Analysis of ground settlement from braced excavation in soft clays

Abstract

Underground structures are increasingly more common in Singapore to create additional space or expanding its train network. In order to build underground structures, braced excavation is one of the most common methods used. Extensive digging of soil inevitably will impact the surrounding soils, namely ground settlement. Excessive ground settlement can be damaging to the supporting structures or underground pipes and cables. 2D finite element analysis is carried out to study the influence of clay layer thickness, excavation width, wall stiffness and ground water lowering on the ground settlement of soft clay. Study on soft clay is chosen because of its properties that is more prone to ground settlement. The results indicate that all four factors have a definite influence on ground settlement. This study concludes that soft clay layer thickness and wall stiffness are two important factors that affect the settlement; hence close attention should be paid to these two factors whenever conducting excavation on soft clay.