黏土中隧道开挖引起的地表及地表以下土体长期 沉降计算方法

基于 Mair 提出的隧道开挖引起的土体瞬时沉降的理论以及进行的有限元数值模拟结果，推出地表及地表以下不同深度土体长期沉降的计算方法。首先模拟了 Ong 的离心机试验以验证数值模型的合理性，然后对隧道开挖引起的不同深度处土体长期沉降问题进行了模拟研究，建立了长期和瞬时情况下地层损失率之间的关系，并推导出长期情况下各深度处沉降槽宽度系数和最大沉降值的计算式，从而可确定沉降槽的形状。经与现场实测资料和数值模拟结果对比，验证了方法的合理性，可作为实际工程的借鉴。

Computation method for long-term surface and subsurface settlements induced by excavation of tunnels in clays

Based on the Mair’s theory of immediate settlement of soil due to tunneling,and the results of finite element simulation,a computation method for the long-term settlement of the soil at surface and subsurface is proposed.Ong’s centrifuge test is simulated first to verify the validity of the finite element model,then a numerical study on the long-term settlement of the soil at different depths is carried out.The relationship between ground losses under immediate and long-term conditions is established.Formulas for width parameter and the maximum settlement of settlement trough at different depths are also given,and the profile of settlement trough can be determined.Compared with the field measurement and numerical simulation,the validity of the proposed method is demonstrated.It can be employed in practical projects.