SEM tests were conducted on four kinds of typical deep rocks in Meilinmiao Mine, and the micro properties were analyzed. The particles of gritstone are unbroken and particle diameter ranges from 80 lam to 400 pro, and the void between particles is wide. The macroscopic failure of gritstone is caused by breakage of the dung distributed between particles, and po- tassium feldspars contained in gritstone are not leached. The failure of medium sandstone is caused by micro cracks distributed in sandstone particles, and potassium feldspars are leached seriously, so the pores penetrate each other and there is close hy- draulic connection in medium sandstone. The particles of fine sandstone are broken, and the particle diameters range from 60 pm to 300 pm, which determines the pores have good connectivity between particles. The dolomites contained in fine sand- stone are corroded, and the micro fracture form belongs to inter-granular fracture. There are no particles and blocks in micro- structure of sandy mudstone, but there are diverse micro cracks. The failure of mudstone arises from the extension of micro cracks, and the microstructure is different from the other three kinds of sandstones obviously.
Ren-Liang SHAN Li-Wei SONG Yan LIU Wen-Feng ZHAO Hui-Xian CHEN
