Application of concentric circular strut system in large deep excavations under complex environment

A foundation pit located within the safety protection control line of Wuhan Yangtze River tunnel is taken as an example. The internal forces, displacements and other technical indices of single circular strut and concentric circular strut are comparatively analyzed. The calculated results show that the concentric circular strut can effectively share the axial forces. It has more reasonable structural stress, higher overall stability and supporting stiffness. It can effectively control the adverse influences of Wuhan Yangtze River tunnel and the surrounding building during the excavation of the foundation pit. Great economic and social benefits are achieved.