Tunnel drilling layout method and system based on maximum unscannable blind area constraint

Abstract

The application relates to a tunnel drilling arrangement method based on a maximum non-probe blind area constraint, which comprises the following steps: four drill holes A, B, D and C are arranged in a symmetrical arrangement mode to form a rectangle ABDC, and the diameter of the maximum non-probe blind area is calculated r 1. The maximum horizontal spacing in this mode is determined based on the diameter setting value of the maximum non-probe blind area; four drill holes E, F, I and G are arranged in a cross arrangement mode to form a parallelogram EFIG, and the diameter of the maximum non-probe blind area is calculated r 2. The maximum horizontal spacing in this mode is determined based on the diameter setting value of the maximum non-probe blind area; and the drill hole arrangement scheme and the horizontal spacing are determined based on a horizontal spacing difference threshold. The application respectively constructs the two mainstream drill hole arrangement schemes of symmetrical arrangement and cross arrangement as drill hole arrangement geometric models, quantitatively calculates the maximum probe blind areas of the two arrangement modes, inversely calculates the optimal horizontal spacing meeting the blind area constraint, and then selects the drill hole arrangement scheme, so that the probe blind area is accurately quantified and controlled.

Description

Technical Field

[0001] This invention relates to the field of tunnel exploration technology, specifically to a method and system for tunnel borehole layout based on the constraint of the maximum undetectable blind zone. Background Technology

[0002] Before and during tunnel construction, cross-hole CT detection technology is required to accurately survey the surrounding soil and rock masses and geological defects (such as cavities, fissures, and water-rich areas) to provide data support for construction safety. The core of cross-hole CT detection is to form a detection network through borehole layout, utilizing the penetrating properties of X-rays to image the geological body. The rationality of the borehole layout directly determines the detection accuracy, efficiency, and construction cost. Due to the discrete layout of boreholes and the linear propagation of X-rays, the triangular area formed by connecting adjacent boreholes has the lowest X-ray coverage density, creating a detection blind zone and easily leading to missed detection of underground cavities, fissures, and other geological defects.

[0003] Among related technologies, cross-hole CT detection technology is mainly divided into two categories: one focuses on optimizing detection accuracy, such as improving the identification accuracy of geological defects through multi-physics field fusion of elastic waves and electromagnetic waves, and color enhancement processing of detection data. However, this type of technology does not involve the optimized design of borehole layout. The other category focuses on the layout of cross-hole CT boreholes in tunnels. The spacing between the boreholes and the tunnel structure is mostly set based on experience. The size of the blind zone formed after the survey lines intersect is uncontrollable, and the geological conditions within the blind zone are unclear. It is easy to miss the detection of poor geological conditions due to an excessively large blind zone, which may lead to the risk of water inrush and collapse. Alternatively, if the survey line length is too large, the radiation attenuation will be aggravated, and the identification accuracy will be greatly reduced. Summary of the Invention

[0004] This application provides a method and system for tunnel borehole layout based on the constraint of the maximum undetectable blind zone, which solves the technical problems in related technologies where the layout spacing between boreholes and tunnel structures is mostly set based on experience, resulting in uncontrollable blind zone size and low identification accuracy.

[0005] This application provides a tunnel borehole layout method based on the maximum undetectable blind zone constraint, which includes the following steps: Four boreholes A, B, D, and C are symmetrically arranged on the outside of the tunnel structure, forming a rectangle ABDC. Calculate the diameter of the maximum undetectable blind zone under this symmetrical arrangement. r 1. Based on the diameter setting value of the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. L ; Four boreholes E, F, I, and G are arranged in a cross-shaped configuration on the outside of the tunnel structure, forming a parallelogram EFIG. The diameter of the maximum undetectable blind zone under this cross-shaped configuration is calculated. r2. Based on the diameter setting value of the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. K ; The hole layout scheme and corresponding horizontal spacing are determined based on the horizontal spacing difference threshold δ.

[0006] In one embodiment, four boreholes A, B, D, and C are symmetrically arranged on the outside of the tunnel structure, forming a rectangle ABDC. The diameter of the maximum undetectable blind zone under the symmetrical arrangement is calculated. r 1. Based on the diameter setting value of the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. L include: Four boreholes A, B, D, and C are symmetrically arranged on the outside of the tunnel structure, forming a rectangle ABDC, with the intersection of diagonals AD and BC at point O. The spacing between AC is the distance H between the upper and lower rows of boreholes, and the spacing between AB is the maximum horizontal spacing between boreholes to meet the blind zone requirements. L ; Calculate the incircle diameters of triangles ABO and ACO respectively. d 1. d 2. Take the maximum value as the diameter of the maximum undetectable blind zone under the symmetrical arrangement. r 1; by r 1 ≤d As a constraint, calculate the maximum horizontal spacing that satisfies the blind zone requirement under this method. L ; Calculate the length of the longest probe ray AD in the symmetrical arrangement. M .

