Fine survey method and system for foundation pit covering rock mass integrity degree

Abstract

The present application belongs to the field of geotechnical engineering, and aims to provide a fine survey method and system for the completeness of the overburden rock mass of a foundation pit to solve the problem that the completeness of the overburden rock mass of a foundation pit cannot be provided before construction. The fine survey method for the completeness of the overburden rock mass of a foundation pit comprises the following steps: identifying all abnormal regions of structural planes and suspected abnormal parts in the rock mass according to the known geology of a set region and existing drilling survey data; fusing cross-hole elastic wave CT re-survey data to re-select structural plane abnormal regions from all suspected abnormal parts; excluding non-rock structural planes according to the new drilling images at each structural plane abnormal region to obtain a set of rock structural planes; obtaining the combination degree of the corresponding rock structure according to the characteristics of each rock structural plane in the set of rock structural planes; and determining the completeness of the rock mass in combination with the type and development degree of the rock structural plane. The method can provide the completeness of the overburden rock mass of a foundation pit before construction, and ensure the actual applicability of the excavation scheme.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering, and in particular relates to a method and system for fine surveying the integrity of the overburden rock mass of foundation pits. Background Technology

[0002] The integrity of the rock mass is a crucial indicator for assessing the surrounding rock grade of underground engineering projects. The surrounding rock grade and rock mass structural planes determine the structural capacity of the rock mass, manifested as its stable vertical height. Utilizing the structural capacity of the rock mass's stable vertical height can reduce or eliminate the need for rock mass support in soil-rock dual-element foundation pits, saving costs. The structural capacity of the rock mass in soil-rock dual-element foundation pits has a significant impact on the design scheme. However, since the rock mass is covered by soil, and the structural planes and integrity of the rock mass must be understood before foundation pit construction to ensure the relevance and applicability of the excavation plan. Existing technologies for assessing the integrity and structural plane characteristics of the rock mass generally rely on geological surveying methods, which are mainly applicable to exposed rock masses or rock masses that can be exposed after excavation, but not to overburdened rock masses.

[0003] In summary, the current lack of methods for surveying the integrity of overburden rock masses makes it impossible to provide information on the structural capacity of overburden rock masses for the design of soil-rock dual-element foundation pits. This results in design schemes lacking pertinence and practicality, causing huge waste or potential safety hazards. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method and system for finely surveying the integrity of the overburden rock mass in foundation pits. It is applicable to rock foundation pit projects where rock mass is the main component and a minimal or no support scheme is to be adopted. It can provide information on the integrity of the overburden rock mass before foundation pit construction, ensuring the practical applicability of the excavation scheme.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The first aspect of the present invention provides a method for detailed surveying of the integrity of the overburden rock mass in foundation pits.

[0007] In one or more embodiments, a detailed survey method for assessing the integrity of the overburden rock mass in a foundation pit is provided, including:

[0008] Based on the known geological and existing borehole exploration data of the designated area, identify all abnormal areas and suspected abnormal locations of structural planes in the rock mass;

[0009] By integrating the cross-hole elastic wave CT re-examination data, structural surface abnormal areas were further screened out from all suspected abnormal areas;

[0010] Based on the newly added borehole images at the abnormal areas of each structural plane, non-rock mass structural planes are excluded to obtain a set of rock mass structural planes, where the depth of the newly added boreholes is greater than the maximum depth of all abnormal areas of structural planes.

[0011] Based on the characteristics of each rock mass structural surface in the set of rock mass structural surfaces, the degree of bonding of the corresponding rock mass structure is obtained. Then, combined with the type and development degree of the rock mass structural surfaces, the integrity of the rock mass is determined.

[0012] As one implementation method, based on the known geological features of the designated area and the location of boreholes, combined with borehole exploration data such as high-density electrical resistivity tomography (EDT) data and transient electromagnetic data, all suspected abnormal locations in the rock mass are identified.

[0013] As one implementation method, a first joint determination function is used to identify all suspected abnormal locations in the rock mass; let the first joint determination function be... Its expression is:

[0014] ;

[0015] ;

[0016] ;

[0017] ;

[0018] ;

[0019] in, This indicates a relative anomaly in the high-density electrical resistivity tomography (EDT). This represents the relative anomaly rate of the transient electromagnetic method; and These are the weighting coefficients, and their sum is 1. For the sliding background resistivity; High-density electrical resistivity; For transient electromagnetic resistivity; Background value; The coordinates of the measuring point; and All are constants; when When the value is greater than or equal to the first threshold, it is determined that there is a structural anomaly region at that location; when When the value is less than the first threshold and greater than or equal to the second threshold, the location is determined to be a suspected abnormality; wherein, the second threshold is less than the first threshold. and This is the normalization function.

[0020] As one implementation method, based on borehole exploration data such as high-density electrical resistivity tomography (EDT) data and transient electromagnetic data, and further integrated with cross-hole elastic wave CT re-exploration data, combined with a second joint judgment function, structural surface abnormal areas are further screened out from all suspected abnormal locations.

