富水全、强风化砂岩强度特性试验及本构关系探讨

摘要

According to the feature of sandstone weathered and absorbed water heavily, the authors analyzed the physical and mechanical properties and chemical composition of the sandstone experimentally, then studied influence of blasting disturbance, water content, sample bedding on stress-strain strength characteristics through uniaxial and triaxial compression tests, and found that the sandstone would become weak in the strength when it absorbed water, and its cohesion decreased and showed significant anisotropy while friction angle was not changed.After the sandstone underwent blasting, its uniaxial compressive resistance and elastic modulus decreased, and Poisson ratio increased. As the sandstone has obvious bedding properties, the strengths of sample obtained from two different loading directions are different obviously. Based on the stress-strain curves from the triaxial tests, the anthors found the stress-strain curves could be described well by the modified Duncan-Zhang model.%针对富水全、强风化砂岩的特点,进行了该砂岩的基本物理力学性质、化学成分实验,然后通过单轴、三轴压缩实验研究了爆破扰动、含水量、试样层理对砂岩应力-应变强度特性的影响.发现砂岩遇水软化,粘聚力大幅度降低,表现出显著的各向异性;爆破扰动后,岩石试样的单轴抗压强度减低,弹模减小,泊松比增大;由于砂岩具有明显的节理性,按两种方向加载所得到的岩石试样强度明显不同;根据实验所得应力-应变曲线特点,发现用修正的Duncan-Zhang模型可以很好地描述砂岩的前应力-应变曲线.