[0007] In one embodiment, four boreholes E, F, I, and G are arranged in a cross-shaped configuration on the outside of the tunnel structure, forming a parallelogram EFIG. The diameter of the maximum undetectable blind zone under this cross-shaped configuration is calculated. r 2. Based on the diameter setting value of the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. K include: Four boreholes E, F, I, and G are arranged in a crisscross pattern on the outside of the tunnel structure, forming a parallelogram EFIG, with the intersection of diagonals EI and GF at point P. The vertical distance from borehole G to EF is equal to the spacing between the upper and lower rows of boreholes. H The EF spacing is the maximum horizontal spacing required to meet the blind zone requirements of the borehole. K ; Calculate the incircle diameters of △EPG and △EFP respectively. d 3.d 4. Take the maximum value as the diameter of the maximum undetectable blind zone under the cross-layout method. r 2; by r 2 ≤d As a constraint, calculate the maximum horizontal spacing that satisfies the blind zone requirement under this method. K ; Calculate the length of the longest probe ray EI under the cross arrangement. N .

[0008] In one embodiment, determining the hole layout scheme and the corresponding horizontal spacing based on the horizontal spacing difference threshold δ includes: Using construction economy as the primary criterion, the relationship between the relative difference in horizontal spacing and the threshold δ of horizontal spacing difference under the two layout methods is determined. If the relative difference in horizontal spacing is ( KL ) / K ≥δ, select the cross arrangement method as the hole layout scheme, and the corresponding horizontal spacing is K ; If the relative difference in horizontal spacing is ( KL ) / K <δ, the hole layout scheme and corresponding horizontal spacing are determined based on the threshold Δ of the difference in survey line length.

[0009] In one embodiment, determining the orifice layout scheme and corresponding horizontal spacing based on the measurement line length difference threshold Δ includes: Using the detection imaging accuracy as the second criterion, the relationship between the relative difference in the length of the measuring line and the threshold Δ of the difference in the length of the measuring line under the two arrangement methods is determined. If the relative difference in the length of the measuring line is ( NM ) / M ≥Δ, the symmetrical arrangement is selected as the hole layout scheme, and the corresponding horizontal spacing is L ; If the relative difference in the length of the measuring line is ( NM ) / M <Δ, choose one.

[0010] In one implementation, the diameter of the inscribed circle is calculated using Heron's formula.

[0011] In one embodiment, the tunnel borehole layout method based on the maximum undetectable blind zone constraint further includes: Based on the length of the tunnel structure and the hole layout scheme, calculate the minimum number of holes required for this method.

[0012] In one implementation, calculating the minimum number of boreholes required for this method based on the length of the tunnel structure and the borehole layout includes: The number of boreholes in a single row is obtained by dividing the length of the tunnel structure by the horizontal spacing corresponding to the borehole layout scheme and rounding up.

[0013] In one embodiment, the borehole is located at a predetermined distance outside the tunnel structure, preferably 3m to 5m.

[0014] This application also provides a tunnel borehole layout system based on the maximum undetectable blind zone constraint, which applies the tunnel borehole layout method based on the maximum undetectable blind zone constraint as described in any of the above claims, and includes: The symmetrical arrangement module is configured to: symmetrically arrange four boreholes A, B, D, and C located outside the tunnel structure, forming a rectangle ABDC; and calculate the diameter of the maximum undetectable blind zone under the symmetrical arrangement. r 1. Based on the diameter setting value of the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. L ; The cross-layout module is configured to: set four boreholes E, F, I, and G located on the outside of the tunnel structure in a cross-layout manner, forming a parallelogram EFIG, and calculate the diameter of the maximum undetectable blind zone under the cross-layout configuration. r 2. Based on the diameter setting value of the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. K ; The scheme selection module is configured to determine the hole layout scheme and the corresponding horizontal spacing based on the horizontal spacing difference threshold δ.

[0015] The beneficial effects of the technical solutions provided in this application include: This application provides a tunnel borehole layout method based on the constraint of the maximum undetectable blind zone. It constructs two mainstream borehole layout schemes, symmetrical layout and cross layout, as the geometric models for borehole layout. The maximum detection blind zone of the two layout schemes is quantitatively calculated, and the optimal horizontal spacing that satisfies the blind zone constraint is back-calculated. Then, the borehole layout scheme is selected. The method clarifies the borehole layout location and standardizes the blind zone quantification calculation process, so as to achieve accurate and controllable quantification of the detection blind zone. The calculation system is unified, which solves the problems of fuzzy blind zone constraints, lack of quantitative standards and uncontrollable size in related technologies. It effectively avoids the omission and misjudgment of geological defects, improves the identification accuracy, and does not rely on the subjective experience of construction personnel. It is easy to implement directly in a procedural and standardized manner. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of the steps of a tunnel drilling layout method based on the constraint of the maximum undetectable blind zone in one embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of a symmetrical arrangement in one embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of a cross-arrangement method in one embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0021] This application provides a tunnel borehole layout method based on the constraint of the maximum undetectable blind zone, which can solve the technical problems in related technologies where the layout spacing between boreholes and tunnel structures is mostly set based on experience, resulting in uncontrollable blind zone size and low recognition accuracy.

