陡倾硬质岩边坡倾倒变形数值模拟与分析

Numerical Simulation and Analysis for Steeply Declined Hard Rock Slope Toppling Deformation

由硬质岩组成的陡倾反向坡会产生倾倒变形,并可进一步发展为滑塌破坏。虽然这种倾倒变形发育的深度有限,但是硬质岩容易形成高陡边坡并产生危害巨大的高位危岩体问题。为此,以开挖高度约200m、总体坡度达42.4°的连云港东疏港高速公路路堑边坡为研究对象,采用地质分析、数值模拟与原型监测相结合的方法,开展倾倒变形特征和边坡加固效果的研究。结果表明,当开挖卸荷作用强烈,并在地下水压力作用下,即使是微风化和新鲜的硬质岩陡倾反向坡也会产生倾倒变形;倾倒变形始于坡脚(当边坡开挖成台阶状时,包括各级台阶的坡脚),上部岩板失去支撑,沿陡倾结构面互相错动而发生倾倒变形。锚杆增大了陡倾岩板间的错动阻力,抑制了倾倒变形的发展。

The steeply declined hard rock reverse slope will produce toppling deformation and further develop into slump failure.Although the development depth of this kind toppling deformation is limited,but hard rock will easily form high steep slope and resulted in great dangerous raised instable rock mass issue.For this purpose,taking the excavation height about 200m,overall slope angle up to 42.4°Lianyungang east port logistics expressway cutting slope as subject investigated,using combined geological analysis,numerical simulation and prototype monitoring have carried out toppling deformation features and slope reinforcement effect studies.The result has shown that when excavation unloading effect is strong,under groundwater pressure,even though slightly weathered or fresh hard rock steeply declined reverse slope will also produce toppling deformation.The deformation is start from slope toe(if excavation is stepwise,every step slope toe will be included),upper rock slabs losing support will be faulted each other along steeply declined structural plane and then toppled and deformed.Anchor bolt can increase faulted resistance between steeply declined rock slabs and restrain toppling deformation development.