经化学溶蚀并高低温作用后砂岩的力学特性试验研究

EXPERIMENTAL RESEARCH ON MECHANICAL PROPERTIES OF SANDSTONE IN CHEMICAL CORROSION UNDER HIGH OR LOW TEMPERATURE ACTION

选取四川黄砂岩为岩样,通过单轴压缩试验,研究砂岩在不同化学溶液（HCl溶液、NaOH溶液、水溶液）中浸泡后经高温,冻融循环后的力学特性,分析各溶液下砂岩的应力-应变关系、峰值应力、峰值应变、弹性模量等物理力学特性在经历不同高温、不同最低冻结温度后的变化规律,从微观力学和化学机理的角度探究砂岩的损伤机理。试验结果表明：冻结温度的降低会对砂岩造成一定的损伤劣化;-40℃以后,砂岩表面孔洞和坑蚀逐渐增多,损伤劣化程度逐渐增大,HCl溶液对冻融损伤劣化有一定的促进作用。高温会使得砂岩表观形态发生改变,延性逐渐提高;600℃时,砂岩的弹性模量和峰值应力达到最大,然后随温度的提高而降低。

The mechanical properties of yellow sandstone collected from the Sichuan Province,China were studied through the uniaxial compression tests after the sandstone was socked in different chemical solutions（HCl solution,NaOH solution,and water） and withstood the effect of high temperatures action and freeze-thaw cycles socked in different solutions. The variation of mechanical properties such as stress-strain curves,peak stress,peak strain,elastic modulus of sandstone in three solutions under different high temperatures and different minimum freezing temperatures were analyzed. The damage mechanism of sandstone was analyzed according to the micromechanics and chemical mechanism. The test results showed that falling freezing temperatures could cause damage and deterioration of sandstone. Below-40 ℃,the pores on the surface of sandstone gradually increased and the degree of damage and deterioration gradually increased. Besides,HCl solution played a certain role in promoting the damage of freeze-thaw damage. High temperature could change the surface appearances of sandstones and gradually increased the ductility of sandstone. The elastic modulus and peak stress reached the maximum in samples exposed to 600 ℃,after which the elastic modulus and peak stress decreased.