Numerical Investigation on Instability of Buildings Caused by Adjacent Deep Excavation

Abstract

The embedded ratio of retaining structures and improved depth of ground at an excavation base are two key factors for the stability of deep excavation. For a collapsed excavation in soft clay in Hangzhou, China, a numerical investigation using the finite-element method (FEM) is carried out on the buildings distressed by excessive settlement and wall deformation. The embedded ratio of retaining piles and improved depth of ground at the excavation base are thus examined for their impact on the ground settlement and wall deformation of the building caused. A dimensionless parameter–wall torsion tilt ω–is introduced to analyze the differential settlement of buildings caused by adjacent excavation. The results indicate the following: (1) the insufficient embedded depth of retaining piles is the main cause of the building instability, and (2) increasing the embedded ratio of a retaining pile or the improved depth of ground at the excavation base can effectively reduce the ground settlement induced by excavation and, thus, limit the large differential vertical deformation on the wall of an adjacent building.