Method and system for evaluating construction disturbance degree of adjacent existing lines

Abstract

The invention relates to the field of tunnel early warning, in particular to an adjacent existing line construction disturbance degree evaluation method and system, and the method comprises the steps: determining stress distribution data and damage factor distribution data of regions where an engine oil tunnel and a construction tunnel are located through finite element analysis; then, a disturbance evaluation area between the existing tunnel and the construction tunnel is extracted, stress concentration areas are extracted from the disturbance evaluation area, and after the areas are unstable, large disturbance can be generated on the existing tunnel. And extracting damage factors of the stress concentration area from the damage factor distribution data, and delimiting a possible influence range based on the stratum and the basic information in the construction process. An attenuation model of vibration transmission during operation of the construction tunnel is constructed, and the attenuation model evaluates vibration energy reaching the stress concentration area. And comprehensively evaluating whether the stress concentration area has an instability risk or not by combining the damage factor data of the stress concentration area.

Description

Technical Field

[0001] The present invention relates to the field of tunnel early warning, and in particular to a method and system for evaluating the degree of construction disturbance adjacent to an existing line. Background Art

[0002] During the construction of adjacent tunnels, it is crucial to assess the degree of disturbance to the existing tunnel, as the construction of a new tunnel may have a significant impact on the structural safety, usability, and surrounding environment of the existing tunnel.

[0003] Existing methods for assessing the disturbance level of existing tunnels involve installing various monitoring devices within the tunnel to monitor the deformation or load changes of the existing tunnel lining during construction of adjacent tunnels. However, geological conditions vary across construction sites. If stress concentration areas exist at the top of an existing tunnel, these areas may become unstable, placing significant loads on the top or side linings of the tunnel, potentially leading to cracking or deformation of the tunnel lining. Existing monitoring equipment cannot promptly predict these types of disturbances. Summary of the Invention

[0004] In view of this, an object of the present invention is to provide a method and system for evaluating the degree of construction disturbance adjacent to an existing line to solve the above technical problems.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for evaluating the degree of disturbance caused by construction adjacent to an existing line according to the present invention comprises the following steps:

[0007] Obtaining basic information of the existing tunnel and the tunnel under construction, wherein the basic information includes the construction location, geometric information, and geological data around the construction location;

[0008] Calculating a finite element analysis model of the geological environment in which the existing tunnel and the construction tunnel are located based on geological data of the construction location, and extracting stress distribution data and damage factor distribution data of the geological environment surrounding the existing tunnel and the construction tunnel from the finite element analysis model, wherein the stress distribution data includes stresses of multiple grids, and the damage factor distribution data includes damage factors of multiple grids;

[0009] determining a disturbance assessment region between the existing tunnel and the construction tunnel based on a construction location, extracting a stress concentration region of the disturbance assessment region from the stress distribution data; and determining damage factor data of the stress concentration region based on the damage factor distribution data;

[0010] Based on the basic information of the construction tunnel, the influence range of the construction tunnel and the vibration attenuation model within the influence range are determined, and construction disturbance assessment is performed based on the vibration generated by the construction tunnel during shield machine construction, the vibration attenuation model, and the damage factor data of the stress concentration area within the influence range.

[0011] This application also provides a system for assessing the degree of construction disturbance adjacent to an existing line, comprising:

[0012] An acquisition module, configured to acquire basic information of existing tunnels and tunnels under construction, wherein the basic information includes construction locations, geometric information, and geological data surrounding the construction locations;

[0013] a feature extraction module for calculating a finite element analysis model of the geological environment in which the existing tunnel and the construction tunnel are located based on geological data at the construction location, and extracting stress distribution data and damage factor distribution data of the geological environment surrounding the existing tunnel and the construction tunnel from the finite element analysis model, wherein the stress distribution data includes stresses of multiple grids, and the damage factor distribution data includes damage factors of multiple grids;

[0014] a region division module, configured to determine a disturbance assessment region between the existing tunnel and the construction tunnel based on the construction location, extract a stress concentration region in the disturbance assessment region from the stress distribution data, and determine damage factor data for the stress concentration region based on the damage factor distribution data;

[0015] The disturbance assessment module is used to determine the influence range of the construction tunnel and the vibration attenuation model within the influence range based on the basic information of the construction tunnel, and to perform construction disturbance assessment based on the vibration generated by the construction tunnel during shield machine construction, the vibration attenuation model, and the damage factor data of the stress concentration area within the influence range.

