THE MECHANICAL PROPERTIES OF NINE KINDS OF ROCKS IN BEIJING, TIANJIN, TANGSHAN AND HUAI-LAI AREAS UNDER THE UPPER CRUSTAL TEMPERATURE AND PRESSURE

The nine kinds of rocks in Beijing, Tianjin, Tangahan and Huailai areas have been tested under the upper crustal temperature and pressure to study their mechanical propertis. We mainly determined the critical limitation stress, such as elastic limit stress, peak stress and main fault throughout stress and the corresponding criticaL strains. On the basis of these data, the regularities of rock strengthes, instability patterns and stress-strain curves of nine kinds of rocks have been discussed and a general conclusion aboutffects of different kinds of rock mechanical properties on earthquake preparaeion process is given.