Railway tunnel portal parametric modeling method based on IFC file

Abstract

The invention discloses a railway tunnel portal parametric modeling method based on an IFC file, and the method specifically comprises the following steps: 1, extracting three types of core parameter sets of an inner contour section, an open cut tunnel lining section and a portal member based on a railway tunnel general reference graph; 2, on the basis of the IFC file structure features and an IfCpenShell toolkit, entity elements of an inner contour, an open cut tunnel lining and a tunnel portal component are constructed in the IFC file through the python language; 3, based on the spatial assembly constraint condition of the railway tunnel portal, establishing a geometric association relationship among the three parts of entity elements, and forming an IFC file of the whole railway tunnel portal; and 4, importing the IFC file formed in the step 3 into BIM software for parametric modeling. According to the method, the problems of poor compatibility of different software and insufficient data interoperability and expansibility in the existing parametric modeling are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of railway tunnel portal engineering modeling, and specifically relates to a parametric modeling method for railway tunnel portals based on IFC files. Background Art

[0002] Building Information Modeling (BIM) technology has been widely used in the field of railway engineering to construct detailed digital representations and full-life cycle management of railway infrastructure. The three-dimensional visualization and information management it provides offer a clear solution path for complex engineering problems in railway projects. With the continuous in-depth application of BIM technology, methods for realizing the generation of various business components in the railway field through secondary development of various BIM modeling software have gradually increased.

[0003] Currently, BIM software represented by Autodesk Revit, Bentley, CATIA, etc. has become the main tool for parametric modeling in the railway tunnel specialty. For the part involving tunnel BIM parametric modeling, the above commercial software is used for secondary development to realize tunnel parameterization generation. This makes individuals or organizations with a need for railway tunnel parametric modeling highly dependent on the above commercial software. This dependence restricts the flexibility and autonomy of users in professional requirements not covered by the software. On this basis, the data closure also hinders interoperability with other software. Although model exchange can be carried out between different BIM software by exporting the IFC file format, partial loss of model information and coordinate system confusion often occur in this process, restricting the effective compatibility of cross-platform parametric modeling. As a result, the current railway tunnel parametric modeling method has poor modeling practicability and insufficient information sharing due to excessive dependence on the above commercial software. Summary of the Invention

[0004] The purpose of the present invention is to provide a parametric modeling method for railway tunnel portals based on IFC files, and solve the problems of poor compatibility between different software, insufficient data interoperability and expandability existing in the existing parametric modeling.

[0005] The technical solution adopted by the present invention is a parametric modeling method for railway tunnel portals based on IFC files, which specifically includes the following steps: Step 1, based on the general reference drawing of the railway tunnel, construct a hierarchical parameter system for the railway tunnel portal, extract three core parameter sets including geometric control parameters and control points of the inner contour section, geometric control parameters and control points of the open cut tunnel lining section, and structural parameters of the portal components, and perform semantic expression on each of them; Step 2: Based on the IFC file structure features and the IfcOpenShell toolkit, using the Python language and the parameters set based on three types of core parameter sets, construct inner contour entity elements, open cut tunnel entity elements, and portal component entity elements in the IFC file respectively; Step 3: Based on the spatial assembly constraint conditions of the railway tunnel portal, establish the geometric association relationships among the three parts of entity elements corresponding to the three types of core parameter sets to form the IFC file of the entire railway tunnel portal; Step 4: Import the IFC file formed in Step 3 into the BIM software for parametric modeling. The features of the present invention also lie in that In Step 1, splitting the railway tunnel portal model to be constructed into three parts: inner contour section, open cut tunnel lining section, and tunnel portal component specifically includes the following steps: Step 1.1: According to the general reference drawings of railway tunnel specialties, divide the inner contour section into 3 types: "one - center circle", "three - center circle", and "five - center circle" based on the number of center points; Step 1.2: Based on the three types of "one - center circle", "three - center circle", and "five - center circle" of the inner contour section, taking the presence or absence of invert as the secondary classification feature, divide the open cut tunnel lining section into 5 forms: "one - center circle without invert", "one - center circle with invert", "three - center circle with invert", "five - center circle with invert", and "three - five - center circle without invert"; Step 1.3: The tunnel portal forms include end - wall type portal, wing - wall type portal, stepped portal, and column - type portal. Split the tunnel portal component according to the portal form, which is divided into main end wall, left / right additional retaining walls, left / right wing walls, stepped end wall, middle wall, left / right piers, and left / right side walls.

[0006] In Step 1.1, set 6 inner contour control parameters for the 3 types of "one - center circle", "three - center circle", and "five - center circle": θ 1 、θ 2 、ch, H, r 1 、r 2 ; and 13 inner contour control points: ICCP_1, ICCP_2, ICCP_3, ICCP_4, ICCP_5, ICCP_6, ICCP_7, ICCP_8, ICCP_9, ICCP_10, ICCP_11, ICCP_12, ICCP_13.