[0021] As one implementation method, let the second joint decision function be: Its expression is:

[0022] ;

[0023] ;

[0024] ;

[0025]

[0026] ;

[0027] ;

[0028] ;

[0029] in, This indicates a relative anomaly in the high-density electrical resistivity tomography (EDT). This represents the relative anomaly rate of the transient electromagnetic method; This indicates the relative abnormality rate of elastography CT. This indicates that the location is based on trans-aperture elastic wave CT technology. x The wave velocity obtained from the inversion; Representation and point x Background wave velocity values ​​reflected in areas where no abnormal changes in lateral wave velocity occur within the same depth range; , , These are weighting coefficients, and the sum of the three is 1; For the sliding background resistivity; High-density electrical resistivity; For transient electromagnetic resistivity; Background value; The coordinates of the measuring point; , , All are constants; when When the value is greater than or equal to a set threshold, it is determined that there is a structural abnormality region at that location; , and This is the normalization function.

[0030] In one implementation, the degree of development is characterized by the number of structural plane groups and the average spacing.

[0031] As one implementation method, the process for determining the number of structural plane groups is as follows:

[0032] Based on the newly added borehole images, the corresponding rock mass structure surface is fitted to obtain the corresponding attitude parameters, which are then converted into a direction vector representation on the corresponding unit sphere.

[0033] The directional vector representation is clustered, and the minimum spherical angle distance is used as a similarity index to identify directional clusters, so as to realize the grouping and determination of rock mass structural surfaces.

[0034] As one implementation method, the average spacing is calculated as follows:

[0035] Extract the center point coordinates of each fitted plane in each group to form a set of center point coordinates;

[0036] Calculate the unit normal vector of each rock mass structural plane, find its average direction, define it as the group normal vector, and normalize it.

[0037] Projecting each center point in the set of center point coordinates onto the normalized group normal vector direction yields a normal distance sequence, which represents the spatial position of the rock mass structural surface in the group normal vector direction.

[0038] All projected values ​​are sorted from smallest to largest, and the average spacing of each group of rock mass structural planes is calculated based on the adjacent normal distances.

[0039] Based on the average spacing of each group of rock mass structural planes and the number of structural plane groups, the equivalent average spacing of all rock mass structural planes is obtained by weighted average method.

[0040] In one or more embodiments, a detailed survey system for assessing the integrity of the overburden rock mass in a foundation pit includes:

[0041] The anomaly screening module is used to identify all structural abnormal areas and suspected abnormal locations in the rock mass based on the known geology and existing borehole exploration data of the set area.

[0042] Anomaly rescreening module, which is used to fuse cross-hole elastic wave CT re-exploration data, and rescreen out structural surface anomalous areas from all suspected anomalous sites.

[0043] The structural plane determination module is used to exclude non-rock mass structural planes based on the newly added borehole images at the abnormal areas of each structural plane, and obtain a set of rock mass structural planes, wherein the depth of the newly added borehole is greater than the maximum depth of all abnormal areas of structural planes.

[0044] The integrity determination module is used to determine the degree of bonding of the corresponding rock mass structure based on the characteristics of each rock mass structure surface in the rock mass structure surface set, and then determine the integrity of the rock mass by combining the type and development degree of the rock mass structure surface.

[0045] A third aspect of the present invention provides a fine surveying device for assessing the integrity of the overburden rock mass in a foundation pit.

[0046] A fine surveying device for assessing the integrity of the overburden rock mass in a foundation pit includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it performs the steps of the fine surveying method for assessing the integrity of the overburden rock mass in a foundation pit as described above.

[0047] Compared with the prior art, the beneficial effects of the present invention are:

[0048] This invention identifies all abnormal areas and suspected abnormal locations of structural planes in rock masses based on existing borehole exploration data. It then integrates cross-hole elastic wave CT re-exploration data to further filter out abnormal areas of structural planes from all suspected abnormal locations. Finally, it combines newly added borehole images to exclude non-rock mass structural planes. Based on the characteristics of each rock mass structural plane in the set of rock mass structural planes, the degree of integration of the corresponding rock mass structure is obtained. Combined with the type and development degree of the rock mass structural planes, the integrity of the rock mass is determined. This invention solves the problem that traditional methods cannot identify deep structural planes under overburden conditions and lack a basis for rock mass integrity evaluation. It significantly improves the accuracy and systematicness of structural plane identification under complex geological conditions, resulting in multiple engineering benefits such as improved parameter determination accuracy, reduced engineering uncertainty, and enhanced reliability of foundation pit design. Attached Figure Description

[0049] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0050] Figure 1 This is a flowchart illustrating the detailed survey method for assessing the integrity of the overburden rock mass in an foundation pit, according to an embodiment of the present invention.

[0051] Figure 2 This is a schematic diagram of the structure of a fine survey system for assessing the integrity of the overburden rock mass in an excavation pit, according to an embodiment of the present invention.

[0052] Figure 3 This is a schematic diagram of a fine surveying device for assessing the integrity of the overburden rock mass in a foundation pit, according to an embodiment of the present invention.

[0053] Figure 4 It is a detailed plan view of the survey to determine the integrity of the overburden rock mass of the foundation pit;

[0054] Figure 5 yes Figure 4 Enlarged view of a portion of the image;

[0055] Figure 6 It is a schematic diagram of a detailed survey profile for assessing the integrity of the overburden rock mass in the foundation pit;

[0056] Figure 7 yes Figure 6 Enlarged schematic diagram of a section of the borehole;

[0057] Figure 8 This is a schematic diagram of the cross-section for identifying the structure of the borehole camera.

