循环荷载下节理岩体边坡动力响应的试验研究

 在振动荷载的长期循环作用下，岩质边坡中的原生结构面可能扩大并产生新的破裂面，直接影响到岩质边坡的稳定性。以某节理岩体边坡为原型，根据相似理论制作模型框架并在其内建造室内节理岩体边坡模型，利用振动台对边坡模型进行振动加载，研究在振幅分别为1.0，1.25，1.5 mm的振动荷载作用下节理岩体边坡的动力响应规律，对比水平方向和竖直方向振幅都为1.5 mm时边坡模型的变形差异。循环加载试验表明，在振动荷载作用下，边坡变形随振动荷载振幅、振动时间的增大而增大；边坡模型对于竖向的振动荷载更加敏感；边坡模型在受到振动荷载作用时，顶部的变形大于底部的变形；长期的振动荷载作用会导致原生裂隙延伸、扩张、贯通，引起边坡变形增大；根据变形情况提出边坡在振动荷载作用下的变形过程及变形导致的整体性滑坡和局部滑塌2种可能的破坏模式。研究结果对节理岩体边坡在循环荷载作用下的动力响应、疲劳劣化机制和边坡工程的长期安全性等理论研究和工程应用具有参考意义。

Experimental study of dynamic response of jointed rock slopes under cyclic loads

Under the long term cyclic vibration loading，the primary structural plane in rock slopes may expand and produce new fracture surfaces，which directly affect the stability of rock slopes. According to the similarity theory，a physical model of a slope was built to simulate a jointed rock slope. The cyclic shear load was applied on the shaking table with the amplitude of 1.0，1.25 and 1.5 mm respectively and the dynamic response of the jointed rock slope under cyclic loads was recorded. The deformation of the jointed rock slope under the horizontal and vertical cyclic loads with the amplitude of 1.5 mm was compared. The deformation of the slope increases with the increasing of vibration amplitudes and vibration time. The slope is more sensitive to the vertical cyclic load，while the deformation at the top of the slope is larger than that at the bottom. The long term vibration load leads to the extension，expansion and coalescence of the primary crack，which increases the deformation of the slope. Two possible failure modes of the slope under cyclic loads，the integral landslide and the partial sliding，were presented according to the deformation results of tests.