考虑孔隙气压力影响的边坡稳定分析

发布时间：2018-05-05 09:38

  本文选题：边坡稳定 + 剩余推力法　； 参考：《水利水电技术》2017年07期

【摘要】：降雨入渗过程中孔隙气压力变化是影响边坡稳定的重要因素,为了分析这种影响,提供一种考虑孔隙气压力影响的边坡稳定分析方法。首先基于水气两相流的理论与方法,计算降雨入渗下坡体的孔隙水压力、孔隙气压力和饱和度的分布,并获取降雨入渗过程中孔隙气压力引起的荷载变化量。而后,结合非饱和土抗剪强度理论及剩余推力法,将孔隙气压力引入到边坡稳定分析中,并以谭家河滑坡为例模拟分析考虑孔隙气压力对边坡稳定的影响。结果显示,降雨导致坡体表层趋于饱和,在坡表与滑带之间的孔隙气压变化较为敏感,而沿滑床向深层方向传递过程中孔隙气压发生衰减;坡体表层饱和区孔隙水压力通过孔隙气向坡脚传递,形成沿坡脚方向的孔隙气压力梯度,增大了滑体的下推力。结果表明,在相同的渗流条件下,考虑孔隙气压力的影响使同一滑动面上的安全系数降低,对边坡稳定分析不利。该方法在坡体濒临失稳时考虑孔隙气压力作用影响显著,对反映某些具体工程滑坡现象更加符合实际。
[Abstract]:The variation of pore gas pressure in the process of rainfall infiltration is an important factor affecting slope stability. In order to analyze this effect, a slope stability analysis method considering the influence of pore gas pressure is provided. Based on the theory and method of two-phase flow of water and gas, the distribution of pore water pressure, pore gas pressure and saturation of slope body under rainfall infiltration is calculated, and the load variation caused by pore gas pressure during rainfall infiltration is obtained. Then, combined with the theory of unsaturated soil shear strength and residual thrust method, the pore gas pressure is introduced into the slope stability analysis, and the influence of pore gas pressure on slope stability is analyzed by taking Tanjiahe landslide as an example. The results show that the surface layer of the slope tends to saturation due to rainfall, and the pore pressure between the slope surface and the slip zone is sensitive to the change of pore pressure, and the pore pressure attenuates in the process of transferring along the slip bed to the deep layer. The pore water pressure in the saturated zone of the surface layer of the slope is transferred through the pore gas to the foot of the slope, and the pore gas pressure gradient along the slope foot is formed, which increases the downward thrust of the sliding body. The results show that under the same seepage condition, considering the influence of pore gas pressure, the safety factor on the same sliding surface is reduced, which is unfavorable to the slope stability analysis. The effect of pore gas pressure on slope is significant when the slope is on the verge of instability, and it is more practical to reflect the landslide phenomenon of some concrete projects.
【作者单位】： 三峡大学水利与环境学院;
【基金】：国家自然科学基金(51279090);国家自然科学基金(51679129)
【分类号】：TV223
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本文编号：1847185