Rock mass quality evaluation method and system

Abstract

The application discloses a rock mass quality evaluation method and system, and belongs to the technical field of geotechnical engineering. The rock mass surface point cloud data of an evaluation area is obtained by scanning the evaluation area through three-dimensional laser scanning. The structural plane group number, structural plane extension, structural plane roughness, structural plane spacing and block volume are extracted. The structural plane group number, structural plane extension, structural plane roughness, structural plane spacing and block volume of the rock mass are used as evaluation parameters to evaluate the quality of the rock mass. The method can obtain relevant parameters in a short time by using three-dimensional laser scanning technology. The evaluation parameters comprehensively consider the geometric characteristics, structural characteristics and mechanical characteristics of the rock mass, and can comprehensively reflect the quality state of the rock mass. Through comprehensive analysis of the parameters, the quality of the rock mass is rapidly evaluated based on the rock mass coordinate data, and the evaluation accuracy and efficiency can be greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geotechnical engineering, and more particularly to a rock mass quality evaluation method and system. BACKGROUND

[0002] Rock mass quality evaluation plays an important role in studying rock slope stability. How to reasonably and effectively evaluate rock mass can not only master the properties of rock mass in the region, but also has important reference value for slope risk classification and determination of prevention methods.

[0003] There are many mature and complete systems and methods for rock mass quality evaluation and classification, such as the widely recognized and applied national standard classification method, referred to as BQ method, Q system method, RMR classification method, GSI system, RQD value method, etc. With the progress of technical means and the in-depth research, scholars have used new technologies and methods in combination, such as using borehole imaging technology, based on the correspondence between core fracture characteristics and borehole imaging fracture characteristics, an rock mass quality evaluation index RQ is established; using Mask-RCNN deep learning instance segmentation network to automatically identify single-row rock core from borehole core image for RQD calculation, realizing fine evaluation of rock mass quality; based on close-range measurement technology, the information of structural plane is extracted through human-computer interaction, which optimizes the traditional rock mass quality evaluation method and realizes the three-dimensional visualization of rock mass classification; based on rock mass structure digital recognition technology, the slope angle, height and rock mass joint fissure density parameters are obtained, and the rock mass BQ classification method is used to complete the rock mass quality classification and evaluation.

[0004] In addition, scholars have also introduced mathematical theories and algorithms to improve the evaluation method, such as using analytic hierarchy process, entropy weight method, game theory and other mathematical relationship theory methods to integrate various rock classification methods, and constructing a new rock risk assessment model suitable for highway tunnels; combining statistical analysis and network simulation, a rock evaluation method suitable for fragmented rock is proposed; dynamic weight and expansion theory are introduced to improve rock mass quality evaluation; considering the action of multiple factors and the system integrity, and based on fuzzy RES and multi-dimensional cloud model, the accuracy and effectiveness of rock evaluation are improved; 3DMine is used to establish a geological drilling database, combined with geological statistical method, a rock mass mechanical parameter block model based on RMR method is established, realizing rock mass quality classification; the calculation formulas of structure surface occurrence correction coefficient K2 and initial geostress state correction coefficient K3 for layered rock mass are proposed by using Jaeger-Donath and Mogi-Coulomb strength criteria, which improves the limitations of the method.

[0005] Although the above improvements improve the accuracy and scope of application of rock mass quality evaluation, most of them need rock mass physical and mechanical properties or contact rock mass data, and for high and steep slopes, reservoir bank slopes and other environments, it is difficult to obtain rock samples, and the traditional test method is difficult to implement, and the three-dimensional structure characteristics of the rock mass are not considered when the point cloud coordinate data is obtained by using the non-contact test technology, which affects the accuracy and evaluation efficiency of the rock mass quality evaluation. SUMMARY

[0006] In view of the problems in the above field, the present application provides a rock mass quality evaluation method and system, which can obtain relevant parameters in a short time through three-dimensional laser scanning technology, and uses the number of rock mass structure surface groups, structure surface extension, structure surface roughness, structure surface spacing and block volume as evaluation parameters. The evaluation parameters obtained comprehensively consider the three-dimensional structure and spatial distribution characteristics of the rock mass, can fully reflect the quality state of the rock mass, and through comprehensive analysis of these parameters, the stability of the rock mass can be more accurately evaluated.

