反倾层状岩质边坡倾倒破坏的离心模型试验研究

针对反倾层状岩质边坡倾倒破坏机理认识的不足,采用平板玻璃作为相似材料,开展不同边坡坡角及岩层反倾角组合条件下的多组离心模型试验;结合图像量测技术,综合分析坡体在离心加载条件下变形倾倒特征,提出反倾层状岩质边坡典型倾倒破坏模式和倾倒破裂面位置的确定方法。研究表明:坡体倾倒变形主要发生在破裂面以上,坡趾岩层起到抗倾倒作用,变形过程分为位移量稳定增长和位移量加速增长两个阶段;坡体倾倒破坏模式经历坡趾岩层断裂、近坡顶张拉裂缝产生、岩层折断渐进式延伸及裂缝贯通瞬间倾倒4个阶段;边坡坡角及岩层反倾角影响坡体破坏时的临界坡高与破裂面位置,可通过计算位移矢量方向确定破裂面位置。上述研究成果,为反倾层状岩质边坡的破坏理论发展、工程地质灾害评价及防灾减灾提供参考。

Study on the anti-dip layered rock slope toppling failure based on centrifuge model test

In view of the insufficient recognition of the toppling failure mechanism of anti-dip layered rock slope, multiple of centrifugal model tests were carried out under different combinations of slope angles and anti-dip angles, in which flat glass was used as similar materials. Based on the image processing, the deformation and toppling failure mechanism of anti-dip layered rock slope under centrifuge loading condition were investigated,and the topping failure mode of anti-dip layered rock slope and the method of determining the location of failure surface were proposed. The results show that the deformation of the slope mainly occurs above the failure surface,the rocks located in the toe of slope prevent toppling failure. The displacement changed against time at the top of the slope is divided into two stages:the steady growth of the displacement and the accelerated growth of the displacement. The slope toppling failure process can be divided into four stages:(a)the toe rock of slope fracture;(b)the generated of slope top tension cracks;(c) rock fracture and progressive extension and (d) rock toppling failure instantly. Slope angle and rock anti-dip angle have a significant influence on the critical slope height and the position of failure surface when the slope is topping failure. The above research results can provide some references for the development of toppling failure theory, the evaluation of engineering geological disasters, and the prevention and mitigation of geo-disaster.