Experimental study on the mechanical properties of rocks at high temperature

The mechanical properties of marble, limestone, and sandstone as well as the stress-strain curve, the varying characteristics of the peak strength, the peak strain and elastic modulus were studied by using the MTS810 Rock Mechanics Servo-controlled Testing System under the action of temperatures ranging from room temperature to 800°C Results show that (1) the peak strength and elastic modulus of marble fluctuate at the temperature from normal to 400°C; and they decrease gradually over 400°C (2) With the rise of the temperature, the peak strength and elastic modulus of limestone show downward trend from normal temperature to 200°C have little change from 200°C to 600°C and decrease sharply over 600°C (3) The peak strength of sandstone shows a downward trend while a little change for elastic modulus at normal temperature to 200°C and from 200°C to 600°C, the peak strength of sandstone increases while a little change for elastic modulus; the peak strength and elastic modulus decrease rapidly at the temperature over 600°C. (4) The peak strain of limestone shows little change at normal temperature to 600°C, however, the peak strain increases rapidly over 600°C; and for marble and sandstone, the peak strain decreases with the rise of the temperature from normal temperature to 200°C, the peak strain increases rapidly over 200°C. The result can provide valuable references for the rock engineering design at high temperature. Supported by the National Natural Science Foundation of China (Grant No. 50490273), the National Key Basic Research and Development Program of China (973 Project) (Grant No. 2007CB209400), and Xuzhou Institute of Technology (Grant No. XKY2007219)