CN104279956B - Determination method for rock structural surface reference plane - Google Patents

Abstract

The invention relates to a method for determining the surface reference plane of a rock structural surface, and belongs to the technical field of rock and soil mechanics. The present invention uses a three-dimensional white light scanner to scan the surface of the rock structure surface to obtain point cloud data on the surface of the rock structure surface; then use MATLAB software to read in the point cloud data on the surface of the rock structure surface, and identify and determine the The median datum on the surface of the rock structure plane; finally, according to the datum equation, determine the center point O ^' of the median datum, the structural translation matrix M, and the rotation matrix R, and further use MATLAB software to obtain the rock structure under the median datum datum Point cloud data of the surface. The present invention can identify and determine the median datum of the rock structural plane, and obtain point cloud data on the surface of the rock structural plane under the median datum reference, which effectively solves the problem that the point cloud data obtained by three-dimensional white light scanning cannot be directly compared to the rock structural plane. The problem of quantitative description of surfaces.

Description

A Method for Determining the Surface Datum Level of Rock Fractural Plane

technical field

The invention relates to a description of the surface morphology of a rock structural surface, and more specifically relates to a method for determining a reference plane of the surface of a rock structural surface, belonging to the technical field of rock and soil mechanics.

Background technique

The physical and mechanical properties of rock are mainly controlled by the rock structural plane, so the accurate measurement of the surface morphology of the structural plane of the rock specimen is a prerequisite for studying the relationship between the surface morphology of the structural plane and the mechanical properties. However, due to the large fluctuations, wide range of changes, and very complex shapes of the rock structural plane, it is very difficult to measure accurately. At present, the main measurement method for measuring the three-dimensional surface morphology of rock discontinuities is the non-contact optical method, especially the rapid development of three-dimensional optical scanning technology in recent years, which has become the main method for measuring the three-dimensional surface of rock specimen discontinuities. However, when using the 3D white light scanning technology to scan the surface of the structural surface, we can only obtain the 3D point cloud data of the surface of the structural surface in the global coordinate system of the landmark points. However, most of the existing parameters describing the three-dimensional structural planes of rocks (such as peaks, troughs, etc.) are based on the datum plane, so the point cloud data obtained by scanning cannot directly describe the surface of rock structural planes quantitatively, and thus cannot accurately describe the structure surface features. Therefore, it is necessary to develop a method for determining the surface datum of rock discontinuities to overcome the difficulty of 3D scanning data processing and to improve the quantitative description of the surface characteristics of rock discontinuities.

Contents of the invention

In view of the above-mentioned existing problems, the object of the present invention is to provide a method for determining the reference plane of the rock structural surface surface, and use the median reference plane as the reference plane of the rock structural surface to process the scanning data obtained by the three-dimensional white light scanner, The 3D point cloud data based on the median datum plane is obtained.

In order to achieve the above object, the technical solution adopted in the present invention is:

A method for determining the datum level of a rock structure plane, the measurement method is carried out in the following steps;

A method for determining the base level of a rock structural plane, characterized in that the measurement method is carried out in the following steps:

① Process the surface of the structural surface of the rock specimen, use a 3D white light scanner to scan the surface of the rock structural surface, and obtain the 3D point cloud data of the surface of the rock structural surface in the global coordinate system of the marker points. The 3D point cloud data is represented by X, Y, Output in the form of Z three-dimensional coordinates;

②Use computer software to read in the 3D point cloud data and store it in a matrix A with N rows and 3 columns, where N is the number of point clouds, and the first column, the second column, and the third column are respectively stored in the X, Y, Z values;

③ Utilize computer software to identify and determine the median datum level on the surface of the rock structural plane; the median datum level uses a plane function to represent the datum level equation of the measured surface, and the function form is z=a+bx+cy, using computer software to Calculate the partial derivative of the function, and automatically calculate the values of a, b, and c in the function, so as to determine the median reference plane of the structural surface surface in the global coordinate system X-Y-Z of the marker point, and display it;

④According to the calculated datum equation, determine the center point O' of the median datum as [0, 0, a], and construct the translation matrix M and rotation matrix R;