[0022] like Figures 1 to 3 As shown, where, Figure 1 This is a flowchart of the steps of a tunnel drilling layout method based on the constraint of the maximum undetectable blind zone in one embodiment of the present invention. Figure 2 This is a schematic diagram of a symmetrical arrangement in one embodiment of the present invention. Figure 3 This is a schematic diagram of a cross-arrangement method in one embodiment of the present invention.

[0023] This embodiment provides a tunnel borehole layout method based on the constraint of the maximum undetectable blind zone, which includes the following steps: Step S1: Set up four boreholes A, B, D, and C on the outside of the tunnel structure in a symmetrical arrangement to form a rectangle ABDC. Calculate the diameter of the maximum undetectable blind zone under the symmetrical arrangement. r 1. Diameter setting based on the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. L ; Step S2: Set up four boreholes E, F, I, and G on the outside of the tunnel structure in a cross arrangement to form a parallelogram EFIG. Calculate the diameter of the maximum undetectable blind zone under the cross arrangement. r 2. Diameter setting based on the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. K ; Step S3: Determine the hole layout scheme and the corresponding horizontal spacing based on the horizontal spacing difference threshold δ.

[0024] This embodiment provides a tunnel borehole layout method based on the constraint of the maximum undetectable blind zone. Two mainstream borehole layout schemes, symmetrical layout and cross layout, are constructed as geometric models for borehole layout. The maximum detection blind zone of the two layout schemes is quantitatively calculated, and the optimal horizontal spacing that meets the blind zone constraint is obtained by back-calculation. Then, the borehole layout scheme is selected. The borehole layout position is clearly defined and the blind zone quantification calculation process is standardized to achieve accurate and controllable quantification of the detection blind zone. The calculation system is unified, which solves the problems of fuzzy blind zone constraints, lack of quantitative standards and uncontrollable size in related technologies. It effectively avoids the omission and misjudgment of geological defects, improves the identification accuracy, and does not rely on the subjective experience of construction personnel, which is convenient for direct procedural and standardized implementation.

[0025] The following provides a detailed explanation of each step.

[0026] In one embodiment, step S1 involves setting four boreholes A, B, D, and C located on the outside of the tunnel structure in a symmetrical arrangement to form a rectangle ABDC, and calculating the diameter of the maximum undetectable blind zone under the symmetrical arrangement. r 1. Diameter setting based on the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. L include: Step S11: Four boreholes A, B, D, and C are symmetrically arranged on the outside of the tunnel structure, forming a rectangle ABDC, with the intersection of diagonals AD and BC at point O; wherein the spacing between AC is the spacing between the upper and lower rows of boreholes. H The AB spacing is the maximum horizontal spacing required for the borehole to meet the blind zone requirements. L ; like Figure 2 As shown, four boreholes A, B, D, and C are symmetrically arranged at a predetermined distance outside the tunnel structure, forming a rectangle ABDC, with the intersection of diagonals AD and BC at point O; the spacing between AC is the spacing between the upper and lower rows of boreholes. H The AB spacing is the maximum horizontal spacing required for the borehole to meet the blind zone requirements. L。 The coordinates of the four boreholes are A(0,0), B(...). L ,0)C(0,H ), D( L , H The coordinates of the three vertices of triangle ABO are A(0,0), B(0,0), and C(0,0). L ,0),O( L / 2, H / 2), the coordinates of the three vertices of △ACO are A(0,0), C ... H ), O( L / 2, H / 2). Spacing between the upper and lower rows of drill holes. H The distance should be set reasonably according to the tunnel height and detection range requirements. The preset distance is preferably 3m to 5m. It should be understood that this distance is only an example. In actual engineering, those skilled in the art can reasonably adjust this distance according to the effective detection radius of the detection instrument, geological conditions or actual working conditions, and all such adjustments should fall within the protection scope of this invention.

[0027] Step S12: Calculate the incircle diameters of △ABO and △ACO respectively. d 1. d 2. Take the maximum value as the diameter of the maximum undetectable blind zone under the symmetrical arrangement. r 1, that is r 1= max ( d 1, d 2).

[0028] Calculate the diameter of the incircle of each triangle using Heron's formula. Specifically: ① Calculate the semi-perimeter of the triangle p : p =( a+b+c ) / 2; ② Calculate the area S of the triangle: S = ; ③ Calculate the diameter of the inscribed circle d 直 : d 直 =2 r =2 S / p ; in, a , b , c These represent the lengths of the sides of the triangle. r Let be the radius of the incircle of the triangle.

[0029] Step S13, with r 1 ≤d As a constraint, calculate the maximum horizontal spacing that satisfies the blind zone requirement under this method. L .

[0030] Specifically, based on the constraints, by substituting the formula for calculating the diameter of the inscribed circle of the corresponding triangle, the maximum horizontal spacing required for the blind zone under this method can be obtained. L Maximum undetectable blind zone diameter setting d The values ​​are set according to the engineering survey requirements. The specific values ​​are determined based on the engineering survey accuracy and the geological complexity of the area surrounding the tunnel. For projects with complex geological conditions and high survey accuracy requirements, smaller values ​​are used. For routine survey projects, the values ​​can be appropriately relaxed to ensure that the detection blind zone meets the requirements of engineering construction safety and survey specifications.

