Study And Analyze On Advanced Small Pipe's Support Parameters And Application In Weak Surrounding Rock Tunnel

The advance support is often used for the surrounding rock's pre reinforcement treatment in the process of tunnel construction under the condition of weak surrounding rock.Advanced small pipe,an important way to advance the tunnel support.Its position in tunnel construction will become more and more important in the future.The tunnel construction method becomes more and more mature presently while many problems have been exposed in the weak surrounding rock's advance support.In order to ensure the safety and effectiveness of tunnel excavation under the condition of weak surrounding rock,it is necessary to carry out further research on advance supporting technology.This paper modifies the defects of the existing specifications about the design parameters of advanced small pipe through extensive research and access to relevant literature at home and abroad under the background.This paper will study the following contents of advanced small pipe.1)A comprehensive review of the existing advanced support means for supporting and advanced small pipe reinforcement technology basic situation,applicable conditions,arrangement form,structural characteristics and application status are introduced in detail.2)Analyze on the action mechanism of the advanced small pipe base on the deformation and failure characteristics of the weak surrounding rock.Analyze on the mechanical behavior of the advanced small pipe base on the Winkler elastic foundation beam theory.3)Introduce several main design parameters according to the relevant regulations.Numerical analysis of the advanced small pipe design parameters by using MIDAS/GTS.Study on the effects of different support parameters on the advance support.Optimize on four parameters of advanced small pipe that is:diameter,ring spacing,length and extrapolation angle.4)Analyze on the excavation process of weak surrounding rock tunnel and study on the effect of advance small pipe in the process of tunnel excavation.5)Analyze on the combined strengthening effect of advanced small pipe and advanced bolt of tunnel face by using Midas/GTS.Compaer with the support effect of combined reinforcement measures and the advanced small pipe.