软土盾构隧道渗流引起的地层和隧道沉降

Leakage-induced Settlement of Ground and Shield Tunnel in Soft Clay

基于复变函数的映射变换,在考虑衬砌作用的前提下,推导了稳定渗流时浅埋隧道周围土体中孔隙水压力分布、地层和隧道长期沉降的解析表达式,并将其运用到上海地铁盾构隧道中,重点分析了不同渗流条件下的孔隙水压力分布及地层和隧道长期沉降发展规律.研究表明,土体与衬砌的相对渗透系数对隧道和地层沉降发展影响显著,不同相对渗透系数引起的渗流量不同,渗漏量不同是影响隧道周围孔压分布及沉降发展的关键因素;地表和隧道的沉降随渗流量的增加线性增加,因此在盾构隧道运营期间,应加强对隧道渗漏水的检测,及时采取补漏措施.

An analytical solution is proposed based on the conformal mapping of the complex variable methods to study the distribution of pore pressure around the tunnel.The tunnel lining is taken into account in the analytical solution.The accuracy of the analytical solution is verified by the numerical solutions.The leakage-induced behavior of Shanghai shield tunnel is studied by using the proposed analytical solution.The results indicate that the relative permeability between soil and lining is essential for water inflow.The water inflow into the tunnel increases with the decrease of the relative permeability of soil and tunnel lining.The settlements of tunnel and ground increase linearly with the increase of water inflow.Therefore,the leakage of the shield tunnel should be monitored carefully and the corresponding waterproof measures should be adopted for operation tunnel to control the tunnel deformation and ground settlement.