[0016] The beneficial effects of the present invention are as follows: a method and system for evaluating the degree of construction disturbance adjacent to an existing line of the present invention determines the stress distribution data and damage factor distribution data of the oil tunnel and the area where the construction tunnel is located through finite element analysis. Then the disturbance assessment area between the existing tunnel and the construction tunnel is extracted, and the stress concentration area is extracted from the disturbance assessment area. After these areas become unstable, they will cause greater disturbance to the existing tunnel. The damage factor of the stress concentration area is extracted from the damage factor distribution data, and the possible impact range is delineated based on the basic information of the stratum and the construction process. An attenuation model for vibration transmission during operation of the construction tunnel is constructed, and the attenuation model evaluates the vibration energy reaching the stress concentration area. Combined with the damage factor data of the stress concentration area, a comprehensive assessment is made on whether there is a risk of instability in the stress concentration area. The present application performs an instability risk assessment on the stress concentration area in the area where the existing tunnel is located between operations, thereby avoiding large disturbances. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0018] Figure 1 is a cross-sectional structural diagram of an existing tunnel and a construction tunnel shown in an embodiment of the present application;

[0019] Figure 2 This is a flow chart of a deformation monitoring and early warning method for an existing tunnel shown in one embodiment of the present application;

[0020] Figure 3 is a schematic diagram of a disturbance assessment area in an embodiment of the present application;

[0021] Figure 4 A schematic diagram of the impact range of the construction tunnel cross section in one embodiment of the present application;

[0022] Figure 5 This is a structural diagram of a system for assessing the degree of disturbance caused by construction near existing lines, as shown in one embodiment of the present application. DETAILED DESCRIPTION

[0023] Figure 1 is a cross-sectional structural diagram of an existing tunnel and a construction tunnel shown in an embodiment of the present application, as shown in FIG. Figure 1 As shown, the scenario targeted in this application is a close distance section where the construction tunnel is nearly parallel to the existing tunnel. Figure 1 In the construction of tunnels, shield machines are used for excavation. During excavation, the shield machine's blades will generate stress on the construction tunnel. Before the side walls of the construction tunnel are completely fixed, they will produce slight inward plastic deformation after each contact with the blades. This will cause periodic ground vibrations. Although the energy of these vibrations is very small compared to blasting operations, if there happens to be an unstable stress concentration area with a large damage factor, this vibration energy may still cause instability in the stress concentration area. After the stress is released, it will cause additional load on the existing tunnel lining, resulting in lining cracking, deformation and other disturbances.

[0024] Therefore, in response to the above situation, this application proposes a method for assessing the degree of construction disturbance adjacent to the existing line, which is used to conduct a comprehensive assessment of the surrounding environment of the existing tunnel before implementing excavation, find possible stress concentration areas, conduct instability risk assessment, and guide the relevant parameters of the shield machine during excavation operation based on the instability assessment results.

[0025] Figure 2 This is a flow chart of a method for evaluating the degree of disturbance of construction adjacent to an existing line shown in one embodiment of the present application. Figure 2As shown in the figure, a method for evaluating the construction disturbance degree of an adjacent existing line in this embodiment may include steps S210 to S230:

[0026] S210, acquiring basic information of the existing tunnel and the tunnel under construction, wherein the basic information includes the construction location, geometric information, and geological data around the construction location;

[0027] Before conducting the assessment, basic information of the existing tunnel and the tunnel under construction needs to be collected.

[0028] Basic information includes the construction location, tunnel integration information, and geological data of the area. Geological data includes rock type (lithology), elastic modulus, Poisson's ratio, compressive strength, tensile strength, density, rock integrity coefficient, joint / crack parameters, in-situ stress, fault distribution, etc.

[0029] Among them, during the collection, basic information is obtained by drilling sampling. For high-risk areas, the drilling spacing is ≤20m. For coefficients such as elastic modulus, Poisson's ratio, compressive strength, and tensile strength, rock sample testing can be carried out in the laboratory. For ground stress parameters, hydraulic fracturing and rock wave velocity testing can be used to obtain them. They will not be elaborated here. In this embodiment, based on the empirical method, geological data extraction is performed within a range of 2-4 times the diameter of the existing tunnel and the construction tunnel.

[0030] The construction location includes the horizontal positioning and burial depth of the construction section. Geometric information includes the tunnel axis position, excavation section dimensions, support design, etc. In this application, a shield machine is used for excavation, so the tunnel lining cross-section is circular.

[0031] S220, calculating a finite element analysis model of the geological environment in which the existing tunnel and the construction tunnel are located based on the geological data of the construction location, and extracting stress distribution data and damage factor distribution data of the geological environment surrounding the existing tunnel and the construction tunnel from the finite element analysis model, wherein the stress distribution data includes stresses of multiple grids, and the damage factor distribution data includes damage factors of multiple grids;

[0032] This application uses finite element analysis tools to construct a finite element analysis model. The model construction process is as follows:

[0033] (1) Construct a three-dimensional geological body based on drilling data (such as hole depth, lithology, and structural surface occurrence) and geophysical data (such as geological radar and seismic waves), and then define stratigraphic units (such as fully weathered rock, strongly weathered rock, and slightly weathered rock), contact relationships, and occurrence.

