Abstract:

 The existing statistics show that serious damages caused by shear strength during earthquake will appear when tunnels cross active fault zones. The tunnel structures cannot withstand  large dislocations (over 1 m). Accordingly, to establish a key technology system of railway tunnels crossing active fault zones, the seismic damage characteristics of Daliang tunnel are analyzed through field investigation, and the deformation and failure mechanism of tunnel crossing active fault zone are examined by model test and numerical simulation. The results show that: (1)The existing antiseismic technology and engineering measures adopted for railway tunnels can guarantee the stability of tunnel structures in the portal, shallowly buried, and inactive fault zone sections during an earthquake, but there is not reliable tunnel structure can withstand largescale (meter level) dislocations. (2)Based on the results of earthquake damage investigation, the fortification zones of tunnels crossing the active fault zone are proposed through theoretical analysis. (3)The damage of tunnels crossing the active fault zone primarily concentrates on areas severely and generally impacted by the active fault dislocation, so fortification should be employed separately according to the different earthquake damage mechanisms. (4)Based on theoretical analyses and literature researches, a new multistage shock absorbing structure and a rapid recovery plan are proposed for the railway tunnels cross the active fault zone.

Key words:

active fault zone, railway tunnel, antiseismic technology, rapid recovery scheme