DETECTION AND TREATMENT OF ROAD TUNNEL DISTRESSES IN LOESS mdash|A CASE STUDY

Physical and mechanical properties of loess are very poor. The loess has big aperture, strong wet subsidence, and low intensity. The complex and varied terrains and landforms of loess regions can result in a lot of disease of road tunnels in loess during construction. According to the characteristics of distresses in the road tunnel in Qijia mountain, the thickness, cavity distribution, crevice water were detected with geo-radar. Material of lining was nondestructively detected with sound locater. Limiting structure of the tunnel was detected with a circumscription apparatus. Based on detected results, causes of the distresses were analyzed. Three treatment schemes were put forward by slurry injection from the back of lining structure, lining reinforcement, treating the water proof system. Stability of surrounding rock and the state of forces of the lining structure were analyzed before and after the treatment. It is showed that the treatment scheme of the tunnel is feasible. Taken construction and cost estimate into account, an optimal scheme is obtained.