Measure for Reducing the Tensile Stress in Cement-Treated Soil Layer in Deep Excavation in Soft Clay

Cement-stabilised soil layers (CSSLs) are often created to enhance lateral support to the retaining wall below the excavation level, such as those widely used in the construction of common service tunnels in Singapore. The CSSLs may be subjected to tensile stress or even cracks due to the underlying uplift pressure. Fully-coupled effective stress analyses were carried out using ABAQUS to explore the effectiveness of three measures for reducing the upheave-induced hogging of the CSSLs, i.e., increasing the thickness, usage of pressure-relief wells and usage of openings in the CSSLs. The results show that the usage of the opening is a more effective and more widely applicable measure compared to the other two measures.