Rock mass quality evaluation method and system

Abstract

The invention discloses a rock mass quality evaluation method and system, and belongs to the technical field of geotechnical engineering.The rock mass quality evaluation method comprises the steps that a to-be-evaluated area is scanned through three-dimensional laser scanning, rock mass surface point cloud data of the to-be-evaluated area is obtained, and the structural plane group number, the structural plane extensibility, the structural plane roughness, the structural plane spacing and the block volume of structural planes are extracted; and evaluating the quality of the rock mass by taking the group number of the structural surfaces of the rock mass, the extensibility of the structural surfaces, the roughness of the structural surfaces, the spacing of the structural surfaces and the volume of the block as evaluation parameters. According to the method, related parameters can be obtained in a short time by using a three-dimensional laser scanning technology, and the obtained evaluation parameters comprehensively consider geometric characteristics, structural characteristics and mechanical characteristics of the rock mass, so that the quality state of the rock mass can be comprehensively reflected. Through comprehensive analysis of the parameters, the rock mass quality is rapidly evaluated based on rock mass coordinate data, and the evaluation precision and efficiency can be greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of geotechnical engineering technology, and more specifically to a rock mass quality evaluation method and system. Background Art

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

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

[0004] In addition, some scholars have introduced mathematical theories and algorithms to improve the evaluation methods. For example, they have used mathematical relationship theory methods such as hierarchical analysis method, entropy weight method, game theory, etc. to integrate various rock classification methods and construct a new rock risk assessment model suitable for highway tunnels; combined with statistical analysis and network simulation, a rock evaluation method suitable for fractured rock is proposed; dynamic weight and extension theory are introduced to improve rock quality evaluation; considering the effects of multiple factors and system integrity, and based on fuzzy RES and multidimensional cloud models, the accuracy and effectiveness of rock evaluation are improved; 3DMine is used to establish a geological drilling database, and combined with geological statistical methods, a rock mechanical parameter block model based on the RMR method is established to achieve rock quality classification; the Jaeger-Donath and Mogi-Coulomb strength criteria are used to propose calculation formulas for the structural surface attitude correction coefficient K2 and the initial ground stress state correction coefficient K3 for layered rock mass, which improves the limitations of the method.

[0005] Although the above improvements have improved the accuracy and scope of application of rock quality evaluation, most of them require the physical and mechanical properties of the rock mass or contact collection of rock mass data. It is difficult to obtain rock samples in environments such as high and steep slopes and reservoir bank slopes. Traditional testing methods are difficult to implement. The use of non-contact testing technology to obtain point cloud coordinate data lacks consideration of the three-dimensional structural characteristics of the rock mass when evaluating rock quality, which affects the accuracy and efficiency of rock quality evaluation. Summary of the invention

[0006] In response to the problems existing in the above-mentioned fields, the present invention proposes a rock mass quality evaluation method and system. Through three-dimensional laser scanning technology, relevant parameters can be acquired in a relatively short time. The number of rock mass structural surface groups, structural surface ductility, structural surface roughness, structural surface spacing and block volume are used as evaluation parameters. The acquired evaluation parameters comprehensively consider the three-dimensional structure and spatial distribution characteristics of the rock mass, and can comprehensively reflect the quality status of the rock mass. Through the comprehensive analysis of these parameters, the stability of the rock mass can be evaluated more accurately.

[0007] In order to solve the above technical problems, the present invention discloses a rock mass quality evaluation method, comprising the following steps:

[0008] Scan the area to be evaluated by three-dimensional laser scanning to obtain point cloud data of the rock surface in the area to be evaluated;

[0009] According to the point cloud data of the rock mass surface in the area to be evaluated, the occurrence information of the structural surface is extracted, the structural surfaces are grouped, and the structural surface groups and the number of structural surface groups are determined; wherein the structural surface groups include structural surfaces of the same group and structural surfaces of different groups;

[0010] An independent coordinate system is constructed for each integrated discontinuous structural surface in the same group of structural surfaces. The length of the dip and strike directions of each integrated discontinuous structural surface is determined, and the maximum length in the dip and strike directions is taken as the extension of the structural surface.

[0011] Extract the structural surfaces in the same group of structural surfaces, set equal-spaced and parallel sections in the direction of the structural surface normal vector; determine the roughness of the structural surface according to the ratio of the line length to the arc length of each section;

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

[0013] The volume of the exposed part of the rock mass is estimated according to the intersection relationship of different groups of structural planes to obtain the block volume;

[0014] The rock mass quality is evaluated using the number of rock mass structural planes, structural plane ductility, structural plane roughness, structural plane spacing and block volume as evaluation parameters.