[0007] In Step 1.2, two control parameters for the open cut tunnel section, of and h, and 14 control points for the open cut tunnel section, LSCP_1, LSCP_2, LSCP_3, LSCP_4, LSCP_5, LSCP_6, LSCP_7, LSCP_8, LSCP_9, LSCP_10, LSCP_11, LSCP_12, LSCP_13, LSCP_14, are set for the 5 forms of "one - centered circle without invert", "one - centered circle with invert", "three - centered circle with invert", "five - centered circle with invert", and "three - and five - centered circle without invert".

[0008] In Step 1.3, the control parameters of the main abutment wall include A, dh, B, H1, α, L; the control parameters of the left / right additional retaining walls include G, n, E, L; the control parameters of the left / right wing walls include b1, h1, a, b2, h2, β, L; the control parameters of the stepped abutment wall include N, B1, H2, H3, γ, L; the control parameters of the intermediate wall include h1, B, H1; the control parameters of the left / right piers include h1, h2, A, B, H1; the control parameters of the left / right side walls include h1, h2, B1, δ, A, B, H1.

[0009] Step 2 specifically includes the following steps: Step 2.1, create an IFC project file, and define the IFC representation method from three aspects: entity element representation, geometric shape representation, and spatial structure description; Step 2.2, based on the defined IFC representation method, create an IFC template file through the IfcOpenShell toolkit; Step 2.3, adopt the method of stretching three - dimensional entities to add three core parameter sets, namely the geometric control parameters and control points of the inner contour section, the geometric control parameters and control points of the open cut tunnel lining section, and the structural parameters of the portal components, to the IFC template file, and create a two - dimensional contour section; Step 2.4, add the two - dimensional section geometric representation based on the two - dimensional contour section to form a three - dimensional entity; Step 2.5, place the created three - dimensional entity in the hierarchical structure to ensure clear logic in the organizational structure of the file; Step 2.6, output the IFC file.

[0010] Step 2.2 specifically includes the following steps: Step 2.2.1, create a new blank IFC project file; Step 2.2.2, create the IFC project element IfcProject as the root object of the IFC project file, and define and describe the basic information of the IFC project file through the root object operation module of IfcOpenshell; Step 2.2.3, define the measurement unit of the IFC project file as millimeters through the unit operation module of IfcOpenshell; Step 2.2.4, create a top-level general model geometric context based on the context operation module of IfcOpenshell to store three-dimensional geometric information; Step 2.2.5, create a basic spatial structure hierarchical element representation of the IFC file for the railway tunnel portal to form an IFC template file.

[0011] Step 2.3 specifically includes the following steps: Step 2.3.1, for the tunnel inner contour section, input the control parameters and control points required for the corresponding "one-centered circle", "three-centered circle", and "five-centered circle" section forms, create the inner contour line through the polyline representation method, connect ICCP_X in ascending order of X, connect in straight line segments by default, and for arc segments, connect with the midpoint index of the arc segment control points as list elements; Step 2.3.2, for the tunnel open cut lining section, input the control parameters and parameter points required for the corresponding "one-centered circle without inverted arch", "one-centered circle with inverted arch", "three-centered circle with inverted arch", "five-centered circle with inverted arch", and "three-five-centered circle without inverted arch" section forms, create the outer contour line through the polyline representation method, connect LSCP_X in ascending order of X, connect in straight line segments by default, and for arc segments, connect with the midpoint index of the arc segment control points as list elements; Step 2.3.3, for different tunnel portal forms, select the required portal components, input the parameters required for the corresponding portal components, automatically obtain the control point coordinates of each portal component, and connect them sequentially in straight line segments through the polyline representation method to form the two-dimensional contour section of the portal component.

[0012] The specific steps for establishing the geometric association between the three parts of entity elements in Step 3 are as follows: Step 3.1, create a Boolean cut result entity class in the IFC file, specify the type of Boolean operation as subtraction, use the open cut three-dimensional entity as the base entity, and specify the inner contour three-dimensional entity as the entity object to be cut, and construct the composite entity at the railway tunnel portal to achieve the geometric association between the open cut three-dimensional entity and the inner contour three-dimensional entity; Step 3.2, set the three-dimensional coordinates of the centroid of the two-dimensional section of the portal entity projected on the X-Y plane as the reference point for global assembly, and construct the coordinate offset matrix between the key control points of each portal component and the reference point according to the tunnel portal structure requirements to achieve the geometric association between the composite entity elements at the portal and the entity elements of the portal components, and form the final overall entity elements of the railway tunnel portal. Step 3.3: Place the overall railway tunnel portal solid element at the bottom layer of the basic spatial structure hierarchy created in Step 2.2.5 to ensure clear logic in the organizational structure of the overall IFC file. Step 3.4: Output the final overall railway tunnel portal IFC file.

[0013] The beneficial effects of the present invention are as follows: (1) The parametric modeling method of the railway tunnel portal based on the IFC file in the present invention writes the IFC file from "0" based on the IfcOpenShell toolkit and the Python programming language, operates the model without relying on any commercial BIM software, and the created model has better compatibility and can be seamlessly integrated into various CAD and BIM software, thus solving the problem of poor compatibility among different software in the prior art.

