高温作用后黄砂岩三轴压缩及细观破裂机制

Triaxial Compression and Meso Fracture Mechanism of Yellow Sandstone after High Temperature

为了研究高温损伤作用后黄砂岩的压缩力学性质和细观破裂机制的变化情况,对高温损伤作用后的黄砂岩进行三轴压缩实验,并对黄砂岩压缩断口进行扫描电镜(scanning electron microscope,SEM)试验,系统地分析了高温损伤对黄砂岩压缩破坏特征、压缩强度及断口细观特征的影响。通过三轴压缩实验发现:随着轴压的不断增加,温度对于黄砂岩整体强度影响更为明显;初始高温损伤程度的增加,黄砂岩三轴抗压强度呈现出先上升后下降的趋势,塑性应变程度增加;细观断口形貌主要以脆性断裂为主,局部范围内存在韧性断裂,随着温度的增加,晶体结构内部中裂纹发育更为完整,从而导致岩石宏观破坏越严重。

In order to study the changes of compression mechanical properties and meso fracture mechanism of yellow sandstone after high temperature damage,triaxial compression tests were carried out on yellow sandstone after high temperature damage,and sca-nning electron microscope(SEM)tests were carried out on compression fracture of yellow sandstone.The effects of high temperature damage on compression failure characteristics,compression strength and meso fracture characteristics of yellow sandstone were syste-matically analyzed.Through triaxial compression test,it is found that with the increasing of axial pressure,temperature has more obvious effect on the overall strength of yellow sandstone.With the increase of initial high temperature damage degree,the triaxial compressive strength of yellow sandstone first increases and then decreases,and the degree of plastic strain increases.The micro fracture morphology is mainly brittle fracture,and there is ductile fracture in local range,with the increase of temperature In addition,the crack development in the crystal structure is more complete,which leads to more serious macro damage of rock.