[0058] Among them, 1-soil-rock interface, 2-first structural plane, 3-geological body, 31-unexcavated soil, 32-unexcavated rock, 33-excavated soil and rock, 4-second structural plane, 5-third structural plane, 6-first borehole, 7-second borehole, 8-first cross-hole elastic wave CT transmitter / receiver, 9-second cross-hole elastic wave CT transmitter / receiver, 10-lateral geophysical detection line, 11-longitudinal geophysical detection line, 12-oblique geophysical detection line, 13-structural plane anomaly area, 14-third borehole, 15-camera, 16-auxiliary light source, 17-cable assembly, 201-anomaly initial screening module, 202-anomaly re-screening module, 203-structural plane determination module, 204-integrity determination module, 301-processor, 302-memory, 303-user interface, 304-network interface, 305-bus system. Detailed Implementation

[0059] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0060] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0061] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0062] Figure 1 This is a flowchart illustrating a detailed survey method for assessing the integrity of the overburden rock mass in an foundation pit, as described in an embodiment of the present invention. Figure 1 The detailed survey method for assessing the integrity of the overburden rock mass in this embodiment may include the following steps S101 to S104.

[0063] The specific implementation process of steps S101 to S104 is as follows:

[0064] Step S101: Based on the known geology and existing borehole exploration data of the designated area, identify all abnormal areas and suspected abnormal locations of structural surfaces in the rock mass.

[0065] Figure 4 The geophysical exploration survey lines 10 (horizontal), 11 (longitudinal), and 12 (diagonal) are arranged along the edge of the excavated section of the foundation pit. A first borehole 6 and a second borehole 7 are installed at the intersections of the survey lines and the intersections of the horizontal and vertical survey lines. The survey lines are high-density electrical resistivity tomography (EDT) and transient electromagnetic method (TEM) survey lines. Cross-hole elastic wave CT tests are conducted in the installed boreholes according to the principle of testing between adjacent boreholes. After completing the three geophysical tests, an anomalous structural surface area 13 will be obtained as shown by the survey lines. A third borehole 14 with a "3×3" range will be added near the anomalous structural surface area 13. Subsequently, borehole imaging tests will be conducted in the third borehole 14 added for the anomalous structural surface area 13 to obtain structural surface characteristics such as opening, roughness, and filling conditions. Figure 5 (a) in the diagram is a partial view of the second borehole 7; Figure 5 (b) is a partial view of the first borehole 6, the structural abnormality area 13, and the third borehole 14.

[0066] In the specific implementation process, based on the known geological conditions of the designated area, the detection lines and borehole locations are determined. Combined with high-density electrical resistivity tomography (EDT) data and transient electromagnetic data, all suspected abnormal locations in the rock mass are identified.

[0067] Using the first joint decision function, all suspected abnormal locations in the rock mass are identified; let the first joint decision function be... Its expression is:

[0068] ;

[0069] ;

[0070] ;

[0071] ;

[0072] ;

[0073] in, This indicates a relative anomaly in the high-density electrical resistivity tomography (EDT). This represents the relative anomaly rate of the transient electromagnetic method; and These are the weighting coefficients, and their sum is 1. For the sliding background resistivity; High-density electrical resistivity; For transient electromagnetic resistivity; Background value; The coordinates of the measuring point; and All are constants (e.g., Set to 40 Ω·m, Set to 40%) If the value is greater than or equal to the first threshold (e.g., 0.7), it is determined that there is a structural anomaly region at that location; when... If the value is less than a first threshold (e.g., 0.7) and greater than or equal to a second threshold (e.g., 0.5), the location is determined to be a suspected abnormality; wherein the second threshold is less than the first threshold. and This is the normalization function.

[0074] It should be noted here that, and The value can be dynamically set according to project requirements; and The value can also be set according to the actual situation; the setting of the first threshold and the second threshold can be set by those skilled in the art according to the actual situation, and will not be described in detail here.

[0075] Here, background resistivity is defined as the typical electrical response value in the neighborhood of the target measurement point. For high-density electrical resistivity tomography (EDT) background values... The median or filtered average value is obtained by using a sliding window with a distance of L = 5~10 meters to the left and right of the target point; for the background value of the transient electromagnetic method Take the median or mean value of the measurement point at the same depth (or the same time window) within the range of 10 to 20 meters on the left and right as a reference.

[0076] Step S102: Integrate the cross-hole elastic wave CT re-examination data and further screen out the structural surface abnormal areas from all suspected abnormal areas.

[0077] Specifically, based on borehole exploration data such as high-density electrical resistivity tomography (EDT) data and transient electromagnetic data, and further integrated with cross-hole elastic wave CT re-exploration data, combined with a second joint judgment function, structural anomaly areas are further screened from all suspected anomaly locations. For example, for areas 0.5≤ D ( x For cases where the velocity is ≤0.7, to improve the accuracy of structural surface identification, this invention introduces wave velocity information retrieved by elastic wave CT technology to construct a three-source joint judgment function to verify the aforementioned abnormal locations. The relative anomalies are obtained based on three geophysical exploration results (high-density electrical resistivity tomography, transient electromagnetic method, and elastic wave CT).