Formula 1

Formula 2

⑤ Utilize the translation matrix and rotation matrix to output the data on the surface of the rock structure plane under the median datum datum of the rock structure plane, and construct a matrix B with N rows and 4 columns, where N is the number of point clouds, and the first and second columns of the matrix , The third column is the value of X, Y, Z respectively, and the fourth column is the value "1" for all the elements; use the translation matrix and rotation matrix to perform B×M×R calculation in the software on the computer, and calculate the operation result After processing, the data of the structural plane surface under the median datum level of the rock structural plane are obtained, and the data are output.

The method for determining the datum level of a rock structural surface according to claim 1, wherein said treating the surface of the structural surface of the rock test piece refers to cleaning the surface of the rock structural surface first, and then spraying A thin layer of surface contrast enhancer is allowed to dry before applying the scan markers.

The method for determining the datum level of a rock structural plane according to claim 1, characterized in that: said computer software is MATLAB software.

A method for determining the rock structure plane datum level according to claim 1, characterized in that: the specific steps of outputting the data of the rock structure plane surface under the rock structure plane median datum level benchmark in the step 5 are:

① Construct a matrix B with N rows and 4 columns, N is the number of point clouds, the first column, the second column, and the third column of the matrix are the values of X, Y, and Z respectively, and the fourth column is all 1 elements, among which, Among them, the X and Y values represent the position of each point on the rock structure plane, and Z represents the height value of the structure plane in the global coordinate system of the marker points;

②Using the translation matrix and rotation matrix, perform B×M×R operation in MATLAB software to obtain a matrix C with N rows and 4 columns, where N is the number of point clouds, and the first and second columns are points in the rock structure. The position below the median datum plane of the surface, and the third column indicates the height value of the structural surface below the median datum plane;

③ Using MATLAB software, store the first column, second column, and third column of matrix C into a matrix D with N rows and 3 columns, where N is the number of point clouds, and convert matrix D into text data and output it to obtain Data on the surface of the structural plane below the mid-level datum of the rock structural plane were obtained.

Due to the adoption of the above technical scheme, the present invention can determine the median datum of the rock structural plane, and can obtain the three-dimensional point cloud data of the surface of the rock structural plane under the median datum reference, because the median datum of the specific rock structural plane It is the only one that exists, so processing the 3D scanning point cloud data with the median datum as the benchmark can effectively solve the problem that the point cloud data obtained by 3D white light scanning cannot directly quantitatively describe the surface of the rock structural plane due to the problem of cloud surface inclination. The problem. It has the following technical effects:

(1) Identify and determine the median datum of the surface of the rock structural plane: the median datum of a rock structural plane exists and is unique. Through the above-mentioned technical scheme, the median datum of the rock structural plane surface can be known and identified, and determine its equation.

(2) Obtained the surface data of the rock discontinuity plane based on the median datum level: the evaluation datum level is the core technology to realize the extraction of surface information. Three-dimensional parameters, through the above technical scheme, the data of three-dimensional white light scanning can be processed to directly obtain the surface data of rock structural planes based on the median datum level, and then quantitatively describe the surface morphology characteristics of rock structural planes.

Description of drawings:

Fig. 1 shows a schematic diagram of implementing translation matrix and rotation matrix in the present invention.

detailed description:

A method for determining the median reference plane of the present invention will be further described in detail below in conjunction with accompanying drawing 1 .

see Attachment

A method for determining the datum level of a rock structure plane, the measurement method is carried out in the following steps;

1 Process the surface of the structural surface of the rock specimen, use a 3D white light scanner to scan the surface of the rock structural surface, and obtain the 3D point cloud data of the surface of the rock structural surface in the global coordinate system of the marker points. The 3D point cloud data is represented by X, Y, Output in the form of Z three-dimensional coordinates; it is divided into the following two steps:

① The surface treatment process of the rock structure surface is to clean the surface of the rock structure surface first, then spray a thin layer of surface contrast enhancer, and then paste the scanning mark points after it dries;

② Turn on the 3D white light scanner to scan the surface of the rock structure surface to obtain point cloud data on the surface of the rock structure surface.

