Abstract:In order to ensure the safe start of shield tunnels in shallow, deep and water-rich soft strata, artificial freezing method is used to reinforce the end of shield tunnels. Through uniaxial compressive test of frozen soil in laboratory, reliable mechanical parameters of frozen soil are obtained. Orthogonal test method is used to analyze the influence law and degree of frozen depth, frozen width and frozen temperature on surface settlement and segment vault settlement, and the optimal freezing reinforcement scheme is selected.The results show that the lower the freezing temperature of soil, the greater the compressive strength; the order of influence on surface settlement and segment vault settlement is freezing depth>freezing width>freezing temperature; the optimum freezing scheme is freezing width of 6 m, freezing depth of 15 m, freezing temperature-20℃.