[0015] Preferably, the step of obtaining the point cloud data of the rock surface in the area to be evaluated specifically includes:

[0016] Determine the scanning area, select the instrument site, and use the scanning area as the area to be evaluated;

[0017] The instrument is set up according to the selected location, and the area to be evaluated is scanned by three-dimensional laser scanning to obtain the point cloud data of the rock surface in the area to be evaluated.

[0018] Preferably, the determining of the structural face group and the number of structural face groups comprises the following steps:

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

[0020] After the structural surfaces are divided, each group of structural surfaces is colored according to the grouping results of the structural surface occurrence, and the same group of structural surfaces is given the same color;

[0021] Count the number of structural face groups based on the number of color types of the structural face groups.

[0022] Preferably, the maximum value in the two directions of inclination and strike is taken as the structural surface extension, which specifically includes:

[0023] The identified discontinuous structural surfaces in the same group and plane are regarded as same-plane clusters, and the number of cluster point clouds N of each same-plane cluster is counted;

[0024] The same-plane cluster with the largest number of point clouds among multiple same-plane clusters is regarded as a large cluster. 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 an integrated discontinuous structure surface J.

[0025] By calculating the length of each integrated discontinuity surface in the dip and strike directions, the maximum length in the two directions is taken as the final extension of the structural surface;

[0026] The integrated discontinuity surface is given an independent coordinate system through a conversion formula, which is transformed from the original global coordinate system OXYZ into an independent coordinate system OiXiYiZi used to calculate the trace length of each discontinuity surface;

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

[0028]

[0029] In the formula, η and θ are the inclination and dip angle of the discontinuity surface after merging, respectively;

[0030] Determine the discontinuous surface group as J, the independent structural surface number is i, and obtain the point set X(j, i), where x'(j, i) and y'(j, i) belong to the local coordinates of the point set, and the dip and strike extension are calculated as follows:

[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] Where LP 倾向 , L.P. 走向 They are the extensions in the dip direction and strike direction respectively, with the unit being / m.

[0034] Preferably, the determining the structural surface roughness specifically includes:

[0035] By extracting structural surfaces from the same group of structural surfaces, equal-spaced and parallel sections are set in the direction of the structural surface normal vector;

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

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

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

[0039]

[0040] Where LP 3D is the structural surface roughness, LP i is the roughness of the intersection line between a certain section and the structural surface, n is the number of sections set, L is the length of a certain section line, and S is the arc length of a certain section.

[0041] Preferably, the determining of the structural surface spacing specifically includes:

[0042] The clusters on the same surface are arranged in ascending order according to their spatial positions and integrated;

[0043] At the same time, the normal vectors calculated in the process of determining the structural surface roughness are averaged and the integrated large cluster C j Get the new cluster face normal vector for the unit;

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

[0045] Calculate the average distance between the intersection of each orthogonal survey line and the projection line, and make statistics on the calculated average distance. By judging whether each orthogonal survey line has an intersection with the projection line, when there is no intersection or only one intersection, ignore the orthogonal survey line.

[0046] Similarly, the average distance between the intersection points of each orthogonal survey line and the projection line is calculated, and the average distance between the intersection points of multiple survey lines and the projection line is calculated, and the average of the average distances is used as the structural surface spacing;

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

[0048]

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

[0050] Preferably, obtaining the block volume specifically includes:

[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 mass is a parallelepiped, the exposed rock mass has three edges;

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

[0054] The volume of the block is 6 times the volume of the tetrahedron. The calculation formula for the block volume is:

[0055]

[0056] Preferably, the rock mass quality evaluation specifically includes:

[0057] Each evaluation parameter is graded and normalized;

[0058] According to the normalized evaluation parameters, weights are assigned through the dynamic weight method to obtain the rock mass quality grade.

