Analysis on characteristics of surrounding rock displacement of karst cave tunnel during construction process

Because of the influence of karst cave,distribution characteristics of displacement of surrounding rock of tunnel in karst zone differs from that of common tunnel.Taking a karst cave tunnel in Yichang-Wanzhou railway as an example,characteristics of displacement of surrounding rock of tunnel with karst cave in it's beside is carried out through physical analogic modeling and field monitoring.Research indicates that after the tunnel is excavated,the surrounding rock is convergented toward the karst cave and the tunnel.The surrounding rock between the karst cave and the tunnel is convergented in opposite direction,and is also the most dangerous zone.The displacement value of surrounding rock of hance and spandrel and valut near the karst cave is larger than the surrounding rock of hance and spandrel and valut away from the karst cave.The results can offer references to the design and construction of karst caves tunnel.