Study On Soil Disturbance In The Launching Section Of Slurry Shield Tunneling

In recent years, with the unprecedented development and utilization of theunderground space, shield method is widely used in underground tunnel constructionprocess of the city subway, municipal, and power, many environmental safety problemsappear. As one of the main links，shield construction in launching section is prone toaccidents. In this paper, three-dimensional Finite Difference Model is built to analysis thesurrounding soil disturbance mechanism and the causes in slurry shield tunneling, the wayhow to calculate the dimension of reinforced soil is studied.Bases on Project Jiang-Ji tunneling of the first phase project of Wuhan Metro LineNo.2, program FLAC3Dhas been adopted for numerical simulation. The launching sectiontunnel excavation model has been built by a comprehensive consideration on key factorssuch as diaphragm wall construction, foundation pit excavation, end reinforcement,synchronized grouting, soil mass stratification, slurry pressure, the gap of shieldempennage, synchronized grouting. The field measurement data shows that the calculationis given a good match on the measured results. Bases on the established numerical model,this paper also analyses the end reinforcement and reinforcement range principle. Thinboard strength theory, slide theory and limit balancing theory are adopted to calculate thereinforcement range of Project Jiang-Ji tunneling of Wuhan Metro, analyses the mainfactors influencing the security. The sensitivity and characteristics of factors are analyzedby numerical simulation. The results provide a reference for practical engineering.