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

Abstract

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 (β) from 0° to 90° at 15° intervals were heated to 200, 300 and 400 °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 β increasing from 0° to 90°; the total damage variable Dt (function of temperature and load applied) tends to increase first and then decrease with β increasing from 0° to 90°; the elastic modulus of specimen is lower with β of 45° or 60° than others. (b) When β is the same, the UCS of specimen tends to increase first and then decrease with the experienced high temperature increasing from room temperature (25 °C) to 400 °C; the elastic modulus is the lowest for specimen after temperature of 300 °C; the total damage variable Dt for specimen after temperature of 25 or 200 °C is generally lower than specimens after higher temperatures.