[0078] Let the second joint decision function be... Its expression is:

[0079] ;

[0080] ;

[0081] ;

[0082]

[0083] ;

[0084] ;

[0085] ;

[0086] in, This indicates a relative anomaly in the high-density electrical resistivity tomography (EDT). This represents the relative anomaly rate of the transient electromagnetic method; This indicates the relative abnormality rate of elastography CT. This indicates that the location is based on trans-aperture elastic wave CT technology. x The wave velocity obtained from the inversion; Representation and point x Background wave velocity values ​​reflected in areas where no abnormal changes in lateral wave velocity occur within the same depth range; , , These are weighting coefficients, and the sum of the three is 1; For the sliding background resistivity; High-density electrical resistivity; For transient electromagnetic resistivity; Background value; The coordinates of the measuring point; , , All are constants (e.g., Set to 40 Ω·m, Set to 40%, Set to 0.3); when When the value is greater than or equal to a set threshold (such as 0.8, which can be set according to the actual situation), it is determined that there is an abnormal area of ​​the structural surface at that location; , and This is the normalization function.

[0087] It should be noted here that, , , The value can be dynamically set according to project requirements; , , The value can also be set according to the actual situation. The median or the mean after removing outliers can be used.

[0088] Step S103: Based on the newly added borehole images at the abnormal areas of each structural surface, exclude non-rock mass structural surfaces to obtain a set of rock mass structural surfaces, wherein the depth of the newly added borehole is greater than the maximum depth of all abnormal areas of structural surfaces.

[0089] The process of excluding non-rock mass structural planes and obtaining the set of rock mass structural planes based on newly added borehole images at the abnormal areas of each structural plane is as follows:

[0090] For areas exhibiting abnormal response to structural surfaces, additional boreholes are drilled into these areas. The depth of these additional boreholes is determined based on the initially identified depth of the abnormal area, ensuring that the entire abnormal area is covered and extends downwards by at least 2 meters. If necessary, the exploration area can be further narrowed to a 3×3 radius (using the center of the abnormal area as a reference point, finding the optimal ratio between 2-5 meters of longitudinal and transverse spacing between adjacent boreholes based on the size of the abnormal location) to pinpoint the location of the abnormal area. Borehole imaging technology is then used to determine whether the abnormal area is indeed a rock mass structural surface.

[0091] Figure 6 It is aimed at Figure 4 The cross-section drawn at the bottom of the survey line shows the unexcavated soil 31, unexcavated rock 32, excavated soil and rock 33, and soil-rock interface 1 contained in geological body 3. The first structural plane 2, second structural plane 4, and third structural plane 5 represent structural planes with different openings in the underlying rock mass. The first borehole 6, second borehole 7, and third borehole 14 correspond to... Figure 4 The boreholes are set up by the geophysical detection line or added to the abnormal area 13 of the structural surface.

[0092] Figure 7 for Figure 6 A magnified view of a portion of the image shows the process of the trans-orifice elastic wave CT test. Figure 7 Taking the first borehole 6 and the second borehole 7 as examples, adjacent borehole tests were conducted by installing a first cross-hole elastic wave CT transmitter / receiver 8 and a second cross-hole elastic wave CT transmitter / receiver 9 inside the boreholes. The transmitters / receivers were arranged in segments with a spacing of 0.5 to 1.0 m along the borehole depth direction. During operation, the transmitters sequentially excited elastic waves, and the receivers synchronously recorded the wave propagation time. Finally, the wave velocity distribution was obtained through travel time inversion of multiple sets of borehole pairs, enabling the imaging and identification of anomalous bodies such as structural surfaces.

[0093] Figure 8This is a schematic diagram of the cross-section for identifying the structural surface of the borehole camera. In actual operation, taking the second structural surface 4 as an example, the camera 15 and the auxiliary light source 16 are lowered together through the cable assembly 17 into the third borehole 14 added for the abnormal area 13 of the structural surface. The camera moves slowly along the hole wall to record the image of the structural surface. Through image magnification and comparative analysis, its opening size, roughness and filling condition can be identified, and the condition of the structural surface can be intuitively judged.

[0094] Step S104: Based on the characteristics of each rock mass structural surface in the rock mass structural surface set, obtain the degree of bonding of the corresponding rock mass structure, and then determine the integrity of the rock mass by combining the type and development degree of the rock mass structural surface.

[0095] In this embodiment of the invention, the characteristics of the rock mass structural surfaces include, but are not limited to, their opening, roughness, and filling condition. As shown in Table 1, the degree of bonding of the corresponding rock mass structure is obtained based on the characteristics of each rock mass structural surface in the set of rock mass structural surfaces.

[0096] Table 1. Relationship between degree of bonding and structural surface features;

[0097]

[0098] According to Table 1, the degree of bonding of rock mass structure is divided into good bonding, average bonding, poor bonding and very poor bonding.

