Control of surface settlement by considering shield tunneling technology

With the high-speed development of subway construction of China, the prediction and control of surface settlement induced by shield tunneling construction is a hot research topic. In this study, the modified Peck formula was established based on the modified gap parameters that concerned with three factors of the shield construction technology, which were included in the fill rate of grouting and shield eccentricity ratio and support pressure ratio. The control limits of Shield Tunneling Parameters ( STP) were presented on the basis of the Maximum Surface Settlement ( MSS), the allowable partial incline and curvature of settlement trough. With the background of the Xi'an Subway line No. 2, the MSS and partial incline of transverse settlement trough near the ancient structures is less than 15 mm and 0.5%, for the ordinary sections, the value of which is less than 30 mm and 3.0%, respectively. The STP near the ancient structures are controlled as follow: lambda >= 0.64, beta >= 0.81, kappa = 0.59%, and the control limits of STP are lambda = 0.60, beta = 0.77 and. = 0.71% for the ordinary sections.