[0031] Step S14: Calculate the length of the longest probe ray AD under the symmetrical arrangement. M .

[0032] In one embodiment, step S2 involves setting four boreholes E, F, I, and G located outside the tunnel structure in a cross-arrangement to form a parallelogram EFIG, and calculating the diameter of the maximum undetectable blind zone under the cross-arrangement. r 2. Diameter setting based on the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. K include: Step S21: Four boreholes E, F, I, and G are arranged in a crisscross pattern on the outside of the tunnel structure to form a parallelogram EFIG, with the intersection of diagonals EI and GF at point P; wherein the vertical distance from borehole G to EF is the spacing between the upper and lower rows of boreholes. H The EF spacing is the maximum horizontal spacing required to meet the blind zone requirements of the borehole. K .

[0033] like Figure 3 As shown, four boreholes E, F, I, and G are arranged in a crisscross pattern at a predetermined distance (e.g., 3m~5m) outside the tunnel structure, forming a parallelogram EFIG. The intersection of diagonals EI and GF is P. The vertical distance from borehole G to EF is the spacing between the upper and lower rows of boreholes. H The EF spacing is the maximum horizontal spacing required to meet the blind zone requirements of the borehole. K The coordinates of the four boreholes are E(0,0), F(...), and F(...). K ,0),I(3 K / 2, H ), G( K / 2, H The coordinates of the three vertices of △EPG are E(0,0), P(3,0), P(4,0), P(5,0), P(6,0), P(7,0), P(8,0), P(9,0), P(10 ... K / 4, H / 2), G( K / 2, H The coordinates of the three vertices of △EFP are E(0,0), F ... K ,0), P(3K / 4, H / 2).

[0034] Step S22: Calculate the incircle diameters of △EPG and △EFP respectively. d 3. d 4. Take the maximum value as the diameter of the maximum undetectable blind zone under the cross-layout method. r 2, that is r 2= max ( d 3, d 4).

[0035] Calculate the diameter of the incircle of each triangle using Heron's formula. Specifically: ① Calculate the semi-perimeter of the triangle p : p =( a+b+c ) / 2; ② Calculate the area S of the triangle: S = ; ③ Calculate the diameter of the inscribed circle d 直 : d 直 =2 r =2 S / p ; in, a , b , c These represent the lengths of the sides of the triangle. r Let be the radius of the incircle of the triangle.

[0036] Step S23, with r 2 ≤d As a constraint, calculate the maximum horizontal spacing that satisfies the blind zone requirement under this method. K .

[0037] Specifically, based on the constraints, by substituting the formula for calculating the diameter of the inscribed circle of the corresponding triangle, the maximum horizontal spacing required for the blind zone under this method can be obtained. K .

[0038] Step S24: Calculate the length of the longest detection ray EI under the cross arrangement method. N .

[0039] In this embodiment, the boreholes in both arrangements are laid out at a preset distance along the outside of the tunnel structure. The preset distance is preferably 3m to 5m as the optimal working condition range. The layout distance is standardized, taking into account both structural safety and detection accuracy. When the distance is less than 3m, the boreholes are too close and may disturb or damage the existing tunnel structure, posing a safety hazard. When the distance is greater than 5m, the detection area deviates from the key exploration range around the tunnel, the radiation attenuation is aggravated, the detection accuracy is greatly reduced, and it is impossible to accurately identify the surrounding geological defects. This layout distance can ensure that the cross-hole CT detection range covers the area to be explored around the tunnel, avoiding the problem of the large arbitrariness of the traditional experience-based layout distance, and better balancing the tunnel structural safety and detection accuracy.

[0040] In this embodiment, since cross-hole CT relies on straight rays between boreholes to detect soil and rock, the triangular area enclosed by the borehole lines is a weak ray coverage area and the main geometric blind zone due to the limitations of the ray straight propagation characteristics. The area with the least ray coverage and the worst detection effect is the inscribed circle area of ​​the triangle. Therefore, the inscribed circle diameter of the triangle is used to represent the maximum undetectable blind zone of the corresponding deployment unit, and the quantification result is consistent with the actual detection conditions.

[0041] In this embodiment, Heron's formula is used as a unified formula to calculate the diameter of the inscribed circle of a triangle, thereby quantifying the blind zone size of the two types of characteristic triangles and ensuring that the blind zone calculation standards of the two hole layout schemes are unified and the results are accurate.

[0042] In one embodiment, step S3, determining the hole layout scheme and the corresponding horizontal spacing based on the horizontal spacing difference threshold δ, includes: Step S31: Using construction economy as the primary criterion, determine the relationship between the relative difference in horizontal spacing and the threshold value of horizontal spacing difference δ under the two layout methods.

[0043] Specifically, a dimensionless horizontal spacing difference threshold can be flexibly pre-set based on the engineering survey accuracy and construction cost requirements.

