砂卵石地层盾构施工引起的纵向地表变形预测

Prediction of longitudinal ground deformation due to shield construction in sandy pebble strata

为了更好地预测盾构施工对砂卵石地层的影响,对Sagaseta法进行了修正.假定土体不排水,利用Mindlin解推导了盾构同步注浆施工过程引起的砂卵石地层三维变形计算式,并结合盾构机外壳与周围土体间的摩擦力以及地层损失引起的纵向地表沉降计算公式,得到了砂卵石地层盾构施工引起的纵向地表沉降计算公式,并将本文理论计算值与现场监测数据、Sagaseta公式理论值、数值模拟值进行了比较.结果表明:本文理论计算结果与现场监测数据较为吻合;理论法较Sagaseta法更适合于砂卵石地层;盾构施工引起的砂卵石地层纵向地表沉降呈S形.

In order to better predict the influence of shield construction on the sandy pebble strata,the Sagaseta method was modified. With assuming that the soil was undrained,the computing formula for the three-dimensional deformation of sandy pebble strata induced by synchronous grouting in shield construction was derived with the Mindlin solution. In combination with the computing formula of longitudinal ground deformation settlement induced by the friction force between shield machine shell and surrounding soil as well as the stratum loss,the computing formula of longitudinal ground deformation settlement caused by the shield construction in sandy pebble strata was obtained. In addition,the theoretically calculated values were compared with the monitored data,the theoretical values obtained from Sagaseta formula and numerical simulated values. The results showthat the theoretically calculated results are in well agreement with the monitored data,and the theoretical method is more suitable for the sandy pebble strata than the Sagaseta method.The longitudinal ground settlement induced by shield construction in sandy pebble strata shows an S-shape.