Method for constructing parameterized finite element model of prestressed composite lining tunnel structure

Abstract

The invention discloses a parameterized finite element model construction method for a prestressed composite lining tunnel structure. The parameterized finite element model construction method comprises the following steps: acquiring a surrounding rock range, inner and outer lining sizes, lining prestressed anchor cable distribution information and target finite element mesh parameters of a target prestressed composite lining tunnel structure; based on the obtained information, a three-dimensional solid tunnel geometric model is constructed through a structural parametric modeling engine, and a tunnel-surrounding rock overall model is obtained; dividing the tunnel-surrounding rock overall model based on the target finite element grid parameters to obtain unit information of surrounding rock and inner and outer linings; based on the geometric structure and function of the unit information, generating contact units between the surrounding rock and the outer lining and between the inner lining and the outer lining, and obtaining a finite element model of the target prestressed composite lining tunnel structure. According to the method, geometric modeling, parameter linkage and grid division are integrated, parametric modeling of the prestressed composite lining tunnel structure is carried out, the modeling efficiency is improved, and meanwhile the rationality of the structure is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of digital water conservancy and hydropower engineering, and more particularly to a parameterized finite element model construction method for a prestressed composite lining tunnel structure. BACKGROUND

[0002] The prestressed composite lining tunnel is a high-performance tunnel structure form combining prestressed technology and composite lining structure, mainly used for tunnel engineering under high internal water pressure, high external water pressure or complex ground stress, and widely used in long-distance and large-buried depth water diversion projects. In order to adapt to its complex stress conditions, such as high internal and external water pressure and ground stress, its structure type is often complex, generally including cast-in-place concrete lining, lining prestressed anchor cable, outer lining segment, drainage cushion between inner and outer lining, surrounding rock, etc.

[0003] Due to the complexity of the structure, the optimization of the inner and outer lining structure section in the early construction stage and the safety evaluation in the construction-operation period can be quickly performed by means of numerical simulation, but the parameterized analysis work around the above problems needs to be repeated multiple times to obtain the reasonable stress state and ideal structure section of the tunnel lining under different geological and water level conditions as the lining thickness, tunnel diameter, anchor cable arrangement and cushion laying range change, so as to meet the engineering design requirements.

[0004] At present, general finite element modeling is often realized by large finite element software such as ANSYS and HyperMesh. Due to the complex structure of the composite tunnel lining, with the continuous increase of the fine degree of the finite element model, the modeling is time-consuming, low in efficiency and prone to errors, and once the structure is slightly adjusted or locally changed, the modeling work needs to be started again in most cases, greatly increasing the time cost and labor cost of modeling. Especially in the early stage of structural design, with the continuous modification of the structure section type, the efficiency and fault tolerance of repeated modeling are more prominent.

[0005] Therefore, for the finite element model construction of the prestressed composite lining tunnel structure, it is an urgent problem for those skilled in the art to provide a parameterized modeling method combining finite element technology. SUMMARY

[0006] Therefore, the present application provides a parameterized finite element model construction method for a prestressed composite lining tunnel structure, which can realize fast and parameterized finite element model construction for complex structure design optimization and safety evaluation of the lining tunnel, thereby avoiding the problems of low efficiency and error-prone in the repeated modeling process.

[0007] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a parameterized finite element model construction method of a prestressed composite lining tunnel structure, comprising the following steps:

[0009] S1, obtaining the surrounding rock range, inner and outer lining sizes, inner and outer lining interlayer, inner lining prestressed anchor distribution information and target finite element grid parameters of the target prestressed composite lining tunnel structure;

[0010] S2, based on the obtained information, constructing a three-dimensional entity tunnel geometric model through a pre-constructed structure parameterized modeling engine to obtain a tunnel-surrounding rock overall model;

[0011] S3, based on the target finite element grid parameters, dividing the tunnel-surrounding rock overall model to obtain the element information of the surrounding rock and the inner and outer linings;

[0012] S4, based on the geometric structure and function of the element information, generating the contact elements between the surrounding rock and the outer lining and between the inner and outer linings to obtain the finite element model of the target prestressed composite lining tunnel structure.

[0013] Further, in step S1, the target finite element grid parameters include: grid minimum size, grid maximum size, boundary grid number and grid type.

[0014] Further, the step S2 specifically includes:

[0015] S21, performing modeling operations on the obtained information through a geometric model parameterization library function to generate a corresponding planar geometric model; wherein the geometric model parameterization library function is constructed based on different tunnel section models and parameters;

[0016] S22, combining the tunnel section and axis direction of the planar geometric model, extending the planar geometric model to obtain a corresponding three-dimensional entity tunnel geometric model;

[0017] S23, expanding the outer range of the three-dimensional entity tunnel geometric model according to the surrounding rock range to obtain a surrounding rock boundary body; subtracting the three-dimensional entity tunnel geometric model from the surrounding rock boundary body to obtain a corresponding tunnel-surrounding rock overall model.

