Pre-supporting small guide pipes are a technique used in tunnel excavation, mainly for pre-supporting sections with short self-stabilization time, such as weak and fractured zones, shallow buried sections, tunnel entrance biased sections, sand layers, gravel sections, and fault fracture zones.

Rigid sleeves, also known as rigid waterproof sleeves, are constructed from A3 steel or stainless steel pipes with welded water-stop rings. The space between the sleeve and the pipe is sealed with rigid material, and there are no internal shock-absorbing components.