Experimental Study on Acoustical Properties and Mechanical Properties of Coal Roof Sandstone

摘要

The acoustical experiment and the mechanical experiment of the coal roof standstone specimens in No.3 coal mine in Hebi under high temperature and after high temperature were introduced. The results show that the varying tendency of the longitudinal wave velocity after high temperature is concordant with that of under high temperature. The longitudinal wave velocity declines as temperature rises, but the obviously declining temperature point is different. The peak strength of sandstone under high temperature declines as temperature rises. The mechanical properties of sandstone are static before 400°C, and the shape of stress-strain curves is same. But the discreteness of stress-strain curves increases after 400°C. The failure state of sandstone is shear and expansion failure after the uniaxial compression. The peak strength, elastic modulus and deformation modulus decline as temperature rises after high temperature. The failure state of sandstone after high temperature is mainly that the cracks are tensed. It has many failure planes but do not form main shear failure planes.