[0014] (2) The parametric modeling method of the railway tunnel portal based on the IFC file in the present invention utilizes the unity of the IFC data model standard to enable different software and different systems to share and understand the same data format, supports more efficient data management and exchange, thus solving the problems of insufficient data interoperability and expandability in the prior art, ensuring the consistency and accuracy of information, and reducing errors caused by information asymmetry.

[0015] (3) The parametric modeling method of the railway tunnel portal based on the IFC file in the present invention selects geometric shape expressions and spatial position descriptions suitable for parametric modeling of tunnel portal components according to the IFC standard, allows users to flexibly define the dimensions, shapes and other key parameters of the tunnel portal according to actual engineering needs, solves the problem of lack of flexibility in modeling in the prior art, and can better and more flexibly describe complex curved surfaces and non-standard shapes, which makes the visualization model of the tunnel portal not only realistic but also in line with actual needs, improving the practicality of the model. Description of the Drawings

[0016] Figure 1 is a schematic flow chart of the parametric modeling method of the railway tunnel portal based on the IFC file in the present invention; Figure 2a is a schematic diagram of the cross-section of the inner contour of a single-center circle tunnel in the present invention; Figure 2b is a schematic diagram of the cross-section of the inner contour of a three-center circle tunnel in the present invention; Figure 2c is a schematic diagram of the cross-section of the inner contour of a five-center circle tunnel in the present invention; Figure 3a is a schematic diagram of the cross-section of a single-center circle tunnel without invert in the present invention; Figure 3b is a schematic diagram of the cross-section of a single-center circle tunnel with invert in the present invention; Figure 3c It is a schematic diagram of the cross-section of a three-centered circular tunnel with an inverted arch in the present invention; Figure 3d It is a schematic diagram of the cross-section of a five-centered circular tunnel with an inverted arch in the present invention; Figure 3e It is a schematic diagram of the cross-section of a three / five-centered circular tunnel without an inverted arch in the present invention; Figure 4 It is a schematic diagram of the 3D model in step 2.3.1 of the embodiment of the present invention; Figure 5 It is a schematic diagram of the 3D model in step 2.3.2 of the embodiment of the present invention; Figure 6 It is a schematic diagram of the 3D model in step 2.3.3 of the embodiment of the present invention; Figure 7 It is a schematic diagram of the 3D model in step 3.4 of the embodiment of the present invention; Specific embodiments Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0017] Embodiment 1 The parametric modeling method of the railway tunnel portal based on the IFC file in the present invention, as Figure 1 shown, specifically includes the following steps: Step 1, based on the general reference drawings of railway tunnels, construct a hierarchical parameter system for railway tunnel portals, extract three core parameter sets of geometric control parameters and control points of the inner contour section, geometric control parameters and control points of the open cut tunnel lining section, and structural parameters of portal components, and perform semantic expressions on them respectively; Step 2, based on the IFC file structure characteristics and the IfcOpenShell toolkit, use the python language and the parameters set based on the three core parameter sets to construct inner contour entity elements, open cut tunnel entity elements, and portal component entity elements in the IFC file respectively; Step 3, based on the spatial assembly constraint conditions of railway tunnel portals, establish geometric association relationships between the three parts of entity elements corresponding to the three core parameter sets to form the IFC file of the entire railway tunnel portal; Step 4, import the IFC file formed in step 3 into the BIM software for parametric modeling.

[0018] Embodiment 2 On the basis of Embodiment 1, in the method for parametric modeling of a railway tunnel portal based on IFC files according to the present invention, the specific steps of splitting the railway tunnel portal model to be constructed into three parts: the inner contour section, the open cut tunnel lining section, and the tunnel portal components in Step 1 are as follows: Step 1.1: According to the general reference drawings of railway tunnels, divide the inner contour section into three types: "one - center circle", "three - center circle", and "five - center circle" based on the number of centers; Six inner contour control parameters are set for the three types of "one - center circle", "three - center circle", and "five - center circle": θ 1 、θ 2 、ch, H, r 1 、r 2 ; Thirteen inner contour control points: ICCP_1, ICCP_2, ICCP_3, ICCP_4, ICCP_5, ICCP_6, ICCP_7, ICCP_8, ICCP_9, ICCP_10, ICCP_11, ICCP_12, ICCP_13.

[0019] For the "one - center circle" inner contour form, as Figure 2a shown, the inner contour control parameters with actual values are θ 1 、ch, r 1 and H, and there are inner contour control points ICCP_1, ICCP_2, ICCP_4, ICCP_7, ICCP_10, ICCP_12, ICCP_13. The inner contour section drawing is formed by connecting the ICCP_X in ascending order of the X value. Among them, those belonging to the straight - line segment connection method (L x，y , where x is the starting point of the line segment and y is the ending point of the line segment, representing the straight - line segment formed by connecting the starting point x and the ending point y, the same hereinafter) are L ICCP_1，ICCP_2 、L ICCP_2，ICCP_4 、L ICCP_10，ICCP_12 、L ICCP_12，ICCP_13 、L ICCP_13，ICCP_1 ; Those belonging to the arc - segment connection method (A x，y，z , where x is the starting point of the arc segment, y is the mid - point of the arc segment, and z is the ending point of the arc segment, the same hereinafter) are A ICCP_4，ICCP_7，ICCP_10 .