[0018] Further, the step S3 specifically includes:

[0019] S31, identifying the middle surface of the surrounding rock and the inner and outer linings in the tunnel-surrounding rock overall model, and unfolding the corresponding three-dimensional middle surface to a two-dimensional parameter space;

[0020] S32, in the two-dimensional parameter space, using a bilinear interpolation algorithm to calculate and generate a planar quadrilateral finite element grid based on the target finite element grid parameters;

[0021] S33, mapping the planar quadrilateral finite element mesh back to three-dimensional space to obtain three-dimensional hexahedral element information of all surrounding rock and inner and outer linings as a three-dimensional hexahedral finite element mesh.

[0022] Further, in step S32, a planar quadrilateral finite element mesh is calculated and generated using a bilinear interpolation algorithm, which is expressed by the formula:

[0023] F(ξ,η)=(1-ξ)(1-η)x1+ξ(1-η)x2+(1-ξ)ηx3+ξηx4

[0024] where F(ξ,η) is the node coordinate of the newly generated planar finite element mesh after interpolation, x1, x2, x3, and x4 are the physical coordinates of the four corner points of the known physical region, and ξ and η are the corresponding horizontal and vertical coordinates.

[0025] Further, in step S33, the formula is:

[0026]

[0027] where N i is the spline basis function corresponding to node i, N j is the spline basis function corresponding to node j, and N k is the spline basis function corresponding to node k, x(u,v,w) is the node coordinate of the three-dimensional hexahedral finite element mesh, and x ijk is the node position coordinate of the original planar finite element mesh.

[0028] Further, the step S4 specifically includes:

[0029] S41, identifying the common surface between the surrounding rock and the inner and outer linings in the three-dimensional hexahedral finite element mesh, and matching with the three-dimensional hexahedral element information;

[0030] S42, defining the master surface and the slave surface based on the structural relationship between the surrounding rock and the inner and outer linings, and determining the contact pair;

[0031] S43, performing distance field projection calculation on the contact pair to generate corresponding contact elements and match them into the three-dimensional hexahedral finite element mesh, thereby obtaining the finite element model of the target prestressed composite lining tunnel structure.

[0032] Further, in step S43, the distance field projection calculation on the contact pair includes:

[0033] Using the distance field projection algorithm, the slave surface nodes in the contact pair that satisfy the contact generation condition are projected onto the master surface to generate the thickness of the corresponding contact elements, which is expressed by the formula:

[0034]

[0035] Wherein, x1, y1, z1 are the coordinates of the surface node, x2, y2, z2 are the coordinates of the main surface node, and delta is the thickness of the generated contact unit.

[0036] Compared with the prior art, the technical scheme can provide a parameterized finite element model construction method of a prestressed composite lining tunnel structure, effectively shorten the modeling time by constructing a structure parameterized modeling engine, generating geometry and finite element grid based on parameterized input, and is especially suitable for multi-scheme comparison and optimization design scenarios.

[0037] The application integrates the technologies of parameterization, automation and visualization, realizes full-process modeling, solves the two core pain points of high cost and poor precision in prestressed composite lining tunnel modeling, and provides an efficient, reliable and low-cost solution for underground engineering design and safety evaluation in the fields of water conservancy and transportation. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0039] Figure 1 A parameterized finite element model construction method of a prestressed composite lining tunnel structure provided for the embodiments of the present application is provided.

[0040] Figure 2 A construction process schematic diagram of a tunnel-surrounding rock overall model provided for the embodiments of the present application is provided.

[0041] Figure 3 A plane geometry model schematic diagram provided for the embodiments of the present application is provided.

[0042] Figure 4 A three-dimensional entity tunnel geometry model schematic diagram provided for the embodiments of the present application is provided.

[0043] Figure 5 A surrounding rock boundary body structure schematic diagram provided for the embodiments of the present application is provided.

[0044] Figure 6 A tunnel-surrounding rock overall model schematic diagram provided for the embodiments of the present application is provided.

[0045] Figure 7 A three-dimensional hexahedral finite element grid schematic diagram provided for the embodiments of the present application is provided.