[0007] To solve the above technical problems, the present application discloses a rock mass quality evaluation method, comprising the following steps:

[0008] Scanning the rock mass surface point cloud data of the region to be evaluated by three-dimensional laser scanning;

[0009] According to the rock mass surface point cloud data of the region to be evaluated, the occurrence information of the structure surface is extracted, the structure surface is grouped, the structure surface group and the number of structure surface groups are determined; wherein the structure surface group includes the same group structure surface and different group structure surface;

[0010] An independent coordinate system is constructed for each integrated discontinuous structure surface in the same group structure surface, the length of the inclination and strike direction of each integrated discontinuous structure surface is determined, and the maximum value of the length in the inclination and strike direction is taken as the structure surface extension;

[0011] The structure surface in the same group structure surface is extracted, and a cross section with equal and parallel spacing is set in the direction of the structure surface normal vector; according to the ratio of the line length to the arc length of each cross section, the structure surface roughness is determined;

[0012] The projection line of the same group structure surface is obtained, and a plurality of orthogonal measuring lines are established on the projection line; the structure surface spacing is determined by the average spacing between the intersection points of the projection line of the same group structure surface and each orthogonal measuring line;

[0013] The volume of the exposed part of the rock mass is estimated according to the intersection relationship of the different group structure surfaces, and the block volume is obtained;

[0014] The number of rock mass structure surface groups, structure surface extension, structure surface roughness, structure surface spacing and block volume are taken as evaluation parameters to evaluate the quality of the rock mass.

[0015] Preferably, the rock mass surface point cloud data of the region to be evaluated is obtained, specifically comprising:

[0016] The scanning region is determined, and a selected instrument station is set, with the scanning region as the region to be evaluated.

[0017] The instrument is erected at the selected position, and the region to be evaluated is scanned by three-dimensional laser scanning to obtain the rock mass surface point cloud data of the region to be evaluated.

[0018] Preferably, the structural plane group and the number of structural plane groups are determined, including the following steps:

[0019] By identifying and segmenting the structural plane, the structural plane occurrence information including the strike, tendency and dip angle of the structural plane is extracted, and the structural plane is divided.

[0020] After the structural plane is divided, the structural planes in each group are colored according to the grouping result of the structural plane occurrence, and the structural planes in the same group are given the same color.

[0021] According to the number of color categories of the structural plane group, the number of structural plane groups is counted.

[0022] Preferably, the maximum value in the two directions of tendency and strike is taken as the extension of the structural plane, specifically comprising:

[0023] The discontinuous structural planes in the same group and on the same plane that are identified are taken as the same plane cluster, and the cluster point cloud number N of each same plane cluster is counted.

[0024] The same plane cluster with the largest number of point clouds in the multiple same plane clusters is taken as a large cluster, and the nearest neighbor search is used to determine whether there are other small clusters around the large cluster, the small clusters are integrated by data merging, and the integrated discontinuous structural plane J is formed.

[0025] The length of the tendency and strike direction of each integrated discontinuous plane is calculated, and the maximum value of the length in the two directions is taken as the final extension of the structural plane.

[0026] The integrated discontinuous plane is given an independent coordinate system by a conversion formula, which is transformed from the original overall coordinate system OXYZ to the independent coordinate system OiXiYiZi used for calculating the length of each discontinuous plane.

[0027] According to the extension extracted in the tendency OiXi direction and the strike OiYi direction of the average normal vector of the integrated discontinuous plane, OiZi is orthogonal to the plane OiXiYi, and the conversion formula is:

[0028]

[0029] In the formula, η and θ are the tendency and dip angle of the integrated discontinuous plane, respectively.

[0030] determining a discontinuous surface group as J, an independent structural surface number as i, obtaining a point set X(j, i), wherein x'(j, i) and y'(j, i) are local coordinates of the point set, and the inclination and the strike extension degree are calculated respectively as:

[0031] LP 倾向 (j, i) = max(x'(j, i)) - min(x'(j, i))

[0032] LP 走向 (j, i) = max(y'(j, i)) - min(y'(j, i))

[0033] In the formula, LP 倾向 , LP 走向 are the extension degrees of the inclination direction and the strike direction respectively, and the unit is: / m.

[0034] Preferably, the determination of the structural surface roughness specifically comprises:

[0035] By extracting the structural surface in the same group of structural surfaces, a section plane parallel and equal in spacing is set in the direction of the normal vector of the structural surface;

[0036] The intersection line of the structural surface and the section plane is taken as the arc length, and the connecting line of the two endpoints of the arc length is taken as the line length;

[0037] By counting the ratio of the line length to the arc length of each section plane, the average of the ratios of the line lengths to the arc lengths of multiple section planes is taken as the result of the structural surface roughness;

[0038] The calculation formula of the structural surface roughness is:

[0039]

[0040] In the formula, LP 3D is the structural surface roughness, LP i is the roughness of the intersection line of a section plane and a structural surface, n is the number of set section planes, L is the line length of a section plane, and S is the arc length of a section plane.

[0041] Preferably, the determination of the structural surface spacing specifically comprises:

[0042] The same surface cluster is arranged in ascending order according to the spatial position and integrated;

[0043] At the same time, the normal vector calculated in the process of determining the structural surface roughness is averaged, and a new cluster surface normal vector is obtained with the integrated large cluster C j as the unit;

[0044] Based on the obtained new cluster surface normal vector, a structural surface projection processing is performed, and n orthogonal measuring lines are established on the projection line;

[0045] The average distance between each orthogonal line and the intersection point of the projection line is calculated, and the calculated average distance is counted, and whether each orthogonal line intersects with the projection line is judged, when there is no intersection point or only one intersection point, the orthogonal line is ignored;

[0046] Similarly, the average distance between each orthogonal line and the intersection point of the projection line is counted, and the average distance between the intersection point of the plurality of lines and the projection line is calculated, and the average value of the average distance is taken as the spacing between the structural surfaces;

[0047] The calculation formula of the structural surface spacing is:

[0048]

[0049] In the formula, S 3D is the average distance between the layer projection lines, is the average distance between the orthogonal line and the intersection point of the projection line, and n is the number of set orthogonal lines.

