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Abstract Experiments are carried out to study sandstone mechanical properties after high temperature under static and dynamic loadings by the SHT4206 electro-hydraulic servo-controlled testing machine and split Hopkinson pressure bar(SHPB) equipment，respectively. The differences of rock failure mode，peak strength and peak strain after high temperature under static and dynamic loadings are analyzed and compared systematically. The effects of temperature on rock mechanical properties are investigated from microcosmic angle. The results show that：(1) The dynamic and static mechanical properties of rock are different evidently. With the increase of temperature，the failure mode of rock exhibits splitting failure with brittle fracture under static loadings while the rock failure mode is tensile fracture under dynamic loading. (2) The peak strength decreases evidently with the increase of temperature in a nearly linear way under static and dynamic loadings. The average peak strength decreases from 126.37 to 64.76 MPa in an extent of 48.8% under static loading，as well as from 176.3 to 83.1 MPa in an extent of 52.9% under dynamic loading. (3) The peak strain increases with the increase of temperature under static and dynamic loadings. Thermal stress and variation of microstructure induce different mechanical properties of sandstone due to the effect of temperature. The different modes of internal crack propagation and formation of microcracks appear due to different loading methods，which results in the difference in resistance of deformation.
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Received: 01 August 2011
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2012, Vol. 31 
