摘要
在MTS试验系统和Hopkinson压杆装置上添加不同倾角的垫块,对山东花岗岩进行3种应变率(3×10-5,50和100 s-1)下倾角为0°,15°,30°,45°和60°五种加载路径的压剪联合加载实验研究。结果表明:花岗岩的法向和切向模量都有一定的加载路径敏感性(即压剪耦合效应)和明显的应变率效应;其中花岗岩的法向模量对剪切应力很敏感;同时,花岗岩的破坏强度也具有明显的加载路径敏感性和应变率效应。应用Drucker-Prager准则拟合了不同加载速率下的破坏面,拟合结果初步揭示了岩石的内摩擦角和黏聚力等强度参数有一定的加载速度效应。基于数字图像相关方法对上述加载过程进行系统的监测和分析,发现岩石动态压剪过程实际上由剪切应变主导,岩石从准静态加载到动态加载,试件内起主导作用的因素由拉应变逐渐过渡到剪应变,这是由岩石材料本身的不均匀性决定的。
By adding cushions with designed oblique surfaces to MTS system and to split Hopkinson pressure bar(SHPB) device,a series of experiments were conducted to investigate the quasi static(strain rate 3×10-5 s-1) and dynamic(strain rate 50 and 100 s-1) responses of Shandong granite under combined compression-shear loading. Five oblique angles,i.e. 0°,15°,30°,45°and 60°,were investigated in the present study. The results showed that both normal and shear modules exhibited the strain rate effect and certain path-load dependency,which revealed the coupled compression-shear effect. The normal modulus was the most sensitive to the shear stress. The failure strength of granite exhibited strain rate effect and path-load dependency. Employing the Drucker-Prager(D-P) criterion model to simulate the failure surfaces of Shandong granite at different loading rates,the strain rate effects of strength parameters,e.g. the inner friction angle and inner cohesion,were analyzed. Digital imaging correlation(DIC) method was employed to systematically analyze the displacement field and strain field. The results showed that the process of dynamic compression and shear loading was controlled by the shear strain. For the rock specimens were compressed from quasi static loading to dynamic loading,the main cause of specimen deformation and failure were turned from the tensile strain to shear strain. All these were resulted from the non-uniformity of rock specimen.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2015年第10期1945-1958,共14页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(11272304
11472264)
关键词
岩石力学
分离式HOPKINSON压杆
压剪联合加载
数字图像相关方法
加载路径效应
花岗岩
rock mechanics
split Hopkinson pressure bar(SHPB)
combined compression and shear loading
digital imaging correlation(DIC) method
load-path dependency
granite
