Study on the Mechanical Properties of Backfill Cream-Body during Coal Mining

Abstract

In order to research the mechanical properties of the backfill cream-body under engineering conditions in the coal mine, the uniaxial compression test of backfill cream-body with different ages abtained from the filling locale of Daizhuang coal mine is conducted with MTS815.03 rock test system. The characteristics of backfill cream-body in the limited space and a certain environment are studied. Research shows that, the strength of backfill cream-body is high, but coagulability is bad and the discreteness of mechanical properties is different; Uniaxial compressive strength is 2.3 ~ 13.17 MPa and the average is 5.436 MPa; The elastic modulus is very low ,which is only 53.66 ~ 2614.35 MPa and the average is 645.14 MPa. The deformation is bigger when absorbing load; Poisson's ratio is low, which is only 0.0001 ~ 0.2112 and the average is 0.0265, which indicates that the backfill cream-body doesn't need the space of transverse deformation when bearing compression deformation; The mechanical parameters of backfill cream-body with different ages are fitted and regressed. Test results is important to control surface mining subsidence effectively, liberate the coal resources under buildings, railways and waterbodies and protect the ecological environment.