strength index calculation unit 321b, and the boundary condition factor calculation unit 321c, and sends the results to the comprehensive evaluation unit 321d. Finally, the results are generated on the display screen through the visualization output module 312. Figure 3 The rose diagram shown and related decision-making suggestions.

[0137] Figure 3 This demonstrates the directional distribution characteristics of rock mass quality in a tunnel project. Figure 3 This allows for a direct comparison of rock mass quality across different excavation directions: the original design's east-west axis traverses a low-quality area (Level IV), while the north-south axis traverses a relatively high-quality area (Level I), providing a scientific basis for engineering optimization. The method described in this invention represents a technological leap from traditional "point evaluation" to "directional surface evaluation" in rock mass quality assessment.

[0138] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for evaluating anisotropic rock masses based on directional structure index, characterized in that, Includes the following steps: S1. Obtain the intrinsic strength factor data, structural strength factor data, and boundary condition factor data of the rock mass to be evaluated; The intrinsic strength factor data includes the complete uniaxial compressive strength (UCS) of rock in at least two directions; S2. Calculate the intrinsic strength factor rating Ri based on the intrinsic strength factor data; Based on the structural strength factor data, the spatial angle between the engineering axis and the normal of the dominant structural surface of the rock mass is defined as the direction angle θ. A direction weight function W(θ) = K1 + K2 × cos(2θ) is constructed in which the engineering properties of the rock mass change periodically with the engineering direction and the angle of the orientation of the structural surface, where K1 and K2 are empirical coefficients. The comprehensive structural condition rating Jc is calculated, and the rock quality index RQD value of the borehole is directionally corrected to obtain RQD(θ). The directional structural strength index DSSI(θ) is then calculated by coupling the calculations. baseline RQD baseline The baseline RQD value; Calculate the boundary condition factor rating Bc based on the boundary condition factor data; S3. Calculate the comprehensive quality index of directional rock mass. W1, W2, and W3 are the weight coefficients of each factor, and W1 + W2 + W3 = 1. The original D-RMR(θ) value is calibrated to obtain the calibrated D-RMR(θ) value; The calibrated D-RMR(θ) values ​​corresponding to different directional angles θ are used to generate a visual representation map; The quality grade of the rock mass to be evaluated is determined based on the visualization representation diagram.

2. The anisotropic rock mass evaluation method based on directional structure index as described in claim 1, characterized in that, The intrinsic strength factor data includes the strength value σp parallel to the dominant structural plane of the rock mass and the strength value σv perpendicular to the dominant structural plane of the rock mass, Ri=UCS score ×f(Ia), Among them, UCS score UCS score, a traditional rock mass quality indicator. Ia is the rock brittleness sensitivity coefficient, where Ia = σv / σp.

3. The anisotropic rock mass evaluation method based on directional structure index as described in claim 1, characterized in that, K1 takes values ​​of 0.6-0.95, K2 takes values ​​of 0.05-0.4; and / or W2 takes values ​​of 0.5-0.7, W1 and W3 take values ​​of 0.15-0.

3.

4. The anisotropic rock mass evaluation method based on directional structure index as described in claim 1, characterized in that, Among them, RQD raw The original borehole rock quality indicators, It is the angle between the engineering axis and the structural surface itself.

5. The anisotropic rock mass evaluation method based on directional structure index as described in claim 1, characterized in that, The structural strength factor data includes the occurrence, average spacing, and surface characteristics of the dominant structural planes of the rock mass, as well as the rock quality index (RQD) value of at least one borehole.

6. The anisotropic rock mass evaluation method based on directional structure index as described in claim 1, characterized in that, Based on the overall rock mass structure, surface features, and a preset scoring criterion, Jc is obtained, wherein the preset scoring criterion refers to rock mass quality indicators or tunnel quality indicators for scoring; and / or, Based on the groundwater conditions and referring to the rock mass quality indicators, a boundary condition factor rating Bc is obtained.

7. The anisotropic rock mass evaluation method based on directional structure index as described in claim 1, characterized in that, The calibration of the original D-RMR(θ) values ​​is achieved by establishing a conversion function between the original D-RMR(θ) values ​​and traditional rock mass quality index values; and / or the visualization representation diagram is a polar rose diagram of rock mass quality, which displays the distribution of D-RMR(θ) values ​​in the range of 0°-360° in polar coordinates.

8. An anisotropic rock mass evaluation system based on directional structure index, characterized in that, include: The data input module is used to receive user-input data on the intrinsic strength factor, structural strength factor, and boundary condition factor of the rock mass to be evaluated. The intrinsic strength factor data includes the complete uniaxial compressive strength (UCS) of rock in at least two directions; A central processing module, connected to the data input module, is configured to execute steps S2 and S3 of the method as described in any one of claims 1-7, calculating and generating the directional rock mass quality composite index D-RMR(θ) and a visualization characterization map; and, A visualization output module, connected to the central processing module, is used to display the visualization representation diagram on the user interface.

9. The anisotropic rock mass evaluation system based on directional structure index as described in claim 8, characterized in that, The central processing module includes: The intrinsic strength factor calculation unit is used to calculate the intrinsic strength factor rating Ri. The directional structural strength index calculation unit is used to couple the calculation of the directional structural strength index DSSI(θ). The coupled calculation includes the construction of the directional weight function W(θ), the calculation of the comprehensive condition rating Jc of the structural surface, and the RQD directional correction. Boundary condition factor calculation unit, used to calculate boundary condition factor rating Bc; and, The comprehensive evaluation unit is used to perform weighted summation of the output results of the intrinsic strength factor calculation unit, the directional structural strength index calculation unit, and the boundary condition factor calculation unit, and to calibrate the original value of D-RMR(θ) to obtain the calibrated D-RMR(θ).

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

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