Abstract: Aiming at the problem of boundary force of the accumulation body in the post-disaster roadway, on the basis of the site investigation and on the premise of slip effect in the process of fragment accumulation, the calculation formula of boundary force of the accumulation body is derived, and the experimental verification is carried out. The results show that the collapse of roadway section in fault fracture zone is mainly filled with rock fragments, and the adjustment mode of “self-organization” in the process of fragment accumulation is divided into transverse movement adjustment, longitudinal movement adjustment and self-rotation adjustment. The force acting on the boundary of the accumulation body originates from the slip effect in the process of fragment accumulation, and the calculation formula of the passive resisting force in accumulation body boundary is derived, which is related to the bulk density of the block, the buried depth, the horizontal distance from the highest point of the accumulation body to the boundary and the stopping angle. The experimental results verify the correctness of the calculation formula, but the applicable condition of the formula depends on the ratio of particle size to the horizontal size of the accumulation body. The smaller the K value is, the more suitable the formula is.