[0034] (2) Input the direction and magnitude of natural ground stress and set the initial stress field.

[0035] (3) Based on the damage data of the existing tunnel (such as crack location), damage units or damage factors are introduced into the model.

[0036] (4) Import the tunnel axis and geological model to establish a three-dimensional geometric model of the existing tunnel and the construction tunnel.

[0037] (5) The lining structure of the existing tunnel needs to be modeled in detail (such as segments and anchors), and the excavation process of the construction tunnel needs to be considered (such as step-by-step excavation).

[0038] (6) Encrypt the mesh (e.g., tetrahedral or hexahedral elements) around the tunnel, on the structural surface, and in the damaged area of the existing tunnel.

[0039] (7) Define the contact surface between the tunnel lining and the surrounding rock (friction coefficient, preload). The intersection area between the existing tunnel and the construction tunnel requires special treatment.

[0040] (8) Define the material model, introduce parameters such as elastic modulus, Poisson's ratio, compressive strength, tensile strength, density, and damage factor, and perform boundary constraints to obtain a finite element analysis model.

[0041] When extracting stress distribution data, the principal stresses (σ1, σ2, σ3), shear stress, etc. of the rock mass around the tunnel are extracted, and the damage factor of the rock mass around the tunnel is extracted.

[0042] The damage factor is a parameter that describes the degree of rock damage. Its value is between 0 and 1. The larger the value, the greater the degree of damage and the worse the stability.

[0043] S230, determining a disturbance assessment area between the existing tunnel and the construction tunnel based on the construction position, extracting a stress concentration area in the disturbance assessment area from the stress distribution data; and determining damage factor data for the stress concentration area based on the damage factor distribution data;

[0044] Figure 3 This is a schematic diagram of a disturbance assessment area in an embodiment of the present application, such as Figure 3 As shown, in order to limit the analysis scope and reduce the amount of analysis, this application defines a three-dimensional range where disturbances may occur. The extraction process of the disturbance assessment area is as follows:

[0045] S2301, obtaining multiple cross sections of the existing tunnel and the construction tunnel;

[0046] First, the tunnel is divided into multiple equally or unevenly spaced sections (e.g., one section every 10 meters) based on the tunnel length and geological variations. Furthermore, the density of sections is increased in areas with sudden geological changes (e.g., fault zones, interfaces between soft and hard rock), or in construction-sensitive areas (e.g., intersections, and areas near existing tunnels).

[0047] S2302: Extracting an evaluation section between the existing tunnel section and the construction tunnel section in each section, wherein the evaluation section is a plane formed by opposite sides of the existing tunnel section and the construction tunnel section;

[0048] In each section, the vertices and bottom points of the existing tunnel and the construction tunnel are determined respectively, and the disturbance assessment surfaces formed on the opposite sides can be constructed by connecting them, such as Figure 3 shown.

[0049] S2303: Construct a three-dimensional disturbance assessment area based on the assessment sections of the multiple sections.

[0050] Finally, the two-dimensional evaluation rectangles of all sections are connected along the tunnel axis to form a continuous three-dimensional disturbance assessment area. The geological data (such as lithology, ground stress, groundwater level), stress distribution data, and damage factor distribution data of each section and between sections are mapped into the three-dimensional area to construct a geological-structural coupling model.

[0051] The geological-structural coupling model contains stress distribution data in the disturbance assessment area. Grids with large stresses and stress concentration factors greater than the set value are extracted as stress concentration areas for subsequent analysis. The extraction process includes:

[0052] S2311, extracting meshes having stress values greater than a preset threshold from the stress distribution data to obtain a target mesh;

[0053] S2312, when there is a target area where the number of target grids is greater than a preset number threshold, the target area is regarded as a high stress area;

[0054] When screening stress concentration areas, adjacent target grids are aggregated into connected areas (such as using Delaunay triangulation or DBSCAN clustering algorithm), and the number of grids in each area is counted. If the number exceeds a preset threshold (such as 50 grids), it is defined as a high stress area.

[0055] S2313, calculating the stress concentration coefficient of each high stress area, and taking the high stress area with a stress concentration coefficient greater than a preset concentration coefficient threshold as the stress concentration area.

[0056] The mathematical expression of stress concentration factor K is: Among them, σ avg is the average stress in the high stress area, σ max is the maximum stress in a high-stress area. The stress concentration factor measures the severity of stress concentration. Because this application uses a shield machine for tunneling, disturbance to adjacent areas is minimal. Therefore, risk assessment is performed only on areas with high stress concentrations that are susceptible to disturbance.

