Abstract：Based on the Mohr-Coulomb criteria and the direct addition principle of stress，the stress intensity criteria of earthquake breakage of frozen roadbed is proposed by introducing in two basic concepts of average normal stress and deviatoric stress，in which the coupling effect of dynamic shearing stress，dynamic normal stress of earthquake，and static normal stress and static shearing stress of soil self-gravity are considered. It is testified that the stress intensity criteria of earthquake breakage is reliable by a computation example of representative frozen roadbed section from Qinghai—Tibet railway in China.
