基于光滑粒子流体动力学的流动法则对土体滑坡大变形的影响探讨

光滑粒子流体动力学（SPH）是近年来发展起来的一种纯拉格朗日无网格法，并因其在大变形领域内的优势而受到广泛关注。在进行滑坡大变形分析时，流动法则及剪胀角的选取对于边坡失稳后的运动特性有重要的影响。采用Fortran自行编写了基于SPH的边坡稳定性及失稳后大变形分析程序，然后通过2个经典的算例，讨论了不同流动法则及剪胀角的选取对滑坡大变形分析精度的影响。结果表明：（1）剪胀角的选取对土体失稳后的滑动距离有显著影响，随着剪胀角的增大，土体的滑动速度与距离呈明显增大趋势；（2）在关联性流动法则及非关联性流动法则? =1/2? （? 为剪胀角，? 为摩擦角）条件下，土体在大变形过程中会产生过度膨胀，且运动速度与距离要大于实际情况，而采用关联性流动法? =0时，对于非膨胀土可以得到比较令人满意的结果，但对于膨胀土体会使得运动速度和运动距离过小，不符合实际情况。建议在计算膨胀土大变形时，采用非关联性流动法则且适当考虑膨胀性（? =(0.1～0.2)? ），可以得到较好的结果。

Determination on flow rules of large deformation analysis of slope using SPH method

Smoothed particle hydrodynamics (SPH) is a new meshless method and is gradually developed to the field of landslide analysis due to its advantages in large deformation simulation. However, flow rule and dilatancy angle has an important influence on the motion characteristics of slope after failure, but the analysis of their influence on large deformation slope is rarely reported. In this paper, the procedure of SPH based on elastic-plastic constitutive and D-P yield criterions was implemented in Fortran. Then, through two typical examples, the influence of flow rules and dilatancy angle on landslide analysis were discussed by using associated flow rule and non-associated flow rule (? =0 and ? =1/2? respectively). The results show that: excessive expansion will be produced when using associate flow rule and non-associated flow rule with ? =1/2? , both cases above are not in conformity with the actual situation. However, the non-associated flow rule with ? =0 can obtain the satisfactory result when calculating non-expansive soil, but will cause smaller speed and sliding distance when simulating expansive soil. Non-associated flow rule with appropriate consideration of expansion (? =(0.1～0.2)?) is suggested when calculating post-failure behavior of expansive soil and could obtain satisfactory results.