Determining the deformation properties of crushed rock under compressive compression conditions

Abstract

The object of this study is the process that forms fill materials from crushed rock under load for managing the condition of side rocks in a coal-bearing massif with preparatory workings. Deformation properties of crushed rock under laboratory conditions were evaluated on the basis of a study of compressive compression of the fill material. It was registered that there is a quadratic functional dependence between the change in the bulk density of crushed rock of different granulometric composition and the specific potential energy of deformation. It was experimentally established that the specific potential energy of deformation reaches the limit values at the maximum compression of crushed rock when the fill material consists of parts of different sizes. For experimental samples with different thickness of the rock layer h0 (m), there was a linear relationship between their longitudinal deformation Dh (m) and the external load F (kN), which determined the behavior of the deforming body at critical levels. Under such conditions, with a relative change in the volume of the fill material dV=0.36, that is, with the same relative deformation at any values of the parameter h0 (m) and the compaction coefficient of the crushed rock kcon=1.57, the maximum stiffness of the rock supports was ensured. With a limited amount of external static load on the experimental samples, in the process of their deformation when the parameter h0 was reduced by 2 times before their compression, the compaction coefficient of the crushed rock increased from kcon=1.33 to kcon=1.57. At the same time, the specific potential energy of deformation increased by 40 %, which made it possible to ensure the maximum rigidity of the fill material at the minimum value of the longitudinal deformation Dh (m) of the experimental samples