MESOSTRUCTURAL INVESTIGATION ON MARBLES UNDER UNIAXIAL CONPRESSION AT HIGH TEMPERATURES
WU Gang1，2，ZHAI Songtao3，LI Yushou2，WU Xueping3
(1. Chinese Underwater Technology Institute，Shanghai Jiaotong University，Shanghai 200231，China；2. State Key Laboratory for GeoMechanics and Deep Underground Engineering，China University of Mining and Technology，Xuzhou，Jiangsu 221008，China；3. Department of Civil Engineering，Shanghai Jiaotong University，Shanghai 200240，China)
Abstract：Exploring the effect mechanism of high temperature on rock，which will has important significance for solving the problems of high temperature rock engineering. The measurement of surface element distribution，the surface morphology and mesostructural analysis have been tested for Xuzhou marbles that failed under uniaxial compression at different temperatures (20 ℃，200 ℃，400 ℃，600 ℃，800 ℃ and experienced 400 ℃，600 ℃ and 800 ℃) using S–3000 N scanning electron microscopy made by Japan's Hitachi Ltd. A rational explanation in the mesoscopic level has been given on the characteristics of deformation，strength and failure of marble which experienced different temperatures. The test results show that the particles of Xuzhou marble are relatively thick，typical cleavage crack，cracks in part particle or between the particles at 20 ℃，while there are apparent fragmentations on the port surface，the particles become smaller，forms are more structured，and slender cracks exist in some areas at 800 ℃；The mesostructure of marbles that failed under uniaxial compression is quite different at high temperature and after high temperature. Generally the atomic percentage of marble doesn?t change significantly before 800 ℃；When temperature reaches 800 ℃，the weight percentage of elements of marble takes place more change. The weight percentage of Ca declines sharply and that of Si raises rapidly which indicate that the structure of marble perhaps occurs phase transition from crystalline to amorphous and results in the plummeting of the mechanical index of marble at 800 ℃.
2012, Vol. 31 
