Tunnel construction whole process numerical simulation method based on non-contact measurement

Abstract

The invention relates to the technical field of numerical simulation, in particular to a tunnel construction whole process numerical simulation method based on non-contact measurement, which comprises the following steps: S1, acquiring a tunnel structure corresponding to the shape and size of a tunnel, a tunnel construction method and construction conditions corresponding to construction steps, dividing the tunnel into a plurality of sample areas according to a tunnel structure and construction conditions; s2, the settlement amount of a measuring point in each sample area is obtained, the center of the tunnel is set as a starting point, and a settlement distribution diagram is obtained according to the distance between the measuring point and the center of the tunnel; s3, according to the settlement distribution diagram, vertical displacement of the bottom of the tunnel, normal displacement of the two sides of the tunnel and the settlement area generated during tunnel construction under the corresponding construction steps are obtained, and the maximum settlement factor and the correction factor are obtained through calculation; s4, identifying a maximum settlement point and a maximum change point in the tunnel, and using the maximum change point as a basis to perform simulation by using the finite element model; and the construction efficiency and quality are improved.

Description

Technical Field

[0001] The invention relates to the technical field of numerical simulation, and in particular to a whole-process numerical simulation method for tunnel construction based on non-contact measurement. Background Art

[0002] The numerical simulation technology of the tunnel construction process is a method that uses computers to simulate and predict the tunnel construction process. This method can simulate the stress, displacement, deformation and other parameters during the tunnel excavation process, so as to evaluate the safety and stability during the construction process. Numerical simulation technology mainly includes finite element method, boundary element method, discrete element method, etc., among which the finite element method is the most widely used method. The finite element method divides the tunnel and the surrounding soil into a finite number of small units, and describes the mechanical behavior of each unit through mathematical equations. By solving these equations, the stress, displacement, deformation and other parameters during the excavation process can be obtained. Numerical simulation technology needs to consider many factors, such as the mechanical parameters of the soil and rock mass, the construction sequence, the construction method, etc., in order to simulate the actual situation more accurately.

[0003] For example, Chinese patent publication number CN116680964A discloses a method and device for numerically simulating water and mud inrush disasters when a tunnel crosses an active fault, wherein the method includes: obtaining geometric parameters of the tunnel, constructing a three-dimensional numerical model of the tunnel crossing the active fault by using a preset finite difference numerical simulation method and a preset particle discrete element numerical simulation method, and applying boundary conditions to set the initial stress state, simulating the water and mud inrush disasters caused by the rupture of the water-isolating rock mass when the tunnel crosses the active fault, and obtaining numerical simulation results. The embodiment of the present application can establish a three-dimensional numerical model of the tunnel crossing the active fault, and by simulating the mechanical behavior of the tunnel surrounding rock and fluid-solid coupling simulation, obtain the whole process of water and mud inrush disasters when the tunnel crosses the active fault under the action of seismic waves of different intensities, frequencies, and directions.

[0004] Existing technologies simulate tunnel disasters by analyzing corresponding faults and flows. However, when tunnel construction conditions and tunnel structures change, it is also necessary to verify the relationship between elements such as settlement and set tunnel conditions, and simulate and evaluate the overall situation to identify the risks that may be caused by the current construction. Summary of the invention

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a numerical simulation method for the entire tunnel construction process based on non-contact measurement, including: S1, obtaining the tunnel structure corresponding to the shape and size of the tunnel, the tunnel construction method and construction conditions corresponding to the construction steps, and dividing the tunnel into multiple sample areas according to the tunnel structure and construction conditions.

[0006] S2, obtaining the settlement amount of the measuring point in each sample area, setting the tunnel center as the starting point, and obtaining the settlement distribution map according to the distance between the measuring point and the tunnel center.

[0007] S3, according to the settlement distribution diagram, obtain the vertical displacement of the tunnel bottom, the normal displacement on both sides of the tunnel and the settlement area generated during tunnel construction under the corresponding construction steps, and calculate the maximum settlement factor and correction factor.

[0008] S4, identify the maximum settlement point and the maximum change point in the tunnel, use the maximum change point as the basis for simulation using the finite element model, and output the settlement-related simulation factors based on the simulation results.

[0009] S5, combining the simulation factor, correction factor and maximum settlement factor to form a final prediction model, coupling the prediction model according to the measurement points used in the calculation, and obtaining the simulation evaluation results of the tunnel construction.

[0010] The beneficial effects of the present invention are as follows: through the combination of non-contact measurement technology and finite element model, the current scheme can more accurately simulate the settlement situation during tunnel construction, thereby improving the accuracy of simulation; through the simulation evaluation results of tunnel construction by the prediction model, construction personnel can more accurately understand the potential risks in the tunnel construction process and take corresponding measures to prevent and control them; the current scheme can also provide construction personnel with simulation results under different construction methods, thereby helping to select the optimal construction method and improve construction efficiency and quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0012] Figure 1 It is a flow chart of a numerical simulation method for the whole process of tunnel construction based on non-contact measurement.

