酸性环境冻融循环对砂岩抗剪强度参数损伤效应

水化学条件与冻融循环的耦合侵蚀作用对寒区岩土工程的稳定性产生重要影响。选取砂岩为研究对象,开展不同水化学溶液以及冻融循环条件下的砂岩常规三轴实验,分析砂岩抗剪强度参数变化规律,定量分析砂岩抗剪强度参数的损伤特征。结果表明:砂岩抗剪强度参数值逐渐减小,劣化度逐渐增大,最大可达到73.06%、49.34%;抗剪强度参数值与冻融循环次数关系可定量表征为指数变化关系,得到砂岩抗剪强度参数变化规律。通过电镜扫描试验分析水化学与冻融循环作用对砂岩微观结构的变化规律,砂岩内部孔隙逐渐扩张、联通,岩石颗粒之间胶结松散,岩体结构呈现疏松多孔。研究为分析酸性冻融循环作用下砂岩力学参数劣化机制提供参考。

Damage effect of acid environment freezing- thawing cycles on shear strength parameters of sandstone

The coupling effect of water chemistry condition and freeze-thaw cycle plays an important role in the stability of geotechnical engineering in cold region. The sandstone is selected as the research object, and the conventional triaxial test of sandstone under different water chemistry and freezing and thawing cycles is carried out. The changing rules of shear strength parameters of sandstone are analyzed, and the damage characteristics of sandstone shear strength parameters are quantitatively analyzed. The results show that the shear strength parameter value of the sandstone is gradually reduced and the maximum degradation degree is 35.62% and 41.23% respectively. The relationship between the shear strength parameter value and the freeze-thaw cycle number can be quantitatively expressed as exponential relationship, Shear strength parameter. The microstructure of the sandstone is changed by the water chemistry and freezing - thawing cycle. The porosity of the sandstone is gradually expanded. The interstices are loose and the rock structure is loose and porous. The study provides a reference for the analysis of the deterioration mechanism of sandstone mechanical parameters under the action of acidic freeze-thaw cycles.