摘要
采用基于细观损伤力学基础上开发的动态版RFPA2D数值模拟软件,对动载荷作用下应力波延续时间、应力波峰值和围压对岩石试样破坏的影响进行了数值研究,结果表明,应力波延续时间较短,则尾随应力波波前的高应力区范围较窄,应力波衰减较快;相反,应力波延续时间较长,则紧跟应力波波前的高应力区范围较大,岩石处于破坏状态的时间延长,岩石的破碎程度加大。此外,存在一个合适的应力波延续时间,过分地加大应力波延续时间,反而不利于岩石裂隙的发育。动载荷的峰值越大,试样的破坏程度越大,当峰值达到一定值时,试样顶部呈现粉碎状,试样从上到下破坏程度逐渐减弱。在冲击载荷作用下的岩石随着围压的增加更难破碎,但当围压增大到一定程度时,岩石会突然失稳破坏。
Based on mesoscopic damage mechanics, numerical code RFPA^2D is developed to simulate the failure process of rock specimen subjected to dynamic loading; and the failure characteristics of rock specimen under different continued times and different amplitudes of stress wave and different confining pressures are studied; in the meantime the failure properties of rock specimen under static and dynamic loadings are compared. Numerical results indicate that the shorter continued time of stress wave, the narrower high stress area after wave front, the faster stress wave attenuates; On the contrary the longer the continued time of stress wave, the larger high stress area after wave front, the longer time is lasted for rock failure, the more cracks initiates and propagates. Furthermore, appropriate continued time is necessary for cracks of rock specimen to initiate and propagate, and on the contrary excessively long continued time goes against cracks growth. The more amplitude of stress wave, the more the fragmentation degree of rock specimen, and to certain amplitude, comminution mode appears at the top of rock specimen; and the breakage degree wears off from top to bottom of rock specimen. Rock is more difficult to break up when confining pressure increases under high speed impact loading, and rock failure occurs suddenly when confining pressure increases to certain value; By contrast to static loading condition, more cracks initiate and propagate under dynamic loading, which cause the damage and fracture of whole rock specimen.
出处
《岩土力学》
EI
CSCD
北大核心
2008年第4期887-892,共6页
Rock and Soil Mechanics
基金
国家自然科学基金重点项目(No.40638040)
973计划(No.2007CB209400)
国家自然科学基金(No.50504005)
中国博士后科学基金(No.2005038250)
关键词
数值模拟
动载荷
破坏过程
应力波延续时间
应力波峰值
围压
numerical simulation
dynamic loading
failure process
continued time of stress wave
amplitude of stress wave
confining pressure
