| description abstract | The upward-moving of shield tunnel during construction has brought about great concern. The reasons of shield tunnel upward-moving were analyzed and classified into six aspects, including buoyancy, axial eccentric force, slurry pressure, foundation rebound, compression of covering soil, and the sand liquescence. The upward moving of shield tunnel brought by buoyancy was discussed with emphasis. Two kinds of calculation models of anti-upward moving were presented considering the transverse and longitudinal characteristics of shield tunnel, which were called partial anti-upward moving model and whole anti-upward moving model respectively. According to the characteristics and affecting area of the buoyancy, the partial anti-upward moving model was divided into single segment analytic model and whole segment ring analytic model. The similarities and differences of settlement and upward-moving were compared in the whole anti-upward moving model, which manifested the coherence of the settlement and upward-moving of shield tunnel. The adaptability of the presented models was also discussed. | |
