Parameterization design method and system for underground tunnel partial excavation and dynamic support

Abstract

The invention relates to the technical field of tunnel engineering, and particularly discloses a parameterization design method and system for underground tunnel partial excavation and dynamic supporting, and the method comprises the steps: constructing a partial excavation parameterization model of an underground tunnel, including tunnel contour drawing, section parting line drawing, step section segmentation and three-dimensional solid model generation; parameterization design of tunnel primary support and secondary lining support is carried out, wherein the parameterization design comprises automatic calculation of positioning coordinates of anchor rods or anchor cables and batch data export; performing meshing processing on the parameterized model, and importing the parameterized model into numerical calculation software for mechanical analysis; dynamically adjusting excavation parameters and support parameters based on the result of the mechanical analysis; importing the optimized three-dimensional parameterized model into BIM (Building Information Modeling) software for processing, and generating a CAD (Computer Aided Design) construction drawing; in the construction process, according to monitoring and detection information of surrounding rocks excavated by tunnel sections, reasonable excavation and support parameters are dynamically adjusted and designed, and then standardized drawings can be generated.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering technology, specifically to a parametric design method and system for sectional excavation and dynamic support of underground tunnels. Background Technology

[0002] Bench excavation is a commonly used construction method in tunnel engineering. It is also frequently employed in large-span, high-sidewall underground caverns, involving segmented excavation. Due to the variable surrounding rock and complex geology during tunnel construction, a dynamic design concept is often adopted. This involves designing first and then dynamically adjusting based on the surrounding rock conditions during excavation. This dynamic design process often involves a lot of repetitive work. Traditional design and calculation processes have the following limitations: Traditional modeling relies on manual CAD drawing or fixed templates. When excavation parameters (such as bench height and advance) are adjusted, the entire model must be redrawn, resulting in low efficiency. The positioning of support structures such as anchor bolts requires manual coordinate calculation, which is prone to errors and affects the accuracy of the support effect simulation. Software like FLAC3D is complex to use alone, and the model's level of detail is insufficient to meet modern engineering needs. The separation of design and calculation processes makes it difficult to achieve parametric optimization iteration and quickly adjust model parameters based on calculation results. These problems lead to traditional processes relying on manual operation, resulting in low efficiency, large errors, and a lack of systematic parameter correlation and collaboration mechanisms, failing to meet the requirements of efficient and accurate engineering design.

[0003] Publication No. CN119740285A discloses a parametric modeling and mesh model construction method for underground powerhouse cavern groups. This method first determines the geometric origin and three-axis orientation for modeling, then determines the geometric parameters of the main structures in the underground powerhouse and the geometric parameters of the connecting caverns connected to the main structures, extracting schematic diagrams of the cross-sectional parameter values ​​for the main structures and connecting caverns. Then, based on these schematic diagrams, the main structural framework and connecting cavern framework of the powerhouse are constructed using the Grasshopper plugin in Rhino software, following a point-line-surface construction logic. Finally, the main structural framework and connecting cavern framework are combined according to their connection relationships, and the underground powerhouse model is obtained based on the geometric origin. This method avoids the repetitiveness and uncertainty of manual operations, greatly improving the modeling speed of cavern groups.

[0004] Although existing technologies have made significant progress in parametric modeling of underground powerhouse cavern groups, some shortcomings still exist in practical applications. First, this method is only applicable to underground powerhouse cavern groups, focusing on the parametric modeling of cavern group nodes, without considering the actual needs of construction excavation and dynamic support design. Second, this method only considers parametric modeling from a parametric modeling perspective and does not integrate parametric modeling into numerical calculations and drawing generation. Parametric modeling integrated with dynamic design is a major trend in underground engineering design and construction. Summary of the Invention

[0005] The purpose of this invention is to provide a parametric design method and system for sectional excavation and dynamic support of underground tunnels, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A parametric design method for sectional excavation and dynamic support of underground tunnels, the method comprising: Construct a parametric model for the sectional excavation of an underground tunnel, including tunnel outline drawing, cross-section segmentation drawing, step section segmentation, and 3D solid model generation; Parametric design of initial support and secondary lining support for tunnels, including automatic calculation of anchor bolt or anchor cable positioning coordinates and batch data export; The parametric model is meshed and imported into numerical calculation software for mechanical analysis. Based on the results of the aforementioned mechanical analysis, the excavation and support parameters are dynamically adjusted. The optimized 3D parametric model is imported into BIM software for processing and CAD construction drawings are generated.

[0007] As a further embodiment of the present invention, the step of constructing a parametric model for the sectional excavation of an underground tunnel specifically includes: Draw the tunnel cross-section profile in Rhino and extract the profile curve; Create the endpoints of the split line located outside the tunnel outline; Obtain the intersection points of the tunnel cross-section and the dividing lines, and use the intersection point information to divide and form the cross-sectional curves of each step; Generate a 3D solid model of a straight tunnel or a curved tunnel.

[0008] As a further embodiment of the present invention, the extraction of the contour curve is implemented using Grasshopper's Curve operator; The creation of the dividing line endpoints is achieved through the Construct Point operator, and the endpoints are connected to form the dividing line through the Line operator; The process of obtaining intersection points and dividing them to form the cross-sectional curves of each step is achieved through a combination of Curve / Curve operators, SplitList operators, Construct Domain operators, and Sub Curve operators. The control arch structure is implemented using a Boolean Toggle arithmetic unit; The generation of the 3D solid model is achieved by using the Scale operator, the Boundary Surfaces operator, and in combination with the Extrude operator or the Sweep1 operator.