[0020] For the "three - center circle" inner contour form, as Figure 2b shown, all inner contour control parameters have actual values. There are inner contour control points ICCP_3, ICCP_5, ICCP_6, ICCP_7, ICCP_8, ICCP_9, ICCP_11, and the inner contour section drawing is formed by connecting the ICCP_X in ascending order of the X value. Among them, those belonging to the straight - line segment connection method are L ICCP_11，ICCP_3 ; Those belonging to the arc - segment connection method are A ICCP_3，ICCP_5，ICCP_6 、AICCP_6，ICCP_7，ICCP_8 , A ICCP_8，ICCP_9，ICCP_11 .

[0021] For the inner contour form of the "five - center circle", as Figure 2c shown, the inner contour control parameters all have actual values. There are inner contour control points ICCP_1, ICCP_2, ICCP_4, ICCP_5, ICCP_6, ICCP_7, ICCP_8, ICCP_9, ICCP_10, ICCP_12, ICCP_13. The inner contour sectional view is formed by connecting in ascending order of the X values in ICCP_X. Among them, those belonging to the straight - line segment connection method are L ICCP_1，ICCP_2 , L ICCP_2，ICCP_4 , L ICCP_10，ICCP_12 , L ICCP_12，ICCP_13 ; those belonging to the arc - segment connection method are A ICCP_4，ICCP_5，ICCP_6 , A ICCP_6，ICCP_7，ICCP_8 , A ICCP_8，ICCP_9，ICCP_10 .

[0022] Step 1.2, based on the three types of "one - center circle", "three - center circle", and "five - center circle" of the inner contour section, and taking the presence or absence of an inverted arch as the secondary classification feature, the open - cut tunnel lining section is divided into 5 forms: "one - center circle without inverted arch", "one - center circle with inverted arch", "three - center circle with inverted arch", "five - center circle with inverted arch", and "three - and five - center circles without inverted arch"; For the 5 forms of "one - center circle without inverted arch", "one - center circle with inverted arch", "three - center circle with inverted arch", "five - center circle with inverted arch", and "three - and five - center circles without inverted arch", 2 open - cut tunnel section control parameters are set: of and h; and 14 open - cut tunnel section control points: LSCP_1, LSCP_2, LSCP_3, LSCP_4, LSCP_5, LSCP_6, LSCP_7, LSCP_8, LSCP_9, LSCP_10, LSCP_11, LSCP_12, LSCP_13, LSCP_14.

[0023] Since the section types of the three - center circle without inverted arch and the five - center circle without inverted arch are similar, they are combined into one; For the open - cut tunnel section form of "one - center circle without inverted arch", as Figure 3a shown, the open - cut tunnel section control parameters all have actual values. There are open - cut tunnel section control points LSCP_2, LSCP_4, LSCP_7, LSCP_10, LSCP_12. The open - cut tunnel section control diagram is formed by connecting in ascending order of the X values in LSCP_X. Among them, those belonging to the straight - line segment connection method are L LSCP_2，LSCP_4 , L LSCP_10，LSCP_12 , L LSCP_12，LSCP_2 ; those belonging to the arc - segment connection method are A LSCP_4，LSCP_7，LSCP_10 .

[0024] For the open - cut tunnel section form of "one - center circle with inverted arch", asFigure 3b As shown, the control parameters of the open cut tunnel section all have actual values, and there are control points LSCP_1, LSCP_3, LSCP_4, LSCP_7, LSCP_10, LSCP_11, LSCP_13, LSCP_14 for the open cut tunnel section. The control diagram of the open cut tunnel section is formed by connecting the values of X in LSCP_X in ascending order. Among them, there is no point relationship belonging to the straight-line segment connection method; those belonging to the arc segment connection method are A LSCP_1，LSCP_3，LSCP_4 、A LSCP_4，LSCP_7，LSCP_10 、A LSCP_10，LSCP_11，LSCP_13 、A LSCP_13，LSCP_14，LSCP_1 。

[0025] For the open cut tunnel section form of "three-centered circle with inverted arch", as Figure 3c shown, the control parameters of the open cut tunnel section all have actual values, and there are control points LSCP_2, LSCP_4, LSCP_5, LSCP_6, LSCP_7, LSCP_8, LSCP_9, LSCP_10, LSCP_12, LSCP_14 for the open cut tunnel section. The control diagram of the open cut tunnel section is formed by connecting the values of X in LSCP_X in ascending order. Among them, those belonging to the straight-line segment connection method are L LSCP_2，LSCP_4 、L LSCP_10，LSCP_12 ;those belonging to the arc segment connection method are A LSCP_4，LSCP_5，LSCP_6 、A LSCP_6，LSCP_7，LSCP_8 、A LSCP_8，LSCP_9，LSCP_10 、A LSCP_12，LSCP_14，LSCP_2 。

