Compaction characteristics test of broken rock in initial lateral pressure

Through rigid testing machine combined with coal-rock compaction bearing device made by ourselves in ini- tial variable lateral pressure,a compression bearing test was operated on four groups of twelve broken rock specimens in different initial lateral pressures. The axial stress-strain characteristics of broken rock in initial lateral pressure were analyzed,the relationships between initial lateral pressure and broken rock deformation,compaction,were determined, and the axial strain laws of broken rock were respectively studied in variable lateral pressure and in different initial one. The results showed that the larger the initial lateral pressure was,the more obvious the stress-strain curve deflec- tion of broken rock was,and the more smoothness of the stress-strain curve,the smaller the gap between the gravel par- ticles was,the blunter the angle was,the larger the load on broken rock was. Axial broken-rock strain and transverse one decreased with initial lateral pressure increase,axial strain rate and transverse one were respectively 1. 74 ∶ 1. 65 ∶ 1. 39 ∶ 1 and 2. 51 ∶ 2. 23 ∶ 1. 72 ∶ 1 in four different initial lateral pressures. The larger the initial lateral pressure on broken rock was,the less the compaction coefficient was,and quadratic polynomial can represent the relationship between initial lateral pressure on broken rock and compaction coefficient. Variable lateral pressure increased with axi- al strain increase,the larger initial lateral pressure was,the less the curve slope was,and axial strain and variable later- al pressure showed linear positive correlation. The larger the initial lateral pressure was,the less the variable lateral pressure on broken rock were,quadratic polynomial can represent the relationship between initial lateral pressure and variable lateral pressure,and the reasonable initial lateral pressure was benefited to broken rock bearing stability.