Study on delamination characteristics and mechanical properties of cemented waste rock backfill with rubber aggregation

Abstract

Since some phosphorus mines use raw ore as a product and do not conduct beneficiation around the mines. This makes it difficult for the amount of waste rock to prepare enough backfill for the filling of underground mined-out areas. Using rubber particles made of waste tires to replace part of the waste rock aggregate (WRA) can not only solve the problem of insufficient WRA, but also improve the environmental problems caused by the large accumulation of waste tires. However, due to the small density of rubber and high density of waste rock, the phenomenon of segregation delamination may occur in the cemented backfill, thus affecting the mechanical properties of cemented waste rock backfill (CWRB). To this end, the effect of rubber aggregate (RA) on the segregation delamination of CWRB was determined by using the section image analysis method of specimens, and the quantitative index of segregation delamination of cemented waste rock backfill with rubber (CWRB-R) was constructed. The mechanical properties and failure characteristics of CWRB-R were studied by acoustic emission (AE) test under uniaxial compression condition. The experimental results showed that the segregation delamination characteristics of CWRB-R were related to the mass concentration. The higher the mass concentration, the weaker the degree of segregation stratification of the aggregate, the more uniform the distribution of the aggregate, and the less the strength loss of CWRB caused by the incorporation of RA. The incorporation of RA in CWRB not only reduced the uniaxial compressive strength (UCS) of the backfill, but also caused more cracks to be produced during the failure process of the backfill, and the failure form changes from brittle failure to ductile failure.