[0013] Figure 2 The present invention is a flow chart of step S1 of a method for numerically simulating the whole process of tunnel construction based on non-contact measurement.

[0014] Figure 3 The present invention is a flow chart of step S2 of a method for numerically simulating the whole process of tunnel construction based on non-contact measurement.

[0015] Figure 4 The present invention is a flow chart of step S23 of a method for numerically simulating the whole process of tunnel construction based on non-contact measurement.

[0016] Figure 5 The present invention is a flow chart of step S3 of a method for numerically simulating the whole process of tunnel construction based on non-contact measurement.

[0017] Figure 6 The present invention is a flow chart of step S31 of a method for numerically simulating the whole process of tunnel construction based on non-contact measurement.

[0018] Figure 7 The present invention is a flow chart of step S32 of a method for numerically simulating the whole process of tunnel construction based on non-contact measurement.

[0019] Figure 8 The present invention is a flow chart of step S4 of a method for numerically simulating the whole process of tunnel construction based on non-contact measurement. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in the art or the product specifications are used.

[0021] See also Figure 1 ,A numerical simulation method for the whole process of tunnel construction based on non-contact measurement, including: S1, obtaining the tunnel shape, the tunnel structure corresponding to the size of the tunnel, the tunnel construction method and the construction conditions corresponding to the construction steps, and dividing the tunnel into a plurality of sample areas according to the tunnel structure and the construction conditions.

[0022] S2, obtaining the settlement amount of the measuring point in each sample area, setting the tunnel center as the starting point, and obtaining the settlement distribution map according to the distance between the measuring point and the tunnel center.

[0023] S3, according to the settlement distribution diagram, obtain the vertical displacement of the tunnel bottom, the normal displacement on both sides of the tunnel and the settlement area generated during tunnel construction under the corresponding construction steps, and calculate the maximum settlement factor and correction factor.

[0024] S4, identify the maximum settlement point and the maximum change point in the tunnel, use the maximum change point as the basis for simulation using the finite element model, and output the settlement-related simulation factors based on the simulation results.

[0025] S5, combining the simulation factor, correction factor and maximum settlement factor to form a final prediction model, coupling the prediction model according to the measurement points used in the calculation, and obtaining the simulation evaluation results of the tunnel construction.

[0026] The shape and size of the tunnel can be expressed as shown below: shape: circular, rectangular, horseshoe, etc.; size: diameter, width, height, etc.

[0027] The tunnel structure is represented by support methods and lining types. Lining types include shotcrete, prefabricated segments, etc.; support methods include anchor rods, steel arch frames, etc.; drainage system: drainage ditches, drainage pipes, etc.; the different tunnel structures used at this time will lead to different initial stresses and stress changes in the entire tunnel, and ultimately lead to different settlements and corresponding displacements.

[0028] The construction conditions represent the current tunnel construction method, geological conditions corresponding to the construction steps, hydrological conditions, etc.; construction methods include drilling and blasting, shield tunneling, TBM, etc.; construction steps are used to clarify the steps and sequence of tunnel construction at this time, to determine the corresponding conditions under each step during the entire tunnel construction process, such as excavation, consolidation, protection, final stage, etc., to verify the changes in the overall settlement and displacement of the tunnel; construction conditions can represent the boundary conditions currently being simulated and verified. Using this boundary simulation condition, it is possible to identify the boundary conditions and geological conditions of the relevant parts of the tunnel after the excavation part is selected to reflect the characteristics of the tunnel during excavation, thereby obtaining a finite difference solution that is more similar to the current actual situation.

[0029] The divided sample areas will be divided according to the number required under each construction condition to generate multiple sample areas of equal size. At the same time, the sample areas set under different construction steps will be adjusted accordingly.

[0030] The simulation method used can be FLAC3D, UDEC, 3DEC, PFC, Abaqus and other software for tunnel construction simulation; when using the simulation software, the boundary conditions and initial conditions of the model are set according to the actual situation of the tunnel. The boundary conditions usually include the fixed boundary, free boundary and stress boundary of the model; the initial conditions include the initial stress state and temperature of the rock and soil body.

[0031] Through the construction simulation function of the software, the construction process of the tunnel is simulated step by step, including the simulation of excavation, support, lining and other steps. During the simulation process, the changes in the displacement, stress and other parameters of the tunnel can be monitored in real time; at this time, multiple areas will be divided as sample areas, and multiple measurement points will be set in each sample area to ensure that the entire area is covered; the data recorded by the measurement points will be integrated, and the three-dimensional coordinates and settlement of each measurement point will be recorded. The unit of settlement is millimeter, which indicates the depth of sinking. Recording the settlement can show the settlement of the entire tunnel relative to the initial position on the bottom surface. At the same time, when the tunnel settles, the change in the center of the tunnel will be more obvious, so the maximum settlement factor, correction factor and other values ​​will be set at the center of the tunnel for the initial judgment position. At the same time, it is necessary to consider whether there is a part with settlement difference in the current tunnel, and whether there is a part with large relative displacement, and combine these contents to obtain a corresponding simulation factor, and finally complete the prediction of the settlement of the entire tunnel to simulate the changes in the corresponding area during the construction process.

