摘要
为了探究动态载荷下大理岩的断口形貌特征,本文先利用分离式霍普金森压杆对岩样进行不同弹速下的冲击压缩和动态劈裂试验。接着,采用钨丝灯扫描电镜对岩样断口形貌进行细观观察,对比分析了不同试验条件下岩样的断裂模式。最后,引入分形维数定量表征了岩样断口细观形貌及其粗糙程度与冲击弹速间的内在关系。结果表明:在动态载荷下大理岩断口呈脆性特性,其基本断裂模式为沿晶断裂或穿晶断裂;高弹速冲击下,岩样断裂花样变小变密,表面附着岩粉趋多;相对于动态劈裂试验,动态压缩后岩样的破碎程度要高,断口花样中穿晶断裂形式所占的比重较大;随着弹速的增加,动态劈裂和动态压缩断裂模式均由耗能较低的沿晶断裂向耗能较高的穿晶断裂转变,分形维数值相应增大,但动态劈裂试验中分形维数值比动态压缩试验的应变率敏感性更加明显。
To investigate the fracture morphology characteristics of marble under dynamic loading,the dynamic compression and splitting tests of rock samples under different impact velocities are carried out using the split-Hopkinson pressure bar.The fracture morphology of the rock samples is observed by tungsten filament lamp scanning electron microscope,and the fracture modes of the rock samples under different test conditions are contrastively analyzed.Finally,the fractal dimension is adopted to quantitatively characterize the internal relationship of the fracture morphology and roughness of the rock sample with the impact velocity.The results show that the dynamic fracture of marble is brittle and its basic fracture mode is the intergranular fracture or transgranular fracture.Under the high impact velocity,the fracture patterns of the rock samples become smaller and denser,and the rock powers adhered to the surface increase.Compared with the dynamic splitting test,the fracture degree of the rock sample after dynamic compression is higher,and the proportion of transgranular fracture in fracture pattern is larger.With the increase of impact velocity,the fracture mode of dynamic splitting and compression changes from the intergranular fracture with low energy consumption into the transgranular fracture with high energy consumption,and the fractal dimension value grows correspondingly.However,the fractal dimension value of the dynamic splitting test is more rate-sensitive than that of the dynamic compression test.
作者
王伟祥
王志亮
贾帅龙
卢志堂
WANG Weixiang;WANG Zhiliang;JIA Shuailong;Lu Zhitang(School of Civil and Hydraulic Engineering,Hefei University of Technology,Hefei,Anhui 230009,China;School of Resource and Environmental Engineering,Hefei University of Technology,Hefei,Anhui 230009,China)
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2022年第3期118-124,共7页
Hydrogeology & Engineering Geology
基金
国家自然科学基金雅砻江联合基金项目(U1965101)
国家自然科学基金项目(51579062,41807266)。
关键词
大理岩
动态试验
断口形貌
扫描电镜
分形维数
marble
dynamic test
fracture morphology
scanning electron microscope
fractal dimension