[0009] As a further embodiment of the present invention, the parametric design steps for the initial support and secondary lining support of the tunnel include: Extract the tunnel boundary curve as a feature line and generate the anchor bolt starting point reference point; Calculate the direction vector of the anchor bolt; Based on the height of the excavation steps, the location coordinates, direction vectors, lengths, and number of segments of the anchor bolts are exported in batches, and command stream files suitable for numerical calculation software are generated.

[0010] As a further embodiment of the present invention, the tunnel boundary curve is extracted as a feature line by the Curve operator, and the Divide Curve operator is used to generate the anchor bolt starting point reference point. The Vector Rotate operator is used to calculate the direction vector of the anchor bolt; Based on the height of the excavation steps, the location coordinates, direction vectors, lengths, and number of segments of the anchor bolts are exported in batches, and a command stream file suitable for numerical calculation software is generated.

[0011] As a further embodiment of the present invention, the step of dynamically adjusting the excavation parameters and support parameters based on the results of the mechanical analysis includes: When the maximum displacement output by the numerical calculation software exceeds the set threshold, the parameter adjustment mechanism is automatically triggered. The adjustment mechanism includes at least one of the following: increasing the anchor bolt length by a set ratio, reducing the anchor bolt spacing, increasing the grade of the lining concrete, and increasing the lining thickness. Repeat the modeling, meshing, and mechanical analysis steps until the displacement, plastic zone volume change rate, and fracture degree RFD value meet the preset iteration termination conditions.

[0012] As a further embodiment of the present invention, the gridding process is implemented through the Griddle plugin, including: The tunnel, primary lining, secondary lining, and surrounding rock model are combined into a non-manifold entity. Different grid sizes were set for the internal surrounding rock, tunnel area and external mountain to achieve fine division; Export the grid file.

[0013] This invention also provides a parametric design system for sectional excavation and dynamic support of underground tunnels, used to realize a parametric design method for sectional excavation and dynamic support of underground tunnels, the system comprising: The model building module is used to build a parametric model of the sectional excavation of underground tunnels, including tunnel outline drawing, cross-section dividing line drawing, step section segmentation, and 3D solid model generation. The parameter design module is used for parameterized design of tunnel initial support and secondary lining support, including automatic calculation of anchor bolt or anchor cable positioning coordinates and batch data export. The analysis module is used to mesh the parameterized model and import it into numerical calculation software for mechanical analysis. The dynamic adjustment module is used to dynamically adjust the excavation and support parameters based on the results of the mechanical analysis. The results generation module is used to import the optimized 3D parametric model into BIM software for processing and to generate CAD construction drawings.

[0014] Compared with the prior art, the beneficial effects of the present invention are: during the construction process, based on the monitoring and detection information of the surrounding rock of the tunnel excavation section, the standardized drawings can be generated by dynamically adjusting the reasonably designed excavation and support parameters, thereby meeting the integrated design requirements of tunnel engineering construction. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention.

[0016] Figure 1 This is a schematic diagram of the overall flow of the integrated design method provided in the embodiments of the present invention; Figure 2 This is a schematic diagram of a three-dimensional parametric model of a three-stage excavation tunnel constructed in an embodiment of the present invention; Figure 3 This is a schematic diagram of the logic AND operation unit implementation for the upper step cross-section segmentation in this embodiment of the invention; Figure 4 This is a schematic diagram of the logic AND operation unit for segmenting the stepped cross-section in an embodiment of the present invention; Figure 5 This is a schematic diagram of the logic and arithmetic unit implementation for the segmentation of the lower step section (including the inverted arch) in an embodiment of the present invention; Figure 6 This is a schematic diagram of the implementation of a linear tunnel logic and arithmetic unit generated by stretching in an embodiment of the present invention; Figure 7 This is a schematic diagram of the implementation of the curve tunnel logic and arithmetic unit generated by sweeping in an embodiment of the present invention; Figure 8 This is a schematic diagram of the initial support and secondary lining model construction in an embodiment of the present invention; Figure 9 This is a schematic diagram of the parametric design and data export logic of the anchor bolt in an embodiment of the present invention; Figure 10This is a diagram showing the effect of using the Griddle plugin to mesh the model in an embodiment of the present invention. Figure 11 This is a grouping effect diagram of the model after importing FLAC3D and performing the first stage of excavation and support in an embodiment of the present invention; Figure 12 Figures (1), (2), and (3) are respectively the displacement cloud map, maximum principal stress cloud map, and plastic zone distribution cloud map after the first stage of excavation and support in the embodiment of the present invention; Figure 13 This is a contour map of the surrounding rock fracture degree (RFD) after the first stage of excavation and support in this embodiment of the invention; Figure 14 This is an example of a standardized CAD construction drawing finally generated in an embodiment of the present invention; Figure 15 This is a design analysis flowchart based on parametric modeling and multi-software collaboration in another embodiment of the present invention. Detailed Implementation

[0017] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0018] Figure 1 This is a flowchart illustrating a parametric design method for sectional excavation and dynamic support of underground tunnels. In this embodiment of the invention, the parametric design method for sectional excavation and dynamic support of underground tunnels includes: Construct a parametric model for the sectional excavation of an underground tunnel, including tunnel outline drawing, cross-section segmentation drawing, step section segmentation, and 3D solid model generation; Parametric design of initial support and secondary lining support for tunnels, including automatic calculation of anchor bolt or anchor cable positioning coordinates and batch data export; The parametric model is meshed and imported into numerical calculation software for mechanical analysis. Based on the results of the aforementioned mechanical analysis, the excavation and support parameters are dynamically adjusted. The optimized 3D parametric model is imported into BIM software for processing and CAD construction drawings are generated.

