中文摘要：

对某软土地区地铁盾构隧道进行了调研与分析，发现盾构隧道在现有计算理论所允许的地表超载作用下极易发生横向变形超限，并引发管片纵缝接头破损与渗漏水，对此展开了模型试验、数值仿真及理论分析。研究表明：地表均布超载导致的隧道附加竖向土压力并不是均匀分布，且在隧道中心正上方一定范围内要大于地表均布超载；隧道的穿越土层越软弱，地表超载导致的隧道周围附加土压力对隧道结构抵抗横向变形越不利；隧道发生横椭圆变形过程中，管片纵缝接头是管片环中的最薄弱部位。最后提出了软土地区盾构隧道采用“刚性衬砌”的设计理念，并给出了加大管片纵缝接头强度与刚度的建议。

英文摘要：

The metro shield tunnel in soft soil area is investigated and analyzed. It is shown that overlarge transverse deformations of the shield tunnel are induced due to the surface surcharge, which is an allowable magnitude according to the current computational theories, and it brings about problems of breakage and leakage of longitudinal segment joints. Through the scaled model tests, numerical simulations and theoretical analyses, the research results show that the additional vertical earth pressure on shield tunnel induced by the uniform surface surcharge is not the uniform pressure, and the vertical earth pressure on the top of shield tunnel is larger than the uniform surface surcharge. The additional earth pressure around the shield tunnel caused by surcharge is more negative for preventing tunnel deformation as the tunnel passes through softer soil. The longitudinal segment joints are the weakest points on the segment ring in the process of transverse deformation. Finally, the design concept of rigid linings for shield tunnels in soft soil areas is proposed, and some suggestions for enhancing the strength and stiffness of longitudinal segment joints are given.