[0059] Preferably, a rock mass quality evaluation system is also included, comprising:

[0060] A point cloud acquisition module is used to scan the area to be evaluated by three-dimensional laser scanning to obtain point cloud data of the rock surface in the area to be evaluated;

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

[0062] The evaluation module is used to evaluate the quality of the rock mass by taking the number of rock mass structural surface groups, structural surface ductility, structural surface roughness, structural surface spacing and block volume as evaluation parameters.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] The rock mass quality evaluation method proposed in the present invention can obtain the rock mass surface point cloud data of the area to be evaluated in a short time through three-dimensional laser scanning technology, and has the advantages of non-contact, high precision and strong anti-interference ability. Through the structural surface group and the number of structural surface groups of the rock mass, the structural surface group includes the same group of structural surfaces and different groups of structural surfaces; for the same group of structural surfaces, the structural surface ductility, structural surface roughness, and structural surface spacing are determined, and the block volume is determined for the different groups of structural surfaces, and the determined parameters are used as evaluation parameters. The reason why these extracted parameters are used as evaluation parameters is that they directly affect the mechanical behavior and stability of the rock mass, so they are given priority. Specifically: the more structural surface groups of the rock mass, the more broken the rock mass may be and the worse the stability; the greater the structural surface ductility, the longer the structural surface, and the greater the negative impact on the stability of the rock mass; the rougher the structural surface, the better the friction characteristics and the better the stability; the smaller the structural surface spacing, the more small-sized blocks there are in the rock mass, and the worse the overall strength of the rock mass; the larger the block volume, the more complete the rock mass. In summary, this method can obtain relevant parameters in a relatively short time through 3D laser scanning technology, and these selected parameters comprehensively consider the geometric characteristics, structural characteristics and mechanical characteristics of the rock mass, and can fully reflect the quality status of the rock mass. Through the comprehensive analysis of these parameters, the stability of the rock mass can be evaluated more quickly and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 A flow chart for determining evaluation parameters of the rock mass quality evaluation method proposed in the present invention;

[0066] Figure 2 The rock mass quality evaluation process proposed by the present invention;

[0067] Figure 3 A schematic diagram of structural surface grouping provided by an embodiment of the present invention;

[0068] Figure 4 A schematic diagram of the ductility of a structural surface provided by an embodiment of the present invention;

[0069] Figure 5 A schematic diagram of the principle of structural surface roughness provided by an embodiment of the present invention;

[0070] Figure 6 A schematic diagram of calculating the distance between structural surfaces provided in an embodiment of the present invention;

[0071] Figure 7 A schematic diagram of block volume calculation provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0072] The following will be combined with the attached embodiment of the present invention Figure 1-Figure 7 , the technical solutions in the embodiments of the present invention are clearly and completely described. It should be understood that the terms described in the present invention are only used to describe specific implementation methods and are not used to limit the present invention.

[0073] Example

[0074] like Figure 1 As shown, the present invention proposes a rock mass quality evaluation method, comprising the following steps:

[0075] Select area and obtain point cloud:

[0076] S1: Scan the area to be evaluated by three-dimensional laser scanning to obtain point cloud data of the rock surface in the area to be evaluated;

[0077] Parameter extraction includes steps S2-S6:

[0078] S2: According to the point cloud data of the rock mass surface in the area to be evaluated, the structural surfaces are grouped by extracting the occurrence information of the structural surfaces, and the structural surface groups and the number of structural surface groups are determined; wherein the structural surface groups include structural surfaces in the same group and structural surfaces in different groups;

[0079] S3: construct an independent coordinate system for each integrated discontinuous structural surface in the same group of structural surfaces, determine the length of the dip and strike directions of each integrated discontinuous structural surface, and take the maximum length in the dip and strike directions as the extension of the structural surface;

[0080] S4: extracting structural surfaces from the same group of structural surfaces, setting equal-spaced and parallel sections in the direction of the structural surface normal vector; determining the roughness of the structural surface according to the ratio of the line length to the arc length of each section;

[0081] S5: obtaining projection lines of the same group of structural surfaces, establishing multiple orthogonal survey lines on the projection lines; determining the spacing between structural surfaces through the average spacing between the intersection points of the projection lines of the same group of structural surfaces and each orthogonal survey line;

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

[0083] Quality evaluation:

[0084] S7: The rock mass quality is evaluated using the number of rock mass structural planes, structural plane ductility, structural plane roughness, structural plane spacing and block volume as evaluation parameters.

[0085] Specifically, in step S1, obtaining the rock surface point cloud data of the area to be evaluated includes:

[0086] like Figure 2 As shown, determine the scanning area, select the instrument site, and use the scanning area as the area to be evaluated;

[0087] The instrument is set up according to the selected location, and the area to be evaluated is scanned by three-dimensional laser scanning to obtain the point cloud data of the rock surface in the area to be evaluated.