[0050] Preferably, the block volume is obtained, specifically comprising:

[0051] For the block volume calculation of the slope rock mass, the volume of the exposed part of the rock mass is estimated through the intersection relationship of different groups of structural surfaces;

[0052] When the rock block is a parallelepiped, the exposed rock mass has three edges;

[0053] According to the three edges, four vertex coordinates (X1, Y1, Z1), (X2, Y2, Z2), (X3, Y3, Z3), (X4, Y4, Z4) are obtained, and a tetrahedron is connected by the four vertexes;

[0054] The block volume is 6 times the volume of the tetrahedron, and the calculation formula of the block volume is:

[0055]

[0056] Preferably, the rock mass quality is evaluated, specifically comprising:

[0057] Each evaluation parameter is graded and normalized;

[0058] According to the normalized evaluation parameters, the weight is assigned by the dynamic weight method, and the rock mass quality grade is obtained.

[0059] Preferably, it also includes a rock mass quality evaluation system, comprising:

[0060] The point cloud acquisition module is used to scan the rock mass surface point cloud data of the evaluation area by three-dimensional laser scanning;

[0061] The evaluation parameter extraction module is configured to extract the occurrence information of the structural surface from the rock mass surface point cloud data of the region to be evaluated, group the structural surfaces, determine the structural surface groups and the number of structural surface groups, wherein the structural surface groups include the same group structural surfaces and different group structural surfaces; construct an independent coordinate system for each integrated discontinuous structural surface in the same group structural surfaces, determine the length of the inclination and strike direction of each integrated discontinuous structural surface, and take the maximum length of the inclination and strike direction as the structural surface extension; extract the structural surfaces in the same group structural surfaces, set the cross sections with equal and parallel spacing in the direction of the structural surface normal vector; determine the structural surface roughness according to the ratio of the line length to the arc length of each cross section; obtain the projection lines of the same group structural surfaces, and establish a plurality of orthogonal lines on the projection lines; determine the structural surface spacing by the average spacing between the intersection points of the projection lines of the same group structural surfaces and the orthogonal lines; and estimate the volume of the exposed part of the rock mass according to the intersection relationship of the different group structural surfaces to obtain the block volume.

[0062] The evaluation module is configured to take the number of rock mass structural surface groups, the structural surface extension, the structural surface roughness, the structural surface spacing and the block volume as the evaluation parameters to evaluate the quality of the rock mass.

[0063] Compared with the prior art, the present application has the following advantages:

[0064] The rock mass quality evaluation method provided by the present application can obtain the rock mass surface point cloud data of the region to be evaluated in a short time through the three-dimensional laser scanning technology, and has the advantages of non-contact, high precision and strong anti-interference capability. The structural surface groups include the same group structural surfaces and different group structural surfaces through the structural surface groups and the number of structural surface groups of the rock mass; the structural surface extension, the structural surface roughness and the structural surface spacing are determined for the same group structural surfaces, and the block volume is determined for the different group structural surfaces, and the determined parameters are taken as the evaluation parameters. The reason for taking the extracted parameters as the evaluation parameters is that these parameters directly affect the mechanical behavior and stability of the rock mass, and therefore are given priority. Specifically, the more the number of structural surface groups of the rock mass, the more broken the rock mass is and the worse the stability is; the larger the structural surface extension, the longer the structural surface is and the greater the negative impact on the stability of the rock mass is; the rougher the structural surface is, the better the friction characteristics are and the better the stability is; the smaller the structural surface spacing is, the more small-size blocks exist in the rock mass and the worse the overall strength of the rock mass is; and the larger the block volume is, the more complete the rock mass is. In summary, the method can obtain the relevant parameters in a short time through the three-dimensional laser scanning technology, and the selected parameters comprehensively consider the geometric characteristics, structural characteristics and mechanical characteristics of the rock mass, and can fully reflect the quality state of the rock mass. Through the comprehensive analysis of the parameters, the stability of the rock mass can be evaluated more quickly and accurately. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 A flow chart for determining evaluation parameters of the rock mass quality evaluation method of the present application is provided.

[0066] Figure 2 A rock mass quality evaluation flow provided by the present application is provided.

[0067] Figure 3 A structural plane grouping schematic diagram provided by the embodiment of the present application is provided.

[0068] Figure 4 A structural plane extension degree schematic diagram provided by the embodiment of the present application is provided.

[0069] Figure 5 A structural plane roughness principle schematic diagram provided by the embodiment of the present application is provided.

[0070] Figure 6 A structural plane spacing calculation schematic diagram provided by the embodiment of the present application is provided.

