以石油类和氯代有机溶剂类为代表的非水相流体（non-aqueous phase fluids, NAPLs）污染问题在我国土壤和地下水污染中越来越突出。由于与水和空气不相混溶的性质，NAPLs在地下环境中迁移为非混溶流体驱替的过程。对于多孔介质中非混溶两相流的问题，已有研究主要集中在对垂向驱替过程的分析上。为了更全面地了解以不同角度驱替过程中NAPLs的形态特征和驱替机制，本研究建立二维可视化砂箱实验装置，将实验模拟由垂向拓展到水平和一定角度的方式。其中，垂向角度（与水平方向夹角α=〖90〗^o）模拟了NAPL-气和NAPL-水的驱替过程，共完成18组实验，获得有效迁移形态影像363幅。水平角度（α=0^o）模拟了水驱替DNAPLs 聚集区以及液滴态DNAPLs的过程，一定角度下（0^o<α<〖90〗^o）模拟了DNAPLs驱替水的过程，这两部分共完成实验18组，获得有效影像487幅。并对迁移形态影像进行分析，识别不同角度驱替条件下迁移形态特征，并以毛细管数C_a和邦德数B_o分析驱替机制和主要驱动力。研究结果表明，非混溶两相流垂向驱替以指进形态迁移，驱替机制为毛细管指进，毛细压力为主要驱动力；水平驱替过程中，形态变化的主要机制为溶解作用，NAPLs面积逐渐减小，毛细管数和邦德数为共同控制因素；DNAPL以一定角度驱替水溶液的过程中，驱替形态不规则，毛细管数为主要控制因素。毛细管数控制的驱替过程中，表面活性剂的引入对驱替形态有非常显著的影响。在驱替形态驱动力分析的基础上，发现非混流两相流以不同角度驱替时，污染面积的大小、污染面积的增加速率与捕集数N_T值负相关，污染面积的消减速率与N_T值正相关。即NAPLs污染面积随着捕集数N_T增加而降低，这为确定地下环境中污染物的分布面积提供了一种判断依据。进一步引入分形维数对非混溶两相流垂向驱替的指流形态参数进行预测。研究发现垂向驱替的指流锋面形态具有分形性质，分形维数与指流面积线性正相关，可以作为污染面积的指示参数。质量分形维数可以用来预测指流宽度和指流波长，预测值与观测值具有很好的线性相关性。相比于传统毛细压力函数方法，分形维数方法对指流参数的预测更准确。

Along with the rapid development of urbanization, soil and groundwater pollution arising from petroleum products and chlorinated solvents (usually exist as non-aqueous phase liquids, NAPLs) has become a serious problem in China. Because of low solubility in water and air, NAPLs-water or NAPLs-air are existed as two immiscible phase in the subsurface. In order to characteristic the morphology and identify the main driving force concerning two immiscible phase displace on different directions, visible two-dimensional sand-box appaturatus were constructed for vertical, horizontal and a certain angle displacement recepectively. On the vertical displacement (α=〖90〗^o), 18 suites experiments were conducted in initially dry (NAPL-air displacement) and saturated porous media (NAPL-water displacement), 363 effective images were obtained. 18 suites of horizontal experiments (α=0^o) were conducted and 483 effective images were obtained concerning water displace DNAPL pool and the blob DNAPL, with displacing experiments of angle between 0o and 90o completed at the same time conserning DNAPL displace water on a certain angle. Displacment patterns were extracted by sofaware. The capillary number (Ca) and the bond number (Bo) were used to identify the main driving forces of different displacements.The results show that infiltration front instability exsit when NAPLs vertically displacing air or water in the homogeneous porous media. The vertical infiltration process is the immiscible capillary fingering with the capillary force as the main driving force. The surfactant plays important role on displacement morphology when C_a is the control factor in the process.Based on the driving forces analysis, the trapping number (NT) was used to give comprehensive analysis of the combination effects of capillary forces, viscous forces and gravity forces. The displacements show that the polluted area of DNAPL, the increasing rate of the DNAPL polluted area are both negatively correlated with NT, and the decrease rate of DNAPL polluted area are positively correlated with NT, which means that on different angle displacements, the DNAPL area show decreasing trend when NT increase. Therefore the NT could be used as an indicator of the polluted area in the two-dimensional porous media.Fractal nature of the two immiscible phase capillary fingering was characterized. The infiltration areas are positively correlated with the fractal dimension, which could be used as an indicator of the polluted area. The mass fractal dimension was used to predict the finger width and the finger wave-length. The predict data are closed correlated with the observed data. Compared with the method used the data of capillary head, the method used the fractal dimension predict the finger width and the finger wave-length more precisely, especially for the DNAPLs.