Study on the Influence of Secondary Grouting on Soil Settlement Above Shield Tunnel

Secondary grouting can effectively control the ground settlement caused by shield construction and is widely used in urban shield tunnel construction. Therefore, it is necessary to study the grouting material and grouting effect of secondary grouting. Based on the background of below-passed Metro Line, this paper determines the optimal ratio of grouting materials by studying the effects of different cement content and superplasticizer addition on the fluidity, consistency, initial setting time and compressive strength of cement inert slurry, this paper also studies the influence of grouting on the settlement of soil above the tunnel by monitoring the settlement value of soil above the tunnel during grouting. This study contributes to the understanding of grouting techniques in urban shield tunnel construction. The results show that Grouting has a significant effect on controlling the settlement of shield machine in the later stage of crossing, and the ground settlement can be basically stable within 4 days.