Feasible research, assessment and preliminary design will be also carried out. Construction quality ensures project security, so previous preparation work is necessary. Choosing suitable support measures to adapt for different geological conditions and guarantee project’s life time. Self drilling rock anchor is actually an effective one. It adopts different materials and processing technologies, with various sizes to suit for different geological conditions.

Hollow self drill anchor was also used for pre-support in in weak ground conditions. Hollow self drill anchor system increased the stability in the working area by transferring loads in the longitudinal direction and decrease excavation induced deformations. The system increased safety in the working area. Beside this standard usage, hollow self drill anchor is often applied to increase stability in portal sections and for the re-excavation of collapsed sections in underground construction. Another application area is ground improvement and waterproofing in combination with all tunnel construction methods.