A system and method for spatially quantifying fault joint fracture characteristics

Abstract

The present application relates to a kind of fault joint fissure feature spatial quantitative description system and method, the system includes at least one coordinate acquisition component and at least one processor, the coordinate acquisition component is connected with the processor in wired and / or wireless manner and establishes connection relationship, the coordinate acquisition component at least acquires the spatial coordinate data of fault joint fissure and sends to the processor;The processor is configured to: determine fault joint fissure feature based on the spatial coordinate data;Based on the spatial coordinate data, construct ellipsoid basic equation capable of covering the spatial distribution range of fissure;The spatial geometric parameters of the ellipsoid basic equation are used to describe the fault joint fissure feature.The present application determines the coefficient of ellipsoid by new fitting mode to ellipsoid, can only realize the quantitative description to the fault joint fissure feature in solid interior by one ellipsoid.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of information analysis of geological fissure structure, and in particular to a system and method for spatial quantitative description of fault joint fissure characteristics. BACKGROUND

[0002] There are often structural defects of different scales inside geological bodies or solid materials, which often have a great influence on the properties of the geological bodies or solid materials. How to quantitatively describe these structural defects is a common problem faced by current rock mechanics, tectonic mechanics and solid material mechanics. Cracks are generated in the solid body under external force, and elastic waves are often generated during the generation of cracks, which are manifested as natural earthquakes, microseisms and acoustic emission at different scales. Acoustic emission is often used for dynamic monitoring and evaluation of structural fatigue damage of bridges and metal pressure vessels, microseisms are widely used for monitoring and early warning of various rock failure related geological disasters, and natural seismic waves are an important means for studying earthquakes and the internal structure of the earth. An important purpose of natural earthquake, microseism and acoustic emission elastic wave detection is to quantitatively describe the cracks so as to judge the evolution state of the system. The existing methods for detecting the size and orientation of the solid body in space mainly include X-ray CT method and elastic wave CT method. The X-ray CT method can obtain accurate three-dimensional structural information of cracks by CT slice detection and three-dimensional reconstruction, and the precision can reach microns. The traditional CT is limited by scanning speed and cannot realize dynamic detection. The latest CT technology uses particle accelerators to obtain high-speed particles, which can obtain a higher slice rate and greatly increase the detection capability of dynamic structural changes. However, the X-ray CT machine is large in size, and the dynamic CT technology requires high-speed particles, which can only detect decimeter-scale features. These characteristics make it impossible to apply to many engineering field practices. The elastic wave CT method scans the solid structure by seismic waves or ultrasonic waves, and measures the crack structure information inside the solid body through the change of wave speed. The detection accuracy and range are affected by the wavelength. The smaller the wavelength, the higher the detection accuracy, but the smaller the detection range. At present, the three-dimensional structural information of cracks cannot be quantitatively described. The above methods (except high-speed CT) cannot quantitatively describe the crack process.

[0003] The crack tensor proposed by Kachanov et al. in the article "Continuum model of medium with cracks" (Journal of the Engineering Mechanics Division, 1980, 106(5): 1039-1051.) is a statistical description inside the internal crack. Li Xuefeng et al. in the article "Quantitative determination of rock fracture fabric" (Rock and Soil Mechanics, 2015, 34(11): 2355-2361) defines the crack tensor by using the normalization idea, although the tensor can better describe the plane distribution characteristics of the crack, but it cannot be used for the three-dimensional dynamic description of the crack because it cannot quantitatively describe the three-dimensional structure.

[0004] Wang Shuguang et al. in the article "Scanning coal rock surface crack ellipsoid reconstruction and tensor characterization and its application" (Journal of Coal Science and Technology, 2022, 47(7): 2593-2608.) proposed a rotating oblate ellipsoid to fit each triangular surface crack, thereby realizing ellipsoid reconstruction of the entire crack structure. However, the ellipsoid crack filling method needs to use multiple ellipsoids, so the accuracy of the description after the crack is generated is insufficient.

[0005] For another example, the Chinese patent with publication number CN111965696A discloses a dynamic disaster prediction method based on elastic wave multi-target analysis, including steps: S1. During the operation, use the acoustic emission monitoring device to collect and send the elastic wave signals propagating in the measured target body; S2. The ground comprehensive signal processing device receives and analyzes the elastic wave signals to obtain the abnormal geological body and stress change dynamic inversion imaging in the measured target body, and extracts the acoustic emission characteristic parameters of the elastic wave signals; S3. The ground comprehensive signal processing device judges and intelligently warns according to the change of the abnormal geological body dynamic inversion imaging or the stress change dynamic inversion imaging or the change of the acoustic emission characteristic parameters in the measured target body. Although this patent can judge the disaster based on the change of the acoustic emission characteristic parameters of the elastic wave, it can only obtain the inversion imaging of the abnormal geological body in the measured target body, and then preliminarily grasp the geological occurrence conditions in the measured target body, and cannot accurately describe the fault joint crack characteristics.

[0006] As described above, the ellipsoid in the prior art either uses multiple ellipsoids to fill and describe, which is more cumbersome and inconvenient to apply, or cannot describe the fault joint crack characteristics.

[0007] The present application hopes to provide a simple ellipsoid to quantitatively describe the three-dimensional structural information of the crack by using a single ellipsoid to represent the fault joint crack characteristics.

[0008] In addition, on the one hand, due to the difference in understanding of those skilled in the art; on the other hand, due to the fact that the applicant studied a large number of literatures and patents when making the present application, but limited by the size and did not list all the details and contents in detail, but this does not mean that the present application does not have these prior art characteristics, on the contrary, the present application has all the characteristics of the prior art, and the applicant reserves the right to add relevant prior art in the background art. SUMMARY

[0009] At present, there is no technical means to quantitatively describe the structural defects in the solid. The reason is that, first, the acquisition accuracy of dynamic CT technology is insufficient and the machine body is large, which is not convenient to carry and transport to multiple sites. Second, the elastic wave CT method is to scan the solid structure by seismic wave or ultrasonic wave, and the crack structure information inside the solid is measured by the change of wave velocity, the detection accuracy and range are affected by the wavelength, the smaller the wavelength, the higher the detection accuracy, but the smaller the detection range. If only the crack structure characteristics scanned by the elastic wave CT are described, the description result will be inaccurate due to the limitation of data acquisition accuracy. Therefore, how to get rid of the limitation of data acquisition accuracy and quantitatively describe the crack according to the data collected by the current equipment is a technical problem to be solved.