[0088] Compared with traditional rock quality evaluation methods that may require a large amount of on-site sampling and laboratory testing, the three-dimensional laser scanning technology used in the present invention can obtain relevant parameters in a shorter time and has the advantages of non-contact, high precision, and strong anti-interference ability.

[0089] In step S2, determining the number of rock mass structural surface groups includes the following steps:

[0090] By identifying and segmenting the structural plane, the occurrence information of the structural plane is extracted, including the strike, dip and inclination of the structural plane, and the structural plane is divided;

[0091] After the structural surfaces are divided, each group of structural surfaces is colored according to the grouping results of the structural surface occurrence, and the same color is given to the structural surfaces in the same group; and the number of structural surface groups is counted according to the number of color types of the structural surface groups.

[0092] The present invention takes the prefabricated concrete soil block stacking model as an example. The concrete soil block sizes are standard blocks of 100*100mm and 50*50mm. The dominant structural surface, that is, the recognition effect of the grouping of the structural surface is as follows: Figure 3 shown.

[0093] Ductility is defined as the length of the structural surface in the direction of dip and strike, as well as the areal extent of discontinuities along the plane.

[0094] Structural surfaces such as joints and cracks are one of the main factors controlling rock mass failure and stability. The number of structural surface groups directly affects the integrity and stability of the rock mass. The more structural surface groups there are, the more broken the rock mass may be and the worse its stability.

[0095] In step S3, the lengths of the inclination and strike directions of each discontinuous structural surface are calculated, and the maximum value of the two directions is taken as the extension of the structural surface, specifically including:

[0096] The identified discontinuous structural surfaces in the same group and plane are regarded as same-plane clusters, and the number of cluster point clouds N of each same-plane cluster is counted;

[0097] The same-plane cluster with the largest number of point clouds among multiple same-plane clusters is regarded as a large cluster. 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 an integrated discontinuous structure surface J.

[0098] By calculating the length of each integrated discontinuity surface in the direction of dip and strike, the maximum value of the two directions is taken as the final extension of the structural surface;

[0099] like Figure 4 As shown, an independent coordinate system is given to the integrated discontinuity surface through a conversion formula, and the original global coordinate system OXYZ is transformed into an independent coordinate system OiXiYiZi for calculating the trace length of each discontinuity surface;

[0100] Assume that the integrated discontinuity point cloud data is J, where J is an n×3 matrix, and each row represents the (x, y, z) coordinates of a point. According to the extension extracted from the average normal vector of the integrated discontinuity in the inclination OiXi direction and the strike OiYi direction, OiZi is orthogonal to the plane OiXiYi, and the conversion formula is:

[0101]

[0102] Where η and θ are the inclination and dip angle of the discontinuity surface after merging, respectively.

[0103] The transformed point cloud data J′ is obtained by multiplying the rotation matrix R and the point cloud data J:

[0104] J′=R·J T

[0105] Determine the point cloud data J′ after the coordinate transformation of the integrated discontinuity surface. The independent structural surface is numbered as 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. The calculation of the dip and strike extension is:

[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] Where LP 倾向 , L.P. 走向 They are the extensions in the dip direction and strike direction respectively, with the unit being / m.

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

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

[0111] By extracting the structural surface, the sections with equal spacing and parallel to each other are set in the direction of the normal vector of the structural surface;

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

[0113] By counting the ratio of each profile line length to the arc length, the average of multiple profile line length to arc length ratios is taken as the result of the structural surface roughness. The principle diagram of the structural surface roughness is shown in Figure 5 shown.

[0114] The calculation formula of structural surface roughness is:

[0115]

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

[0117] In order to ensure the accuracy of the results, the profile spacing can be adjusted and the structural surface roughness can be extracted separately until the statistical results tend to be stable.

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

[0119] In step S5, the distance between structural surfaces is obtained, which specifically includes:

[0120] The spacing of structural surfaces (discontinuous surfaces) is one of the key factors in evaluating the quality of rock mass structural surfaces. The standard defines the spacing of structural surfaces as the vertical distance between discontinuous surfaces, which is usually calculated as the distance between discontinuous surfaces in the same group. In order to obtain the spacing of structural surfaces more accurately, the present invention uses point cloud data for statistics:

[0121] The clusters on the same surface are arranged in ascending order according to their spatial positions and integrated.

