岩石冻融荷载耦合试验及物理力学特性研究

Study on physical and mechanical characteristics of rocks during freeze-thaw and load coupling test

以寒区工程建设为需要,选取两种岩石分别在自然状态和冻融状态下进行物理力学试验,得到块体密度、抗压强度、抗拉强度、弹性模量等基本物理力学参数,获取不同状态下的典型岩石应力-应变曲线。对两组试验结果进行对比分析,结果表明,冻融状态下岩石强度减弱,承载能力下降是多重因素作用叠加的结果;冻融损伤程度与岩石接触面的距离有关;受冻融损伤影响,岩石弹性性能下降,弹性模量减小,冻融损伤劣化具有不可逆性;冻融岩石内部损伤引起岩石直径收缩过程中,泊松比不断减小,甚至可能出现负值。

In order to adapt the development of construction in cold regions, two types of rocks selected from cold area are tested under the conditions of freeze-thaw and nature state respectively. Then the typical stress-stain curve and essential parameters of rocks are presented such as density, compressive strength, tensile strength, mod- ulus elasticity, etc. Comparing with two groups of experiments, analysis of test result shows that intensity attenua- tion of frozen-thawed rocks and the low hearing capacity are the effect of various factors. The extent of damage in rocks is related to the distance between rock interface and damage location. Further, as a result of freeze-thaw, elas- tic properties are weakened and the rock-degradation and deterioration are irreversible. Finally, the contraction of di- ameter due to the degradation is founded, which impacts the reduction of Poisson^s ratio, even ends with a negative value.