[0032] In one embodiment of the present invention, step S1 obtains the tunnel shape, the tunnel structure corresponding to the size, the tunnel construction method and the construction conditions corresponding to the construction steps, and divides the tunnel into multiple sample areas according to the tunnel structure and the construction conditions.

[0033] When obtaining the settlement distribution, it is necessary to predict the settlement-sensitive areas according to the expected tunnel excavation depth, geological conditions, groundwater level and other factors, and set up sample areas and measurement points on this basis to adjust the layout of the observed settlement distribution.

[0034] Therefore, in step S1, it is necessary to adjust the setting of the sample area to identify the sensitive area and set it as the corresponding sample area.

[0035] like Figure 2 As shown, step S1 also includes the following implementation methods: S11, setting a first sample area based on the tunnel structure, the first sample area divides the tunnel into different sample areas according to different lining types, support methods, etc. in the tunnel structure.

[0036] S12, setting a second sample area based on the construction conditions, wherein the second sample area divides the tunnel into different sample areas according to different construction methods, geological conditions, hydrological conditions, etc. in the construction conditions.

[0037] S13, setting the first sample area and the second sample area as output sample areas.

[0038] At this time, the tunnel will be divided according to different tunnel structures and construction conditions to identify areas prone to settlement and stress changes. At the same time, the impact of different tunnel structures and construction conditions on tunnel construction can be evaluated.

[0039] At the same time, these obtained sample areas can be superimposed and analyzed according to the tunnel structure and construction conditions to identify areas with high comprehensive risks and the buffer conditions around the areas. At this time, these risks and buffers will be realized through settlement and corresponding stress analysis to complete the control of settlement analysis.

[0040] In one embodiment of the present invention, step S2 obtains the settlement amount of the measuring point in each sample area, sets the tunnel center as the starting point, and obtains the settlement distribution map according to the distance between the measuring point and the tunnel center.

[0041] At this time, the settlement distribution will first calculate the distance from each measuring point to the tunnel centerline; the settlement of each measuring point is matched with its distance to the tunnel centerline to form a settlement distribution table.

[0042] Use Excel, MATLAB and other tools to generate a settlement distribution map; this settlement distribution map will show the overall settlement distribution, and will also add the three-dimensional coordinates corresponding to the measuring points to indicate the changes in different areas, as well as the distribution of settlement in different settlement areas when the distance between the measuring points and the tunnel centerline is the same, so as to quantify the settlement distribution.

[0043] For example, each measuring point in the settlement distribution map can be represented as (x, y, z, d1, d2); where x, y, z represent the three-dimensional coordinates of the measuring point, d1 represents the settlement, and d2 represents the distance between the measuring point and the center of the tunnel; in order to quantify the settlement distribution, it is necessary to determine the sample area where each measuring point is located to identify the relative relationship between the measuring points.

[0044] At this time, the main purpose is to analyze the stress changes mainly based on settlement, simulate the environment around the tunnel construction team and be affected by the surrounding environment.

[0045] When generating a settlement distribution map, it is necessary to collect settlement amounts in different sample areas according to the generated sample areas, identify the changing trend of settlement amounts, and convert these identified parts into a settlement distribution map. The simulation of settlement amounts can use elastic mechanics models, plastic mechanics models, etc., and based on these simulations, predict the amount of settlement that will occur at this time.

[0046] So Figure 3 As shown, the implementation method of step S2 includes the following contents: S21, based on the settlement of the measuring point, obtaining the envelope ratio of the measuring point, at this time the envelope ratio represents the ratio of the settlement value measured at the measuring point to the reference value, the reference value represents the maximum settlement value of the tunnel, and this value is obtained through the tunnel construction specifications.

[0047] S22, combining the envelope ratios of the measuring points to generate a first envelope curve located on the left side of the tunnel centerline and a second envelope curve located on the right side of the tunnel centerline, introducing the first envelope curve and the second envelope curve into the distance between the measuring points and the tunnel center, and calculating the fluctuation range corresponding to the settlement.

[0048] S23, marking the measuring points according to the fluctuation range of the settlement amount, and forming a settlement distribution map with the marked measuring points.

[0049] The settings of the first envelope curve and the second envelope curve selected in step S22 are used to determine whether there is fluctuation in the relative positions of the settlement on both sides of the tunnel when a symmetrical comparison is performed based on the center line of the tunnel, and the fluctuation range of the settlement on both sides. The fluctuation range represents the numerical range in which the settlement can fluctuate at this time, that is, the maximum and minimum values ​​of the settlement at the corresponding position are obtained to obtain the fluctuation range at this time.

