似层状岩质边坡倾倒变形破坏过程数值模拟

在构造裂隙组合切割下形成的反倾向"似层状"结构边坡在工程中普遍存在。文章以浙江某梯级电站厂房后边坡为例,通过运用二维离散元和三维有限差分法,对"似层状"岩质边坡倾倒变形特征及破坏演化历程进行模拟,结果表明这类边坡变形破坏主要经历三个时期:初期为块体间的相互剪切错动和局部缓倾节理的剪切蠕变;中期岩体加剧倾倒后推动坡体前缘滑动,在坡体表面形成倾倒台阶后地表拉裂;后期倾倒变形剪切错动向坡体内部扩展,剪切带相互连通并逐步追踪缓倾结构面或强弱风化分界面,在空间形态上形成具有"台梯状分布"的滑动带,为深层蠕滑创造条件。

Numerical simulation of deformation and failure process of atoppling-sliding rock slope with a quasi-lamellar structure

The integrated slope is divided based on structure fracture to form the anti-dip and quasi-lamellar structures.This paper takes the slope behind the power house of a cascade hydropower station as an example, and uses a 2D discrete element and 3D finite difference methods to stimulate the deformation characteristics and the failure evolvement of the quasi-lamellar rock slope. The results show that the deformation and damage process of this kind of slope mainly experiences three periods: (1) an initial stage，in which the major deformation is shear dislocation between blocks and shear creep of local gently inclined joint; (2) the metaphase of damage process, in which the speed of rock mass dumping is accelerated, the sliding of the front slope is promoted, and the toppling-steps and cracking on the slope surface form; (3) a later stage, in which the shear deformation spreads toward the interior of the slope, the plastic zone is connected with each other, and gradually traces the gently inclined joints or the interface of weathering to form sliding zones which are characterized by “ladder-like distribution” in the space form. Finally, conditions for deep creeping are created.