[0010] In view of the deficiencies of the prior art, the present application provides a spatial quantitative description system for fault joint crack characteristics, which comprises at least one coordinate acquisition component and at least one processor, the coordinate acquisition component and the processor are connected in a wired and / or wireless manner, the coordinate acquisition component at least acquires spatial coordinate data of the fault joint crack and sends it to the processor; the processor is configured to: determine the fault joint crack characteristics based on the spatial coordinate data; construct an ellipsoid basic equation capable of covering the spatial distribution range of the crack based on the spatial coordinate data; construct a three-dimensional ellipsoid based on the ellipsoid basic equation; and describe the fault joint crack characteristics based on the spatial geometric parameters of the ellipsoid basic equation.

[0011] The present application fits the ellipsoid to the collected spatial coordinate data, and then accurately describes the physical characteristics of the crack according to the spatial geometric parameters of the fitted ellipsoid. That is, the present application can accurately quantitatively describe the crack according to the spatial geometric parameters of the ellipsoid even if the accuracy of the current spatial coordinate data of the crack is generally low by means of three-dimensional ellipsoid fitting. The quantitative description result of the present application is not limited by the accuracy of the spatial coordinate data.

[0012] Preferably, the way of describing the fault joint fissure feature at least includes: describing the width-related geometric feature of the fault and / or fracture zone based on the third principal axis parameter of the ellipsoid; and describing the spatial feature of the fault joint fissure based on the area and / or normal of the principal plane of the ellipsoid. For example, the spatial size of the fault joint fissure is described based on the area of the principal plane of the ellipsoid basic equation; and / or the spatial orientation of the fault joint fissure is described based on the normal of the principal plane of the ellipsoid. In view of the defects of the prior art, the system of the present application constructs the ellipsoid basic equation based on the spatial coordinate data of the fissure of the elastic wave, and the present application can accurately describe the fault joint fissure feature based on the spatial geometric parameters of a single ellipsoid, such as the spatial extension state of the fault, the fault zone width, the opening degree of the fissure, the spatial size, and the like. The present application can even judge the pros and cons of the fitting effect of the ellipsoid by the average coverage of the spatial distribution range of the ellipsoid and the fissure vector, so as to select the ellipsoid with good fitting effect to accurately describe the fault joint fissure feature. The spatial geometric parameters of the ellipsoid and the physical characteristics of the fissure are related, and the geometric feature and the spatial feature of the fissure are described by the spatial geometric parameters of the ellipsoid, which is simple to calculate and unified in standard.

[0013] Preferably, the way of constructing the ellipsoid basic equation capable of covering the spatial distribution range of the fissure based on the spatial coordinate data at least includes: determining the fitting way of the coefficients of the ellipsoid basic equation based on the amount of spatial coordinate data; and determining the spatial geometric parameters of the ellipsoid based on the coefficients of the ellipsoid basic equation.

[0014] For example, in the case that the amount of spatial coordinate data is sufficient, the coefficients of the ellipsoid basic equation can be calculated without the need of supplementing points. Preferably, the amount of spatial coordinate data is at least four, and less than four cannot construct a geometric cube, i.e., the spatial distribution range of the spatial coordinate data cannot be determined. The spatial distribution range is covered by the ellipsoid, and the spatial coordinate data can be converted into a three-dimensional ellipsoid.

[0015] Preferably, the step of determining the fitting way of the coefficients of the ellipsoid basic equation based on the amount of spatial coordinate data at least includes: directly fitting the coefficients of the ellipsoid basic equation in the case that the amount of received spatial coordinate data is not less than a data threshold; and fitting the coefficients of the ellipsoid basic equation in the way of randomly supplementing points on the principal plane of the ellipsoid in the case that the amount of received spatial coordinate data is less than the data threshold.

[0016] In the case of insufficient data, the obtained data is less, and the ellipsoid fitting effect in the prior art is poor, so that the fracture, such as a fault joint, cannot be accurately described. The present application determines the fitting mode of the coefficients of the ellipsoid according to the number of spatial coordinate data, and in the case of insufficient spatial coordinate data, the random point supplement method is used to supplement points and fitting, which makes up for the defect of insufficient data, and does not increase the calculation deviation of the coefficients. The fitting algorithm of the present application is more accurate, and the quantitative description is more accurate.

[0017] Preferably, the step of fitting the coefficients of the ellipsoid basic equation in the main plane of the ellipsoid in a random point supplement manner comprises at least: determining the main plane of the ellipsoid based on the maximum fracture vector direction of the ellipsoid being the first main direction of the ellipsoid; randomly generating points in a preset angle range of the first main direction and the opposite direction of the first main direction; randomly generating points in the second main direction; determining the point generation direction based on the angle between the fracture vector and the main plane and mirroring the fracture vector in the non-main plane; fitting and calculating the coefficients of the ellipsoid basic equation. Preferably, the present application increases the spatial coordinate points in a reasonable range by the random point supplement method, so that the coefficients of the ellipsoid can be accurately calculated.

[0018] Preferably, the processor is further configured to judge the ellipsoid fitting effect based on the average coverage of the ellipsoid and the fracture vector. The average coverage of the present application can reflect the effect of the ellipsoid fitting, so as to exclude the ellipsoid with poor fitting effect.

[0019] Preferably, the calculation step of the average coverage comprises at least: solving the intersection points of the fitted ellipsoid and each fracture vector equation; calculating the average coverage difference of each fracture vector and the intersection points; determining the average coverage based on the average coverage difference.

[0020] The present application can visually describe the coverage of the ellipsoid to the fracture vector through the calculation of the average coverage, and the larger the ellipsoid coverage, the better the fitting effect of the ellipsoid. The calculation process of the average coverage of the present application is simple, the concept is easy to understand, and the advantages and disadvantages of the ellipsoid fitting effect can be objectively and effectively judged, which provides an objective basis for the evaluation of the ellipsoid fitting effect.

