三峡水库水位波动条件下滑坡抗滑工程效果的数值研究

抗滑桩是三峡库区滑坡治理工程中常用的措施，在三峡水库长期的周期性水位波动条件下，抗滑桩工程效果如何，即是否能够保证滑坡的整体稳定，是目前迫切需要研究的重要课题。选择三峡库区巴东县新县城的谭家坪滑坡次级滑坡-白水沟滑坡为研究对象，在分析工程地质条件和设计资料的基础上，建立二维有限元计算模型，选择合理的岩土力学参数和桩计算参数；利用ANSYS软件，依据不同的模拟方案，分别模拟分析了滑坡在仅考虑自重、自重加暴雨在水位变化条件下的变形和稳定性状况以及抗滑桩的工程效果，即滑坡在设桩条件下的变形和稳定情况。结果表明：①白水沟滑坡破坏机理为牵引式。在暴雨和水位下降条件下，滑坡稳定性降低；周期性水位变化后，滑坡稳定性逐步下降，最终失稳；②依据自重和暴雨工况，考虑175m降至145m水位进行的抗滑桩设计，起到了明显的抗滑效果。③周期性水位波动后，滑坡变形破坏逐步加剧，说明抗滑桩虽然起到了的抗滑作用，但阻滑效果逐步下降。因此，在滑坡抗滑工程设计时应考虑该因素的影响，适当提高安全储备。

Numerical simulation of effectiveness of anti-slide piles construction for landslide in Three Gorges Reservoir area under water-level fluctuation

Anti-slide pile is widely used in landslide improvement in the Three Gorges Reservoir area. How about the effectiveness of the anti-slide piles construction and if it can ensure the landslide stability under the long period reservoir level fluctuation, which is one of the important subjects to be studied urgently. Taking Baishuigou landslide, which is the sub-landslide of Tianjiaping paleo-landslide located in the new Badong County, as a example, based on the engineering geological investigation results and anti-slide pile design data, the 2D finile element model was developed and the rational calculation parameters of the rock and soil and pile were chosen. According to the simulation scheme, with ANSYS software, with pile and without pile, the landslide stability under water level fluctuation, considering gravity only and gravity and strom, was simulated and analyzed separately. Based on them, we analyzed the effects of nti-slide pile under water level fluctuation and storm. The results show that: ① the deformation and failure mechanism of Baishuigou landslide is a pull-type. The landslide stability under storm and water level drawdown from 175m to 145m decreases; during the period water level fluctuation, the landslide stability gradually decrease further to failure. ② the piles, designed under water level drawdown considering the storm, is effective under storm and water level drawdown form 175m to 145m; ③ after a long term period water leverl fluctuation, the deformation has apparently gradually further incrtease; the landslide stability decrease further. Even though the anti-slide pile has anti-slide effectiveness, the anti-slide effectiveness is gradually decrease. Hence, we should consider the effect of the period water level fluctuation when we design antl-slide pile.