化学溶液和冻融循环作用后白砂岩三轴压缩力学性能试验研究

Experiment on mechanical property of triaxial compression of white sandstone after effect of chemical solution and freeze-thaw cycle

研究了不同溶液(H2O和HNO3溶液)浸泡与干燥状态下经冻融循环作用后白砂岩的力学性能。根据试验结果分析了白砂岩基本力学性能的变化规律;从微观方面出发,探讨了不同溶液浸泡和冻融循环对白砂岩的损伤破坏作用。研究表明:经过酸浸泡-冻融、水浸泡-冻融和只经冻融处理后的白砂岩峰值应力均有不同程度的降低,经过酸浸泡-冻融组的白砂岩峰值应力降幅最大,水浸泡-冻融组降幅次之,说明溶液浸泡和冻融循环对白砂岩均有损伤劣化作用。只考虑溶液影响时,硝酸溶液对白砂岩的损伤程度最大。前期处理条件相同的情况下,随着围压的增加,白砂岩的抗压强度和塑性变形随之增大。相同围压条件下,白砂岩达到峰值应力时的变形和弹性模量的损失率随前期处理对白砂岩的损伤程度增加而增大。

The paper studied the mechanical property of white sandstone in different solution ( H2 O and HNO3 ) and dry state after the effect of freeze-thaw cycles.It analyzed the change law of mechanical prop-erties of the white sandstone based on the experimental results ,and discussed the damage effect of differ-ent soaking solution and freeze-thaw cycles on the white sandstone from microscopic view .The results in-dicated that chemical solution and freeze-thaw cycles reduce the peak stress of white sandstone .the peak stress of white sandstone with freeze-thaw and acid soaking is reduced mostly , and that with freeze-thaw cycles and water soaking is the next , which illustrated that all the processing methods have damage effect on white sandstone .And HNO3 solution has the biggest damage effect on white sandstone when only con-sider the impact of solution .Under the same preprocessing conditions , the compressive strength and the plastic deformation of white sandstone increase with the increase of confining pressure .In the same confi-ning pressure , the loss ratio of deformation at peak stress and elastic modulus increases with the damage degree due to the preprocessing of white sandstone .