[0057] S240, determining the influence range of the construction tunnel and the vibration attenuation model within the influence range based on the basic information of the construction tunnel, and performing a construction disturbance assessment based on the vibration generated by the construction tunnel during shield machine construction, the vibration attenuation model, and damage factor data of the stress concentration area within the influence range.

[0058] This application also requires determining the possible impact range during tunnel construction. This application uses an empirical formula to determine the possible impact range. The process is as follows:

[0059] S2401, partitioning the area around the construction tunnel to obtain multiple surrounding rock partitions i; and evaluating the surrounding rock quality of the multiple surrounding rock partitions based on the basic information of the construction tunnel to obtain a surrounding rock quality factor Q i , where multiple surrounding rock partitions are obtained by dividing at equal angles with the center of the construction tunnel section as the origin;

[0060] Specifically, the present application divides the surrounding rock area of the tunnel construction into 12 zones at an angle of 30°. Since the vibration transmitted by the shield machine during excavation also propagates in a fan-shaped manner along this path, the surrounding rock quality factor is evaluated by zone.

[0061] When sampling geological data, the upper 7-8 partitions are sampled according to depth and location. This is because the surrounding rock at the bottom of the tunnel generally does not disturb the existing tunnel, so the partitions located at the bottom of the tunnel are ignored.

[0062] The propagation of vibration is related to the quality of the surrounding rock. Higher-quality surrounding rock has higher propagation efficiency, while lower-quality surrounding rock has lower propagation efficiency. Therefore, it is necessary to evaluate the surrounding rock quality of each sub-area to determine the impact radius of each sub-area.

[0063] In this embodiment, the evaluation process of surrounding rock quality includes:

[0064] (1) Extract the elastic modulus E, density ρ, and compressive strength σ of each surrounding rock partition or sub-surrounding rock sub-partition from the basic information c , internal friction angle and obtaining a rock integrity coefficient K of each surrounding rock partition or sub-surrounding rock sub-partition, wherein the rock integrity coefficient K is obtained through on-site measurement;

[0065] Elastic modulus E, density ρ, compressive strength σ c , internal friction angle Both can be obtained from the basic data collection process described above. The rock integrity coefficient K is obtained through field measurement. The rock integrity coefficient K is calculated by the square of the ratio of the longitudinal wave velocity of the rock mass to the longitudinal wave velocity of the rock block. Its field measurement method is mainly based on the acoustic wave method (such as the single hole method or the cross-hole method).

[0066] (2) Based on the elastic modulus E, density ρ, and compressive strength σ of each surrounding rock partition c , internal friction angle Calculate the surrounding rock quality factor Q of multiple surrounding rock partitions using the rock integrity coefficient i , where the surrounding rock quality factor Q i The mathematical expression is:

[0067]

[0068] BQ=90+3R c +250K

[0069] Where W1 is the first weight, W2 is the second weight, W3 is the third weight, W4 is the fourth weight, BQ is the basic quality index of rock, R c is the uniaxial compressive strength of the rock type within the surrounding rock partition.

[0070] In this application, the elastic modulus E, density ρ, and compressive strength σ are introduced into the existing basic quality index BQ. c , internal friction angle To comprehensively evaluate rock quality.

[0071] In the specific embodiment of the present application, since the elastic modulus E has a significant effect on the stiffness, the first weight W1=0.1; since the density ρ has a small effect, the second weight W2=0.05; since the compressive strength σ c is the core parameter, so the third weight W3 = 0.2; due to the internal friction angle It is very important for structural stability, so the fourth weight W4=0.15.

[0072] S2402, determining the diameter D of the construction tunnel, and based on the diameter D of the construction tunnel and the surrounding rock quality factor Q i Determine the influence radius R of multiple partitions of the construction tunnel i , where the influence radius R of the construction tunnel i The mathematical expression is:

[0073]

[0074] Where n is the first proportional parameter, m is the second proportional parameter, and l is the correction parameter.

[0075] After completing the quality assessment of each partition, the influence radius R is estimated by constructing an empirical formula i According to elastic mechanics theory, after tunnel excavation, additional stress in the stratum will diffuse to the surrounding area, and the impact range is usually 2-3 times the tunnel diameter. In soft soil strata, due to the low shear strength of the soil, the stress diffusion range may be wider; in hard rock, due to the good integrity of the rock mass, the impact range is relatively small, but 2-3 times the diameter must still be considered to ensure safety.