[0050] Since the fluctuation range can show the changing trend of settlement with the distance from the tunnel centerline, the settlement distribution map is generated by marking the part with obvious fluctuation range. At the same time, when marking the measuring points, it is also necessary to determine the interval of settlement in different fluctuation ranges, generate multiple images according to each fluctuation range, and superimpose these images to form the final output settlement distribution map.

[0051] In one embodiment of the present invention, when obtaining the settlement distribution map, it is necessary to analyze the changing area of ​​the settlement amount and select the required settlement distribution map according to the changing area of ​​the settlement amount, such as combining the settlement amounts at the measuring points in the rising area into a settlement distribution map, combining the settlement amounts in the descending area into a settlement distribution map, or selecting the settlement amounts with extremely small fluctuations to form a settlement distribution map.

[0052] So Figure 4 As shown, step S23 may also include the following implementations.

[0053] S231, based on the fluctuation range of the settlement, performing trend analysis on the settlement of the measuring point, and obtaining the symmetrical position of the first envelope curve and the second envelope curve.

[0054] S232: Determine the fluctuation trend of the settlement amount as the distance from the tunnel centerline changes according to the symmetrical positions of the first envelope curve and the second envelope curve.

[0055] S233, based on the fluctuation trend quantity of the settlement amount, generating a plurality of initial settlement maps corresponding to the fluctuation trend quantities, superimposing the initial settlement maps according to the positions of the measuring points and the settlement amounts, and generating an output settlement distribution map.

[0056] At this time, based on the fluctuation range of the settlement, the initial settlement maps corresponding to multiple fluctuation ranges are generated, and the initial settlement maps are superimposed according to the position of the measuring point and the settlement to generate an output settlement distribution map. The superposition is performed by taking the weighted average according to the corresponding measuring point position and settlement to determine the final superimposed measuring point position and the settlement value of the measuring point to reflect the overall settlement change.

[0057] The fluctuation value at this time represents the ratio of the settlement to the average settlement; the symmetrical position is the position of the first envelope curve and the second envelope curve relative to the center line of the tunnel, which is usually achieved by calculating the average or median settlement of the two curves at each distance, and selecting the corresponding point of the average or median settlement at each distance as the symmetrical position at this time. For the symmetrical position at each distance, the fluctuation trend is realized by calculating the difference between the fluctuation of each measuring point and the fluctuation of the symmetrical position. Multiple initial settlement maps are generated based on the fluctuation trend at this time, and finally a settlement distribution map that can include the position where the settlement trend changes significantly is superimposed.

[0058] In one embodiment of the present invention, step S3 obtains the vertical displacement of the tunnel bottom, the normal displacement on both sides of the tunnel and the settlement area generated during tunnel construction under the corresponding construction steps according to the settlement distribution diagram, and calculates the maximum settlement factor and the correction factor.

[0059] like Figure 5 As shown, step S3 includes the following implementation methods.

[0060] S31, dividing the acquired settlement distribution map according to the construction conditions and the tunnel structure, and determining a conditional difference map corresponding to the settlement distribution map at this time.

[0061] At this time, the settlement distribution map is obtained, and the settlement distribution map is divided according to the construction conditions and tunnel structure to determine the conditional difference map corresponding to the settlement distribution map at this time. The conditional difference map is used to perform finite difference solution on the settlement distribution map according to the construction conditions and tunnel structure, so as to obtain the settlement solution under the current construction conditions and tunnel structure; this solution process aims to determine the stress change of the model caused by the change of settlement during the construction process. For example, using the finite difference method, the tunnel and its surrounding strata are discretized into a series of nodes and units. The location and density of the nodes should be determined according to the size of the tunnel, geological conditions and expected settlement distribution; for each node, a displacement vector is defined to record the settlement of the point; according to the basic principles of elastic mechanics, differential equations describing the settlement and stress changes of the tunnel and its surrounding strata are established. These equations will take into account the displacement of the nodes, the elastic properties of the materials and the boundary conditions (such as the fixed constraints of the surface, the excavation surface of the tunnel, etc.); the differential equations can be solved by iteration, and the displacement vector of the node is updated at each iteration until the convergence condition is reached; in the process of solving the differential equations, the boundary conditions need to be specially handled. For example, fixed displacement boundary conditions may be set at the surface; at the excavation surface of the tunnel, it may be necessary to consider the stress release and displacement changes caused by excavation; solve the differential equation to obtain the settlement of each node; calculate the stress distribution of the tunnel and its surrounding strata based on the settlement data; this can be achieved by substituting the settlement into the stress-strain relationship of elastic mechanics; analyze the solution results, evaluate whether the settlement distribution and stress changes of the tunnel meet safety standards, compare the calculation results with the field monitoring data, and verify the accuracy and reliability of the model; through these calculation methods, reflect the comparison between the current simulation calculation results and the field monitoring data.