2 Use MATLAB software to read in the 3D point cloud data and store it in a matrix A with N rows and 3 columns, where N is the number of point clouds, and the first column, the second column, and the third column are respectively stored in X, Y and Z values, where X and Y values represent the position of each point on the rock structure plane, and Z represents the height value of the structure plane under the global coordinate system of the marker points;

3Use MATLAB software to identify and determine the median datum of the surface of the rock structural surface; the median datum uses a plane function to represent the datum equation of the measured surface, and the function form is z=a+bx+cy, using MATLAB to the function Calculate the partial derivative, automatically calculate the values of a, b, and c in the function, so as to determine the median reference plane of the structural surface surface in the global coordinate system X-Y-Z of the marker point, and display it;

According to the principle of determining the median datum, the function expression of the median datum is calculated, and the specific principles and methods are as follows:

Let the three-dimensional median datum plane be z[x, y], the datum plane equation:

z=a+bx+cy Formula 3

According to the principle of least squares method, the error sum of squares:

Formula 4

Bring in the mean:

Formula 5

Formula 6

Formula 7

In order to minimize D, D calculates the first-order partial derivatives of a, b, and c respectively, and simplifies to get a, b, and c as follows:

Formula 8

Formula 9

Formula 10

According to the point cloud data on the surface of the rock structural plane, bring the values of a, b, and c into formula 8, formula 9, and formula 10, and substitute them into formula 3 to obtain the equation of the median datum plane; this equation represents The plane of is the median datum plane of the surface of the rock structural plane to be sought;

4 According to the calculated datum equation, determine the center point O' of the median datum as [0, 0, a], and construct the translation matrix M and rotation matrix R according to the relevant knowledge of matrix theory; to achieve this purpose, it is divided into the following Two steps:

① Determine the center point O' of the median datum plane, which is equivalent to the role of the coordinate origin. In principle, this center point only needs to be on the median datum plane. Here, it is recommended to take the intersection of the Z-axis of the global coordinate system of the marker point and the median datum plane of the rock structural plane as the center point, because in actual situations , there must be an intersection point between the median datum plane and the Z axis, which is both special and universal. Then, according to the knowledge of matrix theory, the translation matrix M is constructed, and the origin O of the global coordinate system of the marker points is moved to the center point O' of the median datum plane, as shown in Figure 1. The constructed translation matrix M is as follows:

Formula 1

② Rotate so that the X-O-Y plane of the global coordinate system of the marker points coincides with the median datum plane of the rock structural plane, and the global coordinate system of the marker points X-Y-Z is rotated to the position of the X'-Y'-Z' coordinate system, see attached drawing 1, according to The knowledge of matrix theory constructs the rotation matrix to achieve this purpose, the rotation matrix is as follows:

Formula 2

5 Using the translation matrix and the rotation matrix to output the data on the surface of the rock structure plane under the median datum level of the rock structure plane is divided into the following steps:

① Construct a matrix B with N rows and 4 columns, N is the number of point clouds, the first column, the second column, and the third column of the matrix are the values of X, Y, and Z respectively, and the fourth column is all 1 elements, among which, Among them, the X and Y values indicate the position of each point on the rock structural plane, and Z indicates the height value of the structural plane in the global coordinate system of the marker point.

②Using the translation matrix and rotation matrix, perform B×M×R operation in MATLAB software to obtain a matrix C with N rows and 4 columns, where N is the number of point clouds, and the first and second columns are points in the rock structure. The position below the median datum of the surface, and the third column indicates the height value of the structural surface below the median datum.

③ Using MATLAB software, store the first column, second column, and third column of matrix C into a matrix D with N rows and 3 columns, where N is the number of point clouds, and convert matrix D into text data and output it to obtain Data on the surface of the structural plane below the mid-level datum of the rock structural plane were obtained.

