Development and Application of an Industry Foundation Classes-Based Metro Protection Information Model

Table 4

Extracting major information from the MPIM.

Major factors	Extraction method	IFC type uesd
The horizontal distance between the external project and the metro structure	Utilize Algorithm 1 to calculate L.	All IFC types
Buried depth of metro structure	Traverse the IfcGround and IfcMetroBuilding model, filtering the elements with the largest Z coordinate difference and .	IfcGround; IfcMetroBuilding
Pit depth of external project	Traverse the IfcGround and IfcExternalBuilding, filtering the elements with the largest Z coordinate difference and get	IfcGround; IfcExternalElement
Grade of surrounding rock	Judge from the property IsSoftInterLayer and IsSoftUnderlying	IfcGeoLayer; IfcGeoLayerElement
Support type	Judge from the property Support Type in IfcExternalBuilding entity	IfcExternalBuilding