Discussion on Classification Methods of Special Surrounding Rock of Tunnels

The classification methods of special surrounding rocks of tunnels in loess,swelling soil and fault and fracture zones in China and abroad are summarized.Parameters that can reflect the characteristics of the special surrounding rocks of tunnels are obtained.The study shows that loess can by classified by considering the geologic age,natural water content and dry density,swelling soils can by classified by considering the plastic index,free swelling rate and normal water content and fault and fracture zones can be classified by considering the geological and mechanical characteristics.