Research on mechanical characteristics of metro shield tunnel segment in sandy strata

Based on the Nanjing metro shield tunnel traversing sandy strata, systematic in-situ investigation and theoretical simulation of the beam-spring model with consideration of the interactions between lining structure and surrounding soil during the segment assembly and stabilization are carried out. Influences of the shield tail serum injection, soil stress relaxation, water pressure and segment ring assembly on the distributions and varying laws of sandy strata segment ring soil pressure, the longitudinal joint gap and internal forces are discussed. The characteristics of the interactions between shield tunnel segment and the sandy strata are investigated. The applicable principle and method for metro shield tunnel segment design in sandy strata are also proposed. Key words: shield tunnel; segment ring; soil pressure; longitudinal joint; internal force; beam-spring model