Based on the Deqing Tunnel Project of Guinan high-speed railway crossing the deep sandy gravel soil layer in karst area,where the issues of collapse prevention,water inrush prevention and structural deformation control were present in the construction process,this paper put forward measures such as:increasing the reserved deformation,advanced support of middle pipe shed and small pipe,double-layer support,radial bolt and grouting reinforcement.As for the problems of effective reinforcement and long-term stability of the foundation at the bottom of the tunnel,this paper proposed measures,such as:grouting reinforcement of the bearing soil layer at the bottom of the tunnel,grouting reinforcement of the soil-rock interface layer and rigid sleeve valve tube composite pile.The excavation is optimized from the original design of the double-side wall guide pile raft structure to the three-step reserved core geotechnical method,which greatly improves the construction efficiency.
维普
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