[0044] If the relative difference in horizontal spacing is ( KL ) / K ≥δ, select the cross arrangement method as the hole layout scheme, and the corresponding horizontal spacing is K .

[0045] Specifically, if the relative difference in horizontal spacing is not less than the horizontal spacing difference threshold, it indicates that the horizontal spacing advantage of the cross-layout method is significant, effectively reducing the number of boreholes and lowering construction costs. Therefore, the cross-layout scheme should be prioritized, and the corresponding horizontal spacing is: K .

[0046] If the relative difference in horizontal spacing is ( KL ) / K<δ, the hole layout scheme and corresponding horizontal spacing are determined based on the threshold Δ of the difference in survey line length.

[0047] Specifically, if the relative difference in horizontal spacing is less than the threshold for horizontal spacing difference, it indicates that the difference in horizontal spacing between the two arrangement methods is small and the construction economy is basically the same. Further comparison of the detection ray length is then made.

[0048] In one embodiment, determining the orifice layout scheme and corresponding horizontal spacing based on the measurement line length difference threshold Δ includes: Using the detection imaging accuracy as the second criterion, the relationship between the relative difference in measurement line length and the measurement line length difference threshold Δ under the two arrangement methods is determined.

[0049] Specifically, the dimensionless measurement line length difference threshold can be flexibly pre-set according to the engineering survey accuracy and construction cost requirements.

[0050] If the relative difference in the length of the measuring line is ( NM ) / M ≥Δ, the symmetrical arrangement is selected as the hole layout scheme, and the corresponding horizontal spacing is L .

[0051] Specifically, if the relative difference in measurement line length is not less than the measurement line length difference threshold, it indicates that the symmetrical arrangement results in shorter detection rays, less signal attenuation, and better CT imaging accuracy. Therefore, the symmetrical arrangement should be preferred, with the corresponding horizontal spacing being... L .

[0052] If the relative difference in the length of the measuring line is ( NM ) / M <Δ, choose one.

[0053] Specifically, if the relative difference in the length of the survey line is less than the threshold for the difference in the length of the survey line, it means that there is no significant difference in the construction economy and detection accuracy of the two schemes, and their overall performance is equivalent. One of them can be selected according to the site conditions such as the construction space, drilling rig location, and ease of construction.

[0054] The above scheme uses a horizontal spacing difference threshold to verify construction costs and a survey line length difference threshold to verify imaging accuracy. On the one hand, it adopts dimensionless relative thresholds for comparison and judgment. Compared with traditional absolute value comparison, it is not limited by tunnel size or detection range. It takes into account both construction cost and detection accuracy as needed, and is suitable for various tunnel cross-hole CT exploration projects. It is more versatile and avoids the one-sided problem of the traditional cross-hole layout method of unilateral dominance and single index selection. On the other hand, it establishes a two-level threshold selection system of spacing economy and survey line accuracy, and selects the optimal hole layout scheme in layers. It breaks through the traditional single selection mode of only comparing borehole spacing and establishes a two-level judgment logic of "economic priority and accuracy as a backup". Logically, it is more in line with the actual project and allows both hole layout schemes to be adapted to the corresponding optimal working conditions, with extremely strong adaptability.

[0055] In one embodiment, the tunnel borehole layout method based on the maximum undetectable blind zone constraint further includes: Step S4: Based on the length of the tunnel structure and the hole layout scheme, calculate the minimum number of holes required for this method.

[0056] In one embodiment, calculating the minimum number of boreholes required for this method, based on the length of the tunnel structure and the borehole layout, includes: The number of boreholes in a single row is obtained by dividing the length of the tunnel structure by the horizontal spacing corresponding to the borehole layout scheme and rounding up; twice that is the total number of boreholes in two rows.

[0057] The above scheme calculates the minimum number of boreholes based on the tunnel structure and borehole layout. The calculation method of rounding up the number of boreholes in a single row avoids detection blank areas caused by size division deviation. The two rows of symmetrical layout meet the requirements of conventional cross-hole CT detection network, and complete the uniform and full-coverage borehole layout to ensure seamless connection of the detection range and no blind spots.

[0058] This application's embodiments, from setting blind zone thresholds, dual-mode borehole modeling, blind zone quantification calculation, selection of optimal values ​​for spacing and survey lines, to precise calculation of borehole quantity, have clear and well-defined constraints throughout the entire process. They are highly operable and logically closed-loop, achieving controllable detection blind zones, scientific scheme selection, and minimal borehole quantity. This precisely balances construction costs and detection imaging accuracy, adapting to various tunnel exploration engineering needs with different accuracy and cost requirements. It eliminates reliance on the subjective experience of construction personnel, minimizing the number of boreholes while ensuring detection quality, thus reducing construction workload and project costs.

