循环荷载作用下盐岩三轴变形和强度特性试验研究  

DEFORMATION AND STRENGTH PROPERTIES OF ROCK SALT SUBJECTED TO TRIAXIAL COMPRESSION WITH CYCLIC LOADING

作　　者：马林建[1] 刘新宇[1] 许宏发[1] 华瑞平[2] 李长洪[3] 张磊[3] 王晨[1] 

机构地区：[1]解放军理工大学爆炸冲击防灾减灾国家重点实验室,江苏南京210007 [2]南京军区司令部工程科研设计所,江苏南京210016 [3]北京科技大学土木与环境工程学院,北京100083

出　　处：《岩石力学与工程学报》2013年第4期849-856,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点基础研究发展计划(973)项目(2009CB724608;2010CB732003);国家自然科学创新研究群体基金项目(51021001)

摘　　要：为研究三向应力状态下循环荷载作用对盐岩变形、强度及损伤特性的影响,利用TAW–2000型微机伺服岩石三轴试验机进行不同荷载波形参数(上、下限应力、应力幅值和频率)和不同围压下的盐岩试样的循环加、卸载试验。试验得到盐岩轴向初始变形和稳态变形两阶段演化规律;通过提高循环荷载上限应力、降低下限应力、增大应力幅值或者降低载荷频率、减小围压等途径,均会加速盐岩试样不可逆变形的发展,提高盐岩循环稳态应变速率,减小稳态阶段在整个变形阶段的比例,从而加速试样变形破坏;荷载波形参数中上限应力和应力幅值对循环荷载作用下盐岩变形演化速率、试样损伤发展的影响最大。循环荷载作用下,盐岩弹性模量随循环次数或加载时间呈指数递减趋势,并在50～100个循环后其值接近常数;循环加载后二次压缩盐岩强化与否,取决于循环加载时所施加荷载水平是否造成盐岩内部损伤的累积,通过试验可间接推断盐岩三轴循环变形破坏的上限应力阈值为80%～89%。To investigate the deformation behavior,strength and damage properties of rock salt subjected to cyclic loading under confining pressure condition,a series of triaxial cyclic loading/unloading tests were conducted for rock salt specimens with different loading waveforms（maximum and minimum stress,stress amplitude and loading frequency） and confining pressures utilizing TAW–2000 computer-servo rock triaxial testing machine.A two-stage（primary and steady） evolution law of axial cumulative strain was obtained through test.The irreversible deformation and the steady deformation rate will be accelerated through increasing maximum applied stress,stress amplitude,or reducing minimum stress,confining pressure,and loading frequency.The effects of maximum stress and stress amplitude on the deformation development and the damage degradation are more remarkable compared to other influencing factors.The Young？s modulus of the rock salt decreases with loading cycles as an exponential function and drives to a constant after 50–100 cycles.Whether the secondary compression strength of rock salt increases or not,depends mainly on the damage caused by the applied stress level of cyclic loading.The threshold value of maximum stress for rock salt under triaxial cyclic loading is indirectly deduced among 80%–89% based on experimental results.

关 键 词：岩石力学 盐岩 循环荷载 三轴压缩 不可逆变形 损伤 强度 

分 类 号：TU45[建筑科学—岩土工程]