Study On The Minimum Value Of Curve Radius In Shield Construction

Small radius of the shield tunnel construction has been increasingly applied in subway projects. However, the study on the minimum value of curve radius in shield construction relatively lags down both at home and abroad. Therefore, it is necessary to study on the minimum value of curve radius in shield construction, so that we can make scientific decisions to design the subway lines. In addition, it can also help to guide the subway construction, to ensure the security in the process of construction and reduce the adverse effects of small curve radius in shield construction.This thesis combines the materials about subway construction available; make use of research approaches such as investigation of the scene, theoretical analysis, numerical simulation to make a comprehensive and systematic research on the minimum value of curve radius. Research shows, to achieve small curves radius of shield tunneling, the geometry of shield machine is only a necessary condition, rather than a sufficient condition. As a key factor in deciding the minimum value of curve radius, the segment can be adjusted by its volume and width in practical engineering to meet the requirements of small curve radius in shield construction. The layer along the line also has a significant impact on the minimum value of curve radius in shield construction. Considering the major factors that influence the minimum value of curve radius, we find that, with the existing shield machine, construction of a radius of 150m tunnel is totally feasible.This thesis also combines the practical projects home and abroad to these research results for their verification and application, which provides good guidance and reference for domestic small curve radius of shield tunnel under construction and are to be implemented.