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Abstract Based on 1∶1 load test of the tunnel lining vault，the relationship between lining crack depth and lining stiffness is established；and a beam-spring model is put forward to calculate the stiffness of lining crack. Using the beam-spring model，the effects of crack location，crack depth and strata resistance on bearing capacity of lining structure are analyzed. The calculation results show that the tunnel vault safety factor reduces linearly with the increasing crack depth；when crack depth is 50% of lining thickness，the safety factor is reduced by 78%. Under the same crack depth，cracks in the vault are most disadvantageous；cracks in the arch of the waist，side wall or arch foot，the influence on safety factor is smaller. The effects of strata resistance on safety factor of the vault，side walls and arch waist are larger；but the effect on safety factor of the feet of arch is smaller.
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Received: 31 March 2012
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2012, Vol. 31 