[0059] This application also provides a tunnel borehole layout system based on the maximum undetectable blind zone constraint, which applies the tunnel borehole layout method based on the maximum undetectable blind zone constraint described above, and includes: The symmetrical arrangement module is configured to: symmetrically arrange four boreholes A, B, D, and C located outside the tunnel structure, forming a rectangle ABDC; and calculate the diameter of the maximum undetectable blind zone under the symmetrical arrangement. r 1. Diameter setting based on the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. L ; The cross-layout module is configured to: set four boreholes E, F, I, and G located on the outside of the tunnel structure in a cross-layout manner, forming a parallelogram EFIG, and calculate the diameter of the maximum undetectable blind zone under the cross-layout configuration. r 2. Diameter setting based on the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. K ; The scheme selection module is configured to determine the hole layout scheme and the corresponding horizontal spacing based on the horizontal spacing difference threshold δ.

[0060] The functions of each module have been described above, and the same content will not be repeated here.

[0061] The following specific embodiments illustrate this application.

[0062] Example 1 This embodiment describes a large-diameter tunnel project in the field, with a tunnel diameter of 12m and a length of 1200m. The standard judgment thresholds for the project are set as follows: horizontal spacing difference threshold δ=0.05 and survey line length difference threshold Δ=0.05.

[0063] This embodiment provides a tunnel borehole layout method based on the constraint of the maximum undetectable blind zone, which includes the following steps: Step S1: Set the diameter of the maximum undetectable blind zone according to project requirements. d=8.0m Four boreholes A, B, D, and C are symmetrically arranged 3m outside the tunnel structure, forming a rectangle ABDC, with the intersection of diagonals AD and BC at point O; the spacing between AC is the spacing between the upper and lower rows of boreholes. H， Based on tunnel size and detection range, set H=18m The AB spacing is the maximum horizontal spacing required for the borehole to meet the blind zone requirements. L Calculate the incircle diameters of triangles ABO and ACO respectively. d 1. d 2. Diameter of the maximum undetectable blind zone under symmetrical arrangement r 1= max ( d 1, d 2). With r 1 ≤d As a constraint, calculate the maximum horizontal spacing that satisfies the blind zone requirement under this method. L=19.9m .

[0064] Step S2: Set up the outer side of the tunnel structure in a cross arrangement. 3m Four boreholes, E, F, I, and G, form a parallelogram EFIG, with the intersection of diagonals EI and GF at point P. The vertical distance from borehole G to EF is equal to the spacing between the upper and lower rows of boreholes. H=18m The EF spacing is the maximum horizontal spacing required to meet the blind zone requirements of the borehole. K Calculate the incircle diameters of triangles EPG and EFP respectively. d 3. d 4. Diameter of the maximum undetectable blind zone under the cross-layout configuration r 2= max (d 3, d 4). With r 2 ≤d As a constraint, calculate the maximum horizontal spacing that satisfies the blind zone requirement under this method. K=22.8m .

[0065] Step S3: Using construction economy as the primary criterion, determine the relationship between the relative difference in horizontal spacing and the threshold value of horizontal spacing difference δ under the two layout methods.

[0066] Relative difference in horizontal spacing ( KL ) / K=0.12>δ=0.05, This indicates that the horizontal spacing of the cross-layout arrangement is larger, which reduces the number of boreholes while meeting blind zone constraints. This better suits the high tunnel and long-distance layout requirements of this embodiment. Therefore, the cross-layout arrangement is selected as the borehole layout scheme, with a corresponding horizontal spacing of [missing information]. K=22.8m .

[0067] Step S4: Calculation of the number of holes per row: In the symmetrical arrangement, the number of holes per row is approximately 1200 / 19.9 ≈ 61, and the total number of holes in both rows is 61 × 2 = 122; In the cross arrangement, the number of holes per row is approximately 1200 / 22.8 ≈ 53, and the total number of holes in both rows is 53 × 2 = 106; The difference of 16 holes further confirms the cost advantage of the cross arrangement.

[0068] Therefore, a cross-layout method was chosen as the borehole layout scheme, with 106 boreholes laid out 3m from the outside of the tunnel at a horizontal spacing of 22.8m, completing the borehole layout; the diameter of the maximum undetectable blind zone under the cross-layout method... r 2 < Diameter setting value of the maximum undetectable blind zone d =8.0m, meeting the engineering requirements, while significantly reducing the construction cost of long-distance tunnels.

[0069] Example 2 This embodiment is applicable to complex geological conditions, such as water-rich areas, fissures, and cavities, with a tunnel diameter of 14m and a length of 400m. The following conventional engineering judgment thresholds are set: horizontal spacing difference threshold δ=0.05 and survey line length difference threshold Δ=0.05.

[0070] This embodiment provides a tunnel borehole layout method based on the constraint of the maximum undetectable blind zone, which includes the following steps: Step S1: Set the diameter of the maximum undetectable blind zone according to project requirements. d=5.0m The blind spot control standards are more stringent. Four boreholes A, B, D, and C are symmetrically arranged 3m outside the tunnel structure, forming a rectangle ABDC, with the intersection of diagonals AD and BC at point O; the spacing between AC is the spacing between the upper and lower rows of boreholes. H，Based on tunnel size and detection range, set H=20m The AB spacing is the maximum horizontal spacing required for the borehole to meet the blind zone requirements. L Calculate the incircle diameters of triangles ABO and ACO respectively. d 1. d 2. Diameter of the maximum undetectable blind zone under symmetrical arrangement r 1= max ( d 1, d 2). With r 1 ≤d As a constraint, calculate the maximum horizontal spacing that satisfies the blind zone requirement under this method. L=8.16m The length of the longest detection ray AD. .

