岩质边坡渐进破坏的三维随机分析

层间错动带是岩体结构中普遍存在的一种地质现象，含错动带的岩质边坡三维分析更是岩土工程关注的难点问题。结合国内某高拱坝工程，根据岩体层间错动带的分布状况，利用等厚度节理单元模拟了坝区22层错动带和软弱夹层，利用Mohr-Coulomb准则确定节理单元的破环方式，提出了岩质边坡三维滑动面的确定方法，该方法考虑了岩石和错动带（软弱夹层）的随机性。利用弹塑性理论、可靠度理论和破坏追踪相结合的方法，通过3 000多次有限元的计算，得到了边坡滑动面的位置、形态、破坏的先后顺序、滑动的方向以及滑动到任何程度的概率度量。含层间错动带的岩质边坡渐进破坏模式可概括为边坡的破坏起始于层间错动带的剪切破坏。随着各层间错动带的破坏、边坡结构性能恶化，部分较薄的岩层变成不同支撑形式的板，然后部分岩层开始破坏，边坡开始滑动，形成一个或几个破坏台阶，直至失稳。

Three-dimensional stochastic analysis of progressive failure of rock slopes

The fault zone rock foundation is common in geologic structure. The 3-D analysis of progressive failure of rock slopes including fault zone is very difficult. An interface element style has been put forward according to distribution of fault zone in rock mass to simulate the rock and fault zone in arch-dam zone. The shape function and elastic matrix have been given. And the entire fault zone in the location, 22-fault zone, has been simulated. The Mohr-Coulomb criterion has been selected as yield criterion in plastic analysis. The stochastic distribution of rock and fault zone has been conceded. Cracking analysis has been used to search for critical slip surface based on gradually cracking theory and credibility theory and elastoplasticity theory. Then the probability of slip has been obtained according to reliability theory. Through three thousand times finite element calculation, the location of slip surface, the form of s slip surface and the sequence of cracking have been obtained; the conclusion of the mode of progressive failure of rock slope including fault zone can be drawn as: the failure began at fault zone. With the fault zone cracking, the stress states of slope deteriorate. Some rock layer began changer to plank with different support, then the rock layer began crack, and then the slope began slip. At last the slopes collapse with one or more failure steps.