[0021] The present application also provides a spatial quantitative description method of fault joint fracture characteristics, which comprises at least: collecting spatial coordinate data of the fault joint fracture; determining the fault joint fracture characteristics based on the spatial coordinate data; constructing an ellipsoid basic equation capable of covering the spatial distribution range of the fracture based on the spatial coordinate data; and describing the fault joint fracture characteristics based on the spatial geometric parameters of the ellipsoid basic equation.

[0022] Based on the defects of the progress of the spatial coordinate data of the fissure in the prior art and the insufficient quantitative description of the physical characteristics of the fissure, the physical characteristics of the fissure are expressed by using a three-dimensional ellipsoid, and the geometric characteristics and the spatial characteristics of the fissure are quantitatively described. The advantage of the present application is that the accurate three-dimensional ellipsoid can be calculated without the high-precision spatial coordinate acquisition component, that is, the acquisition precision of the current equipment can meet the needs of the present application, and meanwhile, the accurate quantitative description of the fissure is not affected.

[0023] Preferably, the way of describing the fault joint fissure characteristics at least includes: describing the width-related geometric characteristics of the fault and / or the fracture zone based on the third principal axis parameter of the ellipsoid; and describing the spatial characteristics of the fault joint fissure based on the area and / or normal of the principal plane of the ellipsoid.

[0024] The principal axis parameters, the area of the principal plane and the normal of the three-dimensional ellipsoid of the present application can respectively describe the geometric characteristics and the spatial characteristics of the fissure, and provide accurate information content. In the application field of the fissure information of the solid, more accurate fissure information can be provided.

[0025] Preferably, the way of constructing the ellipsoid basic equation capable of covering the spatial distribution range of the fissure based on the spatial coordinate data at least includes: determining the fitting way of the coefficients of the ellipsoid basic equation based on the data amount of the spatial coordinate data; and determining the spatial geometric parameters of the ellipsoid based on the coefficients of the ellipsoid basic equation.

[0026] The spatial quantitative description method of the fault joint fissure characteristics of the present application simplifies the calculation steps of the current ellipsoid, and only one ellipsoid needs to be fitted to accurately describe the fault joint fissure characteristics.

[0027] The present application adopts the principal plane random supplementary point method, which not only simplifies the fitting steps, but also can obtain an ellipsoid covering more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a spatial coordinate point distribution schematic diagram formed by the spatial coordinate data of 4 fissures provided by the present application;

[0029] Figure 2 is a fissure vector schematic diagram formed by the spatial coordinate data of 4 fissures provided by the present application;

[0030] Figure 3 is a spatial distribution range schematic diagram formed by the spatial coordinate data of 4 fissures provided by the present application;

[0031] Figure 4 is a spatial coordinate point distribution schematic diagram formed by the spatial coordinate data of 6 fissures provided by the present application;

[0032] Figure 5 is a schematic diagram of a fissure vector formed by 6 fissure spatial coordinate data provided by the present application;

[0033] Figure 6 is a schematic diagram of a spatial distribution range formed by 6 fissure spatial coordinate data provided by the present application;

[0034] Figure 7 is a schematic diagram of a main plane determination provided by the present application;

[0035] Figure 8 is a schematic diagram of a random supplementary point provided by the present application;

[0036] Figure 9 is a schematic diagram of an ellipsoid covering fissure vector provided by the present application;

[0037] Figure 10 is a simplified schematic diagram of a hardware structure of a spatial quantitative description system of the present application.

[0038] LIST OF REFERENCE NUMERALS

[0039] 1: coordinate acquisition assembly; 2: processor; 3: fault joint fissure; 4: spatial coordinate point; 5: barycenter; 6: fissure vector; 7: polyhedron. DETAILED DESCRIPTION

[0040] The following will be described in detail in combination with the drawings.

[0041] The present application provides a spatial quantitative description system and method of fault joint fissure characteristics, and can also provide an ellipsoid fitting method and system of fault joint fissure characteristics. The present application can also provide an ellipsoid fitting effect judgment method and system.

[0042] The present application can also provide a processor, which can run the code program of the spatial quantitative description method of fault joint fissure characteristics.

[0043] The present application makes the following explanations on some noun terms.

[0044] Fissure: a crack in rock caused by the influence of geological action.

[0045] Fault (fissure): a rupture of stratum caused by stress, with obvious displacement on both sides of the rupture surface, that is, the fault will cross the stratum boundary. There are many types of faults, and the occurrence is very complex, but the number is generally small.

[0046] Joint (fissure): refers to a series of regular ruptures of rock under geological action, but the rock on both sides of the rupture does not have obvious displacement, and this rupture is called joint.

[0047] Coordinate acquisition component: used for acquiring spatial coordinate data of the fissure to obtain the fault joint fissure characteristics. The coordinate acquisition component can be a sensor, an elastic wave CT, an X-ray CT, etc. For example, various structural planes can be obtained by physical and geophysical means such as X-ray CT, ultrasonic CT, seismic CT, etc.

[0048] Preferably, the sensor is preferably a broadband vibration sensor, and the frequency range is 0-2 kHz (low frequency), 2 kHz-500 kHz (high frequency) according to different monitoring objects. The high frequency can select a R6 type piezoelectric ceramic sensor or a W800 type piezoelectric ceramic sensor, and the low frequency sensor can select a full optical fiber microseismic probe produced by Anhui Zibo Optoelectronic Technology Co., Ltd.

[0049] Processor: refers to a special integrated chip and / or server, CPU, single-chip microcomputer, etc. capable of running the coded program of the spatial quantitative description method of the fault joint fissure characteristics.

[0050] Barycenter: refers to the barycenter of a three-dimensional geometry composed of four or more spatial coordinate data.

[0051] Fissure vector: refers to a vector from the barycenter to the spatial coordinate data of the fissure.

[0052] Fissure ellipsoid: a spherical body with the barycenter as the center, which is used as a reference for calibrating fissure vectors in different directions and distances in space, and covers the three-dimensional geometry composed of spatial coordinate data.

[0053] In the present application, the unit of the spatial coordinate axis of the spatial coordinate system as an example is millimeter (mm). The unit of the spatial coordinate axis can be set to other length units, and the fitting method of the ellipsoid remains unchanged.

[0054] Since the description of the physical characteristics of the fissure in the prior art only depends on the acquisition amount and accuracy of the spatial coordinate data, in the case of insufficient acquisition accuracy, part of the fissure of the solid cannot be accurately described.

