Modelling of tunnel support

The IfcBuiltSystem/TUNNEL_SUPPORT is good, but the tunnel support consists of an "assembly" of various parts, shown here in the attachment TunnelSupport, the classic support consisting of:

Rock bolts
Steel mesh
Steel arch
Shotcrete arch (encloses the other support components)

We generally define a range of support classes (see attached examples), generally 3-6 main Classes, but often sub classes.
These classes are then distributed along the tunnel, depending on the geological conditions, the actual overburden and other non geological risks (surface facilities)
In early project phases we don't model the full support, but usually a place-holder, normally the shotcrete arch that represents all the support.
The included additional items can either be as properties (spacing, length, etc.) or a link to a 2D schedule, or even a detailed model of the complete support over a "round" length

I propose we add:
IfcElementAssembly/TUNNEL_SUPPORT if possible and this can have the support classification as attribute

Is it possible to have an assembly consisting in early project phases of a single element (say shotcrete arch) as a representation of all the support? And later can be either updated with complete set of support measures as requires

Tunnel Support explanation
[TunnelSupport.pdf](https://github.com/bSI-InfraRoom/IFC-Specification/files/10464614/TunnelSupport.pdf)

Tunnel Support classes examples
[GirsbergAusbruchssicherung.pdf](https://github.com/bSI-InfraRoom/IFC-Specification/files/10464548/GirsbergAusbruchssicherung.pdf)
[LimmernUnterwasserstollenSicherungsklassen.pdf](https://github.com/bSI-InfraRoom/IFC-Specification/files/10464552/LimmernUnterwasserstollenSicherungsklassen.pdf)
[NamNgumDiversionAusbruchssicherung.pdf](https://github.com/bSI-InfraRoom/IFC-Specification/files/10464566/NamNgumDiversionAusbruchssicherung.pdf)