基于转移概率随机模拟的DNAPL运移二维和三维数值模拟对比研究

非均质介质的空间维度变化对重非水相流体（DNAPL） 的运移具有重要的影响。在充分考虑地质体的空间连续 性、不对称性以及各向异性等特征的基础上，采用基于马尔可夫链的转移概率（transition probability） 模型来构建非均质 随机场。该文通过TMVOC-MP软件来模拟DNAPL在非均质介质中的运移规律，探讨非均质随机场的水平空间连续性、 空间维度变化以及侧向运移过程对DNAPL运移的影响。结果表明，介质的水平空间连续性越好，DNAPL在水平方向的 迁移范围越大，在垂向的迁移范围越小；相比于三维模型，二维模型中DNAPL在水平方向的展布更大、在透镜体上的蓄 积量更多，在实际应用中以二维模型代替三维模型会加大模拟结果与实际污染情况之间的误差；侧向运移过程削弱了单 个平面的非均质性对DNAPL运移的控制，当存在侧向运移时，DNAPL绕过透镜体所运移的距离以及在透镜体上的蓄积 量会相应减小。
The cChange in the spatial dimension of heterogeneous media significantly influences the migration and distribution of Dense Non-Aqueous Phase Liquid (DNAPL). Based on the Markov Chain transition probability model, we generate stochastic permeability fields and take a fully account of horizontal spatial continuity, asymmetry, and anisotropy of heterogeneous media. By simulating the migration and distribution of DNAPL in heterogeneous media with TMVOC-MP, we investigate the effects of horizontal spatial continuity, reduced dimensionality, and lateral migration on the migration and distribution of DNAPL. Numerical analysis reveals that a better horizontal spatial continuity results in a larger horizontal pollution scope and a smaller vertical migration extent of DNAPL. Compared with the behavior in the three-dimensional model, DNAPL distributes in a larger scope in the horizontal direction, accumulates more on the low-permeability lenses, and is mostly in a pool state in the two-dimensional model. Lateral migration process can reduce the impact of heterogeneity of a single plane on the DNAPL migration. So it is necessary to use the threedimensional model in practical applications instead of two-dimensional model.