[0099] When the structural surface features an opening less than 1 mm, it is cemented by siliceous, ferrous, or calcareous materials, or the structural surface is rough and without filling material; when the structural surface features an opening of 1 mm to 3 mm, it is cemented by siliceous or ferrous materials; when the structural surface features an opening greater than 3 mm, the structural surface is rough and it is cemented by siliceous materials; in these cases, the degree of bonding of the rock mass structure is good.

[0100] When the structural features are: opening less than 1 mm, flat, calcareous mud cement or no filling; opening between 1 mm and 3 mm, calcareous-iron cement; opening greater than 3 mm, rough, ferrous or calcareous cement; in these cases, the degree of bonding of the rock mass structure is generally considered to be moderate.

[0101] When the structural features are an opening of 1mm to 3mm, the structural surfaces are straight, and the surface is cemented with argillaceous or calcareous argillaceous materials; or when the structural features are an opening of more than 3mm, and more than half of the surface is filled with argillaceous materials or rock fragments, the degree of bonding of the rock mass structure is considered poor.

[0102] When the rock mass is filled with mud or mud mixed with rock fragments, and the thickness of the filling material is greater than the undulation difference, the degree of bonding of the rock mass structure is very poor.

[0103] Based on the degree of bonding of the rock mass structure, and combined with the type and development degree of the rock mass structural planes, the integrity of the rock mass is determined, as shown in Table 2. The integrity of the rock mass includes complete, relatively complete, relatively broken, broken, and extremely broken.

[0104] Table 2. The integrity of the rock mass and its corresponding characteristics;

[0105]

[0106] When the number of structural plane groups is 1 to 2, the average spacing is greater than 1.0m, the degree of bonding of the structural planes is good or average, and the structural plane type is joint, fissure or bedding plane, the rock mass is judged to be intact.

[0107] When the number of structural plane groups is 1 to 2, the average spacing is greater than 1.0m, the degree of bonding of structural planes is poor, and the structural plane type is joint, fissure or bedding plane, the rock mass is judged to be relatively intact.

[0108] When the number of structural plane groups is 2 to 3, the average spacing is between 1.0m and 0.4m, the degree of bonding of the structural planes is good or average, and the structural plane type is joint, fissure or bedding plane, the rock mass is judged to be relatively intact.

[0109] When the number of structural plane groups is 2 to 3, the average spacing is between 1.0m and 0.4m, the degree of bonding of the structural planes is poor, and the structural plane type is joint, fissure, bedding plane or small fault, the rock mass is judged to be relatively broken.

[0110] When the number of structural plane groups is greater than or equal to 3, the average spacing is between 0.4m and 0.2m, the structural planes are well bonded, and the structural plane types are joints, fissures, bedding planes, or small faults, the rock mass is judged to be relatively broken.

[0111] When the number of structural plane groups is greater than or equal to 3, the average spacing is between 0.4m and 0.2m, the degree of bonding of the structural planes is generally good, and the structural plane type is joint, fissure, bedding plane or small fault, the rock mass is judged to be relatively broken.

[0112] When the number of structural plane groups is greater than or equal to 3 groups, the average spacing is between 0.4m and 0.2m, the degree of bonding of structural planes is poor, and various structural plane types are used to determine rock mass fracture.

[0113] When the number of structural facet groups is greater than or equal to 3, the average spacing is less than 0.2m, the degree of structural facet bonding is generally good or poor, and various structural facet types are used to determine rock mass fracture.

[0114] When the number of structural facet groups is disordered, the average spacing is disordered, and the degree of bonding between structural facets is very poor, the rock mass is judged to be extremely broken.

[0115] Once the rock mass structural planes are identified, borehole camera technology is used to identify the locations and attitude parameters of points crossing the structural planes:

[0116] For the The point in a borehole that crosses a rock mass structural plane is denoted as... In the formula, The dip direction (in degrees) of the rock mass structural surface. The dip angle (in °) of the rock mass structural surface point; For the first Points in the borehole that cross the rock mass structural plane Coordinates in three-dimensional space The method for obtaining this information is as follows: By unfolding images from borehole cameras, the oblique band features of the rock mass structure on the borehole wall are identified, and their initial depth is recorded. With termination depth The rock mass structural plane at the first The center depth of each borehole is taken as the crossing point depth: ; Compare this depth value with the spatial coordinates of the borehole head Combined with the borehole trajectory direction, the three-dimensional spatial coordinates of the rock mass structural plane crossing point are calculated:

[0117] If the first If the borehole is a vertical well (vertically downwards), then the crossing point is: ;

[0118] If the first Each borehole is an inclined hole, which can be determined according to the borehole inclination angle. and azimuth Calculate its spatial location:

[0119] .

[0120] Determine the structural plane affiliation using the following formula:

[0121] , ,and ;

[0122] In the formula, For the tendency tolerance ; For the tendency tolerance ; The maximum spatial distance (in meters) needs to be determined based on the horizontal and vertical spacing between adjacent boreholes in the added boreholes. Rock mass structural facets that meet the above conditions are clustered into a single set of rock mass structural facets, denoted as [set name missing]. .

[0123] In the specific implementation process, the process of fitting and calculating the normal vector of the rock mass structural surface is as follows:

[0124] The least squares method is used to fit the target fitting plane equation z=Ax+By+C to the rock mass structural surface point set; where the rock mass structural surface point set consists of the coordinates and spatial attitude parameters of the points traversed by the rock mass structural surface in three-dimensional space.

