Factors Influencing Post-Construction Responses of Underlying Tunnel below Excavation Base in Gravelly Clay

This paper investigates the response mechanism behind an existing tunnel subjected to a long and deep collinear excavation in Shenzhen granite residual strata. The maximum depth was 18.0 m minimum soil above crown only 6.3 m, causing appreciable heave transverse deformation. Two-dimensional parametric numerical study is adopted examine impacts of influential factors (excavation dimensions, ground permeability coefficient, exposure time base) on responses. hardening model with small strain (HS-Small) used stress–strain behavior. It found that long-term deformation after unloading cannot be ignored. will continue consolidate deform, due dissipation negative excess pore water pressure. significantly affected by geometry. With increase width B, final increases first then tends stable. Furthermore, relative position base also one major contributors tunnel. growth Δf T are exponentially negatively correlated Ly. change coefficient k has no effect stable Δf, which T.