基于颗粒流的局部强度折减法在边坡稳定分析中的应用

Application of Local Strength Reduction Method Based on Particle Flow Code in Slope Stability Analysis

岩土边坡稳定问题是土力学中仍未圆满解决的重要课题,边坡的渐进破坏过程是数值分析中的难点。颗粒流方法的特质是模拟大变形、可破坏的问题,用于边坡失稳破坏研究能获得该过程的时空演化规律。边坡失稳往往是由于局部土体的强度降低造成的,为此,运用颗粒流程序建立边坡模型,采用传统的强度折减法获得滑裂带土体区域,通过对滑裂带区域内土体强度的折减实现局部强度折减,以此进行边坡稳定分析。研究表明采用颗粒流结合强度折减法开展边坡稳定分析,通过数值双轴试验建立试样宏观力学响应与颗粒流细观参数之间的联系,不断折减宏观强度参数直至边坡破坏得到的安全系数与极限平衡法结果基本一致,并且能直观地显示边坡破坏的渐进过程及滑移面位置和形状。局部强度折减得到的边坡位移变化较传统强度折减略小。

The geotechnical slope stability problem in soil mechanics is an important issue that not resolved sat isfactorily, the progressive failure of slope has also been a difficulty in numerical simulation. The characteristics of particle flow code is to simulate large deformation and damaged problems, which is more suitable for slope instabili ty and failure problems and can obtain the temporal and spatial evolution of the process. The slope instability is usually caused by local soil strength reduction. To this end, a slope model was established by particle flow code, slip area was calculated by traditional strength reduction method, then reduced the soil strength of the sliding zone to achieve the local strength reduction in order to carry out slope stability analysis. The results show that using par ticle flowcode combined with strength reduction method to carry out slope stability analysis, the link between macro scopic parameters and microscopic parameters were established by numerical biaxial test, the safety factor was ob tained by continued reduction of macroscopic strength parameters until slope failure are close to the result of slice method, and particle flow code can visually display the gradual process of slope failure and the position and shape of the slip plane, the displacements of slope obtained by local strength reduction are smaller than traditional strength reduction method.