[0125] The objective is to minimize the sum of squared residuals of all fits, and the coefficients A, B, and C of the target fit plane are solved by linear regression; for example: Where k is the kth rock mass structural surface; n is the total number of rock mass structural surfaces.

[0126] To standardize spatial orientation measurements and facilitate angle calculations with the excavation sidewall direction, the normal vector n of the fitted structural surface needs to be adjusted. 法向量 The expression (-A, -B, 1) is normalized to obtain the unit normal vector. The calculation formula is as follows: .

[0127] In this embodiment, the attitude parameters of the fitted structural surface are also calculated, including:

[0128] inclination The tendency is α = arctan2(B,A).

[0129] The attitude parameter dataset is as follows: S ={( α 1,β1),( α 2, β 2),…,( α k , β k In the formula, α k The inclination of the k-th structural surface; β k Let be the inclination angle of the k-th structural surface.

[0130] In this embodiment of the invention, the degree of development is characterized by the number of structural plane groups and the average spacing.

[0131] Specifically, the process for determining the number of structural plane groups is as follows:

[0132] Step a1: Based on the newly added borehole images, fit the corresponding rock mass structure surfaces to obtain the corresponding attitude parameters (including dip direction). α i With tilt angle β i ), and convert it into a direction vector representation on the corresponding unit sphere:

[0133] x i =(cos αi ·sin β i sin α i ·sin β i cos β i );

[0134] Step a2: Cluster the direction vector representations and use the minimum spherical angle distance as a similarity index to identify direction clusters, so as to realize the grouping and determination of rock mass structural surfaces.

[0135] Set the direction vectors { x i As input to the spherical clustering algorithm, the minimum spherical angular distance is used as the similarity index to automatically identify directional clusters, thereby determining the grouping of structural surfaces. Finally, the clustering output includes the number of structural surface groups G, the average dip and tilt angle of each group, and the number of structural surfaces contained in each group. n j , j=1,2,…,G.

[0136] In the specific implementation process, the calculation process for the average spacing is as follows:

[0137] Step b1: Extract the coordinates of the center point of each fitted plane in each group to form a set of center point coordinates.

[0138] For the j-th group of structural surfaces, extract the coordinates of the center point of each fitted plane to form a set. P j ={ P j1 , P j2 ,…, P jn The coordinates of the center point of the m-th structural surface in the j-th group are: P jm =( x jm , y jm , z jm ).

[0139] Step b2: Calculate the unit normal vector of each rock mass structural plane, find its average direction, define it as the group normal vector, and normalize it.

[0140] Extract and calculate the unit normal vector for each rock mass structural plane. (The unit normal of the fitted plane), find its average direction, and define it as the group of normal vectors: And unitize: .

[0141] Step b3: Project each center point in the set of center point coordinates onto the normalized group normal vector direction to obtain the normal distance sequence, which represents the spatial position of the rock mass structural surface in the group normal vector direction.

[0142] center points of all structural surfaces In the average normal vector Projecting along the direction yields the normal distance sequence. This value represents the spatial position of the structural surface in the normal direction.

[0143] Step b4: Sort all projection values ​​from smallest to largest, and calculate the average spacing of each group of rock mass structural surfaces based on the adjacent normal distance.

[0144] For all projected values Sort by ascending order, and we get: The distance between adjacent normal vectors is The average spacing of each group of structural surfaces is .

[0145] Step b5: Based on the average spacing of each group of rock mass structural planes and the number of structural plane groups, the equivalent average spacing of all rock mass structural planes is obtained by using the weighted average method.

[0146] The equivalent average spacing of all structural surfaces is obtained using a weighted average method: .

[0147] This invention employs a technical solution of "multi-source geophysical identification—drilling and imaging verification—rock mass integrity classification." Specifically, high-density electrical resistivity tomography (EDT), transient electromagnetic methods (TEM), and cross-hole elastic wave CT are used to jointly extract resistivity anomalies in the control zones of structural planes within the overburden area, initially delineating areas with concentrated structural plane development. Subsequently, drilling and imaging techniques are used to extract key parameters such as the opening, spacing, and surface condition of the structural planes, determining their degree of integration and spatial distribution characteristics. Finally, based on engineering rock mass classification standards, qualitative and quantitative classification of rock mass integrity is completed. This solution solves the problems of traditional methods being unable to identify deep structural planes under overburden conditions and lacking a basis for rock mass integrity evaluation. It significantly improves the accuracy and systematic nature of structural plane identification under complex geological conditions, resulting in multiple engineering benefits, including improved parameter determination accuracy, reduced engineering uncertainty, and enhanced reliability of foundation pit design.

[0148] like Figure 2 As shown, the fine survey system for the integrity of the overburden rock mass of the foundation pit provided in this embodiment of the invention can be implemented in software. The fine survey system for the integrity of the overburden rock mass of the foundation pit includes the following software modules: anomaly initial screening module 201, anomaly rescreening module 202, structural surface determination module 203, and integrity determination module 204.