[0055] The present application updates the idea, and describes the physical characteristics of the fissure by using a three-dimensional ellipsoid capable of covering the fissure vector. In this method, the spatial coordinate data acquired by the existing equipment can obtain an accurate three-dimensional ellipsoid, and the fissure can also be quantitatively described based on the spatial geometric parameters of the ellipsoid. Therefore, the present application is simple to calculate and can accurately quantitatively describe the fissure.

[0056] The principle of the present application is:

[0057] The plurality of spatial coordinate data of the fissure is collected and the corresponding spatial coordinate points are connected to form a polyhedron, and an ellipsoid basic equation is fitted according to the center of gravity data of the polyhedron and the plurality of spatial coordinate data. The three-dimensional ellipsoid corresponding to the ellipsoid basic equation covers the center of gravity of the fissure and the plurality of spatial coordinate points, and represents that the ellipsoid covers the spatial structure of the fissure, the fracture zone and the like. For example, the ellipsoid covers the spatial distribution range of the fault joint fissure. The ellipsoid covers the spatial distribution range of the fracture zone. That is, in the case that the spatial distribution range of the fissure is covered by the three-dimensional spatial range of the ellipsoid, the spatial geometric parameters of the ellipsoid are related to the physical characteristics of the fissure. Therefore, the spatial geometric parameters of the ellipsoid can be used to quantitatively describe the geometric characteristics and spatial characteristics of the fault joint fissure.

[0058] The spatial quantitative description system of the fault joint fissure characteristics of the present application, as shown in Figure 10 , comprises at least one coordinate collection component 1 and at least one processor 2. The plurality of coordinate collection components 1 are connected with the processor 2 in a wired and / or wireless manner, so as to send the detected spatial coordinate data of the fault joint fissure 3 to the processor 2.

[0059] When the fault, joint and fissure are generated in the solid such as rock, the spatial coordinate data of the fault, joint and fissure with different sizes can be detected by the coordinate collection component 1. The spatial measurement means of the fissure surface is mature, and the spatial coordinate data of the fissure surface is easy to obtain. The coordinate collection component is arranged around the fissure to collect the spatial coordinate data of the fault joint fissure from multiple directions

[0060] Embodiment 1

[0061] After receiving the spatial coordinate data sent by the plurality of coordinate collection components 1, the processor 2 is configured to process the received data according to the following steps.

[0062] S1: constructing the spatial distribution range of the fault joint fissure 3.

[0063] As shown in Figure 1 , the x-axis, y-axis and z-axis in the spatial coordinate system represent three coordinate axes of the space. The spatial coordinate system is used to characterize the spatial distribution range of the plurality of fissures, and the coordinate origin is determined by the user. It is necessary to receive the spatial coordinate data by the plurality of coordinate collection components to construct the spatial distribution range of the fault joint fissure.

[0064] In the present application, it is suggested that the fitting of the ellipsoid is carried out by more than 4 spatial coordinate data. Because in the case that the spatial coordinate data is less, the obtained data is less, which leads to the poor coverage of the ellipsoid to the spatial distribution range of the plurality of fissures. Especially, in the case that the number of spatial coordinate data is less than 4, the spatial distribution range of the fissure cannot be obtained, and the ellipsoid cannot be fitted and obtained.

[0065] As Figure 1 shown, there are four spatial coordinate points 4 in the spatial coordinate system, representing four spatial coordinate data. As Figure 3 shown, the four spatial coordinate points 4 are connected to form a tetrahedron, representing the spatial distribution range of the spatial coordinate data. As Figure 2 shown, the center of gravity of the tetrahedron is the center of gravity 5. The center of gravity 5 is connected to each spatial coordinate point and forms a fissure vector 6 pointing to the position of each spatial coordinate point.

[0066] As Figure 2 and Figure 3 shown, the tetrahedron of the three-dimensional space, the center of gravity (C x , C y , C z ) is the arithmetic mean of the four vertices (x i , y i , z i ).

[0067]

[0068]

[0069]

[0070] To find the center of gravity of the polyhedron 7 in three-dimensional space, the polyhedron 7 needs to be divided into tetrahedrons, and then the center of gravity coordinates of the tetrahedrons are weighted and averaged according to the volume. The polyhedron 7 is divided into n tetrahedrons. The centers of gravity of the tetrahedrons are respectively The volumes of the tetrahedrons are V1…V n , and the center of gravity of the polyhedron 7 is:

[0071] Table 1 Tetrahedron center of gravity data calculation list

[0072]

[0073] Table 1 shows the data calculation process of a set of tetrahedron center of gravity. The spatial coordinate points of the four fissures are (21.01, 23.4, 14.75), (28.05, 8.26, 46.66), (29.13, 11.16, 14.24), and (41.75, 12.20, 34.76). Then the spatial coordinates of the center of gravity of the tetrahedron are (29.99, 13.76, 27.60).

[0074] S2: Construct a spherical ball covering several fissure vectors.

[0075] As Figure 2 shown, a spherical ball is set to enclose the spatial distribution range of the fissure vectors.

[0076] A sphere is made with the gravity center 5 as the center. Preferably, the radius of the sphere can be arbitrary, and is preferably greater than the fissure vector. The fissure spatial coordinate data detected by the coordinate acquisition assembly in different directions and different distances in space is a spheroid generated by the fissure process. The spatial coordinate data of the fissure is used to obtain the basic equation and the standard form of the spheroid by the least square method, and the structural characteristics of the fissure are further represented.

[0077] S3: The specific form of the spheroid equation is calculated and obtained.

[0078] Preferably, the fitting mode of the coefficients of the spheroid basic equation is determined based on the data amount of the spatial coordinate data.

[0079] In the case that the data amount of the received spatial coordinate data is not less than the data threshold, the coefficients of the spheroid basic equation are directly fitted.

[0080] In the case that the data amount of the received spatial coordinate data is less than the data threshold, the coefficients of the spheroid basic equation are fitted in the main plane of the spheroid in a random point supplementing manner.

[0081] The data threshold is preferably 10. That is, the spatial coordinate data is less than 10, and random point supplementing is needed. The spatial coordinate data is greater than or equal to 10, and random point supplementing is not needed.

