土质边坡动力稳定性试验研究

Dynamic stability model test of soil slope

  • 摘要: 以云贵高原某典型土质边坡为原型,采用了4种加速度震动波输入模式,设计完成了比例为1:6的小型振动台模型试验,结合FLAC3D数值模拟对边坡动力响应特性和边坡变形破坏规律进行分析。结果表明:当输入加速度低于某个临界值时,整个坡体的加速度响应基本保持一致,各部位放大效应增加不明显,当输入加速度逐渐增加,高于临界值时,坡体的卓越频率得到充分激励,各部位加速度响应大幅增加,此时边坡最易发生变形破坏,且加速度响应沿着坡高方向有显著的放大效应;剪应变增量时程曲线反映出在边坡震动破坏过程中,滑体后缘以张拉为主,中部及下部以剪切为主,而且剪出口剪应变增量的变化尤为关键,其增幅速度直接导致该部位抗剪强度降低速度增快;边坡震动变形破坏模式为崩塌-剪切滑移破坏,变形破坏过程可分为4个阶段。

     

    Abstract: This paper, based on a typical soil slopes prototype in Yunnan-Guizhou plateau, designed and completed test on a small vibrostand at scale of 1:6 by using four kinds of acceleration vibration wave input mode. The slope dynamic response characteristics, the deformation and failure law of slope were analyzed by FLAC3D. The results show that when the input acceleration is below certain threshold, the acceleration response of the whole slope is basic consistent in the same way, and amplification effect at each place does not increase obviously, when the input acceleration increases gradually ans is higher than the critical value, the predominant frequency of slope is fully stimulated and the acceleration response of each place increases, the slope is the most prone to deformation and damage. And the acceleration response has significant amplification effect along the direction of the slope height. The shear strain increment time course curve reflects the fact that in the process of the vibration failure, the trailing edge of the landslide mass is mainly effected by tensioning, the middle and the bottom of the slope are mainly effected by shear, and the variation of shear strain increment at the shear outlet particularly critical, its growth speed directly results in rapid decrease of shear strength. The slope deformation process is divided into four stages, and the failure mode is collapse-shear sliding.

     

/

返回文章
返回