Monitoring of Large Section Tunnel Crossing Qiantang River during Operation Period

The foreign precision monitoring equipment was used for long term health monitoring in the large diameter tunnel of Hangzhou Qingchun-road. Based on field monitoring data, the force and deformation of the large section crossing-river tunnel during operation period were summarized and analyzed. A detailed analysis of the effect of tide and scour on the tunnel interface force and tunnel settlement were given. Data shows accumulations of both longitudinal settlement of tunnel segments and the earth pressure distribution around the tunnel lining under the loads of both traffic and tide which results in soil disturbance in the construction period. The settlement becomes stable after about six months. The substratum has a great influence on the longitudinal settlement of tunnel segments. The settlement of tunnel invert in sandy substratum is obviously affected by the tide of Qiantang River for short time, while slight changes appear in the deformation of tunnel diameter, stress of steel bar and earth pressure distribution.