EXPERIMENTAL RESEARCH ON MECHANICAL CHARACTERISTCS OF ROCK WITH CYCLES OF FREEING-THAWING ACTION

the rock failure due to freeze-thaw weathering is a main engineering problem which often occurs in the rock engineering in cold regions. The rock-degradation and deterioration mechanism and mechanical characteristics for three kinds of rocks have been studied through the cycle freezing-thawing test and the scanning electron microscope method. The mechanism of rock failure due to freezing and thawing is studied. The process of freezing and thawing failure of two basic deterioration modes of different nature rocks is studied by experiments. The two modes are the crack propagation degradation mode and the particle precipitation degradation mode. In order to providing reliable experimental foundation for studying the damage and fracture due to freezing and thawing and the construction and the safety operation of similar projects in cold region, the uniaxial compression tests of three types of rocks suffered from the different cycles of freezing-thawing action are conducted. The fitting relations of the uniaxial compressive strength with the cycles of freezing and thawing are formulated. Preliminary quantitative influence of the cycle of freezing and thawing to the rock strength attenuation has certain reference value.