[0026] For the open cut tunnel section form of "five-centered circle with inverted arch", as Figure 3d shown, the control parameters of the open cut tunnel section all have actual values, and there are control points LSCP_1, LSCP_3, LSCP_4, LSCP_5, LSCP_6, LSCP_7, LSCP_8, LSCP_9, LSCP_10, LSCP_11, LSCP_13, LSCP_14 for the open cut tunnel section. The control diagram of the open cut tunnel section is formed by connecting the values of X in LSCP_X in ascending order. Among them, there is no point relationship belonging to the straight-line segment connection method; those belonging to the arc segment connection method are A LSCP_1，LSCP_3，LSCP_4 、A LSCP_4，LSCP_5，LSCP_6 、A LSCP_6，LSCP_7，LSCP_8 、A LSCP_8，LSCP_9，LSCP_10 、A LSCP_10，LSCP_11，LSCP_13 、A LSCP_13，LSCP_14，LSCP_1 。

[0027] For the open cut tunnel section form of "three- and five-centered circles without inverted arch", as Figure 3eAs shown, the control parameters of the open cut tunnel section all have actual values. There are control points LSCP_2, LSCP_4, LSCP_5, LSCP_6, LSCP_7, LSCP_8, LSCP_9, LSCP_10, LSCP_12 for the open cut tunnel section. The control diagram of the open cut tunnel section is formed by connecting the values of X in LSCP_X in ascending order. Among them, the connection methods belonging to the straight line section are L LSCP_2，LSCP_4 and L LSCP_10，LSCP_12 and L LSCP_12，LSCP_2 ; the connection methods belonging to the arc section are A LSCP_4，LSCP_5，LSCP_6 and A LSCP_6，LSCP_7，LSCP_8 and A LSCP_8，LSCP_9，LSCP_10 .

[0028] Step 1.3, determine the tunnel portal form according to the principles of "ensuring safety, adapting to local conditions, protecting the environment, and using simply". The tunnel portal forms include the end wall type portal, wing wall type portal, stepped portal, and column type portal. Split the tunnel portal components according to the portal form, which are divided into the main end wall, left / right additional retaining walls, left / right wing walls, stepped end wall, middle wall, left / right piers, and left / right side walls. All portal forms are composed of partial combinations of these 11 components.

[0029] The control parameters of the main end wall include A, dh, B, H1, α, L; the control parameters of the left / right additional retaining walls include G, n, E, L; the control parameters of the left / right wing walls include b1, h1, a, b2, h2, β, L; the control parameters of the stepped end wall include N, B1, H2, H3, γ, L; the control parameters of the middle wall include h1, B, H1; the control parameters of the left / right piers include h1, h2, A, B, H1; the control parameters of the left / right side walls include h1, h2, B1, δ, A, B, H1.

[0030] The control points of the above walls are derived from the control parameters according to the construction requirements.

[0031] Embodiment 3 Based on Embodiment 2, due to the professional, complex, and functional requirements of the railway tunnel portal model, there are differences between the IFC representation of the railway tunnel portal and that of the standard building. It is necessary to define its IFC representation method from three aspects: entity element representation, geometric shape representation, and spatial structure description, in combination with the specific actual requirements of the railway tunnel portal. Step 2 in the parametric modeling method of the railway tunnel portal based on the IFC file specifically includes the following steps: Step 2.1, create an IFC project file and define the IFC representation method from three aspects: entity element representation, geometric shape representation, and spatial structure description; Step 2.2: Based on the defined IFC representation method, in order to ensure the structural consistency of the IFC file of the railway tunnel portal and improve the reuse efficiency, an IFC template file is created through the IfcOpenShell toolkit. The complete IFC file of the railway tunnel portal mainly includes a header section and a data section. The header section records the relevant information description of the file, and the changing content is not very different and can be predefined. Moreover, in each IFC model file, the basic building elements and their spatial hierarchical relationships need to be predefined in the data section. The template file defines the parts that need to be predefined in the header section and the data section of the IFC file.

[0032] Step 2.3: Adopt the stretched three-dimensional solid representation method to add three core parameter sets, namely the geometric control parameters and control points of the inner contour section, the geometric control parameters and control points of the open cut tunnel lining section, and the structural parameters of the portal components, to the IFC template file, and create a two-dimensional contour section. Step 2.4: Add a two-dimensional section geometric representation based on the two-dimensional contour section to form a three-dimensional solid. That is, add a two-dimensional section geometric representation, where the section is specified as the two-dimensional contour section created in the previous step, specify the stretching length (by default, stretch in the positive direction of the z-axis), and stretch the two-dimensional contour section to form a three-dimensional shape, which corresponds to the stretched solid geometric representation in the swept solid geometric representation in IFC.

[0033] Step 2.5: Place the created three-dimensional solid in the hierarchical structure to ensure that the organizational structure of the file is logically clear. Step 2.6: Output the IFC file.