[0071] Figure 7 A block volume calculation schematic diagram provided by the embodiment of the present application is provided. DETAILED DESCRIPTION

[0072] The technical solutions in the embodiments of the present application will be clearly and completely described in the following with reference to the accompanying drawings. Figures 1-7 The technical solutions in the embodiments of the present application will be clearly and completely described in the following with reference to the accompanying drawings.

[0073] EMBODIMENT

[0074] As shown in the accompanying drawings, the present application provides a rock mass quality evaluation method, comprising the following steps: Figure 1 Selecting a region and obtaining point clouds:

[0075] S1: Scanning the rock mass surface point cloud data of the region to be evaluated by three-dimensional laser scanning;

[0076] Parameter extraction includes steps S2-S6:

[0077] S2: According to the rock mass surface point cloud data of the region to be evaluated, the occurrence information of the structural plane is extracted to group the structural plane, determine the structural plane group and the number of structural plane groups; wherein the structural plane group includes the same group structural plane and different group structural plane;

[0078] S3: Constructing an independent coordinate system for each integrated discontinuous structural plane in the same group structural plane, determining the length of the inclination and strike direction of each integrated discontinuous structural plane, and taking the maximum value of the length in the inclination and strike direction as the structural plane extension degree;

[0079]

[0080] ​S4: extracting structural planes in the same group of structural planes, setting cross sections with equal spacing and parallel to the normal vector direction of the structural planes; determining the roughness of the structural planes according to the ratio of the line length to the arc length of each cross section;

[0081] S5: obtaining the projection line of the same group of structural planes, and establishing a plurality of orthogonal lines on the projection line; determining the spacing between the structural planes by the average spacing between the intersection points of the projection line of the same group of structural planes and each orthogonal line;

[0082] S6: estimating the volume of the exposed part of the rock mass according to the intersection relationship of different groups of structural planes to obtain the volume of the block;

[0083] Quality evaluation:

[0084] S7: taking the number of groups of structural planes of the rock mass, the extension of the structural planes, the roughness of the structural planes, the spacing between the structural planes and the volume of the block as evaluation parameters, and evaluating the quality of the rock mass.

[0085] Specifically, in step S1, the rock mass surface point cloud data of the region to be evaluated is obtained, specifically including:

[0086] As shown in Figure 2 , the scanning area is determined, the instrument station is selected, and the scanning area is taken as the region to be evaluated.

[0087] The instrument is erected according to the selected position, the region to be evaluated is scanned by three-dimensional laser scanning, and the rock mass surface point cloud data of the region to be evaluated is obtained.

[0088] Compared with the traditional rock mass quality evaluation method which may need a large amount of field sampling and laboratory testing, the three-dimensional laser scanning technology used in the present application can obtain the related parameters in a short time, and has the advantages of non-contact, high precision, strong anti-interference ability and the like.

[0089] In step S2, the number of groups of structural planes of the rock mass is determined, including the following steps:

[0090] By recognizing and segmenting the structural planes, the occurrence information of the structural planes including the strike, tendency and dip angle of the structural planes is extracted, and the structural planes are divided;

[0091] After the division of the structural planes, the groups of structural planes are colored according to the grouping result of the occurrence of the structural planes, the same color is given to the structural planes in the same group, and the number of groups of structural planes is counted according to the number of color types of the groups of structural planes.

[0092] The present application takes a precast concrete block stacking model as an example, the size of the concrete block is 100*100mm and 50*50mm standard square block, the advantage structural plane, that is, the identification effect of the grouping of the structural plane is as Figure 3 indicated.

[0093] The extension is defined as the length of the tendency and strike direction of the structural plane, and the area range of the discontinuity along the plane.

[0094] The structural plane such as joint, fracture, etc. is one of the main factors of rock mass damage and stability control. The number of structural plane groups directly affects the integrity and stability of the rock mass. The more the number of structural plane groups, the more broken the rock mass is, and the worse the stability is.

[0095] In step S3, the length of the tendency and strike direction of each discontinuous structural plane is calculated, and the maximum value in the two directions is taken as the extension of the structural plane, which specifically includes:

[0096] The identified discontinuous structural planes in the same group and on the same plane are taken as the same plane cluster, and the number of cluster points N of each same plane cluster is counted;

[0097] The same plane cluster with the largest number of point clouds in the multiple same plane clusters is taken as the large cluster, and the nearest neighbor search is used to determine whether there are other small clusters around the large cluster. The small clusters are integrated by data merging to form the integrated discontinuous structural plane J;

[0098] The length of the tendency and strike direction of each integrated discontinuous plane is calculated, and the maximum value in the two directions is taken as the final extension of the structural plane;

[0099] As shown in Figure 4 , the converted formula is used to give the integrated discontinuous plane an independent coordinate system, which is transformed from the original overall coordinate system OXYZ to the independent coordinate system OiXiYiZi for calculating the length of each discontinuous plane;

[0100] Let the point cloud data of the integrated discontinuous plane be J, where J is an n×3 matrix, each row representing the (x, y, z) coordinates of a point. According to the extension of the average normal vector of the integrated discontinuous plane in the tendency OiXi direction and the strike OiYi direction, OiZi is orthogonal to the plane OiXiYi, and the conversion formula is:

[0101]

[0102] In the formula, η and θ are the tendency and inclination of the integrated discontinuous plane, respectively.

