How to export Civil 3D to Solibri or to a IFC file?
You can't export a file from Civil 3D to Solibri because Solibri doesn't have support for it. According to Autodesk information, the Solibri application is compatible with the following products:
However, there is a way to export to IFC from Civil 3D. There is an ample discussion at the Autodesk forums: http://forums.autodesk.com/t5/autocad-civil-3d-general/civils-3d-to-ifc/td-p/4589219