[0034] In terms of the representation of entity elements in the present invention, the components of the railway tunnel portal include component elements such as the inner contour, open cut tunnel, and portal. Such unique component elements and their semantic descriptions are not predefined in IFC. However, IFC provides the building element proxy IfcBuildingElementProxy to represent components that are difficult to classify into traditional building elements, which reflects the adaptability and extensibility of the classification of model component elements in specific engineering projects. Therefore, the semantic definition and description are provided for the component elements of the railway tunnel portal through the building element proxy IfcBuildingElementProxy, and different components are distinguished by IfcBuildingElementProxy from the naming attribute Name and the description attribute Description.

[0035] In terms of geometric shape representation, the IFC standard predefines geometric shape representations applicable to the entity objects of railway tunnel portal components, mainly including three representation methods: boundary description entity, geometric construction entity, and swept entity. Among them, the boundary description entity is a geometric expression based on a face set, and it is difficult to describe the process information of the geometric construction of model entities, resulting in poor overall geometric description ability; the geometric construction entity model is used to create entities through one or more Boolean operations (such as union, intersection, difference, etc.) on basic entities, but it does not contain geometric information such as vertices and edges, and is restricted by the types of voxels and their operations, making it difficult to complete local operations on the geometric bodies of the model; the swept entity model generates geometric bodies by defining a two-dimensional profile plane and sweeping it along a straight or curved path, and mostly uses the sweeping operation of linearly stretching a plane. The generation and modification of model geometry can be quickly achieved, and the precise geometric information of the object can be created. Therefore, by using the swept entity representation method to define the geometric shape representation of railway tunnel portal components, the advantage of this representation method is that it can record the original characteristic parameters and process information of the generation of component entities, facilitating subsequent modification and adjustment. When the entity shape needs to be changed, it can be quickly achieved by modifying the voxel parameters.

[0036] In terms of spatial structure description, the IFC standard defines a detailed spatial structure hierarchy for organizing and managing spatial and physical elements in engineering projects. For standard buildings, the basic representation of its spatial structure hierarchy in IFC is the project element IfcProject, the site element IfcSite, the building element IfcBuilding, and the storey element IfcBuildingStorey. The site is assigned to the project, the building is placed on the site, and the storey is placed in the building, thus establishing the spatial structure hierarchy relationship, and then adding more component elements and associating them with the corresponding spatial organization levels. IFC4×3 makes an extended definition for the railway spatial hierarchy. The railway element IfcRailway is used to represent the entire railway section and is the core entity of railway infrastructure for organizing and managing all railway-related components and settings; the railway section element IfcRailwayPart is further subdivided to represent specific parts in the railway system. Therefore, for the IFC spatial hierarchy representation of railway tunnel portals, its organizational method is defined as IfcProject, IfcSite, IfcRailway, and IfcRailwayPart from top to bottom.

[0037] Embodiment 4 Based on Embodiment 3, step 2.2 of the present invention specifically includes the following steps: Step 2.2.1, create a new blank IFC project file; To access and manipulate information such as the root object, units, context, geometric representations, and spatial structures in the IFC file, import the corresponding sub-modules in the IfcOpenshell library to use the relevant methods defined in the modules. After import, initialize a new blank IFC project file to provide a basic framework for subsequent operations such as adding components, defining geometric shapes, and setting attributes.

[0038] Step 2.2.2, create the IFC project element IfcProject as the root object of the IFC project file, and define and describe the basic information of the IFC project file through the root object operation module of IfcOpenshell; Step 2.2.3, define the measurement unit of the IFC project file as millimeters through the unit operation module of IfcOpenshell; Specifically, specify the unit type as a length unit, specify the unit system as the International System of Units, and specify the unit prefix (the English prefix for millimeters) as Milli.

[0039] Step 2.2.4, create the top-level general model geometric context based on the context operation module of IfcOpenshell to store three-dimensional geometric information; Since the IFC model of the railway tunnel portal is a three-dimensional solid model, create a sub-context of the top-level context by defining the context identifier "Body" (the identifier of the three-dimensional geometric body) to store the entity shape geometric information of the object.

[0040] Step 2.2.5, create a representation of the basic spatial structure hierarchy elements of the railway tunnel portal IFC file to form an IFC template file.

[0041] As described in Step 2.1.3, the creation of the spatial hierarchy specifically includes creating the site element IfcSite, the railway element IfcRailway, and the railway subdivision element IfcRailwayPart, and assigning the site to the top-level project, placing the railway in the site, and placing the railway subdivision in the railway through the element combination sub-module of IfcOpenshell to form a nested representation of the spatial hierarchy of the railway tunnel portal IFC file. After this step, an IFC template file is created, forming a unified template representation for the parts that need to be predefined in the header section and data section of the railway tunnel portal IFC file. The generated IFC file has a complete hierarchy after being opened and conforms to the IFC model file description.