[0019] In this embodiment, based on the specific underground engineering design requirements, the tunnel cross-sectional dimensions, shape and styling characteristics are analyzed. Based on the characteristics of sectional excavation construction, key feature parameters are extracted to construct a parametric model of sectional excavation of the underground tunnel. Specifically, this includes tunnel outline drawing, cross-sectional segmentation line drawing, step cross-section segmentation and three-dimensional solid model generation. The parametric design of tunnel initial support and secondary lining support is integrated, especially the anchor bolt (anchor cable) parametric module, which realizes the automatic calculation and data export of anchor bolt (anchor cable) positioning coordinates, including feature line extraction, direction vector calculation and batch support data export; The parametric model is meshed using the Griddle plugin and imported into numerical calculation software such as FLAC3D for mechanical analysis. The excavation and support parameters are dynamically adjusted based on the calculation results to obtain the optimal excavation and support design scheme. The three-dimensional parametric model of this scheme is then exported to BIM, and CAD construction drawings that meet engineering standards are generated through model view configuration, layer standardization processing, and data export optimization.

[0020] In a preferred embodiment of the present invention, the step of constructing a parametric model of the sectional excavation of the underground tunnel specifically includes: Draw the tunnel cross-section profile in Rhino and extract the profile curve; Create the endpoints of the split line located outside the tunnel outline; Obtain the intersection points of the tunnel cross-section and the dividing lines, and use the intersection point information to divide and form the cross-sectional curves of each step; Generate a 3D solid model of a straight tunnel or a curved tunnel.

[0021] The extraction of the contour curve is achieved using Grasshopper's Curve operator. The creation of the dividing line endpoints is achieved through the Construct Point operator, and the endpoints are connected to form the dividing line through the Line operator; The process of obtaining intersection points and dividing them to form the cross-sectional curves of each step is achieved through a combination of Curve / Curve operators, SplitList operators, Construct Domain operators, and Sub Curve operators. The control arch structure is implemented using a Boolean Toggle arithmetic unit; The generation of the 3D solid model is achieved by using the Scale operator, the Boundary Surfaces operator, and in combination with the Extrude operator or the Sweep1 operator.

[0022] Please see Figures 2 to 5In this embodiment, the tunnel outline is drawn as follows: In Rhino software, the cross-sectional shape of the tunnel is drawn using the curve drawing tool. Whether the bottom includes an invert needs to be drawn separately. The portion excluding the bottom curve is extracted to the calculator using the Curve function (set one curve mode). If the tunnel bottom includes an invert, the invert curve needs to be drawn separately using the Curve tool to ensure a smooth connection between the invert and the main tunnel outline. After drawing, the outline curve is extracted to the calculator using the Curve function (set one curve mode) in Grasshopper to achieve digital association of the curve data. During this process, the continuity of the curve must be ensured to avoid broken lines or discontinuities, so as to ensure the accuracy of subsequent segmentation and modeling.

[0023] Cross-section dividing line drawing: The two endpoints of the cross-section dividing line are created using Grasshopper's Construct Point operator. These endpoints must be located outside the tunnel outline to ensure effective segmentation. For the horizontal dividing line, the X-coordinates of the two endpoints are 100 and -100, respectively, and the Y-coordinate is 0. The Z-coordinate is customized using the Number Slider operator with a step size of 0.1, and a maximum and minimum value of 10 and 0. The Z-coordinate is also customized using the Number Slider operator to parameterize the step height. For the vertical dividing line, the X-coordinates of the two endpoints are also customized using the Number Slider operator to parameterize the step height. The absolute value of the difference between the Y-coordinates is greater than the tunnel height, and the Z-coordinate is coplanar with the tunnel cross-section curve. To ensure the dividing line effectively divides the tunnel cross-section into upper, middle, and lower steps, the endpoints must meet the following spatial constraints: The absolute value of the difference between the X coordinates of the two endpoints must be greater than the maximum width of the tunnel (e.g., when the tunnel width is 10m, the difference in X coordinates should be ≥10.5m) to ensure that the dividing line completely penetrates the tunnel outline. The Y-coordinates of both endpoints must be on the same plane as the tunnel cross-section curve (i.e., the Y-coordinate values ​​are the same) to avoid the dividing line and the cross-section curve intersecting in space and to ensure the accuracy of the intersection calculation. The Z coordinates of the two endpoints can be customized using the Number Slider calculator (e.g., the range is set to 0~10m, with a step size of 0.1m). By adjusting the Z coordinate values, the step height can be parameterized (e.g., when Z1=Z2=6m, the step height is 6m).

[0024] After creating the endpoints, use the Line operator to connect the two points and generate the section dividing line.

[0025] The tunnel excavation section is divided into sections. The Curve / Curve operator connects the tunnel section curve and the section dividing line. The coordinates and position information of the intersection point are obtained at the output. The Split List operator is used to divide the information and determine the number of segments (when the number of intersection points is n, the number of segments is n-1. In this example, there are only two intersection points with the tunnel section in the horizontal direction). The Construct Domain operator forms the interval. The Sub Curve operator is used to extract the upper step arch curve. The Line operator connects the intersection points to form the straight line at the bottom of the upper step. Finally, the Join curves operator is used to merge them into the upper step section curve. By reasonably selecting the required curves, the Join curves operator can divide the tunnel surface into various required shapes. This step utilizes multi-processor collaboration to achieve precise segmentation of the upper, middle, and lower step sections. The specific process is as follows: Intersection calculation: Connect the tunnel cross-section curve to end A of the Curve / Curve calculator, and connect the cross-section dividing line to end B. The calculator outputs the coordinates of the intersection point of the two, such as (-4.733607,0,6) and (4.733607,0,6) at end P. The curve parameters of the intersection point on the tunnel cross-section are output at end A (such as 11688.091672 and 13260.076226), and the straight line parameters of the intersection point on the dividing line are output at end B.

