澜沧江上游典型倾倒—滑动组合型滑坡特征及形成机理的数值模拟

鉴于目前倾倒-滑动组合型滑坡的变形特征及形成机理研究尚少,以云南省澜沧江上游两处典型的大型倾倒-滑动组合型滑坡(争岗滑坡、根达坎滑坡)为例,通过现场工程地质调查,分析了该类滑坡发生倾倒变形破坏的基本特征,并利用离散元模型对其形成机理进行数值模拟。结果表明,该类倾倒变形主要发育在临空条件较好、软硬岩体相间、较广范围硬岩、岩体倾角大于75°的边坡中;岩体依次经历弯曲、倾倒、折断、坠覆,从而形成倾倒体;硬岩内受剪切作用发育多条顺坡向软弱层带;折断面相继贯通,且超过其抗剪强度,坡体沿倾倒折断面及软弱层带发生滑动破坏,进而形成滑坡。

Landslide Characteristics of Typical Dump-sliding Combination in Upstream of Lancangjiang River and Its Forming Mechanism of Numerical Simulation

There is little research of deformation characteristics and formation mechanism of the dump-sliding combination landslide. Taking the typical large Zhenggang landslide and Gengdakan landslide located in the upper reaches of the Lancangjiang River for an example, based on the field engineering geological survey, the basic characteristics of toppling deformation damage of the landslide was analyzed. And the formation mechanism was simulated by discrete element model. The results show that the toppling deformation is mainly developed in the good airport condition, a wide range of soft and hard rock, hard rock, and rock slope with dip angle greater than 75 degrees. Rock mass in turn undergoes bending, dumping, breaking and falling, and forms the dumping body. The hard rock is affected by the shearing action, which is developed along the slope to the weak layer. The broken surface is connected with one another, which exceeds the shear strength. The slope appears sliding damage along the toppling broken surface and the weak layer, and the landslide is formed.