[0103] The transformed point cloud data J' is obtained by the product of the rotation matrix R and the point cloud data J:

[0104] J' = R·J T

[0105] Determine the point cloud data J' of the integrated discontinuous plane after coordinate transformation, the independent structural plane number is i, and the point set X(j, i) is obtained, where x'(j, i) and y'(j, i) belong to the local coordinates of the point set, and the tendency and strike extension are calculated as:

[0106] LP 倾向 j, i) = max(x'(j, i)) - min(x'(j, i))

[0107] LP 走向 j, i) = max(y'(j, i)) - min(y'(j, i))

[0108] wherein, LP 倾向 , LP 走向 are the extension of the dip direction and strike direction, respectively, with the unit of: / m.

[0109] The extension describes the spatial extension of the structural plane, which is an important indicator for evaluating the development degree of the structural plane. The greater the extension of the structural plane, the longer the structural plane, and the greater the negative impact on the stability of the rock mass.

[0110] In step S4, the roughness of the structural plane is determined according to the ratio of the line length to the arc length of each section, specifically including:

[0111] By extracting the structural plane, set the sections with equal and parallel spacing in the direction of the normal vector of the structural plane;

[0112] The intersection line of the structural plane and the section is taken as the arc length, and the line connecting the two endpoints of the arc length is taken as the line length;

[0113] By counting the ratio of the line length to the arc length of each section, take the average of the ratio of the line length to the arc length of multiple sections as the result of the roughness of the structural plane, and the principle diagram of the roughness of the structural plane is shown in Figure 5 .

[0114] The calculation formula of the roughness of the structural plane is:

[0115]

[0116] wherein, LP 3D is the roughness of the structural plane, LP i is the roughness of the intersection line of a section and the structural plane, n is the number of set sections, L is the line length of a section, and S is the arc length of a section.

[0117] In order to ensure the accuracy of the result, the section spacing can be adjusted, and the roughness of the structural plane is extracted respectively until the statistical result tends to be stable.

[0118] The roughness reflects the degree of unevenness of the structural plane, and is related to the shear strength and friction characteristics of the rock mass. The rougher the structural plane, the better the friction characteristics, which has a positive effect on the stability of the rock mass.

[0119] In step S5, the distance between the structural planes is obtained, specifically including:

[0120] The interval of structural plane (discontinuous plane) is one of the key elements for evaluating the quality of the structural plane of rock mass. The interval of structural plane is defined as the vertical distance between discontinuous planes in the standard, and the distance between discontinuous planes in the same group is usually calculated. In order to more accurately obtain the interval of structural plane, the application carries out statistics through point cloud data:

[0121] The same plane cluster is arranged in ascending order according to the spatial position, and is integrated.

[0122] Meanwhile, the normal vector calculated in the process of determining the roughness of the structural plane is averaged, and a new cluster surface normal vector is obtained in the unit of the integrated large cluster.

[0123] Based on the obtained new cluster surface normal vector, the projection processing of the structural plane is carried out, and n orthogonal measuring lines are established on the projection line, as shown in Figure 6

[0124] The average distance between the intersection points of each orthogonal measuring line and the projection line is calculated, and the calculated average distance is counted. By judging whether each orthogonal measuring line and the projection line have intersection points, when there is no intersection point or only one intersection point, the orthogonal measuring line is ignored.

[0125] Similarly, the average distance between the intersection points of each orthogonal measuring line and the projection line is counted, and the average distance between the intersection points of multiple measuring lines and the projection line is calculated, and the average value of the average distance is taken as the interval of the structural plane.

[0126] The calculation formula of the interval of the structural plane is:

[0127]

[0128] In the formula, S 3D is the average distance between the layer projection lines, is the average distance between the intersection points of the orthogonal measuring line and the projection line, and n is the number of set orthogonal measuring lines.

[0129] The interval of the structural plane affects the block size of the rock mass and the strength of the rock mass. The smaller the interval is, the more small-size blocks exist in the rock mass, which can reduce the overall strength of the rock mass.

[0130] In step S6, the block volume is obtained, specifically including:

[0131] For the calculation of the block volume of the slope rock mass, since the rock mass is exposed limitedly in general cases, the volume of the rock mass cannot be accurately obtained, so the application estimates the volume of the rock mass through the exposed part of the rock mass.

[0132] Suppose that the rock block is a parallelepiped, and three edges of the exposed rock mass can be seen.

[0133] ​According to the three edges, four vertex coordinates (X1, Y1, Z1), (X2, Y2, Z2), (X3, Y3, Z3), (X4, Y4, Z4) are obtained, and a tetrahedron is obtained by connecting the four vertices, as shown in Figure 7 .