[0062] So Figure 6 As shown, the implementation process of step S31 can be shown as follows.

[0063] S311, based on the settlement distribution map, determine the difference area for finite difference solution; this area should cover the parts with significant settlement changes, complex construction conditions or special tunnel structures.

[0064] S312, based on the tunnel structure and construction conditions, the differential area is divided into multiple differential grids; in the determined differential area, the differential grids are divided according to certain rules; the grid division should take into account the complexity of the construction conditions and tunnel structure, as well as the accuracy requirements of the solution. Square or rectangular grids are usually used for division to ensure that the same form of differential equations is obtained at each grid node.

[0065] S313, extract the difference grid solution accuracy and calculation conditions, and set the difference format corresponding to the difference grid; common difference formats include upwind format, Lax-Wendroff format, Maccormack format, etc.; when selecting the difference format, factors such as wave propagation direction, numerical stability, and calculation efficiency should be considered.

[0066] S314, constructing a differential equation group according to the differential format and the settlement distribution diagram, wherein each equation in the differential equation group corresponds to a differential equation on a differential grid node; by solving the differential equation group, a numerical solution of the settlement amount can be obtained;

[0067] S315, graphically display the differential equation group and generate a conditional difference diagram; the conditional difference diagram should clearly mark the position of each grid node, the coefficients of the differential equation, and the boundary conditions to be solved.

[0068] When the conditional difference diagram is obtained, the key areas and abnormal values ​​of settlement and stress changes are identified to determine whether the settlement and stress at this time are within an acceptable range. The analysis of the conditional difference diagram is quantified to verify the maximum settlement factor corresponding to the settlement and stress changes under different conditions.

[0069] S32, performing finite difference solution on the conditional difference diagram to obtain the solution result of the conditional difference, the solution result includes the position of the grid nodes after the difference equation is solved, the settlement amount obtained by solving the solution, and the boundary conditions, so as to identify the value of the settlement amount and the value of the maximum settlement factor in the conditional difference diagram under different circumstances.

[0070] like Figure 7 As shown, the implementation process of step S32 may include the following methods.

[0071] S321, discretize the tunnel and the surrounding bottom layer to generate multiple target nodes. The location and density of the target nodes should be determined according to the size of the tunnel, geological conditions and the distribution of the fluctuation trend in the settlement distribution diagram; each target node corresponds to a unit.

[0072] S322, set the displacement vector corresponding to the target node, continuously iterate the displacement vector until the convergence condition is reached, and output the displacement vector that reaches the convergence condition as the target displacement vector; the displacement vector represents the vertical displacement of the bottom of the tunnel and the normal displacement on both sides of the tunnel.

[0073] S323, based on the target displacement vector, obtaining a displacement boundary condition of the target displacement vector;

[0074] S324, based on the displacement boundary conditions, determine the settlement and stress distribution of the tunnel and the surrounding strata, and output them as conditional difference solution results.

[0075] At this time, considering the displacement of the target node, the elastic properties of the material and the corresponding boundary conditions, the differential equation is set, and the differential equation can be expressed as shown below.

[0076] Ku=F; wherein, Ku=F can represent the differential equation currently required, K is the stiffness matrix, representing the elastic properties of the material, u is the displacement vector; F is the external force vector, representing the external load and boundary conditions.

[0077] The stiffness matrix is ​​determined by the elastic modulus and Poisson's ratio of the material and can be expressed as shown below.

[0078] K = ∫ V B T DBdV; where K represents the stiffness matrix, which is used to represent the stiffness relationship between target nodes; ∫ V Indicates integration over the integral domain V, V represents the volume of the unit corresponding to the target node, B represents the strain-displacement matrix, and converts the target node displacement into unit strain. T represents the transpose of the strain-displacement matrix, D represents the elastic matrix, which represents the elastic properties of the material; dV represents the volume element.

[0079] The external force vector is mainly affected by the external force and the corresponding material, as shown below.

[0080] Where F is the external force vector, ∫ V represents the integration over the integral domain, N represents the shape function matrix, which is used to interpolate the node displacement to any point in the unit; N T represents the transpose of the shape function matrix, ρ represents the density of the material, g represents the acceleration of gravity, dV represents the volume element, Indicates at the border Integrate on represents the boundary of the unit; t represents the external force on the boundary, represents the surface force acting on the boundary; dA represents the area element.

[0081] At this time, the strain-displacement matrix B corresponding to the stiffness matrix K is used to convert the displacement vector of the target node into unit strain, which depends on the shape and displacement field of the unit divided from the tunnel at this time, for example, it can be expressed as.

[0082] Among them, x and y represent the coordinates of the target node, and N1 and N2 represent the values ​​of the shape function matrix.