[0071] Step S2: Set up the outer side of the tunnel structure in a cross arrangement. 3m Four boreholes, E, F, I, and G, form a parallelogram EFIG, with the intersection of diagonals EI and GF at point P. The vertical distance from borehole G to EF is equal to the spacing between the upper and lower rows of boreholes. H=20m The EF spacing is the maximum horizontal spacing required to meet the blind zone requirements of the borehole. K Calculate the incircle diameters of triangles EPG and EFP respectively. d 3. d 4. Diameter of the maximum undetectable blind zone under the cross-layout configuration r 2= max ( d 3, d 4). With r 2 ≤d As a constraint, calculate the maximum horizontal spacing that satisfies the blind zone requirement under this method. K=8.35m The length of the longest detection ray EI. .

[0072] Step S3: Using construction economy as the primary criterion, determine the relationship between the relative difference in horizontal spacing and the horizontal spacing difference threshold δ under the two layout methods. Relative difference in horizontal spacing ( KL ) / K≈0.02<δ=0.05 The two schemes have basically the same horizontal spacing and no significant difference in construction economy, so they proceed to the second level of detection accuracy verification.

[0073] Using the detection imaging accuracy as the second criterion, the relationship between the relative difference in measurement line length and the measurement line length difference threshold Δ under the two arrangement methods is determined. NM ) / M≈0.09>Δ=0.05This indicates that the borehole spacing and construction costs of the two schemes are basically the same. However, the symmetrical arrangement results in a shorter probe ray length, less attenuation of electromagnetic / elastic wave signals, and higher CT imaging resolution and recognition accuracy. It can accurately identify minute geological defects and is suitable for the high-precision exploration needs of complex geology. Therefore, the symmetrical arrangement is selected as the borehole layout scheme, with a corresponding horizontal spacing of [missing information]. L=8.16m .

[0074] Step S4: Calculation of the number of boreholes in a single row: In the symmetrical arrangement, the number of boreholes in a single row is approximately 400 / 8.16 ≈ 49, and the total number of boreholes in both rows is 49 × 2 = 98; In the cross arrangement, the number of boreholes in a single row is approximately 400 / 8.35 ≈ 48, and the total number of boreholes in both rows is 48 × 2 = 96. The difference of 2 in the total number indicates that the construction cost is not significantly increased, but the maximum survey line distance is significantly reduced, and the detection imaging quality is significantly improved. This can effectively avoid the problems of missed or misjudged defects under complex geological conditions, ensure the safety of tunnel construction, and result in better overall project benefits.

[0075] The above two embodiments fully verify the scientific nature of the two-level selection system provided in this application: under conventional geological and cost-sensitive conditions, the cross-arrangement method is optimized based on the horizontal spacing threshold to achieve cost reduction and efficiency improvement; under complex geological and accuracy-sensitive conditions, the symmetrical arrangement method is optimized based on the survey line threshold to ensure exploration accuracy; it solves the problem that the traditional borehole layout scheme has no basis for selection and cannot balance accuracy and cost, and the scheme has strong adaptability and can be fully adapted to different exploration needs of tunnel engineering.

[0076] It should be noted that the sequence numbers of the embodiments in this application are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not represent a sequential order, nor do they limit "first," "second," and "third" to different types.

[0077] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0078] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0079] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0080] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for tunnel borehole layout based on the constraint of maximum undetectable blind zone, characterized in that, It includes the following steps: Four boreholes A, B, D, and C are symmetrically arranged on the outside of the tunnel structure, forming a rectangle ABDC. Calculate the diameter of the maximum undetectable blind zone under this symmetrical arrangement. r 1. Based on the diameter setting value of the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. L ; Four boreholes E, F, I, and G are arranged in a cross-shaped configuration on the outside of the tunnel structure, forming a parallelogram EFIG. The diameter of the maximum undetectable blind zone under this cross-shaped configuration is calculated. r 2. Based on the diameter setting value of the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. K ; The hole layout scheme and corresponding horizontal spacing are determined based on the horizontal spacing difference threshold δ.

2. The tunnel borehole layout method based on the maximum undetectable blind zone constraint as described in claim 1, characterized in that, The four boreholes A, B, D, and C, located symmetrically on the outside of the tunnel structure, form a rectangle ABDC. The diameter of the maximum undetectable blind zone under this symmetrical arrangement is calculated. r 1. Based on the diameter setting value of the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. L include: Four boreholes A, B, D, and C are symmetrically arranged on the outside of the tunnel structure, forming a rectangle ABDC, with the intersection of diagonals AD and BC at point O. The spacing between AC is the distance H between the upper and lower rows of boreholes, and the spacing between AB is the maximum horizontal spacing between boreholes to meet the blind zone requirements. L ; Calculate the incircle diameters of triangles ABO and ACO respectively. d 1. d 2. Take the maximum value as the diameter of the maximum undetectable blind zone under the symmetrical arrangement. r 1; by r 1 ≤d As a constraint, calculate the maximum horizontal spacing that satisfies the blind zone requirement under this method. L ; Calculate the length of the longest probe ray AD in the symmetrical arrangement. M .