[0026] Information segmentation: The curve parameters output by the tA end are segmented by the Split List operator, and the L end is connected to the parameter list. The i end is input with the number of segments by the Number operator (in this example, the number of intersection points is 2, so input 1), so that the parameter information of the two intersection points is listed separately (e.g., the A end outputs 11688.091672, and the B end outputs 13260.076226).

[0027] Upper step arch curve extraction: Connect the outputs of Split List operator A and B to Construct Domain operator A and B respectively to form a parameter range (e.g., 11688.091672~13260.076226); connect the tunnel profile curve to Sub Curve operator C and the output of Construct Domain operator D to extract the upper step arch curve (corresponding to the upper arc segment of the tunnel cross section).

[0028] Generate the bottom straight line of the upper step: Extract the coordinates of the two intersection points output by the Split List operator, connect them to the two endpoint input ports of the Line operator, and generate the bottom straight line of the upper step, such as the horizontal straight line connecting (-4.733607,0,6) and (4.733607,0,6).

[0029] Upward step cross-section integration: Use the Join curves operator to connect the arch curve of the upward step with the bottom straight line to form a closed upward step cross-section curve (ensure curve closure, error ≤ 0.01m). The overall effect is as follows: Figure 3 As shown.

[0030] The middle and lower bench section segmentation adopts the same principle as the upper bench section segmentation. The endpoint of the lower section with a Z coordinate not greater than the upper straight line is selected. The side curves and upper and lower straight lines of the middle bench section are extracted to form the middle bench section curve. The start and end points of the tunnel section curve are obtained through the EndPoint operator. The position information on the curve is determined by the Curve Closest Point operator. After the side wall curve is extracted, it is combined with the invert curve and the endpoint line segment. The invert setting is controlled by Boolean Toggle to merge and form the lower bench section curve. Middle step section division: Create a new section dividing line at the lower part of the tunnel cross-section (the Z coordinates of the two endpoints are no greater than the Z coordinate of the straight line at the bottom of the upper step, such as Z1=Z2=6m>Z3=Z4=3m). Repeat the steps of intersection calculation, information segmentation, and curve extraction to extract the side curves (one segment on the left and one on the right) and the upper and lower straight lines (the upper straight line is the bottom straight line segment of the upper step, and the lower straight line is the middle segment of the new dividing line). Merge these lines using the Join curves operator to form the cross-sectional curve of the middle step. The overall effect is as follows: Figure 4 As shown.

[0031] Step-down section segmentation: Endpoint extraction: Connect the tunnel cross-section curve to the End Point calculator. The output terminal obtains the starting point of the cross-section curve, such as (4.402521,0,1.354747) and the ending point, such as (-4.402521,0,1.354747).

[0032] Location information acquisition: Connect the starting point and the ending point to the P terminal of the Curve Closest Point operator, and connect the tunnel cross-section curve to the C terminal. The output terminal obtains the curve parameters of the two points on the cross-section (such as 11221.596289 and 13726.571609).

[0033] Side wall curve extraction: Combining the parameter information of the intersection point at the lower part of the middle step (such as 11387.033894, 13561.134003), the left and right side wall curves of the tunnel section are extracted by the Sub Curve calculator (corresponding to the curve segments with parameters 13726.571609~13561.134003 and 11221.596289~11387.033894).

[0034] Inverted Arch Curve Integration: Connect the drawn inverted arch curve and the starting and ending line segments (the straight line connecting (4.402521,0,1.354747) and (-4.402521,0,1.354747)) to the L end of the List Item operator, and the BooleanToggle operator to the i end (True for including the inverted arch, False for not including it). Then, merge the side wall curves and the inverted arch curve (or the bottom straight line) using the Join Curve operator to form the lower step cross-sectional curve. The overall effect is as follows: Figure 5 As shown.

[0035] 3D solid model generation: Cross-sectional size control: Connect the upper, middle and lower step cross-sectional curves to the G end (geometric input) of the Scale operator, and connect the Number Slider operator (range 0.5~2.0, step size 0.1) to the F end (scaling factor). Adjust the scaling factor to control the overall size of the tunnel (e.g., when the scaling factor is 1.2, the tunnel width increases from 10m to 12m).

[0036] Cross-sectional surface generation: Connect the output of the Scale operator to the Boundary Surfaces operator to generate a closed stepped cross-sectional surface (the integrity of the surface needs to be checked to avoid holes).

[0037] Solid Extrusion: Straight Tunnel: Connect the cross-sectional surface to the B end (base surface) of the Extrude operator, and connect the NumberSlider operator (range 10~100m, step size 1m) to the D end (extrusion length) via the Unit Y operator (defining the extrusion direction as the Y-axis) to generate a straight tunnel solid (e.g., extrusion length 50m), the effect is as follows. Figure 6 As shown; Curved Tunnel: Connect the cross-sectional surface to the S end (section curve) of the Sweep1 calculator, and connect the tunnel direction curve (such as a circular arc curve with a radius of 500m) to the R end (path curve) to generate a tunnel entity along the curve (ensure that the normal direction of the cross-section and the path is consistent to avoid distortion), the effect is as follows. Figure 7 As shown.