[0046] Figure 8 A contact unit grid structure schematic diagram provided for an embodiment of the present application. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0048] An embodiment of the present application discloses a parameterized finite element model construction method of a prestressed composite lining tunnel structure, referring to FIG. Figure 1 The method comprises the following steps:

[0049] S1, obtaining the surrounding rock range, inner and outer lining sizes, inner and outer lining pad, inner lining prestressed anchor distribution information and target finite element grid parameters of a target prestressed composite lining tunnel structure;

[0050] S2, based on the obtained information, constructing a three-dimensional entity tunnel geometric model through a pre-constructed structure parameterized modeling engine to obtain a tunnel-surrounding rock overall model;

[0051] S3, based on the target finite element grid parameters, dividing the tunnel-surrounding rock overall model to obtain unit information of the surrounding rock and inner and outer linings;

[0052] S4, based on the geometric structure and function of the unit information, generating contact units between the surrounding rock and the outer lining and between the inner and outer linings to obtain a finite element model of the target prestressed composite lining tunnel structure.

[0053] An embodiment of the present application takes a certain prestressed composite lining tunnel as an example to construct a parameterized finite element model thereof. The embodiment comprises a visual human-computer interaction interface based on an embedded scientific visualization platform software ParaView and a program for executing background parameterized modeling and finite element grid division developed based on python. Python source code is used to realize composite lining tunnel structure parameterized modeling and an embedded ParaView human-computer operation interaction interface. The method comprises the following steps:

[0054] Step 1, developing a parameterized input interface based on the ParaView platform to allow a user to input parameters of different typical tunnel sections to drive generation of a tunnel section model.

[0055] Step 2, the program creates a surrounding rock body and tunnel lining assembly through a structure parameterized modeling engine according to the information of the surrounding rock range, inner and outer lining sizes, inner lining prestressed anchor distribution and the like input by the user in step 1.

[0056] Step 3, the procedure is to divide the finite element grid for the surrounding rock and the tunnel lining according to the component unit size input by the user.

[0057] Step 4, according to the surrounding rock and the inner and outer lining unit information, the contact unit between the surrounding rock and the outer lining and between the inner and outer linings is automatically expanded and generated, thereby establishing an integrated contact system among the surrounding rock, the outer lining and the inner lining.

[0058] The detailed steps of the embodiment are further described below.

[0059] Step 1 of the embodiment includes the development of a ParaView interactive plug-in, i.e. creating a customized graphical interface component embedded in ParaView to realize the model information input of the visual human-computer interaction interface.

[0060] The input parameters include: surrounding rock range, lining geometric size, prestressed tendon arrangement, drainage cushion thickness between the inner and outer linings and other geometric related information and related function menus.

[0061] The finite element grid division control parameters include: grid minimum size, grid maximum size, boundary grid number, grid type, etc.

[0062] The double-layer prestressed composite lining of the embodiment is a circular cross-section, the inner lining is cast-in-place concrete + ring-shaped anchor cable + outer lining prefabricated segment + drainage cushion, the hole diameter is 6.0 m, the burial depth is 300 m, the inner lining concrete thickness is 0.8 m, the outer lining segment thickness is 0.6 m, the cushion thickness is 0.02 m, the full length is 1.3 km, a standard tunnel section is set every 13 m, the ring-shaped anchor cable spacing is 0.5 m, and there are 12 bundles in a standard tunnel section. The input parameters of the ParaView visualization interface in the embodiment are shown in Table 1:

[0063] Table 1 Input parameters of the ParaView visualization interface

[0064]

[0065]

[0066] Step 2 of the embodiment includes constructing a structural parameterized modeling engine using Python language. The main function is to use Python program to connect the parameters input by the user in step 1 with the geometric creation function of ParaView, i.e. according to the cross-section type and parameters, the geometric library of ParaView is called through Python macro command writing to generate a planar geometric model.

[0067] The main content thereof, with reference to Figure 2 is divided into the following 4 steps:

[0068] Step 2.1, develop a geometric model parameterized library function.

[0069] This embodiment is based on different cross-section models and corresponding input parameters to develop corresponding geometric creation functions. For example, the circular cross-section uses `Disk`, the rectangular cross-section uses `Plane`, the horseshoe-shaped cross-section uses a spline curve function, and is written into the paraview.simple geometry library, waiting for the next step to call.

[0070] Step 2.2, according to the input parameters of step 1, the parameter macro command is compiled by python to call the paraview.simple geometry library to execute the modeling command, and finally generate a plane geometric model, as shown in Figure 3 .

[0071] Step 2.3, create a three-dimensional entity geometric model.

[0072] Combined with the tunnel axis direction in the plane geometric model, based on the tunnel cross-section along the axial direction, the three-dimensional entity tunnel geometric model is generated by sweeping or expanding operation, as shown in Figure 4 .

