Study on Dynamic Deformation Rules and Control Technology of Surrounding Rock for Tunnel

Based on existing research results and the Japanese Guipu tunnel surrounding rock deformation test,and combined with Zhengzhou-Xi'an Passenger Dedicated Line's engineering practice of large deformation of loess tunnel surrounding rock in the large cross section,this paper elaborates the dynamic deformation rules of surrounding rock deformation under the influence of tunnel construction,proposes the technical points and measures for surrounding rock deformation control and makes the appropriate recommendations.The results indicate that: after excavation,the deformation can be divided into three forms: displacement in front of the tunnel face,on the tunnel face and behind the tunnel face;and these displacements occur simultaneously.The controlling of the excavation face instability,unstable vault,arch springing submersion and large deformation is the key factor for tunnel surrounding rock deformation control.Excavation process control and auxiliary construction method control is the emphasis;especially how to close the primary support timely and how to select auxiliary construction method reasonably are the crucial point.