循环荷载下冻结裂隙砂岩动疲劳特性研究(英文)

Dynamic fatigue properties of the cracked sandstone samples under freezing and cyclic loading

通过在砂岩样中预制裂隙的方法来模拟实际裂隙岩体 ,借助于中低频率 (2 0 .0Hz和 2 .0Hz)动循环加载和常规加载试验 ,对烘干、饱水和饱水冻结砂岩样在循环作用下引起的低周疲劳特性和不同加载频率下的速率效应进行了研究 ,试验结果表明 :①疲劳效应 ,冻结状态下 ,裂隙砂岩样比无裂隙砂岩样疲劳效应明显 ;②冻结效应 ,冻结作用减弱了试样的疲劳效应 ,尤其是对无裂砂岩隙样 ;③加载 (频率 )率效应 ,冻结作用降低了裂隙砂岩样加载率效应 ,意味着饱水岩样强度随加载 (频率 )率增加而增加的幅度较冻结样明显。

Based on the idea of using the prefabricated cracks in the sandstone samples to simulate the actual rock mass, the mechanic properties of rock samples with the intermittent cracks are studied by means of dynamic cyclic loading (2.0 Hz, 20.0 Hz). Moreover, the dynamic fatigue properties of the cracked samples in the frozen state (-15 ℃) are also studied via the contrast of their deformation and strength with those of the saturated samples.The test results indicate that (1)fatigue effect: the cracked samples have more obvious fatigue effects than the non cracked samples under frozen condition;(2)freezing effect: the freezing lightens the fatigue effect much more for non cracked samples than for cracked samples;(3)loading frequency (rate) effect: freezing also reduces the loading rate effect for cracked samples, which means that the strength increasing with loading frequency (rate) for saturated rock samples is more obvious than that for frozen rock samples.