[0083] For example N i represents the value of the shape function at the i-th node in the unit corresponding to the target node, ξ′ and η′ represent the coordinates of the target node, ξ i , η iRepresents the coordinates of the i-th node in the unit corresponding to the target node; here we simply explain the way of transformation on the plane. When it becomes three-dimensional, the coordinate z is introduced to complete the corresponding strain-displacement transformation.

[0084] At this time, the coordinates in the strain-displacement matrix can be the product of the shape function of the target node, the coordinates of the target node, and the coordinates of the nodes in the unit corresponding to the target node, so as to adjust the node values ​​in the unit and realize the conversion of the displacement vector of the target node into the unit strain.

[0085] The elasticity matrix D can be expressed in the following form.

[0086] Where E is the elastic modulus and ν is Poisson's ratio. This matrix converts strain to stress.

[0087] The matrix set above can be used to solve stress, strain, and displacement-related content to obtain the settlement and corresponding stress that need to be identified at this time.

[0088] During the iteration of step S322, the displacement vector is calculated each time until the displacement increment calculated by the displacement vector is less than the convergence threshold. Then, it is considered that the current displacement vector meets the requirements and is output as the target displacement vector.

[0089] In step S323, the initial value of the displacement boundary condition is set to 0, and the displacement change generated during the construction of the tunnel is set as the displacement boundary condition.

[0090] In step S324, the stress and settlement around the calculated displacement boundary condition are obtained, and the solution result at this time is output to process the settlement distribution and stress change of the tunnel.

[0091] In step S32, the corresponding displacement value can be calculated by solving the change value of the displacement vector. According to the direction of the tunnel, the displacement amount solved at this time can be directly calculated to identify the current displacement status. At the same time, the stress condition converted at this time will also be solved to assist in identifying the current settlement amount that needs to be output and prevent the occurrence of unreasonable stress conversion.

[0092] S33, obtaining the maximum settlement factor of the settlement amount according to the solution result.

[0093] The maximum settlement factor is expressed as the ratio of the settlement corresponding to the maximum value of the fluctuation trend in the settlement distribution diagram to the settlement in the solution result, to reflect the corresponding displacement boundary conditions and the settlement under the corresponding circumstances. If the maximum settlement factor is close to 1, it means that the settlement trend set before is similar to the solution analysis at this time, and the overall prediction is relatively accurate; if it is significantly greater than 1, it means that the previous settlement trend was significantly less predicted, and the overall prediction underestimated the value of the settlement affected by the boundary conditions and other contents; if it is significantly less than 1, it means that the affected value was overestimated before, or the overall prediction value is different.

[0094] For the displacement and settlement area generated at this time, the corresponding correction factor is obtained by combining the displacement, settlement area and the calculated settlement solution. The correction factor is used to evaluate the stability of the tunnel and determine whether there are safety hazards in the tunnel. According to the size and change trend of the correction factor, the parameter adjustment and optimization during the construction process are guided to ensure the safety and stability of the tunnel construction.

[0095] S34, combining the solution result with the displacement and settlement area to obtain a correction factor.

[0096] The correction factor is expressed here as a comprehensive value of the settlement area, settlement, displacement vector, and stress change in the solution results. The settlement area, settlement, displacement vector, and stress change in the solution results are obtained, the settlement area, settlement, displacement vector, and stress change are normalized, and the correction factor is calculated.

[0097] Among them, λ j represents the correction factor of the jth element, ε j represents the stress change of the jth element, u j represents the displacement vector of the jth element, SA 1,j represents the sedimentation of the jth element, SA 2,j Represents the settlement area of ​​the jth element. The displacement vector is normalized by taking the modulus of the displacement vector and then performing normalization, or by directly normalizing the vector.

[0098] In one embodiment of the present invention, step S4 identifies the maximum settlement point and the maximum change point in the tunnel, uses the maximum change point as a basis for simulation using a finite element model, and outputs settlement-related simulation factors based on the simulation results.

[0099] The simulation factor is used to simulate the most obvious points in the tunnel construction process and verify the changes of the most obvious points in the overall construction to identify the parts of the tunnel construction that obviously need attention; in this step, these changes are mainly identified by obtaining the settlement amount.

[0100] The maximum settlement point is used to identify the point with the largest settlement at this time, and to find out the point with the largest settlement change when the model is simulated, so as to identify the point that is most susceptible to impact at this time; for example, to identify and select settlement rates and settlements under different tunnel structures and construction conditions to quantify simulation factors, and output the simulation results at this time as simulation factors.

[0101] The simulation is performed in the same manner as the finite element solution in step S3. At this time, the sedimentation rate and the amount of sedimentation are identified according to the calculated displacement vector. Figure 8 As shown, step S4 also includes the following implementation.

[0102] S41, obtaining the settlement rate and settlement amount of the maximum change point under different tunnel structures and construction conditions.