[0122] At the same time, the normal vectors calculated in the process of determining the structural surface roughness are averaged, and a new cluster surface normal vector is obtained using the integrated large cluster as a unit.

[0123] Based on the new cluster surface normal vector obtained, the structural surface projection processing is performed, and n orthogonal survey lines are established on the projection line, such as Figure 6 shown.

[0124] The average distance between the intersection of each orthogonal survey line and the projection line is calculated, and the calculated average distance is statistically analyzed. It is determined whether each orthogonal survey line has an intersection with the projection line. When there is no intersection or only one intersection, the orthogonal survey line is ignored.

[0125] Similarly, the average distance between the intersection points of each orthogonal survey line and the projection line is calculated, and the average distance between the intersection points of multiple survey lines and the projection line is obtained, and the average of the average distances is used as the structural surface spacing.

[0126] The calculation formula of the structural surface spacing is:

[0127]

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

[0129] The spacing between structural planes affects the block size and strength of the rock mass. Smaller spacing means there are more small-sized blocks in the rock mass, which can reduce the overall strength of the rock mass.

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

[0131] Regarding the block volume calculation of the slope rock mass, since the rock mass exposure is generally limited, it is impossible to accurately obtain the rock mass volume. Therefore, the present invention estimates the rock mass volume based on the exposed part of the rock mass.

[0132] Assuming that the rock block is a parallelepiped, its three edges can basically be seen when the rock is exposed.

[0133] According to the three edges, we obtain the coordinates of the four vertices (X1, Y1, Z1), (X2, Y2, Z2), (X3, Y3, Z3), and (X4, Y4, Z4), and connect the four vertices to get a tetrahedron, such as Figure 7 shown.

[0134] The volume of the block is 6 times the volume of the tetrahedron. The calculation formula for the block volume is:

[0135]

[0136] Block volume is an important parameter for evaluating the size and stability of rock mass. A larger block volume usually means that the rock mass is more complete and is more beneficial to engineering stability.

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

[0138] The present invention classifies the evaluation parameters by BQ method, RMR classification method and GSI classification system method, and performs normalization processing.

[0139] The evaluation parameters are divided into five levels, among which level I represents the best parameter indicator, level II is the second best, and so on. The classification of each indicator is shown in Table 1.

[0140] Table 1 Evaluation parameter classification

[0141] Evaluation parameters grade Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ Number of structural face groups <2 2～3 3～4 4～5 >5 Structural surface ductility / m >30 10～30 3～10 1～3 <1 Structural surface roughness <0.92 0.92-0.94 0.94-0.96 0.96-0.98 >0.98 Structural surface spacing / m >2 0.6-2 0.2-0.6 0.06-0.2 <0.06 Block volume / lgVcm3 >7 5～7 3～5 1～3 <1

[0142] Since the units and sizes of each group of parameters are not uniform, in order to conduct comparable analysis, each indicator is normalized. The processing results are shown in Table 2 below.

[0143] Table 2 Normalization of evaluation parameter levels

[0144] Evaluation parameters grade Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ Number of structural face groups 0.80-1.00 0.60-0.80 0.40-0.60 0.20-0.40 0.00-0.20 Structural surface ductility 0.50-1.00 0.17-0.50 0.05-0.17 0.02-0.05 0.00-0.02 Structural surface roughness 0.80-1.00 0.60-0.80 0.40-0.60 0.20-0.40 0.00-0.20 Structural surface spacing 0.30-1.00 0.10-0.30 0.03-0.10 0.01-0.03 0.00-0.01 Block volume 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, weights are assigned through the dynamic weight method to obtain the rock mass quality grade, including:

[0146] First, let the parameter index be c i , and its corresponding normalized result is v i , the corresponding weight is a i , parameter evaluation level is j, rock mass evaluation level is J * , where i, j = 1, 2, 3, 4, 5;

[0147] Correlation coefficient γ ij calculate:

[0148]

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

[0150] The weight calculation formula is as follows:

[0151]

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

[0153]

[0154] Among them, ρ(v i ),|V ij |The calculation formulas are:

[0155]

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

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

[0158]

[0159] Rock mass evaluation grade J * :

[0160]

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

[0162] A point cloud acquisition module is used to scan the area to be evaluated by three-dimensional laser scanning to obtain point cloud data of the rock surface in the area to be evaluated;

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

[0164] The evaluation module is used to evaluate the quality of the rock mass by taking the number of rock mass structural surface groups, structural surface ductility, structural surface roughness, structural surface spacing and block volume as evaluation parameters.