[0082] The data threshold of the present application is not limited to 10, but can also be 8, 9, 11, 12, etc. In the experimental data analysis process, the data threshold is taken as 10, which can meet the fitting needs of the spheroid. If the data threshold is less than 10, for example, in the case of 9 spatial coordinate data, no point supplementing is performed, and the fitting effect of the spheroid is poor. If the data threshold is greater than 10, for example, in the case of 10 spatial coordinate data, point supplementing is performed, and the fitting effect of the spheroid is not much different between the random point supplementing and the non-random point supplementing, and it is meaningless to distinguish between the two cases.

[0083] Therefore, after analyzing a large amount of spatial coordinate data and the fitting effect of the spheroid, it is found that the data threshold taken as 10 is more appropriate.

[0084] In the case that the data amount of the received spatial coordinate data is not less than the data threshold (for example, 10), the coefficients of the basic equation of the spheroid are calculated according to steps S31-S32.

[0085] S31: The coefficients of the spheroid equation are obtained based on the acquired spatial coordinate data.

[0086] The basic equation of the spheroid can be expressed as:

[0087] F(x,y,z)=a 11 x2 +a 22 y 2 +a 33 z 2 +2a 12 xy+2a 13 xa+2a 23 yz+2a 14 x+2a 24 y+2a 34 z+a 44 (1)

[0088] In the basic equation of the ellipsoid, the x, y, z coordinates represent the spatial coordinates of the corresponding fracture on the sphere, and the sizes are respectively the fracture vector multiplied by the direction cosine. a represents a coefficient, which is the coefficient of the ellipsoid equation (1) obtained by fitting based on the spatial coordinate data collected by the coordinate collection component.

[0089] The spatial geometric parameters of the ellipsoid at least include the ellipsoid center, the axis length, the focal point coordinates, etc. However, the spatial geometric parameters of the ellipsoid cannot be directly obtained based on the basic equation (1) of the ellipsoid. Therefore, it is necessary to modify the basic equation (1) of the ellipsoid into a standard form.

[0090] S32: modifying the basic equation of the ellipsoid into a standard form of the ellipsoid.

[0091] Preferably, the least square method is used to fit to obtain the coefficients of the basic equation of the ellipsoid.

[0092] The standard form of the ellipsoid can be expressed as:

[0093]

[0094] In the above formula, x0, y0, z0 represent the coordinates of the center of the ellipsoid, and a, b, c represent the long, medium and short half-axis lengths of the ellipsoid respectively.

[0095] The coefficients of the basic equation of the ellipsoid are simplified as follows:

[0096]

[0097] K3 = |A|, I3 = |A*| (3)

[0098] Wherein, I3 represents the third invariant of the matrix A*, and K3 represents the third semi-invariant of A, and their values are respectively the determinants of the corresponding matrices.

[0099] At the same time, the eigenvalues (λ1, λ2, λ3) and unit eigenvectors (η1, η2, η3) corresponding to A* can also be obtained.

[0100] Using the above parameters, the center coordinates X c = (xc ,y c ,z c ), half-axes (a, b, c), half-focal length (pseudo) are respectively:

[0101] X c T =-(A * ) - [a 14 a 24 a 34 T (4)

[0102]

[0103]

[0104] The first principal axis (i.e. the long axis) of the ellipsoid corresponds to the direction determined by the eigenvector η1, and the focal point of the ellipsoid is on its long axis, the coordinates of which can be calculated using the spherical center coordinates. At this point, all the spatial geometric parameters of the ellipsoid have been obtained.

[0105] With the center of gravity as the focal point on the long axis of the ellipsoid, the spatial geometric parameters of the ellipsoid are the physical characteristic parameters of the fissure, i.e. the fissure can be quantitatively described by the ellipsoid parameters.

[0106] In the present application, the first principal axis direction of the ellipsoid is the direction of the largest fissure vector. The principal plane is determined based on the first principal axis. On the principal plane, the first principal axis is perpendicular to the second principal axis. The projection size of the largest fissure vector direction on the second principal axis is the size of the second principal axis. The third principal axis is an axis perpendicular to the first principal axis and the second principal axis. Preferably, the opening degree of the fault joint fissure is described based on the third principal axis parameter of the ellipsoid. The spatial size of the fault joint fissure is described based on the area of the principal plane of the ellipsoid. The spatial orientation of the fault joint fissure is described based on the normal of the principal plane of the ellipsoid.

[0107] The ellipsoid has good adaptability in covering various joints, fissures, faults and fracture zones.

[0108] The covering mode of the ellipsoid of the present application for the fissure is not limited to the only mode of covering the spatial distribution range of several fissures. It also includes the following covering modes.

[0109] First, for a single fault joint fissure, the ellipsoid can be directly used for covering.

[0110] Second, for regularly distributed joints, appropriate spatial distribution range can also be covered using the ellipsoid.

[0111] Third, for multiple fissures with large differences in size, the ellipsoid can be used for complete coverage of the main fissure while taking into account the distribution space of most small fissures.​

[0112] Fourth, for the rest of the rock mass structure surface, such as dense fracture zone (cleavage zone), fault fracture zone, metamorphic structure surface, sedimentary structure surface, weak interlayer, etc., the processing method is similar.

[0113] In summary, various structure surfaces determined by geology can be quantitatively represented by the tensor of the fracture ellipsoid, so as to be directly applied to the constitutive relation, meeting the needs of quantitative calculation in mechanics or numerical simulation.

[0114] S4: Calculate the coefficients of the basic equation (1) of the ellipsoid.

[0115] Preferably, when the spatial coordinate data is greater than or equal to 10, the processor does not need to randomly supplement the principal plane of the ellipsoid. When receiving fracture data collected by 9 or more coordinate acquisition components (i.e. 9 groups of coordinate data), the coefficients of the basic equation (1) of the ellipsoid can be obtained by least square fitting.

[0116] S5: Calculate the spatial geometric parameters of the ellipsoid.

[0117] Preferably, the processor calculates the spatial geometric parameters of the ellipsoid based on the least square method as follows.

[0118]

[0119] Wherein, min G(A) represents the objective function, a represents the long axis half axis length, b represents the medium axis half axis length, and c represents the short axis half axis length.

