Study on limit supporting pressure and stabilization of excavation face for shallow shield tunnels in sand

During construction of shield tunnel,support pressure was usually applied to prevent large displacement of soil or collapse of excavated surface.However,the design and control of appropriate supporting pressure were difficult for the large variation of soil conditions and uncertainties in actual filed construction.Supporting pressure and deformation and stabilization of excavation surface were studied by use of numerical simulation.It could provide some guidance to the stabilization of excavation face of shield tunnels.