水化学及冻融循环对砂岩物理力学特性试验研究

Experimental Study on Physical and Mechanical Properties of Sandstone by Water Chemistry and Freeze-Thaw Cycling

以寒区砂岩为研究对象,考虑水化学溶液的侵蚀和冻融循环的影响,开展不同酸性条件下岩石冻融循环试验,引入岩石损伤变量,定量分析砂岩力学损伤规律。结果表明:随着酸性增强及冻融循环次数的增大,砂岩的弹性模量、抗压强度逐渐减小,砂岩内部损伤逐渐增大;酸性条件与冻融循环的耦合作用加剧岩石的损伤,酸性最强条件下(p H=2),经历60次冻融循环试件弹性模量、抗压强度下降55.70%和54.57%;分析砂岩的弹性模量、抗压强度及损伤变量与冻融循环次数关系,定量关系可表征为指数变化关系。建立岩石力学参数损伤变量,对水化学冻融循环耦合机理进行研究,探究岩石力学性质的劣化机制。研究成果将为不同水化学条件下寒区工程长期稳定性分析提供试验依据。

Taking the red sandstone in cold area as the research object,considering the influence of water chemistry solution erosion and freezing and thawing cycle,the rock freezing and thawing cycle test under different acidic conditions was carried out,and the rock damage variable was introduced to quantitatively analyze the mechanical damage law of red sandstone. The results show that the elastic modulus and compressive strength of red sandstone decrease with the increase of acidity and the number of cycles of freeze-thaw cycles,and the internal damage of red sandstone increases gradually. With coupling of acid condition and freeze-thaw cycle. The compressive strength and elastic modulus of the red sandstone were decreased by 55. 70% and 54. 57% under the condition of the strongest acidity( p H = 2),respectively. The elastic modulus,compressive strength and damage variable of the red sandstone were analyzed. The relationship between the number of freeze-thaw cycles and the quantitative relationship can be characterized by exponential change. The damage mechanism of rock mechanics parameters ave established,and the coupling mechanism of freezing and thawing cycles ave studied,and the mechanism of rock mechanics ave explored. The research results will provide the experimental basis for the longterm stability analysis of the cold area under different hydrochemical conditions.