锚固岩质边坡震后位移实时动态Newmark滑块位移法

The real-time dynamic Newmark sliding block displacement method for post-earthquake displacement of anchored rock slope

Newmark滑块位移法在计算锚固岩质边坡震后位移时,一般假设边坡屈服加速度系数为定值,没有考虑在地震时程中因滑块下滑引起的锚索轴力实时动态变化对边坡屈服加速度系数的影响。基于拟静力模型,针对典型锚固岩质边坡,考虑锚索轴力实时动态变化对边坡屈服加速度系数的影响,推导出锚固岩质边坡在地震作用下锚索实时轴力、边坡实时屈服加速度系数和震后位移计算公式,提出了锚固岩质边坡震后位移计算的实时动态Newmark滑块位移法。结合算例分析表明:随着滑块位移的增加,锚索实时轴力和边坡实时屈服加速度系数会相应增大;实时动态Newmark滑块位移法较传统Newmark滑块位移法计算的震后位移要偏小,且两者之间的差异会随着边坡整体稳定性的提高而逐渐减小。实时动态Newmark滑块位移法弥补了传统Newmark滑块位移法未考虑锚索轴力实时动态变化影响的不足,可为地震作用下锚固岩质边坡稳定性分析提供参考。

In the calculation of post-earthquake displacement of anchored rock slope, the Newmark sliding block method generally assumes that the yield acceleration coefficient of slope is a fixed value, without considering the influence of real-time dynamic change of axial force of anchor cable caused by sliding block in earthquake time history on the yield acceleration coefficient of slope. Based on the quasi-static model, the dynamic change of the real-time anchor cable axial force on the yield acceleration coefficient of the typical anchored rock slope is considered, the calculation formulas of the dynamic change of the real-time anchor cable axial force, the real-time yield acceleration coefficient of slope and the post-earthquake displacement of the anchored rock slope under the earthquake are derived, and the real-time dynamic Newmark sliding block displacement method for calculating the post-earthquake displacement of anchored rock slopes is proposed. The results of a numerical example show that the real-time anchor cable axial force and the real-time yield acceleration coefficient of anchored rock slope increase with the increase of the slide displacement, the post-earthquake displacement of anchored rock slope calculated by the real-time dynamic Newmark sliding block displacement method is smaller than that by the traditional Newmark sliding block method, and the difference between them will gradually decrease with the improvement of the overall stability of slope. The real-time dynamic Newmark sliding block displacement method makes up for the deficiency that the traditional Newmark sliding block method does not consider the dynamic change of the axial force of the anchor cable, which can provide a reference for the stability analysis of the anchored rock slope under the action of earthquake.