3. The tunnel borehole layout method based on the maximum undetectable blind zone constraint as described in claim 2, characterized in that, The four boreholes E, F, I, and G, located on the outside of the tunnel structure in a cross-arrangement, form a parallelogram EFIG. The diameter of the maximum undetectable blind zone under this cross-arrangement is calculated. r 2. Based on the diameter setting value of the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. K include: Four boreholes E, F, I, and G are arranged in a crisscross pattern on the outside of the tunnel structure, forming a parallelogram EFIG, with the intersection of diagonals EI and GF at point P. The vertical distance from borehole G to EF is equal to the spacing between the upper and lower rows of boreholes. H The EF spacing is the maximum horizontal spacing required to meet the blind zone requirements of the borehole. K ; Calculate the incircle diameters of △EPG and △EFP respectively. d 3. d 4. Take the maximum value as the diameter of the maximum undetectable blind zone under the cross-layout method. r 2; by r 2 ≤d As a constraint, calculate the maximum horizontal spacing that satisfies the blind zone requirement under this method. K ; Calculate the length of the longest probe ray EI under the cross arrangement. N .

4. The tunnel borehole layout method based on the maximum undetectable blind zone constraint as described in claim 3, characterized in that, The method of determining the hole layout scheme and the corresponding horizontal spacing based on the horizontal spacing difference threshold δ includes: Using construction economy as the primary criterion, the relationship between the relative difference in horizontal spacing and the threshold δ of horizontal spacing difference under the two layout methods is determined. If the relative difference in horizontal spacing is ( KL ) / K ≥δ, select the cross arrangement method as the hole layout scheme, and the corresponding horizontal spacing is K ; If the relative difference in horizontal spacing is ( KL ) / K <δ, the hole layout scheme and corresponding horizontal spacing are determined based on the threshold Δ of the difference in survey line length.

5. The tunnel borehole layout method based on the maximum undetectable blind zone constraint as described in claim 4, characterized in that, The method for determining the hole layout scheme and corresponding horizontal spacing based on the threshold Δ of the difference in survey line length includes: Using the detection imaging accuracy as the second criterion, the relationship between the relative difference in the length of the measuring line and the threshold Δ of the difference in the length of the measuring line under the two arrangement methods is determined. If the relative difference in the length of the measuring line is ( NM ) / M ≥Δ, the symmetrical arrangement is selected as the hole layout scheme, and the corresponding horizontal spacing is L ; If the relative difference in the length of the measuring line is ( NM ) / M <Δ, choose one.

6. The tunnel borehole layout method based on the maximum undetectable blind zone constraint as described in claim 2 or 3, characterized in that, Calculate the diameter of the inscribed circle using Heron's formula.

7. The tunnel borehole layout method based on the maximum undetectable blind zone constraint as described in claim 1, characterized in that, The tunnel borehole layout method based on the maximum undetectable blind zone constraint also includes: Based on the length of the tunnel structure and the hole layout scheme, calculate the minimum number of holes required for this method.

8. The tunnel borehole layout method based on the maximum undetectable blind zone constraint as described in claim 7, characterized in that, The calculation of the minimum number of boreholes required for this method, based on the length of the tunnel structure and the borehole layout scheme, includes: The number of boreholes in a single row is obtained by dividing the length of the tunnel structure by the horizontal spacing corresponding to the borehole layout scheme and rounding up.

9. The tunnel borehole layout method based on the maximum undetectable blind zone constraint as described in claim 1, characterized in that, The borehole is located at a predetermined distance outside the tunnel structure.

10. A tunnel borehole layout system based on maximum undetectable blind zone constraints, employing the tunnel borehole layout method based on maximum undetectable blind zone constraints as described in any one of claims 1 to 9, characterized in that, It includes: The symmetrical arrangement module is configured to: symmetrically arrange four boreholes A, B, D, and C located outside the tunnel structure, forming a rectangle ABDC; and calculate the diameter of the maximum undetectable blind zone under the symmetrical arrangement. r 1. Based on the diameter setting value of the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. L ; The cross-layout module is configured to: set four boreholes E, F, I, and G located on the outside of the tunnel structure in a cross-layout manner, forming a parallelogram EFIG, and calculate the diameter of the maximum undetectable blind zone under the cross-layout configuration. r 2. Based on the diameter setting value of the maximum undetectable blind zone d Determine the maximum horizontal spacing that meets the blind zone requirements under this method. K ; The scheme selection module is configured to determine the hole layout scheme and the corresponding horizontal spacing based on the horizontal spacing difference threshold δ.

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