[0042] Example 5 Based on Example 3, Step 2.3 of the present invention specifically includes the following steps: Step 2.3.1: For the tunnel inner contour section, input the control parameters and control points required for the corresponding "one-centered circle", "three-centered circle", and "five-centered circle" section forms. Create the inner contour line by means of the polyline representation method. Connect ICCP_X in ascending order of the X value, and connect them in a straight line segment by default. For the arc segment line, connect it with the midpoint index of the arc segment control points as the list elements; the formed 3D model is as shown in Figure 4 shown.

[0043] Step 2.3.2: For the tunnel open cut lining section, input the control parameters and parameter points required for the corresponding "one-centered circle without inverted arch", "one-centered circle with inverted arch", "three-centered circle with inverted arch", "five-centered circle with inverted arch", and "three- and five-centered circle without inverted arch" section forms. Create the outer contour line by means of the polyline representation method. Connect LSCP_X in ascending order of the X value, and connect them in a straight line segment by default. For the arc segment line, connect it with the midpoint index of the arc segment control points as the list elements; the formed 3D model is as shown in Figure 5 shown.

[0044] Step 2.3.3: For different tunnel portal forms, select the required portal components, input the parameters required for the corresponding portal components, automatically obtain the control point coordinates of each portal component, and connect them in sequence in a straight line segment by means of the polyline representation method to form the 2D contour section of the portal component. The formed 3D model is as shown in Figure 6 shown.

[0045] Example 6 Based on Example 3, the topological relationship and positioning combination method of the three parts of the model in step 3 of the present invention specifically include the following steps: The establishment of the geometric association between the three parts of entity elements in step 3 specifically includes the following steps: Step 3.1: Create a Boolean cut result entity class in the IFC file, specify the type of Boolean operation as subtraction, use the open cut 3D entity as the base entity, and specify the inner contour 3D entity as the entity object to be cut, so as to construct the composite entity of the railway tunnel portal and realize the geometric association between the open cut 3D entity and the inner contour 3D entity; Step 3.2: Set the 3D coordinates of the centroid of the 2D section projected by the portal entity on the X-Y plane as the reference point for global assembly. According to the tunnel portal structure requirements, construct the coordinate offset matrix between the key control points of each portal component and the reference point to realize the geometric association between the composite entity elements of the portal and the entity elements of the portal component, and form the final overall entity elements of the railway tunnel portal; Step 3.3: Place the formed overall entity elements of the railway tunnel portal at the bottom layer of the basic spatial structure hierarchy created in step 2.2.5 to ensure the clear logic of the organizational structure of the overall IFC file; Step 3.4: As shown inFigure 7 As shown, the final overall IFC file of the railway tunnel portal is output.

[0046] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0047] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A parametric modeling method for railway tunnel portal based on IFC file, characterized in that: The specific steps include: Step 1: Based on the general reference map of railway tunnels, a railway tunnel portal hierarchical parameter system is constructed to extract three core parameter sets: inner contour section geometry control parameters and control points, open hole lining section geometry control parameters and control points, and portal component construction parameters, and express them semantically respectively; Step 2, based on the IFC file structure characteristics and IfcOpenShell toolkit, using Python language and the parameters set by the three core parameter sets, construct the inner contour solid element, the open hole solid element and the portal component solid element in the IFC file respectively; Step 3: Based on the spatial assembly constraints of the railway tunnel portal, the geometric association relationship between the three parts of the entity elements corresponding to the three types of core parameter sets is established to form the IFC file of the entire railway tunnel portal; Step 4: Import the IFC file generated in step 3 into the BIM software for parametric modeling.

2. The parametric modeling method for railway tunnel portal based on IFC file according to claim 1 is characterized in that: In step 1, the railway tunnel portal model to be constructed is split into three parts: inner contour section, open hole lining section and tunnel portal component, which specifically includes the following steps: Step 1.1, according to the railway tunnel professional general reference drawing, the inner contour section is divided into three types according to the number of circle centers: "one-center circle", "three-center circle" and "five-center circle"; Step 1.2, based on the three types of inner contour sections, namely "one-center circle", "three-center circle" and "five-center circle", the open hole lining sections are divided into five types, namely "one-center circle without inverted arch", "one-center circle with inverted arch", "three-center circle with inverted arch", "five-center circle with inverted arch" and "three or five-center circle without inverted arch" according to the presence or absence of inverted arch as the secondary classification feature; Step 1.3, the tunnel portal forms include end wall portal, wing wall portal, step portal and column portal. The tunnel portal components are divided into main end wall, left / right additional retaining wall, left / right wing wall, step end wall, middle wall, left / right pier column and left / right side wall according to the portal form.

3. The parametric modeling method for railway tunnel portal based on IFC file according to claim 2 is characterized in that: In the step 1.1, six inner contour control parameters are set for the three types of "one-center circle", "three-center circle" and "five-center circle": θ1, θ2, ch, H, r1, r2; and 13 inner contour control points: ICCP_1, ICCP_2, ICCP_3, ICCP_4, ICCP_5, ICCP_6, ICCP_7, ICCP_8, ICCP_9, ICCP_10, ICCP_11, ICCP_12, ICCP_13.

