Abstract:
The buried depth of the receiving end of Longquan inverted siphon tunnel is 72. 3 m in Yunnan province.The water-earth pressure of the stratum is large, and the water and sand gushing accidents are prone to occur during the shield receiving process. Therefore, a three-dimensional model of the shield receiving end considering the influence of seepage was establish to analyze the deformation of the diaphragm wall, the stratum deformation and the variation of groundwater seepage field caused by shield tunnel receiving process using large pipe roof grouting and freezing method.The results show that the freezing method is superior to the large pipe roof reinforcement in the ability to limit the horizontal deformation of the diaphragm wall and the deformation of the surrounding soil in the shield receiving process.Large buried depth shield receiving has little effects on ground settlement and cannot be used as a key risk source for control. The groundwater pore pressure field forms a low pressure area surrounding the excavation surface, and the pore pressure isopleth surface far from the excavation surface is evenly distributed. The seepage velocity of groundwater after shield tunneling to the freezing reinforcement area is far less than that of the large pipe shed reinforcement area.For the shield receiving project in large buried depth and high-water pressure stratum, the freezing method is obviously better than the large pipe shed reinforcement in resisting water and sand gushing. The research results can provide reference for similar large-buried shield receiving projects in the future.