[0073] Step 2.4, surrounding rock generation.

[0074] This embodiment first expands the surrounding rock boundary body according to the outer range of the tunnel three-dimensional model, specifies the distance in step 1, and calls the paraview.simple geometry library to form the surrounding rock boundary body, as shown in Figure 5 , in this embodiment, it is a cuboid, and then the paraview platform embedded visualization command is called to perform Boolean difference operation, and the tunnel three-dimensional entity is subtracted from the surrounding rock boundary body to obtain the tunnel-surrounding rock whole model, as shown in Figure 6 .

[0075] Step 3 of this embodiment is mainly based on Python language, which uses finite element grid automatic subdivision algorithm to realize automatic generation of finite element grid. Specifically, it includes:

[0076] Step 3.1, identify the middle surface of the surrounding rock and inner and outer lining in the tunnel-surrounding rock whole model obtained in step 2, and extract;

[0077] Step 3.2, parameterized expansion, expand the extracted three-dimensional middle surface to two-dimensional parameter space.

[0078] Step 3.3, use bilinear interpolation mapping algorithm to generate plane quadrilateral finite element grid, the specific formula is as follows:

[0079] F(ξ,η)=(1-ξ)(1-η)x1+ξ(1-η)x2+(1-ξ)ηx3+ξηx4

[0080] Wherein, F(ξ,η) is the new generated plane finite element grid node coordinates after interpolation, x1, x2, x3, x4 are the physical coordinates of the four corner points of the known physical region, ξ and η are the corresponding position plane horizontal axis coordinates, taking values 0-1.

[0081] Step 3.4, three-dimensional grid mapping. Based on the one-to-one mapping principle, the plane quadrilateral grid is mapped to generate a three-dimensional hexahedral finite element grid, as shown in Figure 7 The specific formula is as follows:

[0082]

[0083] Wherein, N i is the spline basis function corresponding to node i, N j is the spline basis function corresponding to node j, N k is the spline basis function corresponding to node k, x(u,v,w) is the three-dimensional hexahedral finite element grid node coordinates, x ijk is the original plane finite element grid node position coordinates, corresponding to x1, x2, x3, x4, etc.

[0084] Step 4 of this embodiment is used to generate face-face contact elements and match them into the three-dimensional hexahedral finite element grid.

[0085] Specifically, the following steps are included:

[0086] Step 4.1, identify the common surface between the inner and outer liners, surrounding rock and outer liner in the three-dimensional hexahedral finite element grid obtained in step 3.

[0087] Step 4.2, set master and slave contact surfaces, and establish contact pairs respectively.

[0088] For surrounding rock-outer liner, the surrounding rock is the master contact surface and the outer liner is the slave contact surface. For inner liner-outer liner, the outer liner is the master contact surface and the inner liner is the slave contact surface.

[0089] Step 4.3, for each identified contact pair, generate a contact element using a projection algorithm based on a distance field, as shown in Figure 8 The Figures 3-8 addition, purple represents the inner liner, red represents the outer liner, and black represents the surrounding rock.

[0090] This embodiment pre-calculates the distance field function φ(x,y,z) of the master contact surface; the contact generation condition of the slave contact surface is φ(x,y,z,s)≤δ; wherein φ(x,y,z,s) is the distance field function of the master contact surface, and δ is the thickness of the generated contact element; by calculating the local coordinates and shape function values of the projection point, the "slave contact surface" node is projected onto the "master contact surface" to generate a new cushion contact element, and the calculation process of the projection point is as follows:

[0091] For a face node X c (x1,y1,z1), find a projection point X m (x2,y2,z2) on the main contact surface, so that the normal distance between them is equal to delta:

[0092]

[0093] This embodiment generates contact elements between surrounding rock and outer lining, between inner and outer lining, thereby establishing an integrated contact system among surrounding rock, outer lining and inner lining, matching to the corresponding three-dimensional hexahedral finite element grid, obtaining the finite element model of the prestressed composite lining tunnel structure of this embodiment.

[0094] The prestressed composite lining tunnel parameterized modeling method based on ParaView and Python of the application generates geometry and finite element grid through parameterized input, such as diameter, lining thickness, surrounding rock range, etc., one-key, shortens the modeling time to minutes, and is especially suitable for multi-scheme comparison and selection or optimization design scene; another benefit of the application is that the "parameterization + automation + visualization" technology is integrated, based on ParaView (open source) + Python (free), realizes the whole-process modeling with zero cost, solves the two core pain points of high cost and poor precision in prestressed composite lining tunnel modeling, and can provide an efficient, reliable and low-cost solution for underground engineering design and safety evaluation in the fields of water conservancy and transportation.

