为了预测圆形隧道施工引起地表以下不同埋深地层沉降特征，首先，通过理论推导不同地层最大沉降位移与沉降槽宽度系数的函数关系；然后，建立包括试验台架、地层模型、圆形隧道开挖模型以及测量地层变形装置的平面应变模型试验系统。通过理论解析和模型试验可知： 1）地表以下地层的最大沉降位移与沉降槽宽度系数成反比； 2）不同深度地层的沉降位移随着地层埋深的增加而增大，且地表以下地层沉降槽曲线仍然符合正态分布； 3）通过对模型试验数据进行回归分析，得到黏土地表以下不同深度地层沉降槽宽度系数的计算公式，从而为预测圆形隧道施工地表以下不同深度地层竖向位移提供了一种可靠的计算方法。

In order to predict the ground settlement characteristics in different depths induced by circular tunnel construction, the function relationship between maximum ground settlement in different depths and the width coefficient of settlement trough is theoretically deduced; and then the plane strain model experiment system, including experiment platform, soil model, circular tunnel excavation model and ground settlement monitoring device, is established. The results show that: 1) The maximum ground settlement is inversely proportional to width coefficient of settlement trough. 2) The ground settlement increases with the depth increases; and the underground settlement trough shows normal distribution. 3) The calculation formula for relationship between ground settlement and settlement trough in different depths of clay soil is derived by regression analysis. The results can provide a reliable calculation method for vertical ground settlements in different depths induced by circular tunnel construction.