Numerical Simulation Of Reasonable Pile-Pitch Spacing Of Slope Of Tunnel With Anti-slide Piles

During the construction of mountain tunnel,landslides may occur due to the influence of geological structure and external factors.During the construction and operation of tunnels,problems such as initial lining cracking,collapse or collapse,secondary lining cracking,disturbance deformation or collapse often occur,which directly affect the construction and operation safety of tunnels.When anti-slide piles are used to treat these diseases,when the distance between anti-slide piles and tunnel structure is small,anti-slide piles will squeeze the tunnel and increase the landslide thrust acting on the tunnel lining structure;if the distance between piles and tunnels is large,the soil between anti-slide piles and tunnel structure may slide relatively and form a secondary landslide,which will produce a very large impact on tunnel structure.From this,it can be seen that the distance between anti-slide pile and tunnel structure is one of the key factors for successful landslide control.The relative position relationship between tunnel and landslide is also the key factor affecting landslide treatment.Based on the orthogonal system of tunnel-landslide,this paper divides the relative position relationship between tunnel and sliding surface into three kinds:tunnel intersects with sliding surface,tunnel lies above sliding surface and tunnel lies below sliding surface.From this,the mechanical model of tunnel structure corresponding to it is ed:lateral shear type.Ship-riding smooth type and vault disturbance type.Pile-tunnel spacing is very sensitive to the relative position relationship between tunnel and sliding surface.Therefore,in this paper,the interaction mechanism between landslide,tunnel and anti-sliding pile will be studied,and the effect of pile-tunnel spacing between anti-sliding pile and tunnel structure on the sensitivity of the change of the relative position relationship between tunnel and sliding surface will be emphatically studied.In order to further study,this paper will establish a three-dimensional finite element model on the basis of the above tunnel analysis combined with an example of tunnel collapse at the entrance of a Expressway in Zhangjiajie,and analyze the sensitivity of the distance between anti-slide pile and tunnel structure to the change of the relative position relationship between tunnel and sliding surface,so as to determine the optimal distance between piles and tunnels.The main research work is as follows:(1)Summarize the landslide formation mechanism,inducing factors and the main factors of tunnel deformation.The types of tunnel-landslide system are briefly classified,the corresponding geomechanical models are summarized,and the stress and deformation characteristics of the tunnel are analyzed.(2)Using Midas/GTS software,the relationship between different relative positions of tunnel and sliding surface is analyzed,and reasonable spacing between piles and tunnels is obtained.(3)Taking the Ma Liya Tunnel Project of Zhang-Sang Expressway as the background,the engineering characteristics of stratum lithology,hydrogeology and geological structure in the tunnel site area are analyzed and summarized,and the practical engineering is analyzed by Midas/GTS software,and the optimal spacing between piles and tunnels is obtained.