[0134] The volume of the block is 6 times the volume of the tetrahedron, and the calculation formula of the volume of the block is:

[0135]

[0136] The volume of the block is an important parameter for evaluating the scale and stability of the rock mass. A larger block volume usually means that the rock mass is more complete, and is more beneficial to the stability of the project.

[0137] In step S7, the rock mass quality is evaluated, specifically including:

[0138] The present application divides each evaluation parameter into grades by BQ method, RMR classification method and GSI classification system method, and performs normalization processing.

[0139] The evaluation parameter indicators are divided into five grades, wherein grade I represents the best parameter indicator condition, grade II is the second, and so on. The grading of each indicator is shown in Table 1.

[0140] Table 1: Evaluation parameter grade division

[0141] Evaluation parameter Grade Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ Number of structural plane sets <2 2～3 3～4 4～5 >5 Extension of structural plane / m >30 10～30 3～10 1～3 <1 Roughness of structural plane <0.92 0.92-0.94 0.94-0.96 0.96-0.98 >0.98 Spacing of structural plane / m >2 0.6-2 0.2-0.6 0.06-0.2 <0.06 Volume of block / lg V cm3 >7 5～7 3～5 1～3 <1

[0142] Since the units and sizes of each group of parameters are not unified, in order to perform comparative analysis, each indicator is normalized, and the processing results are shown in Table 2.

[0143] Table 2: Normalization of evaluation parameter grade division

[0144] Evaluation parameter Grade Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ Number of structural plane sets 0.80-1.00 0.60-0.80 0.40-0.60 0.20-0.40 0.00-0.20 Extension of structural plane 0.50-1.00 0.17-0.50 0.05-0.17 0.02-0.05 0.00-0.02 Roughness of structural plane 0.80-1.00 0.60-0.80 0.40-0.60 0.20-0.40 0.00-0.20 Spacing of structural plane 0.30-1.00 0.10-0.30 0.03-0.10 0.01-0.03 0.00-0.01 Volume of block 0.80-1.00 0.60-0.80 0.40-0.60 0.20-0.40 0.00-0.20

[0145] According to the normalized evaluation parameters, the weight is assigned by dynamic weight method, and the rock mass quality grade is obtained, specifically including:

[0146] First, let the parameter indicator be c i , the corresponding normalized result is v i , the corresponding weight is a i , the parameter evaluation grade is j, and the rock mass evaluation grade is J * , wherein i, j=1, 2, 3, 4, 5.

[0147] The correlation coefficient γ ij is calculated as:

[0148]

[0149] In the formula, a ij b ij These are the upper and lower limits, respectively, for a parameter result of level j.

[0150] The weight calculation formula is as follows:

[0151]

[0152] Parameter evaluation value v i The correlation coefficient K of the evaluation j (v i )for:

[0153]

[0154] Wherein, ρ(v i ),|V ij The calculation formulas are as follows:

[0155]

[0156] |V ij |=|b ij -a ij |

[0157] Evaluation parameter c i Rank correlation coefficient K j (p) is:

[0158]

[0159] Rock mass evaluation grade J * :

[0160]

[0161] This invention also proposes a rock mass quality evaluation system, comprising:

[0162] The point cloud acquisition module is used to scan the area to be evaluated using 3D laser scanning to acquire point cloud data of the rock surface of the area to be evaluated.

[0163] The evaluation parameter extraction module is configured to extract the occurrence information of the structural surface from the rock mass surface point cloud data of the to-be-evaluated region, group the structural surfaces, determine the structural surface groups and the number of structural surface groups; wherein, the structural surface groups include the same-group structural surfaces and different-group structural surfaces; construct an independent coordinate system for each integrated discontinuous structural surface in the same-group structural surfaces, determine the length of the inclination and the strike direction of each integrated discontinuous structural surface, and take the maximum length of the inclination and the strike direction as the structural surface extension; extract the structural surfaces in the same-group structural surfaces, set the cross sections with equal and parallel spacing in the direction of the structural surface normal vector; determine the structural surface roughness according to the ratio of the line length to the arc length of each cross section; obtain the projection lines of the same-group structural surfaces, and establish a plurality of orthogonal lines on the projection lines; determine the structural surface spacing by the average spacing between the intersection points of the projection lines of the same-group structural surfaces and the orthogonal lines; and estimate the volume of the exposed part of the rock mass according to the intersection relationship of the different-group structural surfaces to obtain the block volume.

[0164] The evaluation module is configured to take the number of structural surface groups, the structural surface extension, the structural surface roughness, the structural surface spacing and the block volume as the evaluation parameters to evaluate the quality of the rock mass.

[0165] The selected evaluation parameters of the present application have a direct correlation with the stability and engineering characteristics of the rock mass, and the selected parameters can be conveniently and quickly obtained by using the three-dimensional laser scanning technology. The number of structural surface groups, the structural surface extension, the structural surface roughness, the structural surface spacing and the block volume directly affect the mechanical behavior and stability of the rock mass, and therefore are given priority.

