Study on Damage Evolution Law of Rock Mechanics Parameters Under Water-Rock Interaction

The open pit locating in Cangshang was closed in 2005 because the reusing of pumping water resulted in the cyclic change of slope water level. In order to study the influence of water level fluctuation on mechanics parameters of the slope rocks, two kinds of typical rocks are selected to have the uniaxial compression tests of different saturation-dehydration circulation. The damage evolution law of rock mechanics parameters under water-rock interaction is found, whose results show that the mechanical properties of rock are weakened obviously by the water-rock interaction. In addition, the stronger the water-rock interaction becomes, the more obvious the weakening phenomenon is. Due to the different sensitivity to various parameters of water-rock interaction, the extent of elastic modulus decrease is the largest and uniaxial anti-compressive strength takes the second place while Poisson's ratio is essentially constant. Moreover, the uniaxial compressive strength and modulus of elasticity present exponential distribution with times of saturation-dehydration circulation. With the increase of the saturationdehydration times, the damage value increases accordingly while the increment tends to zero. Generally, the rock mechanical properties are hardly affected by water-rock interaction in the latter period; there are differences among the damage degree of various qualities of rocks, the better the quality, the smaller the damage, and the less the times reaching 95% limit damage value.