Mobilisable strength design for adjacent excavations in clay

Adjacent excavations induce a deformation superposition effect in the soil between them, and this effect is closely associated with the stability of the retaining systems. However, the current codes do not consider the mutual effect but design the two excavations individually, causing errors in the calculations of soil deformation and earth pressures. In this study, a novel framework is established based on the Mobilisable Strength Design (MSD) method, incorporating the deformation superposition effect, for simultaneously calculating both the deformation and stability of the retaining system for adjacent excavations in clay. Based on case studies of adjacent excavations in Nanjing and Shanghai, China, the proposed method was validated through comparisons with field measurements and finite element method (FEM) results. The proposed method provides a simplified calculation approach for adjacent excavations in clay, enabling the identification of retaining-system configurations that simultaneously satisfy both stability and deformation requirements.