Experimental study on the uniaxial compressive strength of artificial jointed rock mass specimen after high temperatures

The mechanical properties of rock mass specimen with a single joint plane after high temperatures were studied by conducting uniaxial compressive strength (UCS) testing on the artificial jointed rock mass specimens. Specimen sets with selected dip angles of artificial joint plane (beta) from 0A degrees to 90A degrees at 15A degrees intervals were heated to 200, 300 and 400 A degrees C and then tested for UCS after being cooled to room temperature. Test results show that (a) after experiencing a same high temperature, the UCS of specimen tends to decrease first and then increase gradually with beta increasing from 0A degrees to 90A degrees; the total damage variable D (t) (function of temperature and load applied) tends to increase first and then decrease with beta increasing from 0A degrees to 90A degrees; the elastic modulus of specimen is lower with beta of 45A degrees or 60A degrees than others. (b) When beta is the same, the UCS of specimen tends to increase first and then decrease with the experienced high temperature increasing from room temperature (25 A degrees C) to 400 A degrees C; the elastic modulus is the lowest for specimen after temperature of 300 A degrees C; the total damage variable D (t) for specimen after temperature of 25 or 200 A degrees C is generally lower than specimens after higher temperatures.