[0038] like Figure 8 As shown, the model construction of the initial lining concrete and the secondary lining: Initial lining modeling: Draw the outline curve of the initial lining concrete in Rhino (offset along the inner side of the tunnel, the offset amount is the initial lining thickness, such as 0.3m), pick the curve through the Curve operator, connect it to the Scale operator (scaling factor slightly less than 1, such as 0.94, corresponding to a thickness of 0.3m) to control the thickness, and generate the initial lining cross-sectional surface through the Boundary Surfaces operator; for straight tunnels, generate solids through the Extrude operator (extension length is consistent with the tunnel), and for curved tunnels, generate solids through the Sweep1 operator.

[0039] Secondary lining modeling: Repeat the initial lining modeling process, draw the outline curve of the secondary lining (offset along the inner side of the initial lining, thickness such as 0.5m), and generate the secondary lining entity through the same combination of calculators, ensuring that it is concentric with the initial lining entity and the spacing is uniform (error ≤ 0.02m).

[0040] A mountain model is established based on engineering geological conditions, or a mountain model with a rough equivalent geological background is constructed as the external condition for the tunnel.

[0041] Importing and processing mountain models: Data Acquisition: Obtain digital elevation model data of the area where the tunnel is located from GIS data sources.

[0042] Format conversion: Use a Rhino plugin to convert the data into a format that Rhino can recognize, and use a coordinate transformation tool to convert the data coordinate system into the local coordinate system of the tunnel model (with the tunnel starting point as the origin and the Y-axis as the direction).

[0043] 3D surface generation: Import the converted data into Rhino, and use the tool to convert the elevation data into a 3D mountain surface. In this example, the calculation is simplified to extract the area within the influence range of the tunnel (cube, length 120m, width and height approximately 3 times the tunnel diameter from the center, width and height both taken as 50m).

[0044] Surrounding rock division: The curved surface of the mountain is offset inward by 10m to form an internal surrounding rock area (about 40m from the center of the tunnel), which is used for subsequent fine grid division.

[0045] Tunnel model import and integration: Use the Bake function in Grasshopper (right-click the calculator and select Bake) to export the parameterized tunnel, primary lining, and secondary lining models to the Rhino main interface and perform Boolean union operations with the mountain model to ensure that there is no overlap or gap between the models (gap ≤ 0.05m).

[0046] Parameter input and management: The initial geometric parameters for three-stage excavation, as well as the thicknesses of the initial support and secondary lining, are input through Grasshopper's parametric module. These parameters include: stage length, stage height, tunnel dimensions, and excavation advance for each stage. For example, under Class IV surrounding rock conditions, when the surrounding rock is relatively hard, a two-stage method can be used to excavate small-section railway tunnels. The z-coordinate value of the stage height is 0~10m, the step length is 0.1m, and the excavation advance is 1~2m. If the surrounding rock grade is Class V, the stage height should be ≤3.5m, the excavation advance is set to 0.6~0.8m, and temporary invert support is required.

[0047] In a preferred embodiment of the present invention, the parametric design steps for the initial support and secondary lining support of the tunnel include: Extract the tunnel boundary curve as a feature line and generate the anchor bolt starting point reference point; Calculate the direction vector of the anchor bolt; Based on the height of the excavation steps, the location coordinates, direction vectors, lengths, and number of segments of the anchor bolts are exported in batches, and command stream files suitable for numerical calculation software are generated.

[0048] The tunnel boundary curve is extracted as a feature line by the Curve operator, and the Divide Curve operator is used to generate the anchor bolt starting reference point. The Vector Rotate operator is used to calculate the direction vector of the anchor bolt; Based on the height of the excavation steps, the location coordinates, direction vectors, lengths, and number of segments of the anchor bolts are exported in batches, and a command stream file suitable for numerical calculation software is generated.

[0049] like Figure 9 As shown, in this embodiment, the boundary curve is obtained by extracting the tunnel boundary curve (excluding the bottom straight line or invert arch) as a feature line using the Curve operator. Equal division point generation: Connect the feature line to the Divide Curve operator, set the number of equal division points in the operator (e.g., 10, which can be adjusted via Number Slider), and generate the anchor rod starting point reference point (e.g., 10 points, with a step feature line length of 10m and a time interval of 1m).

[0050] Rotation parameter settings: Use the Vector Rotate operator to set the rotation angle (e.g., 270°, i.e., pointing outwards from the tunnel) in the XZ plane (the plane where the tunnel curve is located).

[0051] Direction vector generation: The normal vector of the anchor bolt starting point reference point (obtained through the T end of the Divide Curve operator) is connected to the V end of the Vector Rotate operator (the vector to be rotated). The output of the operator is the anchor bolt direction vector, such as (0.994485,0,-0.104878).

[0052] Collision detection module: If the end of the anchor bolt extends beyond the tunnel outline or intrudes into the secondary lining, the angle will be automatically adjusted or the anchor bolt will be removed, and a warning log will be output.