[0076] In this application, the impact range is roughly determined based on the surrounding rock quality. The higher the surrounding rock quality, the smaller the impact range. This application introduces empirical parameters (n, m, l) to constrain the impact radius to between 2-3 times the diameter. The higher the surrounding rock quality, the smaller the impact range, while the lower the surrounding rock quality, the larger the impact range.

[0077] Figure 4 Schematic diagram of the influence range of the construction tunnel section in one embodiment of the present application, such as Figure 4 As shown in the figure, the influence ranges of multiple partitions are different, so they can be closed into closed ranges by fitting.

[0078] After obtaining the influence radius of multiple partitions, it is necessary to evaluate the vibration propagation characteristics within the partitions with corresponding quality scores to simulate the amplitude attenuation process when the vibration propagates in the surrounding rock. The construction process of the vibration attenuation model includes:

[0079] S2411, dividing each surrounding rock partition i into multiple surrounding rock sub-partitions ij along the vibration propagation direction;

[0080] Since the surrounding rock in each sub-zone is heterogeneous, the degree of vibration attenuation varies. In this application, each sub-zone is further divided along the propagation direction based on the sampling points mentioned above. This allows geological data to be obtained for different sub-zones.

[0081] S2412, calculating the surrounding rock quality factor Q of the surrounding rock sub-region ij based on the basic information of the multiple surrounding rock sub-regions ij. ij ;

[0082] Surrounding rock quality factor Q of surrounding rock sub-region ij The calculation process is similar to the surrounding rock quality factor Q in the previous partition i The calculation process is the same as that of , please refer to the previous article and will not be repeated here.

[0083] S2413, based on the influence radius R of each surrounding rock partition i i And the surrounding rock quality factor Q of multiple surrounding rock sub-regions ij within surrounding rock region i ij , construct the vibration amplitude attenuation calculation formula for each surrounding rock partition i, where the vibration amplitude attenuation calculation formula is:

[0084]

[0085] In the above formula, it satisfies: ε0 is the basic attenuation coefficient, β is the frequency-related coefficient, α is the constraint parameter, f is the vibration frequency, r j is the propagation distance of vibration in the surrounding rock sub-region ij, value is the reference value, A i (r) is the amplitude when the total propagation distance is r, A ij (0) is the initial amplitude when the vibration enters the surrounding rock sub-region ij, R j_begin is the starting position of the surrounding rock sub-region ij, R j_end is the end position of the surrounding rock sub-region ij;

[0086] The propagation process of mechanical waves (generated by vibration) in the surrounding rock is generally characterized by rapid decay first and then slow decay. Its waveform characteristics can be characterized by a function with e as the base.

[0087] In addition, since different rock properties correspond to different attenuation amounts, it is necessary to consider that the attenuation amounts at different locations are different. Based on the above considerations, this application constructs the above formula to simulate the attenuation process of mechanical waves in the surrounding rock. The principle is as follows:

[0088] First build To roughly describe the attenuation process of mechanical waves in each sub-area. Among them, the negative n-th power of e is used to describe the process of mechanical waves attenuating from 1 times to close to 0 inside the surrounding rock. In this process, the attenuation degree of mechanical waves of different frequencies is different (the absorption attenuation coefficient is proportional to the frequency f). Therefore, the basic attenuation coefficient ε0 and the frequency are used to construct the overall attenuation coefficient ε0+βf;

[0089] Then, considering the influence radius mentioned above, the mechanical wave propagation process within the influence radius can be approximated as a process of decreasing from 1 to 0, so the constraint parameter α is introduced and the constraint is constructed. To limit the value of the constraint parameter α, and use the sub-partition quality factor Q ij and the quality factor Q within the partition i The above model is constructed by modifying the attenuation within each sub-region using the ratio of . This model can well describe the propagation of mechanical waves within the surrounding rock, providing a basis for the mechanical wave perturbation analysis described later.

[0090] In addition, the above model is a segmented calculation model. When it is actually used, it needs to be calculated one by one according to the sub-partitions of the mechanical wave path.

[0091] S2414: Construct a vibration attenuation model based on the vibration amplitude attenuation calculation formula of multiple surrounding rock partitions i.

[0092] After obtaining the vibration amplitude attenuation calculation formula for multiple surrounding rock partitions i, attenuation models in multiple directions can be constructed. Once all the required basic data and theoretical models have been constructed, disturbance assessment can be carried out based on the construction plan. The disturbance assessment process includes:

[0093] S2421, obtain the predicted vibration amplitude A generated by the shield machine on each surrounding rock partition of the construction tunnel side wall when constructing under the target working condition i (0) and the vibration frequency f i , and obtain the critical energy E of the lithology in the stress concentration area crit , wherein the vibration prediction amplitude A i (0) and the vibration frequency f i Generated based on historical operation data;

[0094] The above vibration prediction amplitude A i (0) and the vibration frequency f i It is not an actual measured value, but a predicted value based on historical experience.