[0166] In addition, the traditional rock mass quality evaluation method may need a large amount of field sampling and laboratory testing, while the three-dimensional laser scanning technology used in the present application can obtain the related parameters in a short time, and has the advantages of non-contact, high precision, strong anti-interference ability and the like.

[0167] The selected evaluation parameters of the present application comprehensively consider the geometric characteristics, structural characteristics and mechanical characteristics of the rock mass, and can comprehensively reflect the quality state of the rock mass. Through the comprehensive analysis of these parameters, the stability and engineering applicability of the rock mass can be more accurately evaluated, and scientific basis can be provided for the prevention and engineering design of the rock slope.

[0168] The above description is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent substitutions or changes to the technical solutions and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

[0169] In addition, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs unless clearly indicated otherwise. The mention of any document herein is for the purpose of describing and disclosing the methods, products, and devices described in it, which have been invented by others. In case of conflict, the content of the present specification will control.

Claims

1. A rock mass quality evaluation method characterized by, The method comprises the following steps: Scanning the area to be evaluated by three-dimensional laser scanning to obtain rock mass surface point cloud data of the area to be evaluated; According to the rock mass surface point cloud data of the area to be evaluated, the occurrence information of the structural surface is extracted to group the structural surface, and the structural surface group and the number of structural surface groups are determined; wherein the structural surface group comprises same-group structural surfaces and different-group structural surfaces; An independent coordinate system is constructed for each integrated discontinuous structural surface in the same-group structural surface, the length of the inclination and strike direction of each integrated discontinuous structural surface is determined, and the maximum length of the inclination and strike direction is taken as the structural surface extension degree: The identified coplanar discontinuous structural planes in the same group are taken as coplanar clusters, and the number of cluster point clouds of each coplanar cluster is counted N ; The point cloud with the largest number in the plurality of coplanar clusters is taken as a large cluster, and whether there is another small cluster around the large cluster is determined by using the nearest neighbor search, the small clusters are integrated by data merging to form the integrated discontinuous structural surface J ; The length of the inclination and strike direction of each integrated discontinuous structural surface is calculated, and the maximum length of the two directions is taken as the final extension degree of the structural surface; The integrated discontinuous structural surface is given an independent coordinate system through a conversion formula, which is transformed from the original overall coordinate system OXYZ to an independent coordinate system OiXiYiZi for calculating the trace length of each discontinuous structural surface; According to the extension degree extracted in the inclination OiXi direction and the strike OiYi direction of the average normal vector of the integrated discontinuous structural surface, OiZi is orthogonal to the plane OiXiYi, and the conversion formula is: wherein and respectively are the tendency and the dip angle of the merged discontinuity. determining discontinuity plane groups as J , structure plane number as i , obtaining point set X j , i , wherein, and local coordinates belonging to the point set, the inclination and the strike extension calculation are respectively:​ In the formula, LP 倾向 , LP 走向 respectively are the extension of the inclination direction and the strike direction, units: / m; The structural surface in the same-group structural surface is extracted, and a profile with equal and parallel spacing is set in the direction of the structural surface normal vector; according to the ratio of the line length to the arc length of each profile, the structural surface roughness is determined; The projection line of the same-group structural surface is obtained, and a plurality of orthogonal survey lines are established on the projection line; the structural surface spacing is determined by the average spacing between the intersection points of the projection line and each orthogonal survey line of the same-group structural surface; The volume of the rock mass exposed part is estimated according to the intersection relationship of different-group structural surfaces, and the block volume is obtained; The rock mass quality is evaluated by taking the number of rock mass structural surface groups, structural surface extension degree, structural surface roughness, structural surface spacing and block volume as evaluation parameters.

2. The rock mass quality evaluation method according to claim 1, characterized by, The rock mass surface point cloud data of the area to be evaluated is obtained, specifically including: Determine the scanning area, select the instrument site, and take the scanning area as the area to be evaluated; According to the selected position, the instrument is erected, the area to be evaluated is scanned by three-dimensional laser scanning, and the rock mass surface point cloud data of the area to be evaluated is obtained.

3. The rock mass quality evaluation method according to claim 2, characterized in that, The determination of the structural surface group and the number of structural surface groups comprises the following steps: By identifying and segmenting the structural surface, the occurrence information of the structural surface including the strike, inclination and dip angle of the structural surface is extracted, and the structural surface is divided; After the structural surface is divided, the structural surface of each group is colored according to the grouping result of the structural surface occurrence, and the same-group structural surfaces are given the same color; The number of structural surface groups is counted according to the number of color categories of the structural surface group.

4. The rock mass quality assessment method according to claim 1, characterized in that, The determination of the structural surface roughness specifically includes: The structural surface in the same-group structural surface is extracted, and a profile with equal and parallel spacing is set in the direction of the structural surface normal vector; The intersection line of the structural surface and the profile is taken as the arc length, and the line connecting the endpoints of the arc length is taken as the line length; The average of the ratio of the line length to the arc length of each profile is taken as the result of the structural surface roughness by counting the ratio of the line length to the arc length of each profile; The calculation formula of the structural surface roughness is: In the formula, is the structural surface roughness, is the roughness of the intersection of a certain profile with the structural surface, is the number of profiles set, L is the length of a certain profile, S is the arc length of a certain profile.

