DIGITAL/BIM | TECHNICAL
Table 1: Used software for the BIM Ground Model of the Tunnel Angath Software (developer)
MOVE (Petroleum Experts) Rhino (Robert McNeel & Associates)
Grasshopper (Robert McNeel & Associates) BricsCAD BIM (Bricsys NV)
Version 2020.1
6.34/7.8 22
Use-case Geological 3D modelling
Computer aided design and platform for parametric modelling with Grasshopper Parametric modelling of volumes and boreholes Data modelling and attribution of the final geometries
The cover of glacial sediments above the UAFm
consists mostly of fine to coarse grained glaciofluvial to glaciolacustrine deposits (Ilyashuk et al., 2022). In the portal area there are mostly fluviial sediments of the Inn Valley, consisting of sandy to gravely river deposits under a layer of topsoil with high organic content. The portal is also located near highway A12 Inntalautobahn, which is why extensive anthropogenic deposits and re- modelling of the landscape is expected in this area.
5.2. STRUCTURE OF BIM GROUND MODEL In order to meet different use cases of the BIMGM, three sub-discipline models (see Section 4). An overview of the models is shown in Figure 7. For the 3D modelling and attribution of the BIM
elements of this case study, a combination of different software packages was used (see Table 1). Similar ground models can be created with alternative software products on the market and commonly used by the industry. Export and data exchange are done in the .ifc data
format in the latest available version at the time of modelling (IFC 4x1). Since there are no suitable classes (BIM Types) for ground modelling yet, all objects are classified as ‘BuildingElementProxy’. To still be able to have some classification of the object types and to ensure more clarity in the IFC viewers when examining the BIMGM, and to differ between the three sub- discipline models, the objects have been assigned to ‘buildings’ and ‘stories’ similar to structural engineering projects. Three ‘buildings’ were created for the three sub-discipline models, as seen in Figure 7, with the individual objects assigned to their own ‘stories’/classes. Table 2 shows the applied allocation of the ‘story’/
class (for the Classification System) to the corresponding ‘building’. It must be noted that this is a workaround, as a result of the current state of technology that does not allow for creation of custom classes/ object types. Some IFC viewers allow additional sorting by using
classification systems. In this case study, for the Angath Tunnel project, a user defined classification system was created with classes analogue to the previously defined ‘stories’ and each object was assigned a class. An exemplary BIMGM with the described classification methods can be found in the supplementary material of this paper. The three sub-discipline models of the BIMGM
consist of objects that are modelled from geometries with associated attributes. To ensure that the information content/ semantics of the BIMGM are fully understandable for other involved companies,
an attribute list was developed from the start of the project that assigns attributes to each object. These attributes were created as user defined PSets with the data modelling function of BricsCAD BIM. A simplified attribute sheet for exemplary purposes also can be found in the supplementary material. To fulfill all requests from the client and other
planning companies, it was agreed that the BIMGM should horizontally cover an area of at least 60m around Angath Tunnel, the connecting tunnels and the access route to the construction site (see red dashed line in Figure 6). The lower boundary of the BIMGM was set to 440m a.s.l. as the lowest point of the tunnel is at 473.75m and it was the goal to have the model extend at least 30m below its lowest point. Considering a possible application of the BIMGM for numerical/ FE modelling, the model extent was based on the suggestions of EANG (2014); it was recommended to have a model extent around the tunnel of 4–5 tunnel diameters horizontally and 2–3 tunnel diameters vertically.
5.3. Sub discipline models For the Geotechnical Model, homogeneous areas with the same geotechnical properties were modelled as 3D volumes. The volumes are provided with the percentage distribution of individual rock mass types (see Section 4.3) as well as further geological information. For each volume, five rock mass types with associated attributes can be defined. The following attributes can be added to each rock
mass type in the Geotechnical Model: ● Identification of the rock mass type ● Volumetric percentage of the rock mass within the volume
● Associated description ● Link to a data sheet with further geotechnical parameters
Table 2: Classification of the BIMGM into “Building” and “Stories” Building
Geotechnical model
Classes for the Classification System
Geotechnical unit Cross section
GSM_Geology Geotechnical synthesis model Factual data model
GSM_Discontinuity GSM_Water GSM_Gas
GSM_Swelling Boring
Associated Stories/
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