[0095] The shield machine has different vibration effects on the side walls of the tunnel under different working conditions, which are determined by the stratum information, construction parameters and equipment status. Therefore, this application obtains the historical vibration data of the shield machine on the tunnel side walls during tunneling operations under various working conditions, wherein the historical vibration data is collected based on vibration sensors; then the historical vibration data under each working condition are averaged to obtain the vibration prediction amplitude A under each working condition. i (0) and the vibration frequency f i .

[0096] S2422: Calculate the vibration amplitude A of the stress concentration area based on the vibration attenuation model and the distance S between the vibration starting point and the stress concentration area in the surrounding rock partition. i (S);

[0097] The vibration starting point is at the inner wall of the tunnel and the end point is at the center of the stress concentration area. i , initial vibration prediction amplitude A i (0) and the propagation distance S are substituted into the vibration attenuation model, and the remaining vibration amplitude A when the mechanical wave is transmitted to the stress concentration area can be obtained. i (S).

[0098] S2423, vibration amplitude A based on stress concentration area i (S) and the vibration frequency f i Calculate the vibration energy E, where the mathematical expression of the vibration energy E is:

[0099]

[0100] Where m is the equivalent mass of the surrounding rock in the stress concentration area, and k is the equivalent stiffness of the surrounding rock in the stress concentration area;

[0101] Then based on the remaining vibration amplitude A i (S) is used to calculate the vibration energy, which takes into account mass and stiffness. Mass is estimated from density and volume, and stiffness is a measured value.

[0102] S2424, based on the damage factor data, the critical energy of the stress concentration area is corrected to obtain a corrected critical energy E crit_fix ; Corrected critical energy E crit_fix The mathematical expression is:

[0103] E crit_fix =(1-D)E crit

[0104] Where D is the average damage factor of the stress concentration area;

[0105] Then, the critical energy is corrected based on the damage factor to obtain the corrected critical energy E under the current damage condition. crit_fix The critical energy is obtained by testing rocks of the same type or structure in the laboratory.

[0106] S2425, the vibration energy E and the modified critical energy E crit_fix Compare and crit_fix When , it is determined that the stress concentration area has the risk of instability.

[0107] Finally, if the energy generated by the vibration approaches or exceeds the modified critical energy E crit_fix If the stress concentration area is located within the disturbance range, there is a risk of instability. If the stress concentration area releases stress during instability, it could potentially disrupt the existing tunnel. When there is a risk of instability, the construction section with this risk is marked. In this embodiment, this marking can be done within the 3D model.

[0108] like Figure 5 As shown, the present application also provides a system for assessing the degree of construction disturbance adjacent to an existing line, comprising:

[0109] An acquisition module, configured to acquire basic information of existing tunnels and tunnels under construction, wherein the basic information includes construction locations, geometric information, and geological data surrounding the construction locations;

[0110] a feature extraction module for calculating a finite element analysis model of the geological environment in which the existing tunnel and the construction tunnel are located based on geological data at the construction location, and extracting stress distribution data and damage factor distribution data of the geological environment surrounding the existing tunnel and the construction tunnel from the finite element analysis model, wherein the stress distribution data includes stresses of multiple grids, and the damage factor distribution data includes damage factors of multiple grids;

[0111] a region division module, configured to determine a disturbance assessment region between the existing tunnel and the construction tunnel based on the construction location, extract a stress concentration region in the disturbance assessment region from the stress distribution data, and determine damage factor data for the stress concentration region based on the damage factor distribution data;

[0112] The disturbance assessment module is used to determine the influence range of the construction tunnel and the vibration attenuation model within the influence range based on the basic information of the construction tunnel, and to perform construction disturbance assessment based on the vibration generated by the construction tunnel during shield machine construction, the vibration attenuation model, and the damage factor data of the stress concentration area within the influence range.

[0113] The present invention provides a method and system for evaluating the degree of construction disturbance adjacent to an existing line. The method determines the stress distribution data and damage factor distribution data of the oil tunnel and the area where the construction tunnel is located through finite element analysis. The disturbance assessment area between the existing tunnel and the construction tunnel is then extracted, and the stress concentration areas are extracted from the disturbance assessment area. These areas will cause greater disturbance to the existing tunnel after becoming unstable. The damage factor of the stress concentration area is extracted from the damage factor distribution data, and the possible impact range is delineated based on the basic information of the stratum and the construction process. An attenuation model for vibration transmission during operation of the construction tunnel is constructed, and the attenuation model evaluates the vibration energy reaching the stress concentration area. Combined with the damage factor data of the stress concentration area, a comprehensive assessment is made on whether there is a risk of instability in the stress concentration area. The present application performs an instability risk assessment on the stress concentration area in the area where the existing tunnel is located between operations, thereby avoiding large disturbances.