[0120] In the case of setting the objective function as the volume of the ellipsoid, then:

[0121]

[0122] min G'(A) represents the volume of the ellipsoid.

[0123] The above formula is further simplified, which is equivalent to:

[0124] min G"(A) = |I3| (7-3)

[0125] min G"(A) represents the volume of the ellipsoid, and I3 = |A*|.

[0126] The first constraint condition is n linear equations established by the fracture vector, that is, n basic equations of the ellipsoid. At this time, the variable is the element of the matrix A, and x, y, z represent the spatial coordinate data. That is:

[0127] a 11 x 2 +a 22 y 2 +a33 z 2 +a 12 xy+a 13 xz+a 23 yz+a 14 x+a 24 y+a 34 z+a 44 =0 (8)

[0128] The second constraint is the coefficient condition in the standard form of the ellipsoid equation, namely:

[0129]

[0130] The third constraint is the condition for solving the characteristic equation of the quadratic coefficient matrix of the ellipsoid equation, that is, the condition that the cubic equation in one variable has three real roots, namely:

[0131] Δ=4I1 3 I3-I1 2 I2 2 -18I1I2I3+27I3 2 ≤0 (10)

[0132] Where I1 represents the first invariant of matrix A*; I2 represents the second invariant of matrix A*; and I3 represents the third invariant of matrix A*.

[0133] The fourth constraint is the focus constraint, and the source point coordinates (x) c ,y c ,z c The focal coordinates are the same as those calculated using the semi-axis length and semi-focal length, and their expression is:

[0134] x c =x0-C0η1(1),y c =y0-C0η1(2),z c =z0-C0η1(3) (11)

[0135] Where x0, y0, and z0 represent the coordinates of the ellipsoid center, C0 represents the semi-focal length, and η1 represents the unit principal vector along the principal axis. Equations (1), (2), and (3) in this formula contain three direction vectors, each of which is represented by three components.

[0136] When there are fewer than 10 spatial coordinate data points, the processor needs to randomly fill in the points on the principal plane of the ellipsoid. The steps for randomly filling in the points on the ellipsoid are as follows.

[0137] S51: Determine the principal plane.

[0138] like Figure 7As shown, the first principal direction of the ellipsoid is the maximum fissure vector direction, the maximum value of the maximum fissure vector module is the major axis, i.e. The cross product of each fissure vector and the maximum fissure vector direction is taken, and the maximum value of the module is the minor axis, i.e. The cross product of the maximum fissure vector and the corresponding fissure vector is taken, and the maximum value of the module is the minor axis, i.e. The corresponding fissure vector The fissure vector The unit vector obtained by the cross product of the maximum fissure vector direction and the fissure vector is the principal plane normal, i.e. The normal of the principal plane is determined, i.e. the principal plane is determined. The fissure vector is represented by The fissure vector with the maximum module is represented by The module of is represented. The direction perpendicular to the first principal axis on the principal plane is the second principal axis direction. The projection size of the fissure vector on the second principal axis is the second principal axis size, i.e. The second principal axis size is represented.

[0139] S52: Randomly generate points.

[0140] As shown in Figure 8 , within a 5-degree range in the first principal direction, 2 points are randomly generated with a size of 0.9-1.1 Within a 15-degree range in the opposite direction of the first principal direction, 2 points are randomly generated with a size of 0.9-1.1 2 points are randomly generated in the second principal direction with a size of 0.9-1.1

[0141] In addition to the two fissure vectors that determine the principal plane, mirror points are generated for the other fissure vectors, which have an angle of α with the principal plane normal. When the angle α is less than , points are generated in the direction with an angle of π-2α with the fissure vector with a size of 0.9-1.1 When the angle is greater than , points are generated in the direction with an angle of 2α-π with the fissure vector with a size of 0.9-1.1

[0142] Figure 7 The schematic diagram for determining the principal plane of the present application is Figure 8 The schematic diagram for randomly generating points is

[0143] S53: Determine the fitting effect.

[0144] The smaller the ellipsoid area and the more fissure vectors that can be covered, the better the fitting effect.

[0145] Specifically, the intersection of the ellipsoid formed by fitting and each fracture vector equation is solved, the square root of the square sum of the residual error of each fracture vector and the intersection point is taken, and then divided by the number of spatial coordinate points, that is, the average coverage difference of the fracture vector is obtained. Divide the average coverage difference by the sum of the fracture vector modulus and multiply by the percentage to get the coverage difference ratio. Subtract 1 from the value, and the ellipsoid coverage rate is obtained. The larger the ellipsoid coverage rate is, the better the fitting effect of the ellipsoid is.

[0146] The method of randomly generating points in the main plane of the present application makes the average coverage difference within 10 mm.

[0147] For example, the ellipsoid expression is:

[0148] F(x,y,z)=a 11 x 2 +a 22 y 2 +a 33 z 2 +a 12 xy+a 13 xz+a 23 yz+a 14 x+a 24 y+a 34 z+a 44 =0.

[0149] The gravity center coordinates M0(x0,y0,z0) in the space polyhedron 7 and the fracture vector The vertex coordinates of the fracture vector are (x2,y2,z2), and M(x,y,z) is any point on the fracture vector. The fracture vector equation is

[0150] The intersection M1(x1,y1,z1) of the ellipsoid and the fracture vector equation is solved.

[0151] The residual error (distance) of the fracture vector and the intersection point

[0152] The average coverage difference of the fracture vector is

[0153] The sum of the fracture vector modulus is The ellipsoid coverage rate is

[0154] S6: Quantitatively describe the characteristics of faults and joints based on the fitted ellipsoid.

[0155] The present application can uniquely determine the spatial geometric parameters of the ellipsoid by least square fitting of the ellipsoid to the maximum fissure. In the ellipsoid, the first principal axis direction represents the maximum fissure vector direction. The principal plane refers to the plane in which the first principal axis and the second principal axis are located. The second principal axis is perpendicular to the first principal axis in the principal plane. The direction perpendicular to the first principal axis direction in the principal plane is the second principal axis direction. The axis perpendicular to the first principal axis and the second principal axis is the third principal axis.