[0149] The following is an introduction to the functions of each software module in the detailed survey system for assessing the integrity of the overburden rock mass in foundation pits:

[0150] The anomaly screening module 201 is used to identify all structural abnormal areas and suspected abnormal parts in the rock mass based on the known geology and existing borehole exploration data of the set area.

[0151] Anomaly rescreening module 202 is used to fuse cross-hole elastic wave CT re-exploration data and rescreen structural surface abnormal areas from all suspected abnormal areas.

[0152] The structural surface determination module 203 is used to exclude non-rock mass structural surfaces based on the newly added borehole images at the abnormal areas of each structural surface, and obtain a set of rock mass structural surfaces, wherein the depth of the newly added borehole is greater than the maximum depth of all abnormal areas of structural surfaces.

[0153] The integrity determination module 204 is used to determine the degree of bonding of the corresponding rock mass structure based on the characteristics of each rock mass structure surface in the rock mass structure surface set, and then determine the integrity of the rock mass by combining the type and development degree of the rock mass structure surface.

[0154] It should be noted that each module in the detailed survey system for the integrity of the overburden rock mass of the foundation pit corresponds one-to-one with each step in the detailed survey method for the integrity of the overburden rock mass of the foundation pit described above, and their specific implementation processes are the same, so they will not be repeated here.

[0155] The following is a detailed description of the structure of the fine-scale surveying equipment for assessing the integrity of the overburden rock mass in foundation pits, according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the composition and structure of a fine-grained surveying equipment for assessing the integrity of the overburden rock mass in a foundation pit, provided in an embodiment of the present invention. It can be understood that... Figure 3 Only an exemplary structure of a fine surveying device for assessing the integrity of the overburden rock mass of an excavation pit is shown, not the entire structure. Some or all of the structures shown may be implemented as needed.

[0156] The detailed surveying equipment for assessing the integrity of overburden rock mass in foundation pits provided in this embodiment of the invention includes: at least one processor 301, a memory 302, a user interface 303, and at least one network interface 304. The various components in the detailed surveying system for assessing the integrity of overburden rock mass in foundation pits are coupled together via a bus system 305. It can be understood that the bus system 305 is used to realize communication between these components. In addition to a data bus, the bus system 305 also includes a power bus, a control bus, and a status signal bus. However, for clarity, in... Figure 3 The general designated all buses as Bus System 305.

[0157] The user interface 303 may include a monitor, keyboard, mouse, trackball, click wheel, buttons, touchpad, or touch screen.

[0158] It is understood that memory 302 can be volatile memory or non-volatile memory, or both. In this embodiment of the invention, memory 302 is capable of storing data to support the operation of the terminal. Examples of this data include any computer programs used to operate on the terminal, such as operating systems and applications. The operating system includes various system programs, such as framework layers, core library layers, driver layers, etc., used to implement various basic services and handle hardware-based tasks. Applications can include various applications.

[0159] In some embodiments, the detailed survey system for assessing the integrity of the overburden rock mass in foundation pits provided by this invention can be implemented using a combination of hardware and software. For example, the detailed survey system for assessing the integrity of the overburden rock mass in foundation pits provided by this invention can be a processor in the form of a hardware decoding processor, programmed to execute the detailed survey method for assessing the integrity of the overburden rock mass in foundation pits provided by this invention. For instance, the processor in the form of a hardware decoding processor can employ one or more application-specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs), or other electronic components.

[0160] As an example, processor 301 can be an integrated circuit chip with signal processing capabilities, such as a general-purpose processor, a digital signal processor (DSP), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., wherein the general-purpose processor can be a microprocessor or any conventional processor, etc.

[0161] As an example of the hardware implementation of the fine survey system for the integrity of the overburden rock mass of the foundation pit provided in the embodiments of the present invention, the device provided in the embodiments of the present invention can be directly executed by a processor 301 in the form of a hardware decoding processor. For example, it can be executed by one or more application specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs), or other electronic components to implement the fine survey method for the integrity of the overburden rock mass of the foundation pit provided in the embodiments of the present invention.

[0162] The memory 302 in this embodiment of the invention is used to store various types of data to support the operation of a fine-grained survey system for assessing the integrity of the overburden rock mass in foundation pits, or to store data for execution. Figure 1 The program code for the method shown. Examples of this data include: any executable instructions for operation on a fine survey system for assessing the integrity of the overburden rock mass in a foundation pit, such as executable instructions. A program implementing the fine survey method for assessing the integrity of the overburden rock mass in a foundation pit according to embodiments of the present invention can be included in executable instructions.

[0163] Specifically, according to embodiments of this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program including functions for executing... Figure 1 The program code for the method shown. In such an embodiment, the computer program can be downloaded and installed from a network via a communication component, and / or installed from a removable medium. When the computer program is executed by the central processing unit, it performs the various functions defined in the apparatus of this application.