Claims

1. A method for evaluating the degree of disturbance caused by construction near an existing line, characterized in that: Including steps: Obtaining basic information of the existing tunnel and the tunnel under construction, wherein the basic information includes the construction location, geometric information, and geological data around the construction location; Calculating a finite element analysis model of the geological environment in which the existing tunnel and the construction tunnel are located based on geological data of the construction location, and extracting stress distribution data and damage factor distribution data of the geological environment surrounding the existing tunnel and the construction tunnel from the finite element analysis model, wherein the stress distribution data includes stresses of multiple grids, and the damage factor distribution data includes damage factors of multiple grids; determining a disturbance assessment region between the existing tunnel and the construction tunnel based on a construction location, extracting a stress concentration region of the disturbance assessment region from the stress distribution data; and determining damage factor data of the stress concentration region based on the damage factor distribution data; Based on the basic information of the construction tunnel, the influence range of the construction tunnel and the vibration attenuation model within the influence range are determined, and construction disturbance assessment is performed based on the vibration generated by the construction tunnel during shield machine construction, the vibration attenuation model, and the damage factor data of the stress concentration area within the influence range.

2. The method for evaluating the degree of disturbance caused by construction adjacent to an existing line according to claim 1, wherein: Determining a disturbance assessment area between the existing tunnel and the construction tunnel based on a construction location includes: Acquire multiple cross sections of the existing tunnel and the construction tunnel; In each cross section, an evaluation cross section is extracted between the existing tunnel cross section and the construction tunnel cross section, wherein the evaluation cross section is a plane formed by opposite sides of the existing tunnel cross section and the construction tunnel cross section; A three-dimensional disturbance assessment area is constructed based on the assessment sections of multiple sections.

3. The method for evaluating the degree of disturbance caused by construction adjacent to an existing line according to claim 1, wherein: Extracting the stress concentration area of the disturbance assessment area from the stress distribution data includes: Extracting grids whose stress values are greater than a preset threshold from the stress distribution data to obtain a target grid; When there is a target area where the number of target grids is greater than a preset number threshold, the target area is regarded as a high stress area; The stress concentration factor of each high stress area is calculated, and the high stress area with a stress concentration factor greater than a preset concentration factor threshold is regarded as a stress concentration area.

4. The method for evaluating the degree of disturbance caused by construction adjacent to an existing line according to claim 1, wherein: Determining the impact range of the construction tunnel based on basic information of the construction tunnel includes: The surrounding area of the construction tunnel is divided into multiple surrounding rock partitions i; and the surrounding rock quality of the multiple surrounding rock partitions is evaluated based on the basic information of the construction tunnel to obtain the surrounding rock quality factor Q i , where multiple surrounding rock partitions are obtained by dividing at equal angles with the center of the construction tunnel section as the origin; Determine the diameter D of the construction tunnel, and based on the diameter D of the construction tunnel and the surrounding rock quality factor Q i Determine the influence radius R of multiple partitions of the construction tunnel i , where the influence radius R of the construction tunnel i The mathematical expression is: Where n is the first proportional parameter, m is the second proportional parameter, and l is the correction parameter.

5. The method for evaluating the degree of disturbance caused by construction adjacent to an existing line according to claim 4, wherein: The vibration attenuation model within the affected area is determined based on the basic information of the construction tunnel, including: Each surrounding rock partition i is divided into multiple surrounding rock sub-partitions ij along the vibration propagation direction; Calculate the surrounding rock quality factor Q of the surrounding rock sub-region ij based on the basic information of multiple surrounding rock sub-regions ij ij ; Based on the influence radius R of each surrounding rock partition i i And the surrounding rock quality factor Q of multiple surrounding rock sub-regions ij within surrounding rock region i ij , construct the vibration amplitude attenuation calculation formula for each surrounding rock partition i, where the vibration amplitude attenuation calculation formula is: In the above formula, it satisfies: ε0 is the basic attenuation coefficient, β is the frequency-related coefficient, α is the constraint parameter, f is the vibration frequency, r j is the propagation distance of vibration in the surrounding rock sub-region ij, value is the reference value, A i (r) is the amplitude when the total propagation distance is r, A ij (0) is the initial amplitude when the vibration enters the surrounding rock sub-region ij, R j_begin is the starting position of the surrounding rock sub-region ij, R j_end is the end position of the surrounding rock sub-region ij; A vibration attenuation model is constructed based on the vibration amplitude attenuation calculation formula of multiple surrounding rock partitions i.

