Behavior of Cofferdam Using Non-uniform Geotextile Mats on Soft-overlying-stiff Foundation

Abstract

Abstract Non-uniform geotextile mats are employed as soft foundations in cofferdams. However, investigations on the influence of complicated geological conditions on the mechanical behavior of cofferdams are limited. We investigated the behavior of a cofferdam using non-uniform geotextile mats to explore the failure mechanism of non-uniform geotextile mats over a soft overlying stiff foundation and quantify its stability. The two typical failure modes, global and local failure modes, differed distinctly in the velocity field and sliding surface shape. Geometric factors may partially affect the failure mode, whereas a higher soil strength can enhance the stability of the cofferdam, especially when stiff soil is involved. The failure mechanisms of cofferdams using non-uniform geotextile mats on soft overlying stiff clay and a corresponding stability prediction method are proposed to guide the design of cofferdams using non-uniform geotextile mats.