Strength and Failure Characteristics of Natural and Water‐Saturated Coal Specimens under Static and Dynamic Loads

Abstract

Rock bursts occur frequently in coal mines, and the mechanical properties of saturated coal specimens under coupled static‐dynamic loading need to be studied in detail. Comparative tests of coal specimens having different water content under static and static‐dynamic loading are conducted using the split Hopkinson pressure bar (SHPB) and RMT‐150C test systems. The results demonstrate that the natural specimen strength is greater than that of seven‐day (7D) saturated specimens under both uniaxial compression and triaxial static compression loading; however, the dynamic strength of 7D saturated specimens is lower than that of natural specimens under one‐dimensional static‐dynamic loading. The particle size of the 7D saturated specimens is relatively small under uniaxial static compression and one‐dimensional static‐dynamic loading, and the specimen particle sizes before and after static triaxial loading tests and three‐dimensional static‐dynamic loading tests do not exhibit an obvious difference.