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

[0166] In addition, traditional rock quality evaluation methods may require a large amount of on-site sampling and laboratory testing, while this article uses three-dimensional laser scanning technology to obtain relevant parameters in a shorter time, and has the advantages of non-contact, high precision, and strong anti-interference ability.

[0167] The evaluation parameters selected by the present invention comprehensively consider the geometrical properties, structural properties and mechanical properties of the rock mass, and can fully reflect the quality status 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, providing a scientific basis for the prevention and control of rock slopes and engineering design.

[0168] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0169] In addition, unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as commonly understood by those skilled in the art to which the present invention belongs. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods related to the documents. In the event of any conflict with any incorporated document, the content of this specification shall prevail.

Claims

1. A rock mass quality evaluation method, characterized in that: The following steps are involved: Scan the area to be evaluated by three-dimensional laser scanning to obtain point cloud data of the rock surface in the area to be evaluated; According to the point cloud data of the rock mass surface in the area to be evaluated, the occurrence information of the structural surface is extracted, the structural surfaces are grouped, and the structural surface groups and the number of structural surface groups are determined; wherein the structural surface groups include structural surfaces of the same group and structural surfaces of different groups; An independent coordinate system is constructed for each integrated discontinuous structural surface in the same group of structural surfaces. The length of the dip and strike directions of each integrated discontinuous structural surface is determined, and the maximum length in the dip and strike directions is taken as the extension of the structural surface. Extract the structural surfaces in the same group of structural surfaces, set equal-spaced and parallel sections in the direction of the structural surface normal vector; determine the roughness of the structural surface according to the ratio of the line length to the arc length of each section; The projection lines of the same group of structural surfaces are obtained, and a plurality of orthogonal survey lines are established on the projection lines; the spacing between the structural surfaces is determined by the average spacing between the intersection points of the projection lines of the same group of structural surfaces and each orthogonal survey line; The volume of the exposed part of the rock mass is estimated according to the intersection relationship of different groups of structural planes to obtain the block volume; The rock mass quality is evaluated using the number of rock mass structural planes, structural plane ductility, structural plane roughness, structural plane spacing and block volume as evaluation parameters.

2. The rock mass quality evaluation method according to claim 1, characterized in that: The step of obtaining the rock surface point cloud data of the area to be evaluated specifically includes: Determine the scanning area, select the instrument site, and use the scanning area as the area to be evaluated; The instrument is set up according to the selected location, and the area to be evaluated is scanned by three-dimensional laser scanning to obtain the point cloud data of the rock surface in the area to be evaluated.

3. The rock mass quality evaluation method according to claim 2, characterized in that: The step of determining the structural face group and the number of structural face groups comprises the following steps: By identifying and segmenting the structural plane, the occurrence information of the structural plane is extracted, including the strike, dip and inclination of the structural plane, and the structural plane is divided; After the structural surfaces are divided, each group of structural surfaces is colored according to the grouping results of the structural surface occurrence, and the same group of structural surfaces is given the same color; Count the number of structural face groups based on the number of color types of the structural face groups.

4. The rock mass quality evaluation method according to claim 3, characterized in that: The maximum value of the two directions of dip and strike is taken as the extension of the structural surface, specifically including: The identified discontinuous structural surfaces in the same group and plane are regarded as same-plane clusters, and the number of cluster point clouds N of each same-plane cluster is counted; The same-plane cluster with the largest number of point clouds among multiple same-plane clusters is regarded as a large cluster. 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 an integrated discontinuous structure surface J. By calculating the length of each integrated discontinuity surface in the dip and strike directions, the maximum length in the two directions is taken as the final extension of the structural surface; The integrated discontinuity surface is given an independent coordinate system through a conversion formula, which is transformed from the original global coordinate system OXYZ into an independent coordinate system OiXiYiZi used to calculate the trace length of each discontinuity surface; According to the extension extracted from the average normal vector of the integrated discontinuity in the dip direction OiXi and the strike direction OiYi, OiZi is orthogonal to the plane OiXiYi, and the conversion formula is: In the formula, η and θ are the inclination and dip angle of the discontinuity surface after merging, respectively; Determine the discontinuous surface group as J, the independent structural surface number is i, and obtain the point set X(j, i), where x'(j, i) and y'(j, i) belong to the local coordinates of the point set, and the dip and strike extension are calculated as follows: LP 倾向 (j,i)=max(x'(j,i))-min(x'(j,i)) LP 走向 j,i)=max(y'(j,i))-min(y'(j,i)) Where LP 倾向 , L.P. 走向 They are the extensions in the dip direction and strike direction respectively, with the unit being / m.