6. A method for evaluating the degree of disturbance caused by construction adjacent to an existing line according to claim 4 or 5, characterized in that: Based on the basic information of the constructed tunnel, the surrounding rock quality of multiple surrounding rock partitions is evaluated to obtain the surrounding rock quality factor Q i ,include: Extract the elastic modulus E, density ρ, and compressive strength σ of each surrounding rock partition or sub-surrounding rock sub-partition from the basic information c , internal friction angle and obtaining a rock integrity coefficient K of each surrounding rock partition or sub-surrounding rock sub-partition, wherein the rock integrity coefficient K is obtained through on-site measurement; Based on the elastic modulus E, density ρ, compressive strength σ of each surrounding rock partition c , internal friction angle Calculate the surrounding rock quality factor Q of multiple surrounding rock partitions using the rock integrity coefficient i , where the surrounding rock quality factor Q i The mathematical expression is: <h2 style=";text-align:left;direction:ltr">BQ = 90 + 3R<h2 style=";text-align:left;direction:ltr"> c <h2 style=";text-align:left;direction:ltr"> +250K Where W1 is the first weight, W2 is the second weight, W3 is the third weight, W4 is the fourth weight, BQ is the basic quality index of rock, R c is the uniaxial compressive strength of the rock type within the surrounding rock partition.

7. The method for evaluating the degree of disturbance caused by construction adjacent to an existing line according to claim 1, wherein: Construction disturbance assessment is conducted based on the vibration generated by the shield machine during tunnel construction, the vibration attenuation model, and the damage factor data of the stress concentration areas within the affected area, including: Obtain the predicted vibration amplitude A generated by the shield machine on each surrounding rock partition of the tunnel side wall during construction under the target working conditions i (0) and vibration frequency f i , and obtain the critical energy E of the lithology in the stress concentration area crit , wherein the vibration prediction amplitude A i (0) and the vibration frequency f i Generated based on historical operation data; The vibration amplitude A of the stress concentration area is calculated based on the vibration attenuation model and the distance S between the vibration starting point and the stress concentration area in the surrounding rock partition. i (S); The vibration amplitude A based on the stress concentration area i (S) and the vibration frequency f i Calculate the vibration energy E, where the mathematical expression of the vibration energy E is: Where m is the equivalent mass of the surrounding rock in the stress concentration area, and k is the equivalent stiffness of the surrounding rock in the stress concentration area; Based on the damage factor data, the critical energy of the stress concentration area is corrected to obtain the corrected critical energy E crit_fix ; Corrected critical energy E crit_fix The mathematical expression is: AND crit_fix =(1-D)E crit Where D is the average damage factor of the stress concentration area; The vibration energy E and the modified critical energy E crit_fix Compare and crit_fix When , it is determined that the stress concentration area has the risk of instability.

8. The method for evaluating the degree of disturbance caused by construction adjacent to an existing line according to claim 7, wherein: The predicted vibration amplitude A i (0) and vibration frequency f i The methods for obtaining include: Acquire historical vibration data of the tunnel sidewall during tunneling operations of the shield machine under various working conditions, wherein the historical vibration data is collected based on a vibration sensor; The historical vibration data under each working condition are averaged to obtain the vibration prediction amplitude A under each working condition. i (0) and vibration frequency f i , where the working conditions are determined by the formation information, construction parameters and equipment status.

9. The method for evaluating the degree of disturbance caused by construction adjacent to an existing line according to claim 7, wherein: Also includes: When there is a risk of instability, the construction section with the risk of instability will be marked.

10. A construction disturbance assessment system adjacent to an existing line, characterized in that: include: An acquisition module, configured to acquire basic information of existing tunnels and tunnels under construction, wherein the basic information includes construction locations, geometric information, and geological data surrounding the construction locations; a feature extraction module for calculating a finite element analysis model of the geological environment in which the existing tunnel and the construction tunnel are located based on geological data at the construction location, and extracting stress distribution data and damage factor distribution data of the geological environment surrounding the existing tunnel and the construction tunnel from the finite element analysis model, wherein the stress distribution data includes stresses of multiple grids, and the damage factor distribution data includes damage factors of multiple grids; a region division module, configured to determine a disturbance assessment region between the existing tunnel and the construction tunnel based on the construction location, extract a stress concentration region in the disturbance assessment region from the stress distribution data, and determine damage factor data for the stress concentration region based on the damage factor distribution data; The disturbance assessment module is used to determine the influence range of the construction tunnel and the vibration attenuation model within the influence range based on the basic information of the construction tunnel, and to perform construction disturbance assessment based on the vibration generated by the construction tunnel during shield machine construction, the vibration attenuation model, and the damage factor data of the stress concentration area within the influence range.

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