基于随机介质理论的盾构穿越富水砂卵石地层扰动分析

Random medium theory analysis of shield tunneling through water rich sandy cobble stratum

在富水砂卵石地层进行隧道开挖会诱发地层损失、引起周围建筑变形失稳等问题,为了对富水砂卵石地层中隧道开挖引起的地层扰动进行分析,基于传统随机介质理论推导了地表竖向位移、水平位移、倾斜曲线、横向变形及曲率的计算公式,并以万家丽电力隧道为依托,计算得到了反映地层扰动的位移曲线。研究表明盾构开挖后隧道地表沉降量呈现单峰状态、水平位移呈现双峰状态,且盾构穿越富水砂卵石地层对地表产生的倾斜、横向变形都非常小,不会对地表敏感建构筑物结构产生过大倾斜或横向变形而破坏,因此盾构下穿敏感建构筑物扰动效应控制应以控制其结构的最大竖向位移和最大水平位移为主。

Tunnel excavation in water rich sandy pebble stratum will induce stratum loss and cause deformation and instability of surrounding buildings.In order to analyze the stratum disturbance caused by tunnel excavation in water rich sandy pebble stratum,this paper deduces the calculation formulas of surface vertical displacement,horizontal displacement,inclination curve,transverse deformation and curvature based on the traditional random medium theory,moreover,the displacement curve reflecting stratum disturbance in Wanjiali power tunnel engineering is calculated.It is found that after shield excavation,the surface settlement of the tunnel presents a single peak state and the horizontal displacement presents a double peak state,and the inclination and transverse deformation of the ground surface are very small when shield tunnel passes through the water rich sandy pebble stratum,which will not cause excessive inclination or transverse deformation to the surface sensitive buildings and structures.Therefore,the control of the disturbance effect of shield tunneling through sensitive buildings and structures should mainly concentrate on the maximum vertical displacement and maximum horizontal displacement of the structure.