5. The rock mass quality evaluation method according to claim 4, characterized in that: Determining the structural surface roughness specifically includes: By extracting structural surfaces from the same group of structural surfaces, equal-spaced and parallel sections are set in the direction of the structural surface normal vector; The intersection line of the structural surface and the section is taken as the arc length, and the line connecting the two end points of the arc length is taken as the line length; By counting the ratio of each profile line length to the arc length, the average of multiple profile line length to arc length ratios is taken as the result of the structural surface roughness; The calculation formula of structural surface roughness is: Where LP 3D is the structural surface roughness, LP i is the roughness of the intersection line between a certain section and the structural surface, n is the number of sections set, L is the length of a certain section line, and S is the arc length of a certain section.

6. The rock mass quality evaluation method according to claim 5, characterized in that: Determining the structural surface spacing specifically includes: The clusters on the same surface are arranged in ascending order according to their spatial positions and integrated; At the same time, the normal vectors calculated in the process of determining the structural surface roughness are averaged and the integrated large cluster C j Get the new cluster face normal vector for the unit; Based on the obtained new cluster surface normal vector, the structural surface projection processing is performed, and n orthogonal survey lines are established on the projection line; Calculate the average distance between the intersection of each orthogonal survey line and the projection line, and make statistics on the calculated average distance. By judging whether each orthogonal survey line has an intersection with the projection line, when there is no intersection or only one intersection, ignore the orthogonal survey line. Similarly, the average distance between the intersection points of each orthogonal survey line and the projection line is calculated, and the average distance between the intersection points of multiple survey lines and the projection line is calculated, and the average of the average distances is used as the structural surface spacing; The calculation formula of the structural surface spacing is: In the formula, S 3D is the average distance between slice projection lines, is the average distance between the intersection points of the orthogonal survey lines and the projection lines, and n is the number of orthogonal survey lines set.

7. The rock mass quality evaluation method according to claim 6, characterized in that: The obtaining of the block volume specifically includes: 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; When the rock mass is a parallelepiped, the exposed rock mass has three edges; According to the three edges, the coordinates of four vertices are obtained (X1, Y1, z1), (X2, Y2, Z2), (X3, Y3, Z3), and (X4, Y4, Z4), and the four vertices are connected to obtain a tetrahedron; The volume of the block is 6 times the volume of the tetrahedron. The calculation formula for the block volume is:

8. The rock mass quality evaluation method according to claim 7, characterized in that: The rock mass quality evaluation specifically includes: Each evaluation parameter is graded and normalized; According to the normalized evaluation parameters, weights are assigned through the dynamic weight method to obtain the rock mass quality grade.

9. A rock mass quality evaluation system, characterized in that: include: A point cloud acquisition module is used to scan the area to be evaluated by three-dimensional laser scanning to obtain point cloud data of the rock surface in the area to be evaluated; The evaluation parameter extraction module is used to extract the occurrence information of the structural surface according to the point cloud data of the rock surface in the area to be evaluated, group the structural surfaces, 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; construct an independent coordinate system for each integrated discontinuous structural surface in the same group of structural surfaces, determine the length of the dip and strike direction of each integrated discontinuous structural surface, and take the maximum length in the dip and strike directions as the extension of the structural surface; extract the structural surfaces in the same group of structural surfaces, set equal-spaced and parallel sections in the direction of the structural surface normal vector; determine the roughness of the structural surface according to the ratio of the line length to the arc length of each section; obtain the projection line of the same group of structural surfaces, and establish multiple orthogonal survey lines on the projection line; determine the spacing of the structural surfaces by the average spacing between the intersection points of the projection line of the same group of structural surfaces and each orthogonal survey line; estimate the volume of the exposed part of the rock mass according to the intersection relationship of different groups of structural surfaces to obtain the block volume; The evaluation module is used to evaluate the quality of the rock mass by taking the number of rock mass structural surface groups, structural surface ductility, structural surface roughness, structural surface spacing and block volume as evaluation parameters.

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