[0053] Data export and command stream generation: Python scripting: In Rhino's Grasshopper plugin, an automated export program is written using Python 3 Script to generate the raw data for anchor bolts, making it usable in FLAC3D software. The core code logic is as follows: Exporting in batches: The program exports the anchor support data in batches to the corresponding files according to the excavation sequence of the upper, middle, and lower steps (T.f3dat corresponds to the upper step, M.f3dat corresponds to the middle step, and D.f3dat corresponds to the lower step). Each batch includes parameters such as excavation advance (3m), anchor coordinates (e.g., (-4.48958,0,4.277934)), direction vector (e.g., (-0.994485,0,-0.104878)), length (3m), and number of segments (10 segments). The omitted part is the anchor at different positions within the same plane at the same step height.

[0054] Based on the excavation height sequence of different strata, anchor bolts are generated in batches sequentially. For example, taking the intersection of the straight line at the bottom of the tunnel sidewall and the tunnel centerline as the origin, if the first layer of excavation height is 6m and the excavation advance is 3m, only anchor bolts with a Z coordinate greater than or equal to 6 are generated; if the second layer of excavation height is 3m, only anchor bolts with a Z coordinate greater than or equal to 3 and less than 6 are generated, and so on. The core of the command flow after importing into FLAC3D is mainly as follows: fish define create_cables loop y (0,a) new_y = 0 + y command structure cable create by-ray x [new_y] z segments ɑ end_command ... end_loop end The initial excavation face is the ZOX plane, where a is the excavation advance, and x, [new_y], and z are the x, y, and z coordinates of the anchor bolt starting point, respectively. , , Let l be the direction vector of the anchor bolt starting point, l be the anchor bolt length, ɑ be the number of segments of the anchor bolt, and the longitudinal spacing of the anchor bolts is 1m.

[0055] In a preferred embodiment of the present invention, the gridding process is implemented through the Griddle plugin, including: The tunnel, primary lining, secondary lining, and surrounding rock model are combined into a non-manifold entity. Different grid sizes were set for the internal surrounding rock, tunnel area and external mountain to achieve fine division; Export the grid file.

[0056] In this embodiment, the entity is combined by using the "join non-manifold surface" command of the Griddle tool to combine the tunnel, primary lining, secondary lining and internal surrounding rock model into a non-manifold entity, ensuring that the entity has no overlapping surfaces.

[0057] Initial mesh generation: Execute the Mesh command in Rhino to set both the mesh density and subdivision level to their maximum values ​​to generate the initial mesh.

[0058] Refined mesh generation: such as Figure 10 As shown, the GS command (Griddle mesh optimization) is executed, with parameters set as follows: Mode=Quadom (quadrilateral dominant), MinEdgelength=0.75m, MaxEdgelength=0.75m, to refine the mesh of the internal surrounding rock. The Extract surface command is used to extract the tunnel mesh separately, assigning a mesh edge length of 0.5m. The GS command is executed again (with unchanged parameters) to divide the tunnel mesh every 0.5m. The same meshing process is performed on the external mountain model, setting the mesh edge length to 1.5m to ensure a smooth transition between the mountain mesh and the internal surrounding rock mesh. Mesh welding and file generation: The GI command (Mesh Integration) is used, setting Meshtype=Mix (mixed mesh type), to weld the connection between the internal and external surrounding rock (welding tolerance 0.01m). The GV command (Mesh Export) is executed, setting Meshsetting=HexDom (hexahedral dominant), to generate a .f3grid format mesh file (for importing into FLAC3D).

[0059] FLAC3D Mechanical Analysis Settings: Model initialization: In FLAC3D, execute the "model new" command to clear historical data and initialize the computing environment.

[0060] Mesh import: Execute the command "zone import 'model.f3grid'" to import the .f3grid file generated by the meshing process, which will automatically create the mesh cells for the computational domain (e.g., approximately 500,000 cells in total).

[0061] Surface Extraction: Execute the “zone face skin” command to generate the outer surface of the model and group it by direction (east, west, south, north, top surface, bottom surface) to prepare for applying boundary conditions.

[0062] If non-manifold edges appear in the Griddle mesh generation, the 'ExtractBadSrf' command is automatically executed to extract the problem surfaces and the Grasshopper is sent back to readjust the segmentation curves; if the FLAC3D calculation does not converge, the excavation advance is automatically reduced by 20% and the calculation is resubmitted.

[0063] Constitutive model and material property definition: The entire region is specified with a "model strain-softening" to simulate the attenuation characteristics of the strength of soil and rock materials with plastic strain; Set material parameters using the "zone property" command: Surrounding rock: density, Young's modulus, Poisson's ratio, initial internal friction angle, initial cohesion, residual internal friction angle, residual cohesion; Primary lining concrete: density, Young's modulus, Poisson's ratio, compressive strength; Secondary lining: density, Young's modulus, Poisson's ratio, compressive strength.

[0064] Boundary condition settings: Set displacement boundary conditions to simulate the actual engineering situation (such as applying fixed X, Y, and Z displacements to the bottom surface of the model, and applying fixed X and Y displacements to the east, west, south, and north sides respectively), and set the top surface as a free end (simulating an unfixed ground surface).

[0065] Initial stress field: The magnitude of the stress in the east, west, south, north, and bottom is determined by actual measured ground stress.

[0066] Step-by-step excavation and support simulation: The alternating "excavation → support" method is used to simulate a three-stage step-by-step construction process, consisting of three phases: Phase 1 (Excavation and Support of the Upper Bench): Excavation: Execute the command "zone cmodel assign null range group'1'" to set the constitutive model of the upper step area (group'1') to null (simulate excavation unloading); Solution: Execute the "solve" command and calculate until equilibrium is reached (unbalanced force ratio ≤ 1e-5). Support: Execute the command “call 'T.f3dat'” to call the upper step anchor data file and generate anchor support; execute the command “zone cmodel assign strain-softening range group 'p1'” to restore the strain softening model for the initial lining concrete (group 'p1'), set the material properties and solve, and save the state.

