Semi-analytical prediction for tunnelling-induced ground movements in multi-layered clayey soils

Abstract

This paper develops a semi-analytical method to calculate the ground movements due to tunnelling in multi-layered clayey soils which are usually encountered in urban areas. The proposed method is based on the modified Loganathan-Poulos formula combined with the elastic equivalent theory. The key issue disposed in current study is the transformation of the boundary of excavation and the boundary after convergence from multi-layered soil system into single layer soil system. The proposed method is verified through the comparisons with previous associated studies associated with the field measurements from five well-documented cases. A parametric study based on the situation that the interlayer is arranged between the upper and lower soil layer is conducted to explore the effects of the mechanical properties and dimensional variables of the interlayer on ground settlements. The results indicate that the soil stratification has a significant impact on ground movements induced by tunnelling in multi-layered clayey soils.