4. The parametric modeling method for railway tunnel portal based on IFC file according to claim 2 is characterized in that: In the step 1.2, two open hole section control parameters of and h are set in five forms of "one center circle without inverted arch", "one center circle with inverted arch", "three center circles with inverted arch", "five center circles with inverted arch", and "three and five center circles without inverted arch": 14 open hole section control points: LSCP_1, LSCP_2, LSCP_3, LSCP_4, LSCP_5, LSCP_6, LSCP_7, LSCP_8, LSCP_9, LSCP_10, LSCP_11, LSCP_12, LSCP_13, and LSCP_14.

5. The parametric modeling method for railway tunnel portal based on IFC file according to claim 2 is characterized in that: In the step 1.3, the control parameters of the main end wall include A, dh, B, H1, α, and L; the control parameters of the left / right additional retaining wall include G, n, E, and L; the control parameters of the left / right wing wall include b1, h1, a, b2, h2, β, and L; the control parameters of the stepped end wall include N, B1, H2, H3, γ, and L; the control parameters of the middle wall include h1, B, and H1; the control parameters of the left / right pier include h1, h2, A, B, and H1; and the control parameters of the left / right side wall include h1, h2, B1, δ, A, B, and H1.

6. The parametric modeling method for railway tunnel portal based on IFC file according to claim 1 is characterized in that: The step 2 specifically includes the following steps: Step 2.1, create an IFC project file and define the IFC representation method from three aspects: entity element representation, geometric shape representation and spatial structure description; Step 2.2, based on the defined IFC representation method, create an IFC template file through the IfcOpenShell toolkit; Step 2.3, using the stretched 3D entity representation method, add three core parameter sets of inner contour section geometry control parameters and control points, open hole lining section geometry control parameters and control points, and portal component construction parameters to the IFC template file, and create a 2D contour section; Step 2.4, adding a two-dimensional cross-sectional geometric representation based on the two-dimensional contour section to form a three-dimensional entity; Step 2.5, place the created 3D entities in a hierarchical structure to ensure that the organization structure of the file is logically clear; Step 2.6, export the IFC file.

7. The parametric modeling method for railway tunnel portal based on IFC file according to claim 6 is characterized in that: The step 2.2 specifically includes the following steps: Step 2.2.1, create a new blank IFC project file; Step 2.2.2, create an IFC project element IfcProject as the root object of the IFC project file, and define and describe the basic information of the IFC project file through the root object operation module of IfcOpenshell; Step 2.2.3, define the measurement unit of the IFC project file as millimeter through the unit operation module of IfcOpenshell; Step 2.2.4, creating a top-level general model geometry context based on the context operation module of IfcOpenshell to store three-dimensional geometry information; Step 2.2.5, create the basic spatial structure hierarchical element representation of the railway tunnel portal IFC file to form an IFC template file.

8. The parametric modeling method for railway tunnel portal based on IFC file according to claim 6 is characterized in that: The step 2.3 specifically includes the following steps: Step 2.3.1, for the tunnel inner contour section, input the control parameters and control points required for the corresponding "one-center circle", "three-center circle" and "five-center circle" section forms, create the internal contour line through the polyline representation method, connect ICCP_X from small to large according to the size of X, and connect them in straight line segment mode by default. For arc segment lines, use the midpoint index of the arc segment control point as the list element for connection; Step 2.3.2, for the tunnel open hole lining section, input the control parameters and parameter points required for the section forms of "single center circle without invert", "single center circle with invert", "three center circles with invert", "five center circles with invert", "three and five center circles without invert", create the external contour line by the polyline representation method, connect LSCP_X from small to large according to the size of X, connect by straight line segment by default, and for arc segment lines, connect by the midpoint index of the arc segment control point as the list element; Step 2.3.3, for different tunnel portal forms, select the required portal components, input the required parameters of the corresponding portal components, automatically obtain the control point coordinates of each portal component, and connect them in sequence in the form of straight line segments through the representation method of polylines to form a two-dimensional contour section of the portal component.

9. The parametric modeling method for railway tunnel portal based on IFC file according to claim 7 is characterized in that: The step 3 of establishing the geometric association between the three parts of the entity elements specifically includes the following steps: Step 3.1, create a Boolean clipping result entity class in the IFC file, specify the type of Boolean operation as subtraction, take the open hole 3D entity as the base entity, specify the inner contour 3D entity as the clipped entity object, construct a railway tunnel opening composite entity, and realize the geometric association between the open hole 3D entity and the inner contour 3D entity; Step 3.2, set the three-dimensional coordinates of the centroid of the two-dimensional cross section of the portal entity projected on the XY plane as the reference point of the global assembly, and construct the coordinate offset matrix of the key control points and the reference points of each portal component according to the construction requirements of the tunnel portal, so as to realize the geometric association between the composite entity element of the portal and the entity element of the portal component, and form the final overall railway tunnel portal entity element; Step 3.3, placing the entity element that forms the entire railway tunnel portal at the bottom of the basic spatial structure hierarchy created in step 2.2.5 to ensure that the organizational structure logic of the entire IFC file is clear; Step 3.4, output the final integrated railway tunnel portal IFC file.

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