[0067] Phase 2 (Intermediate Bench Excavation and Support): Excavation: Execute the command "zone cmodel assign null range group'2'" to excavate the middle step area (group'2'); Solve and support: The logic is the same as in stage 1. Call the "M.f3dat" file to set parameters for the initial lining of the middle step (group 'p2'), and save the state after solving.

[0068] Phase 3 (Bench Excavation and Support): Excavation: Execute the command "zone cmodel assign null range group'3'" to excavate the lower step area (group'3'); Solve and support: Call the "D.f3dat" file, set the parameters for the initial lining of the lower step (group 'p3'), solve and save the final state, such as... Figure 11 As shown.

[0069] The process is repeated from stage 1 to stage 3 until the excavation is completed.

[0070] In a preferred embodiment of the present invention, the step of dynamically adjusting the excavation parameters and support parameters based on the results of the mechanical analysis includes: When the maximum displacement output by the numerical calculation software exceeds the set threshold, the parameter adjustment mechanism is automatically triggered. The adjustment mechanism includes at least one of the following: increasing the anchor bolt length by a set ratio, reducing the anchor bolt spacing, increasing the grade of the lining concrete, and increasing the lining thickness. Repeat the modeling, meshing, and mechanical analysis steps until the displacement, plastic zone volume change rate, and fracture degree RFD value meet the preset iteration termination conditions.

[0071] like Figures 13 to 15As shown, in this embodiment, the results are viewed as follows: After the calculation is completed, the generated displacement cloud map, stress cloud map, plastic zone distribution, and fracture degree RFD value are retrieved (the RFD value is defined by the command flow in FLAC3D, and then saved by another command flow as a .dat format recognizable by Tecplot, and the fracture degree magnitude is defined in the layer). The status is checked (e.g., maximum displacement ≤ 50mm is acceptable, stress concentration factor ≤ 2.0 is acceptable, RFD ≤ 2.0 is acceptable). Figure 11 , Figure 12 As shown.

[0072] Parameter adjustment triggering conditions: If the calculation results do not meet the design requirements (such as displacement exceeding 60mm, plastic zone penetration, principal stress exceeding the limit, or fracture degree RFD value exceeding the limit, etc.), the parameter optimization mechanism will be automatically triggered.

[0073] Parameter optimization strategy: Anchor bolt parameters: Reduce the anchor bolt spacing from 1.5m to 1.2m, and increase the length from 3m to 3.5m; Step parameters: The length of the upper step is shortened from 8m to 6m, and the height is increased from 4m to 4.5m to reduce the disturbance range of a single excavation; Lining parameters: Increase the initial lining thickness from 0.3m to 0.4m to improve support stiffness.

[0074] Iterative calculation: Based on the adjusted parameters, return to the steps and regenerate the model, repeat the meshing and FLAC3D analysis process until the calculation results meet the design requirements (e.g., displacement ≤ 50 mm, plastic zone not connected), iterate until the maximum displacement change is ≤ 2 mm / iteration, the volume change rate of the plastic zone is ≤ 5%, and the RFD value is ≤ 0.8. The process terminates after three consecutive iterations that meet the above conditions.

[0075] Results Export and Engineering Applications In Rhino, the optimized tunnel model, excavation boundaries, and support parameters are exported to CAD format (.dwg) using the "Export" command. This includes the following: tunnel cross-section (marking step height, width, and invert dimensions); longitudinal section (marking step length, excavation advance, and support mileage); anchor bolt layout (marking anchor bolt spacing, angle, and length); and lining thickness distribution (primary and secondary lining thicknesses). The exported file must meet engineering drawing standards and serve as the official drawing for the construction plan. Figure 14 As shown.

[0076] During construction, based on the monitoring and detection information of the surrounding rock during the tunnel excavation, if it is necessary to dynamically optimize the excavation and support scheme, only the parameters of the relevant established parametric model need to be changed, thereby achieving rapid modeling, rapid calculation and rapid generation of design change drawings, which can save a lot of manpower and financial resources.

[0077] Taking railway tunnel design as an example, this scheme is significantly more efficient than traditional methods and greatly reduces the overall design cost, as shown in Table 1.

[0078] Table 1. Efficiency Comparison Data (Taking the Design of Sichuan-Tibet Railway Tunnels as an Example)

[0079] This invention utilizes Rhino+Grasshopper for tunnel outline drawing, section segmentation, step section division, and parametric generation of 3D underground tunnel solid models. It also enables collaborative parametric modeling of initial support and secondary lining structures. For the anchor bolt parametric module, it proposes precise calculation of anchor bolt positioning coordinates and batch data export through feature line extraction, direction vector calculation, and automated Python script programming to meet model and calculation requirements. The parametric model is meshed using the Griddle plugin and can be imported into numerical calculation software such as FLAC3D for mechanical analysis. Based on the calculation results, excavation and support parameters can be dynamically adjusted to obtain the optimal excavation and support design scheme. The resulting 3D parametric model is then imported into BIM software for further refinement. Through model view configuration, layer standardization, and data export optimization, CAD construction drawings conforming to engineering standards are generated. This invention can be used for parametric modeling, numerical calculation, construction drawing generation, and refinement of underground tunnel excavation and support structures, achieving integrated design throughout the entire underground tunnel process. It can meet the dynamic design requirements of underground engineering and has broad application prospects.

