Abstract: The Second Line Project of West-east Gas Transmission is a northwest corridor for gas import,and it is important in the distribution of gas pipe network. In this paper,field investigation is done on Section Guozigou of the tunnel in Second Line Project of West-east Gas Transmission. The physical geography and geological environmental conditions of the project area and its surrounding are found out. The type,distribution,scale and dangerous state of geologic hidden trouble are investigated. And t...