Abstract:The deformation problem caused by the upper light loading and unloading action of the rail transit operated in soft soil area has received wide attention in the engineering field. A road project in Shanghai spans the section of the double-circle shield of the subway, and the project involves the construction of river diversion. Therefore, there is a complex light loading and unloading action in the upper part of the tunnel. Through the deformation monitoring of the double-circle shield tunnel in the underlying soft soil, the influence of light loading and unloading on the operation of the shield tunnel is analyzed. And the focus is on the analysis of river diversion section. The main reasons for the settling funnel are summarized. Combined with the field monitoring data and settling reasons, the pavement structure of the key area is treated. The monitoring result shows that the key treatment technical measures based on the monitoring data are effective. It has important engineering practice value for operating safety protection of double-circle shield tunnel under the light loading and unloading action.