[0156] The third principal axis parameter of the ellipsoid is used to describe the width-related geometric characteristics of the fault and / or fracture zone. The area and / or normal of the principal plane of the ellipsoid are used to describe the spatial characteristics of the fault joint fissure. Specifically, the area of the principal plane of the ellipsoid basic equation is used to describe the spatial size of the fault joint fissure. The normal of the principal plane of the ellipsoid is used to describe the spatial orientation of the fault joint fissure. Therefore, the present application obtains the physical characteristics of the fissure through the geometric characteristics of the spatial ellipsoid, which is simple in calculation and clear in physical process, and can be understood without professional background.

[0157] Embodiment 2

[0158] This embodiment is a further improvement of the foregoing, and the repeated contents will not be described again.

[0159] A spatial quantitative description method of fault joint fissure characteristics, the method at least comprises:

[0160] Collecting spatial coordinate data of the fault joint fissure;

[0161] Determining the fault joint fissure characteristics based on the spatial coordinate data;

[0162] Constructing an ellipsoid basic equation capable of covering the spatial distribution range of the fissure based on the spatial coordinate data;

[0163] Describing the fault joint fissure characteristics based on the spatial geometric parameters of the ellipsoid basic equation.

[0164] Preferably, the way of describing the fault joint fissure characteristics at least comprises:

[0165] First, the third principal axis parameter of the ellipsoid is used to describe the width-related geometric characteristics of the fault and / or fracture zone. For example, the third principal axis parameter of the ellipsoid is used to describe the opening degree, width, etc. of the fault joint fissure; or the third principal axis parameter of the ellipsoid is used to describe the opening degree, width, etc. of the fracture zone; and can also be used to describe the opening degree or width of the dense fracture zone (cleavage zone), fault fracture zone, metamorphic structural plane, sedimentary structural plane, weak interlayer, etc.

[0166] Second, the area and / or normal of the principal plane of the ellipsoid are used to describe the spatial characteristics of the fault joint fissure.

[0167] Specifically, the area of the major plane of the ellipsoid is used to describe the spatial size of the fault joint fissure.

[0168] The ellipsoid of the present application is not limited to the above three ways of characterizing the fault joint fissure, and can also include other aspects of the fault joint fissure.

[0169] Preferably, the way of constructing the ellipsoid basic equation capable of covering the spatial distribution range of the fissure based on the spatial coordinate data at least includes:

[0170] The fitting way of determining the coefficients of the ellipsoid basic equation based on the data amount of the spatial coordinate data. The spatial geometric parameters of the ellipsoid are determined based on the coefficients of the ellipsoid basic equation.

[0171] The step of fitting the coefficients of the ellipsoid basic equation based on the fitting way of determining the coefficients of the ellipsoid basic equation based on the data amount of the spatial coordinate data at least includes:

[0172] In the case that the data amount of the received spatial coordinate data is not less than the data threshold, the coefficients of the ellipsoid basic equation are directly fitted. In the case that the data amount of the received spatial coordinate data is less than the data threshold, the coefficients of the ellipsoid basic equation are fitted in the major plane of the ellipsoid in a random supplementary point manner. The data threshold ranges from 10.

[0173] Preferably, the step of fitting the coefficients of the ellipsoid basic equation in the major plane of the ellipsoid in a random supplementary point manner at least includes: determining the major plane of the ellipsoid based on the maximum fissure vector of the ellipsoid as the first principal direction of the ellipsoid; randomly generating points within a preset angle range of the first principal direction and the opposite direction of the first principal direction; randomly generating points in the second principal direction; determining the point generation direction based on the included angle between the fissure vector and the major plane and mirror generating points for the fissure vector not in the major plane; fitting and calculating the average coverage of the fissure vector.

[0174] Preferably, the fitting effect of the ellipsoid is judged based on the average coverage of the ellipsoid and the fissure vector. In the case of good fitting effect, the spatial geometric parameters of the ellipsoid basic equation are used to describe the characteristics of the fault joint fissure.

[0175] Embodiment 3

[0176] This embodiment further illustrates the ellipsoid fitting based on six spatial coordinate data representing the fissure characteristics, as shown in Figures 4-6 , Figure 9 The repeated calculation process of Embodiment 1 is not repeated here. The tetrahedron in Table 2 refers to each tetrahedron formed after the hexahedron is divided.

[0177] Table 2 Hexahedron center of gravity calculation data list

[0178]

[0179]

[0180] As Figure 4 The six spatial coordinate data of the fissure collected by the spatial coordinate collection component 1 are (32.40, 7.40, -11.39), (36.33, 0.72, 18.86), (32.33, 15.35, -10.47), (34.37, 19.61, 18.11), (47.48, 11.62, -2.50), and (19.89, 11.57, -1.07), as shown in Table 2.

[0181] As Figure 6 shown, the six spatial coordinate points are connected to form a hexahedron. The hexahedron is divided into four tetrahedrons. The centers of the four tetrahedrons are (30.24, 8.76, -1.01), (30.73, 11.81, 6.36), (37.14, 8.77, -1.37), and (37.63, 11.82, 6.00), respectively. The volumes of the four tetrahedrons are 563.15, 1233.92, 578.09, and 1274.87, respectively. Based on the centers of gravity and the volumes of the four tetrahedrons, the spatial coordinates of the center of gravity of the hexahedron are calculated as:

[0182] As Figure 5 shown, the center of gravity 5 is connected to each of the six spatial coordinate points 4 to form six fissure vectors 6.

[0183] Since the number of spatial coordinate points is less than 10, a random supplementary point is used to calculate the coefficients of the ellipsoid basic equation. As Figure 9 shown, after the coefficients of the ellipsoid basic equation are calculated, the ellipsoid is fitted in the three-dimensional spatial coordinate system. According to Figure 9 It can be seen that the three-dimensional ellipsoid covers most of the fissure vectors. The average coverage rate of the ellipsoid and the fissure vectors is calculated, as shown in Table 3.

[0184] Table 3 Ellipsoid coverage rate calculation list of six spatial coordinate points

[0185]

[0186]

[0187] Table 3 is the ellipsoid coverage of the fissure vector of the ellipsoid calculated based on the spatial coordinate data of the six fissures and the related parameters. The average coverage difference is 5.533, and the ellipsoid coverage is 95.21%, indicating that the fitting effect of the ellipsoid is good. In the case of confirming the fitting effect of the ellipsoid, the spatial geometric parameters based on the basic equation of the ellipsoid are used to quantitatively describe the fissure.