Specific examples:

1 Process the surface of the structural surface of the rock specimen, scan the surface of the structural surface of the rock with a 3D white light surface scanner, and obtain the 3D point cloud data of the surface of the structural surface of the rock, the following is the extraction of 3D data of 20 points in the structural surface of the rock, As an example, as shown in Table 1:

Table 1

2 Use MATLAB software to read in the 3D point cloud data, and store the data in Table 1 into matrix A, as follows;

3Use MATLAB software to identify and determine the median datum on the surface of the rock structural plane, and the datum equation is as follows;

z=-0.137301229-0.000305767x-0.001847973y

4 According to the calculated datum equation, the center point O' of the median datum is [0, 0, -0.137301229], and according to formula 1 and formula 2, the translation matrix M and rotation matrix R are obtained:

Formula 1

Formula 2

Five ① construct matrix B:

② Use MATLAB software to calculate B×M×R, and calculate C, the results are as follows:

③ Use MATLAB software to output the data on the surface of the structural plane below the median datum level of the rock structural plane, as shown in Table 2:

Table 2

Claims (3)

1. a method for determining a rock structure plane datum level is characterized in that the measuring method is carried out in the following steps: ① Process the surface of the structural surface of the rock specimen, use a 3D white light scanner to scan the surface of the rock structural surface, and obtain the 3D point cloud data of the surface of the rock structural surface in the global coordinate system of the marker points. The 3D point cloud data is represented by X, Y, Output in the form of Z three-dimensional coordinates; ②Use computer software to read in the 3D point cloud data and store it in a matrix A with N rows and 3 columns, where N is the number of point clouds, and the first column, the second column, and the third column are respectively stored in the X, Y, Z values; ③ Utilize computer software to identify and determine the median datum level on the surface of the rock structural plane; the median datum level uses a plane function to represent the datum level equation of the measured surface, and the function form is z=a+bx+cy, using computer software to The partial derivative of the function is calculated according to the point cloud data of the surface of the rock structural surface, and the values of a, b, and c in the function are automatically calculated, so that the median datum of the structural surface surface is determined in the global coordinate system X-Y-Z of the marker point, and displayed ; ④According to the calculated datum equation, determine the center point O' of the median datum as [0, 0, a], and construct the translation matrix M and rotation matrix R; ⑤ Utilize the translation matrix and rotation matrix to output the data on the surface of the rock structure plane under the median datum datum of the rock structure plane, and construct a matrix B with N rows and 4 columns, where N is the number of point clouds, and the first and second columns of the matrix , the third column is the value of X, Y, Z respectively, and the fourth column is the value "1" for all the elements; use the translation matrix formula 1 and rotation matrix formula 2 to perform B×M×R calculation in the software on the computer , after processing the operation results, the data of the structural surface surface under the median datum of the rock structural plane are obtained, and the data are output. 2. the determining method of a kind of rock structural surface datum level according to claim 1, is characterized in that: described to the structural surface surface of rock test piece is handled, refers to the surface of rock structural surface is cleaned up earlier, and then Spray a thin layer of surface contrast enhancer, let it dry, and then paste the scanning markers. 3. the determining method of a kind of rock structure plane datum level according to claim 1, is characterized in that: in the described step 5., output the concrete step of the data of the rock structure plane surface under the rock structure plane median datum level benchmark for: ① Construct a matrix B with N rows and 4 columns, N is the number of point clouds, the first column, the second column, and the third column of the matrix are the values of X, Y, and Z respectively, and the fourth column is all 1 elements, among which, Among them, the X and Y values represent the position of each point on the rock structure plane, and Z represents the height value of the structure plane in the global coordinate system of the marker points; ②Using the translation matrix and rotation matrix, perform B×M×R operation in MATLAB software to obtain a matrix C with N rows and 4 columns, where N is the number of point clouds, and the first and second columns are points in the rock structure. The position below the median datum plane of the surface, and the third column indicates the height value of the structural surface below the median datum plane; ③ Using MATLAB software, store the first column, second column, and third column of matrix C into a matrix D with N rows and 3 columns, where N is the number of point clouds, and convert matrix D into text data and output it to obtain Data on the surface of the structural plane below the mid-level datum of the rock structural plane were obtained.