[0103] S42, based on the sedimentation rate and sedimentation amount, the simulation factors related to the sedimentation are calculated.

[0104] Therefore, the simulation factor is expressed as follows: obtain the sedimentation rate, sedimentation amount, and the maximum sedimentation area corresponding to the current sedimentation amount, normalize the sedimentation rate, sedimentation amount, and maximum sedimentation area, and calculate the simulation factor.

[0105] Among them, ψ represents the simulation factor, represents the maximum settlement area, SA1 represents the settlement amount, SA3 represents the settlement rate, and e represents the exponential constant; at this time, the settlement amount represents the settlement value at the maximum change point, the settlement rate also represents the settlement rate at the maximum change point, and the maximum settlement area represents the maximum settlement area corresponding to the current maximum change point, to quantify the value of the simulation factor at this time, as well as the change of settlement under the corresponding simulation.

[0106] In one embodiment of the present invention, step S5 combines the simulation factor, the correction factor and the maximum settlement factor to form a final prediction model, and couples the prediction model according to the measurement points used in the calculation to obtain a simulation evaluation result of the tunnel construction.

[0107] Therefore, the coupling method at this time is to respectively identify the measurement points used in the calculation of the simulation factor, correction factor and maximum settlement factor, as well as the positions of the measurement points, and couple and splice the measurement points directly involved in the calculation according to their relative positions, determine the simulation evaluation results of the settlement caused by the tunnel construction at the same position at this time, and output the relative simulation evaluation results to obtain an evaluation of the tunnel construction.

[0108] For example, the simulation factor, the correction factor and the maximum sedimentation factor may be directly combined to obtain the combined simulation evaluation result. For example, the simulation evaluation result may be expressed as.

[0109] Among them, L represents the simulation evaluation result, ψ represents the simulation factor, λ represents the correction factor, and δ max represents the maximum sedimentation factor, w1 represents the weight of the simulation factor, w2 represents the weight of the correction factor, and w3 represents the weight of the maximum sedimentation factor. According to the order of simulation factor, correction factor and maximum sedimentation factor, the weights are set to 0.4, 0.3 and 0.3 respectively.

[0110] The final simulation evaluation result is used to represent the analysis results of the settlement and the current construction process after the simulation, and is used to simulate whether the project under construction at this time meets the requirements. For example, when the simulation evaluation result is a negative number, it means that there is an error between the current simulation content and the expected requirements, and the construction content needs to be adjusted to reduce the possible risks in the construction. The value at this time needs to be close to the set threshold. For example, the set threshold is 0.6. When it is close to this value, it means that the overall evaluation result meets the requirements. The current construction can be observed to continuously adjust the simulation content to improve the safety of the construction.

[0111] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention and they are still covered by the protection scope of the present invention.

Claims

1. A method for numerical simulation of the whole process of tunnel construction based on non-contact measurement, characterized in that: include: S1, obtaining the tunnel structure corresponding to the shape and size of the tunnel, the construction method of the tunnel and the construction conditions corresponding to the construction steps, and dividing the tunnel into multiple sample areas according to the tunnel structure and construction conditions; S2, obtaining the settlement amount of the measuring point in each sample area, setting the tunnel center as the starting point, and obtaining the settlement distribution map according to the distance between the measuring point and the tunnel center; S3, according to the settlement distribution diagram, obtain the vertical displacement of the tunnel bottom, the normal displacement on both sides of the tunnel and the settlement area generated during the tunnel construction under the corresponding construction steps, and calculate the maximum settlement factor and correction factor; S4, identifying the maximum settlement point and the maximum change point in the tunnel, using the maximum change point as a basis for simulation using a finite element model, and outputting settlement-related simulation factors based on the simulation results; S5, combining the simulation factor, correction factor and maximum settlement factor to form a final prediction model, coupling the prediction model according to the measurement points used in the calculation, and obtaining the simulation evaluation results of the tunnel construction.

2. A method for numerical simulation of the whole process of tunnel construction based on non-contact measurement according to claim 1, characterized in that: Step S1 also includes the following implementation: S11, setting a first sample area based on the tunnel structure, wherein the first sample area divides the tunnel into different sample areas according to different lining types, support methods, etc. in the tunnel structure; S12, setting a second sample area based on the construction conditions, wherein the second sample area divides the tunnel into different sample areas according to different construction methods, geological conditions, hydrological conditions, etc. in the construction conditions; S13, setting the first sample area and the second sample area as output sample areas.

3. The method for numerical simulation of the whole process of tunnel construction based on non-contact measurement according to claim 1 is characterized in that: The implementation of step S2 includes the following contents: S21, obtaining an envelope ratio of the measuring point based on the settlement amount of the measuring point; S22, combining the envelope ratios of the measuring points to generate a first envelope curve located on the left side of the tunnel centerline and a second envelope curve located on the right side of the tunnel centerline, introducing the first envelope curve and the second envelope curve into the distance between the measuring points and the tunnel center, and calculating the fluctuation range corresponding to the settlement; S23, marking the measuring points according to the fluctuation range of the settlement amount, and forming a settlement distribution map with the marked measuring points.