[0164] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0165] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for fine surveying the integrity of a foundation pit covering rock mass, characterized in that, The method comprises the following steps: According to the known geology and existing drilling survey data of the set area, identify all structural plane abnormal areas and suspected abnormal parts in the rock mass; Fuse cross-hole elastic wave CT re-survey data to re-screen structural plane abnormal areas from all suspected abnormal parts; According to the image of the new drill hole at each structural plane abnormal area, exclude non-rock mass structural planes to obtain a set of rock mass structural planes, wherein the depth of the new drill hole is greater than the maximum depth of all structural plane abnormal areas; According to the characteristics of each rock mass structural plane in the set of rock mass structural planes, obtain the combination degree of the corresponding rock mass structure, and determine the integrity of the rock mass by combining the type and development degree of the rock mass structural plane. Based on borehole exploration data including high-density electrical resistivity tomography (EDT) and transient electromagnetic method (TEM) data, and further integrated with cross-hole elastic wave CT re-exploration data, and combined with a second joint judgment function, structural anomaly regions are further screened from all suspected anomaly areas; let the second joint judgment function be... Its expression is: ； ； ； ； ； ； wherein, represents high-density electrical method relative anomaly; represents transient electromagnetic method relative anomaly rate; represents elastic wave CT relative anomaly rate; represents wave velocity obtained by inversion based on cross-hole elastic wave CT technology at position x ; ( x ) represents background wave velocity value reflected by the area with no abnormal wave velocity change in the lateral direction within the same depth interval as point x ; , , are weight coefficients, and the sum of the three is 1; is a sliding background resistivity; is high-density electrical method resistivity; is transient electromagnetic method resistivity; is a background value; is a measurement point coordinate; , , are all constants; when is greater than or equal to a set threshold value, it is determined that there is a structural plane abnormal area at the position; f 1, f 2 and f 3 are normalization functions.

2. The method for fine survey of the integrity of a foundation pit covering rock mass according to claim 1, characterized in that, According to the known geology of the set area, determine the geophysical survey line and drill hole position, and identify all suspected abnormal parts in the rock mass by combining high-density electrical method data and transient electromagnetic method data.

3. The method for fine survey of the integrity of the rock mass of the foundation pit covering soil according to claim 1, characterized in that, All suspected abnormal parts in rock mass are identified by using the first joint decision function; the first joint decision function is and its expression is: ； ； ； ； ； wherein, represents a high-density electrical method relative anomaly; represents a transient electromagnetic method relative anomaly rate; and are weight coefficients, and the sum of the two is 1; is a sliding background resistivity; is a high-density electrical method resistivity; is a transient electromagnetic method resistivity; is a background value; is a survey point coordinate; and are both constants; when is greater than or equal to a first threshold value, it is determined that the location is a structural plane abnormal area; when is less than the first threshold value and greater than or equal to a second threshold value, it is determined that the location is a suspected abnormal part; wherein the second threshold value is less than the first threshold value; f 1 and f 2 are normalization functions.

4. The method for fine survey of the integrity of a foundation pit covering rock mass according to claim 1, characterized in that, The development degree is represented by the number of structural plane groups and the average interval.

5. The method for fine survey of the integrity of the rock mass covered by the foundation pit according to claim 4, characterized in that, The determination process of the number of structural plane groups is as follows: According to the image of the new drill hole, fit the corresponding rock mass structural plane to obtain the corresponding occurrence parameters, and convert them into direction vectors on the corresponding unit sphere; Cluster the direction vector representation, use the minimum spherical angle distance as the similarity index, identify the direction aggregation cluster, and realize the grouping determination of the rock mass structural plane.

6. The method for fine survey of the integrity of a foundation pit covering rock mass according to claim 4, characterized in that, The calculation process of the average interval is as follows: Extract the center point coordinates of each fitted plane in each group to form a set of center point coordinates; Calculate the unit normal vector of each rock mass structural plane, find its average direction, define it as the group normal vector and unitize it; Project each center point in the set of center point coordinates in the direction of the unitized group normal vector to obtain a normal distance sequence, which represents the spatial position of the rock mass structural plane in the direction of the group normal vector; Sort all projection values from small to large, and calculate the average interval of each group of rock mass structural planes according to the adjacent normal distance; According to the average interval and the number of structural plane groups of each group of rock mass structural planes, use the weighted average method to obtain the equivalent average interval of all rock mass structural planes.

7. A system for fine surveying the integrity of a foundation pit covering rock mass, characterized in that, The steps of the method for fine survey of the integrity of the foundation pit overburden rock mass according to any one of claims 1-6 are implemented, comprising: An abnormal preliminary screening module for identifying all structural plane abnormal areas and suspected abnormal parts in the rock mass according to the known geology and existing drilling survey data of the set area; An abnormal re-screening module for re-screening structural plane abnormal areas from all suspected abnormal parts by fusing cross-hole elastic wave CT re-survey data; A structural plane determination module for excluding non-rock mass structural planes to obtain a set of rock mass structural planes according to the image of the new drill hole at each structural plane abnormal area, wherein the depth of the new drill hole is greater than the maximum depth of all structural plane abnormal areas; An integrity determination module for determining the integrity of the rock mass by obtaining the combination degree of the corresponding rock mass structure according to the characteristics of each rock mass structural plane in the set of rock mass structural planes, and combining the type and development degree of the rock mass structural plane.

8. A device for fine surveying the integrity of a foundation covering rock mass, comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the program to implement the steps of the method for fine survey of the integrity of the foundation pit overburden rock mass according to any one of claims 1-6.

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