Contrastive Analysis On The Construction Methods Of Tong Luochuan Loess Tunnel

According to 45 loess tunnels, a analysis is proposed in this paper about surrounding rock condition, construction method, major diseases. Taking the TONG LUOCHUAN tunnel as background, two different construction ways are analyzed and constrasted by numerical simulation method and in-situ testing. The study work is summarized as follows:(1) According to the investigation and analysis of loess tunnels, many scientific papers and loess tunnel-related research reports are gathered. By the data, a table of the information for 45 loess tunnel are made to summarize the rules about surrounding rock condtion, construction method and major diseases.(2) Two different construction ways—CD and curve drift heading—are analyzed by FLAC. The construction condition is analyzed for stress, displacement, plastic zone and force characteristics . The result shows that the construction effect of curve drift heading method is better. The displacement value caused by curve drift heading is smaller the ones caused by CD ;As for the stress value and the range of stress , curve drift heading method is better than CD method; Force characteristics of shotcrete and blot also shows that drift heading method is better than CD method. But, plastic zone caused by curve drift heading is larger the one caused by CD.(3)Based on the site monitoring data, the deformations of the surrounding rock are analyzed in detail .the result shows that curve drift heading vertical displacement and level displacement is smaller than CD. the values caused by the two methods are higher than normative values, espcially vertical displacement.Superiority-inferiority of the two construction ways comprehensively evaluated in the paper. Based on the analysis and constrast, proper exeavation method is recommend for corresponding conditions.