4. A method for numerical simulation of the whole process of tunnel construction based on non-contact measurement according to claim 3, characterized in that: Step S23 may also include the following implementations: S231, performing trend analysis on the settlement of the measuring point based on the fluctuation range of the settlement, and obtaining the symmetrical position of the first envelope curve and the second envelope curve; S232, determining a fluctuation trend of the settlement amount as the distance from the tunnel centerline changes according to the symmetrical positions of the first envelope curve and the second envelope curve; S233, based on the fluctuation trend quantity of the settlement amount, generating a plurality of initial settlement maps corresponding to the fluctuation trend quantities, superimposing the initial settlement maps according to the positions of the measuring points and the settlement amounts, and generating an output settlement distribution map.

5. The method for numerical simulation of the whole process of tunnel construction based on non-contact measurement according to claim 1 is characterized in that: Step S3 includes the following implementations: S31, dividing the acquired settlement distribution map according to the construction conditions and the tunnel structure, and determining a conditional difference map corresponding to the settlement distribution map at this time; S32, performing a finite difference solution on the conditional difference graph to obtain a solution result of the conditional difference; S33, obtaining the maximum settlement factor of the settlement amount according to the solution result; S34, combining the solution result with the displacement and settlement area to obtain a correction factor.

6. A method for numerical simulation of the whole process of tunnel construction based on non-contact measurement according to claim 5, characterized in that: The implementation process of step S31 can be shown as follows: S311, determining a difference region for performing a finite difference solution based on the settlement distribution map; S312, dividing the differential area into a plurality of differential grids based on the tunnel structure and construction conditions; S313, extracting the difference grid solution accuracy and calculation conditions, and setting the difference format corresponding to the difference grid; S314, constructing a group of difference equations according to the difference format and the settlement distribution map; S315, graphically displaying the differential equation group to generate a conditional difference graph.

7. The method for numerical simulation of the whole process of tunnel construction based on non-contact measurement according to claim 5 is characterized in that: The implementation process of step S32 may include the following methods: S321, discretize the tunnel and the surrounding bottom layer to generate multiple target nodes, the location and density of the target nodes should be determined according to the size of the tunnel, geological conditions and the distribution of the fluctuation trend quantity in the settlement distribution map; each target node corresponds to a unit; S322, setting a displacement vector corresponding to the target node, continuously iterating the displacement vector until a convergence condition is reached, and outputting the displacement vector that reaches the convergence condition as a target displacement vector; S323, based on the target displacement vector, obtaining a displacement boundary condition of the target displacement vector; S324, based on the displacement boundary conditions, determine the settlement and stress distribution of the tunnel and the surrounding strata, and output them as conditional difference solution results.

8. The method for numerical simulation of the whole process of tunnel construction based on non-contact measurement according to claim 5 is characterized in that: The correction factor is expressed as: Get the settlement area, settlement amount, displacement vector, and stress change in the solution, normalize the settlement area, settlement amount, displacement vector, and stress change, and calculate the correction factor: Among them, λ j represents the correction factor of the jth element, ε j represents the stress change of the jth element, u j represents the displacement vector of the jth element, SA 1,j represents the sedimentation of the jth element, SA 2,j represents the settlement area of ​​the jth element.

9. The method for numerical simulation of the whole process of tunnel construction based on non-contact measurement according to claim 1, characterized in that: Step S4 also includes the following implementation: S41, obtaining the settlement rate and settlement amount of the maximum change point under different tunnel structures and construction conditions; S42, based on the sedimentation rate and sedimentation amount, the simulation factors related to sedimentation are calculated; The simulation factor is expressed as follows: the sedimentation rate, sedimentation amount, and the maximum sedimentation area corresponding to the current sedimentation amount are obtained, the sedimentation rate, sedimentation amount, and maximum sedimentation area are normalized, and the simulation factor is calculated; Among them, ψ represents the simulation factor, represents the maximum settlement area, SA1 represents the settlement amount, SA3 represents the settlement rate, and e represents the exponential constant.

10. The method for numerical simulation of the whole process of tunnel construction based on non-contact measurement according to claim 1, characterized in that: The simulation evaluation result is expressed as the combination of the simulation factor, the correction factor and the maximum settlement factor to obtain the combined simulation evaluation result: Among them, L represents the simulation evaluation result, ψ represents the simulation factor, λ represents the correction factor, and δ max represents the maximum sedimentation factor, w1 represents the weight of the simulation factor, w2 represents the weight of the correction factor, and w3 represents the weight of the maximum sedimentation factor.

Images