[0080] This invention also provides a parametric design system for sectional excavation and dynamic support of underground tunnels, the system comprising: The model building module is used to build a parametric model of the sectional excavation of underground tunnels, including tunnel outline drawing, cross-section dividing line drawing, step section segmentation, and 3D solid model generation. The parameter design module is used for parameterized design of tunnel initial support and secondary lining support, including automatic calculation of anchor bolt or anchor cable positioning coordinates and batch data export. The analysis module is used to mesh the parameterized model and import it into numerical calculation software for mechanical analysis. The dynamic adjustment module is used to dynamically adjust the excavation and support parameters based on the results of the mechanical analysis. The results generation module is used to import the optimized 3D parametric model into BIM software for processing and to generate CAD construction drawings.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A parametric design method for sectional excavation and dynamic support of underground tunnels, characterized in that, The method includes: Construct a parametric model for the sectional excavation of an underground tunnel, including tunnel outline drawing, cross-section segmentation drawing, step section segmentation, and 3D solid model generation; Parametric design of initial support and secondary lining support for tunnels, including automatic calculation of anchor bolt or anchor cable positioning coordinates and batch data export; The parametric model is meshed and imported into numerical calculation software for mechanical analysis. Based on the results of the aforementioned mechanical analysis, the excavation and support parameters are dynamically adjusted. The optimized 3D parametric model is imported into BIM software for processing and CAD construction drawings are generated.

2. The parametric design method for sectional excavation and dynamic support of underground tunnels according to claim 1, characterized in that, The steps for constructing the parametric model of the sectional excavation of the underground tunnel specifically include: Draw the tunnel cross-section profile in Rhino and extract the profile curve; Create the endpoints of the split line located outside the tunnel outline; Obtain the intersection points of the tunnel cross-section and the dividing lines, and use the intersection point information to divide and form the cross-sectional curves of each step; Generate a 3D solid model of a straight tunnel or a curved tunnel.

3. The parametric design method for sectional excavation and dynamic support of underground tunnels according to claim 2, characterized in that, The extraction of the contour curve is achieved using Grasshopper's Curve operator. The creation of the dividing line endpoints is achieved through the Construct Point operator, and the endpoints are connected to form the dividing line through the Line operator; The process of obtaining intersection points and dividing them to form the cross-sectional curves of each step is achieved through a combination of Curve / Curve operators, Split List operators, Construct Domain operators, and Sub Curve operators. The control arch structure is implemented using a Boolean Toggle arithmetic unit; The generation of the 3D solid model is achieved by using the Scale operator, the Boundary Surfaces operator, and in combination with the Extrude operator or the Sweep1 operator.

4. The parametric design method for sectional excavation and dynamic support of underground tunnels according to claim 1, characterized in that, The parametric design steps for the initial support and secondary lining support of the tunnel include: Extract the tunnel boundary curve as a feature line and generate the anchor bolt starting point reference point; Calculate the direction vector of the anchor bolt; Based on the height of the excavation steps, the location coordinates, direction vectors, lengths, and number of segments of the anchor bolts are exported in batches, and command stream files suitable for numerical calculation software are generated.

5. The parametric design method for sectional excavation and dynamic support of underground tunnels according to claim 4, characterized in that, The tunnel boundary curve is extracted as a feature line by the Curve operator, and the Divide Curve operator is used to generate the anchor bolt starting reference point. The Vector Rotate operator is used to calculate the direction vector of the anchor bolt; Based on the height of the excavation steps, the location coordinates, direction vectors, lengths, and number of segments of the anchor bolts are exported in batches, and a command stream file suitable for numerical calculation software is generated.

6. The parametric design method for sectional excavation and dynamic support of underground tunnels according to claim 1, characterized in that, The steps for dynamically adjusting excavation and support parameters based on the results of the mechanical analysis include: When the maximum displacement output by the numerical calculation software exceeds the set threshold, the parameter adjustment mechanism is automatically triggered. The adjustment mechanism includes at least one of the following: increasing the anchor bolt length by a set ratio, reducing the anchor bolt spacing, increasing the grade of the lining concrete, and increasing the lining thickness. Repeat the modeling, meshing, and mechanical analysis steps until the displacement, plastic zone volume change rate, and fracture degree RFD value meet the preset iteration termination conditions.

7. The parametric design method for sectional excavation and dynamic support of underground tunnels according to claim 1, characterized in that, The gridding process is implemented through the Griddle plugin and includes: The tunnel, primary lining, secondary lining, and surrounding rock model are combined into a non-manifold entity. Different grid sizes were set for the internal surrounding rock, tunnel area and external mountain to achieve fine division; Export the grid file.

8. A parametric design system for sectional excavation and dynamic support of underground tunnels, used to implement the parametric design method for sectional excavation and dynamic support of underground tunnels as described in any one of claims 1-7, characterized in that, The system includes: The model building module is used to build a parametric model of the sectional excavation of underground tunnels, including tunnel outline drawing, cross-section dividing line drawing, step section segmentation, and 3D solid model generation. The parameter design module is used for parameterized design of tunnel initial support and secondary lining support, including automatic calculation of anchor bolt or anchor cable positioning coordinates and batch data export. The analysis module is used to mesh the parameterized model and import it into numerical calculation software for mechanical analysis. The dynamic adjustment module is used to dynamically adjust the excavation and support parameters based on the results of the mechanical analysis. The results generation module is used to import the optimized 3D parametric model into BIM software for processing and to generate CAD construction drawings.

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