[0095] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between various embodiments can be referred to each other. For the device disclosed by the embodiments, since it corresponds to the method disclosed by the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0096] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for constructing a parametric finite element model of a prestressed composite lined tunnel structure, characterized in that, The method comprises the following steps: S1, obtaining the surrounding rock range, inner and outer lining sizes, inner and outer lining interlayer, inner lining prestressed anchor distribution information and target finite element grid parameters of the target prestressed composite lining tunnel structure; S2, based on the obtained information, constructing a three-dimensional entity tunnel geometric model through a pre-constructed structure parameterized modeling engine to obtain a tunnel-surrounding rock overall model; S3, based on the target finite element grid parameters, dividing the tunnel-surrounding rock overall model to obtain unit information of the surrounding rock and inner and outer linings; S4, based on the geometric structure and function of the unit information, generating contact units between the surrounding rock and the outer lining and between the inner and outer linings to obtain a finite element model of the target prestressed composite lining tunnel structure.

2. The method of claim 1, wherein the method further comprises: In step S1, the target finite element grid parameters include: grid minimum size, grid maximum size, boundary grid number and grid type.

3. The method of claim 1, wherein the method further comprises: The step S2 specifically comprises: S21, performing a modeling operation on the obtained information through a geometric model parameterization library function to generate a corresponding plane geometric model; wherein the geometric model parameterization library function is constructed based on different tunnel section models and parameters; S22, extending the plane geometric model in combination with the tunnel section and axis direction of the plane geometric model to obtain a corresponding three-dimensional entity tunnel geometric model; S23, expanding the outer range of the three-dimensional entity tunnel geometric model according to the surrounding rock range to obtain a surrounding rock boundary body; the surrounding rock boundary body is subtracted from the three-dimensional entity tunnel geometric model to obtain a corresponding tunnel-surrounding rock overall model.

4. The method of claim 3, wherein the method further comprises: The step S3 specifically comprises: S31, identifying the middle surface of the surrounding rock and inner and outer linings in the tunnel-surrounding rock overall model and unfolding the corresponding three-dimensional middle surface to a two-dimensional parameter space; S32, in the two-dimensional parameter space, calculating and generating a plane quadrilateral finite element grid based on the target finite element grid parameters using a bilinear interpolation algorithm; S33, mapping the plane quadrilateral finite element grid back to the three-dimensional space to obtain three-dimensional hexahedral unit information of all surrounding rock and inner and outer linings as a three-dimensional hexahedral finite element grid.

5. The method for constructing a parameterized finite element model of a pre-stressed composite lined tunnel structure as claimed in claim 4, wherein, In step S32, the bilinear interpolation algorithm is used to calculate and generate a plane quadrilateral finite element grid, which is expressed by a formula as follows: F(ξ,η)=(1-ξ)(1-η)x1+ξ(1-η)x2+(1-ξ)ηx3+ξηx4 Wherein, F(ξ,η) is the node coordinate of the newly generated plane finite element grid after interpolation, x1, x2, x3 and x4 are respectively the physical coordinates of the four corner points of the known physical region; ξ and η are respectively the horizontal and vertical coordinates of the corresponding position.

6. The method for constructing a parameterized finite element model of a pre-stressed composite lined tunnel structure as claimed in claim 5, wherein, The step S33 is expressed by a formula as follows: where N i is the spline basis function corresponding to node i, N j is the spline basis function corresponding to node j, N k is the spline basis function corresponding to node k, x(u, v, w) is the three-dimensional hexahedral finite element mesh node coordinate, x ijk is the original plane finite element mesh node position coordinate.

7. The method of claim 4, wherein the method further comprises: The step S4 specifically comprises: S41, identifying the common surface between the surrounding rock and the inner and outer linings in the three-dimensional hexahedral finite element grid; and matching with the three-dimensional hexahedral unit information; S42, defining a master surface and a slave surface based on the structural relationship between the surrounding rock and the inner and outer linings and determining a contact pair; S43, a distance field projection calculation is performed on the contact pair to generate a corresponding contact element and match it into the three-dimensional hexahedral finite element grid, thereby obtaining a finite element model of the target prestressed composite lining tunnel structure.

8. The method of claim 7, wherein the method further comprises: In step S43, the distance field projection calculation on the contact pair includes: In the distance field projection algorithm, the slave node in the contact pair that satisfies the contact generation condition is projected onto the master surface to generate a corresponding contact element thickness; and the formula is expressed as: where x1, y1, and z1 are the slave node coordinates, x2, y2, and z2 are the master surface node coordinates, and δ is the generated contact element thickness.

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