冻融循环作用下腐蚀黄砂岩失稳破坏预警研究

Study on early warning of instability failure of corroded yellow sandstone under freeze-thaw cycle

为研究预制裂隙黄砂岩的力学特性和破坏预警,将含2条贯通性平行裂纹的黄砂岩试样在不同冻融循环次数条件下分别经过化学腐蚀处理后进行双轴压缩试验,并采用数字图像相关技术(DIC)和红外热像技术实时监测岩石试样的变形破坏过程。结果表明:黄砂岩试件的强度随冻融循环次数的增加而降低,碱性溶液对冻融循环造成的劣化起到抑制作用;黄砂岩试件的破坏模式主要由翼型裂纹和剪切裂纹构成,翼型裂纹萌生于预制裂隙端部,剪切裂纹在翼型裂纹沿轴向向两端扩展及贯通过程中出现;结合应变局部化带对应裂纹出现的潜在位置与红外辐射温度的前兆异常,可以对岩石的破坏进行预警。

In order to study the mechanical properties and failure early warning of prefabricated fractured yellow sandstone,the biaxial compression test was carried out on the yellow sandstone specimens with two penetrating parallel cracks which treated by chemical corrosion under different freeze-thaw cycles.Digital image correlation technology(DIC)and infrared thermal imaging technology were used to monitor the deformation and failure process of rock samples in real time.The results show that:the strength of the yellow sandstone specimen decreases with the increase of the number of freeze-thaw cycles.The alkaline solution inhibits the deterioration caused by the freeze-thaw cycles.The failure mode of the yellow sandstone specimen is mainly composed of airfoil cracks and shear cracks.The airfoil cracks are initiated at the end of the prefabricated cracks,and the shear cracks appear when the airfoil cracks expand and penetrate through the two ends along the axial direction.Combined with the potential location of cracks corresponding to the strain localization zone and the precursory anomalies of infrared radiation temperature,early warning of rock damage can be made.