On failure mode and shear behavior of rock mass with interlayer staggered zone

Because of existence worldwide of interlayer staggered zone,there have been many engineering rock mass stability problems and geological disasters occurred over the world.In this paper,some cases of distortion failure or destruction of engineering rock mass structure induced by interlayer staggered zone are summarized.Rock mass structure controlling theory is adopted to categorize the failure modes of rock mass with staggered zone into tension crack failure,block-fall and interfacial shear slip failure.After that,it is shown that shear strength model is the main point when modeling for the mechanical behavior of interlayer staggered zone.A deep review of the existing test methods and the modeling theory for its shear behavior shows that the elasto-viscoplastic model is the fundamental constitutive model for describing the mechanical behavior of interlayer staggered zone.