5. The rock mass quality assessment method according to claim 1, characterized in that, The determination of the structural surface spacing specifically includes: The same surface cluster is arranged in ascending order according to the spatial position and integrated; At the same time, the normal vector calculated in the process of determining the roughness of the structural surface is averaged, and the large cluster C j The new cluster surface normal vector is obtained as a unit. Based on the obtained new cluster surface normal vector, a structural surface projection processing is performed, and a n A strip of orthogonal lines; The average distance between the intersection points of each orthogonal line and the projection line is calculated, and the calculated average distance is counted, and whether each orthogonal line intersects with the projection line is judged, and when there is no intersection point or only one intersection point, the orthogonal line is ignored; Similarly, the average distance between the intersection points of each orthogonal line and the projection line is counted, and the average distance between the intersection points of multiple lines and the projection line is calculated, and the average value of the average distance is taken as the spacing between the structural surfaces; The calculation formula of the spacing between the structural surfaces is: wherein is the average distance between the layer projection lines, is the average distance between the intersection points of the orthogonal lines and the projection lines, n is the number of set orthogonal lines.

6. The rock mass quality assessment method according to claim 1, characterized in that, The obtained block volume specifically includes: For the calculation of the block volume of the slope rock mass, the volume of the exposed part of the rock mass is estimated through the intersection relationship of different groups of structural surfaces; When the rock block is a parallelepiped, there are three edges of the exposed rock mass; The coordinates of the four vertices are obtained from the three edges. , , ), ( , , ), ( , , ), ( , , Connecting the four vertices yields a tetrahedron; The block volume is 6 times the volume of the tetrahedron, and the calculation formula of the block volume is: 。 7. The rock mass quality assessment method according to claim 1, characterized in that, The evaluation of the rock mass quality specifically includes: Each evaluation parameter is graded and normalized; According to the normalized evaluation parameters, the weight is assigned by the dynamic weight method, and the rock mass quality grade is obtained.

8. A rock mass quality assessment system, characterized by, It includes: The point cloud acquisition module is used to scan the rock surface point cloud data of the evaluation area by three-dimensional laser scanning; The evaluation parameter extraction module is used to group the structural surfaces by extracting the occurrence information of the structural surfaces according to the rock surface point cloud data of the evaluation area, determine the structural surface group and the number of structural surface groups; wherein the structural surface group includes the same group of structural surfaces and different groups of structural surfaces; an independent coordinate system is constructed for each integrated discontinuous structural surface in the same group of structural surfaces, the length of the inclination and strike direction of each integrated discontinuous structural surface is determined, and the maximum value of the length in the inclination and strike direction is taken as the structural surface extension; the structural surface in the same group of structural surfaces is extracted, and the cross section with equal and parallel spacing is set in the direction of the structural surface normal vector; the structural surface roughness is determined according to the ratio of the line length to the arc length of each cross section; the projection line of the same group of structural surfaces is obtained, and a plurality of orthogonal lines are established on the projection line; the average distance between the intersection points of the projection line of the same group of structural surfaces and each orthogonal line is determined to determine the structural surface spacing; the volume of the exposed part of the rock mass is estimated according to the intersection relationship of different groups of structural surfaces to obtain the block volume; The evaluation module is used to evaluate the rock mass quality by taking the number of rock structural surface groups, structural surface extension, structural surface roughness, structural surface spacing and block volume as evaluation parameters; The maximum value of the length in the inclination and strike direction is taken as the structural surface extension, specifically including: The identified coplanar discontinuous structural planes in the same group are taken as coplanar clusters, and the number of cluster point clouds of each coplanar cluster is counted N ; The point cloud with the largest number in the plurality of coplanar clusters is taken as a large cluster, and whether there is another small cluster around the large cluster is determined by using the nearest neighbor search, the small clusters are integrated by data merging to form the integrated discontinuous structural surface J ; The length of the inclination and strike direction of each integrated discontinuous structural surface is calculated, and the maximum value of the length in the two directions is taken as the final extension of the structural surface; An independent coordinate system is given to the integrated discontinuous structural surface through the conversion formula, which is transformed from the original overall coordinate system OXYZ to the independent coordinate system OiXiYiZi for calculating the trace length of each discontinuous structural surface; According to the extension extracted in the inclination OiXi direction and the strike OiYi direction of the average normal vector of the integrated discontinuous structural surface, OiZi is orthogonal to the plane OiXiYi, and the conversion formula is: wherein and respectively are the tendency and the dip angle of the merged discontinuity. determining discontinuity group as J , structural plane number as i , obtaining point set X ( j , i ), wherein, and local coordinates belonging to the point set, the inclination and the strike extension are calculated respectively: wherein LP 倾向 , LP 走向 respectively the extension of the inclination direction and the strike direction in units of: / m.

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