根据中国科学院成都山地灾害与环境研究所刘希林和云南省地理研究所唐川所做的泥石流堆积模型实验，对论文(Ⅰ) 建立的泥石流流团模型进行了验证。文中首先介绍有关实验与计算的基本概况,然后分别根据不同的实验条件，应用数值模型计算泥石流的堆积范围，并对平面堆积形态进行分析。通过与实验结果的对比表明，计算与实测值符合较好，泥石流流团模型的正确性从而得以证实。

对粘性泥石流的堆积过程，给出平面二维运动的基本方程。用固液两相流模型来模化阻力项，并讨论了泥石流中液、固两相分界粒径的选取以及有关特征参数的计算问题。最后结合已有的应力—应变本构关系，建立泥石流的流团模型，包括运动方程和数值计算方法。

用广义Fokker-Planck扩散模型描述液相湍动对颗粒的挟带作用，用修正的BGK模型描述粒间碰撞效应，建立了封闭的颗粒相PDF输运方程。运用Chapmar-Enskog迭代法求得方程的二阶近似解，获得颗粒相脉动速度二阶矩和三阶矩闭合关系。模型与颗粒流模型相容，与液相湍流闭合模型是否相容依赖于扩散模型的具体形式，并据此比较了不同的涡-颗粒作用模型。模型与二维明渠流轻质沙和天然沙试验资料符合很好。表明细小粒径颗粒能够充分跟随水流运动；大粒径颗粒的相间平均速度差和壁面滑移速度明显，近壁区内的颗粒沿流向和垂向脉动强度都可能大于水流，并存在一定程度的颗粒碰撞效应。

A discrete element model (DEM) is developed for investigation of the dynamic behavior of sand grains, in which the motion of individual grains is considered. The DEM has been used for simulating 9000 grains" motion blown by wind, resulting in ripples and saltating paths. Exchange between saltation and creep along the surface is also calculated, which is helpful for revealing the intrinsic mechanism of ripple formation. A critical event in the trajectory of sand grain saltating in the air is its interaction with the surface. As another application of DEM, the numerical experiment of a sand bed impacted by a single grain traveling at 8ms-1 and I 1.5 is performed to quantitatively evaluate the splash process. A normalized Maxwellian distribution function f(uy)=a ucy exp(-b. uyd) is proposed for the vertical velocity distribution of splashed grains, where the parameters a, b. c. and d can be regressed from the vertical velocity component of sahating grains. Generally, the vertical velocity of saltating grains fits the Maxwellian function well, with the correlation coefficients larger than 0.8. The result also shows that the restitution and surface friction coefficients of grains have negligible influence on the Maxwellian function. Therefore, the DEM can simulate sand movement and offer more detailed information as to what happens inside the flow. which could be applied in a wider suitable range in comparison with previous models.