[0188] Table 4 shows the spatial geometric parameters of one of the basic equations of the ellipsoid calculated by the present application. As shown in Table 4, the third principal axis parameter of the ellipsoid is 2.18, indicating that the opening of the fault and / or fracture zone is 2.18 mm. The area of the principal plane based on the basic equation of the ellipsoid is 87.55, indicating that the spatial size of the fissure is -87.55 mm 2 . The normal vector of the principal plane of the ellipsoid is (-0.96, -0.085, 0.26), indicating that the coordinates of the spatial orientation of the fissure are (-0.96, -0.085, 0.26).

[0189] Table 4 Spatial geometric parameters of the ellipsoid

[0190]

[0191] As shown above, the present application performs ellipsoid fitting on the spatial coordinate data of the six fissures, and the fitting effect is good according to the average coverage. In the case of good fitting, the physical characteristics of the fissure are quantitatively described.

[0192] In the entire calculation process, the calculation results of the present application are not affected by the collection accuracy of the spatial coordinate data of the fissure, and the characteristics of the fissure and its fracture zone can be accurately described.

[0193] It should be noted that the above specific embodiments are exemplary, and those skilled in the art can think of various solutions under the inspiration of the disclosure of the present application, and these solutions also belong to the disclosed range of the present application and fall within the protection scope of the present application. Those skilled in the art should understand that the specification and drawings of the present application are illustrative and not constitute a limitation on the claims. The protection scope of the present application is defined by the claims and their equivalents. The specification of the present application contains multiple inventive concepts, such as "preferably", "according to a preferred embodiment" or "optionally", which all indicate that the corresponding paragraph discloses an independent concept, and the applicant reserves the right to file a divisional application according to each inventive concept.

Claims

1. A system for spatially quantifying the description of fault joint fracture features, comprising at least one coordinate acquisition component and at least one processor, characterized in that, The coordinate acquisition component is connected with the processor in a wired and / or wireless manner, The coordinate acquisition component at least acquires spatial coordinate data of the fault joint fissure and sends the data to the processor; The processor is configured to: determine the fault joint fissure characteristics based on the spatial coordinate data; construct an ellipsoid basic equation capable of covering the spatial distribution range of the fissure based on the spatial coordinate data; construct a three-dimensional ellipsoid based on the ellipsoid basic equation; describe the fault joint fissure characteristics based on the spatial geometric parameters of the ellipsoid.

2. The system for spatially quantifying the description of fault joint fracture features according to claim 1, wherein, The way of describing the fault joint fissure characteristics at least includes: describe the width-related geometric characteristics of the fault and / or the fracture zone based on the third principal axis parameter of the ellipsoid; describe the spatial characteristics of the fault joint fissure based on the area and / or normal of the principal plane of the ellipsoid.

3. A system for spatially quantifying the description of fault-joint-fracture features according to claim 1 or 2, characterized in that, The way of constructing an ellipsoid basic equation capable of covering the spatial distribution range of the fissure based on the spatial coordinate data at least includes: determine the fitting way of the coefficients of the ellipsoid basic equation based on the data amount of the spatial coordinate data; determine the spatial geometric parameters of the ellipsoid based on the coefficients of the ellipsoid basic equation.

4. The system for spatially quantifying the description of fault joint fracture features according to claim 3, wherein, The step of determining the fitting way of the coefficients of the ellipsoid basic equation based on the data amount of the spatial coordinate data at least includes: directly fit the coefficients of the ellipsoid basic equation when the data amount of the received spatial coordinate data is not less than a data threshold value; fit the coefficients of the ellipsoid basic equation in a random point supplementing manner on the principal plane of the ellipsoid when the data amount of the received spatial coordinate data is less than the data threshold value.

5. The system for spatially quantifying the description of fault joint fracture features according to claim 4, wherein, The step of fitting the coefficients of the ellipsoid basic equation in a random point supplementing manner on the principal plane of the ellipsoid at least includes: determine the principal plane of the ellipsoid based on the first principal direction of the ellipsoid in the direction of the maximum fissure vector of the ellipsoid; randomly generate points within a preset angle range of the first principal direction and the opposite direction of the first principal direction; randomly generate points in a second principal direction; determine the point generation direction based on the included angle between the fissure vector and the principal plane and mirror generate points for the fissure vectors other than the principal plane; fit and calculate the coefficients of the ellipsoid basic equation.

6. The system for spatially quantifying the description of fault joint fracture features according to claim 5, wherein, The processor is further configured to: judge the ellipsoid fitting effect based on the average coverage of the ellipsoid and the fissure vector.

7. The system for spatially quantifying the description of fault joint fracture features according to claim 6, wherein, The calculation step of the average coverage at least includes: solve the intersection points of the fitted ellipsoid and each fissure vector equation to obtain the intersection points; calculate the average coverage difference based on each fissure vector and the intersection points; determine the average coverage based on the average coverage difference.

8. A method of spatially quantifying the description of fault joint fracture features, characterized in that, The method at least includes: acquire spatial coordinate data of the fault joint fissure; determine the fault joint fissure characteristics based on the spatial coordinate data; construct an ellipsoid basic equation capable of covering the spatial distribution range of the fissure based on the spatial coordinate data; describe the fault joint fissure characteristics based on the spatial geometric parameters of the ellipsoid.

9. The method for spatially quantifying the description of fault joint fracture features according to claim 8, characterized in that, The way of describing the fault joint fissure characteristics at least includes: describe the width-related geometric characteristics of the fault and / or the fracture zone based on the third principal axis parameter of the ellipsoid; describe the spatial characteristics of the fault joint fissure based on the area and / or normal of the principal plane of the ellipsoid. The spatial characteristics of the fault joint fissure are described based on the area and / or normal of the major plane of the ellipsoid.

10. A method according to claim 8 or 9, c h a r a c t e r i s e d in that, The manner of constructing an ellipsoid basic equation capable of covering the spatial distribution range of the fissure based on the spatial coordinate data at least includes: The fitting manner of determining the coefficients of the ellipsoid basic equation based on the data amount of the receiving channel of the spatial coordinate data; The spatial geometric parameters of the ellipsoid are determined based on the coefficients of the ellipsoid basic equation.

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