Study On Ground Surface Settlement Due To Metro Shield Tunnelling In Red Beds Rock

In recent years, with the constantly appearance of superiority of shield method construction in the process of city subway construction,shield construction method get more and more popularization and application, becoming one of the main construction way of constructing urban subway tunnel in China. Earth surface settlment induced by metro shield is a very concerned problem in the process of subway tunnel design and construction. Geological conditions seems to be the prerequisite for the settlement of the ground, Due to the partic ularity of red beds rock, Red beds rock are mostly argillaceous cementation, with poor water resistance ability and weathering resistance ability, which were easy to softening and disintegration under the influence of water, when do shield construction in this layer, it prone to occur some problems such as surface subsidence, pavement cracking. So the research on the earth surface settlment law induced by metro shield in red beds rock becomes very necessary to study the surface subsidence rule.Combining the research methods of theoretical analysis, field measurement and numerical simulation, this paper use the construction of Wangkang shield tunnel---one branch of Guangzhou metro line 14 as the research object to investigate the rule of surface subsidence induced by metro shield under red beds rock geological conditions. The main contents are as follows:(1)I summarizes predecessors’ research results and theories, analyzes the mechanism and laws of surface subsidence in red beds rock induced by shield construction.(2)I use Guangzhou metro line 14 feeder wang kang shield interval as the research background, using the three-dimensional finite element analysis software MIDAS/GTS to simulate and analysis shield tunnelling construction, comparing the result of numerical simulation analysis with the measured surface monitoring data;(3)According to red beds rock geological features, I studied ground surface settlement law under different mining pressures, grouting thickness, tunnel overburden soil thickness, shield tunnel excavation methods, then I analysis the time duration of ground surface settlement and its influence scope.(4)I briefly analysis the control technology of ground deformation in red beds rock.