Abstract: When the rock is difficult to cut and support in fracture zones,forepoling is usually used as auxiliary reinforcement support.In order to study the arch structure mechanism of bolt forepoling in surrounding fractured rock and its displacement evolution,bolt forepoling at the Ramp 230 in Wupin Zijin Mining Company was taken as an example,and the displacement evolution of the arch structure,which is taken as a flawed one,was analyzed on the basis of the buckling theory and the membrane theory.This study improves the simplification problem of reinforced arches.