中文摘要：

为了研究孔隙结构和水动力对悬浮颗粒在饱和多孔介质中沉积和迁移特性的影响,对天然硅粉（悬浮颗粒）和荧光素钠（示踪剂）在饱和多孔介质中的渗流迁移特性进行土柱试验,分别得到了5种不同渗流速度（0.033、0.066、0.132、0.199、0.265 cm/s）、两种不同多孔介质（石英砂和玻璃球）的悬浮颗粒和示踪剂全组合下的20条穿透曲线。根据试验结果,研究孔隙结构、渗流速度对饱和多孔介质中颗粒迁移和沉积过程中水动力作用机制、弥散效应、加速效应的影响。研究表明,悬浮颗粒的穿透曲线可以用一阶沉积动力学对流弥散方程的解析解来描述。随着渗流速度的增大,水动力学作用对颗粒出流浓度的影响越来越大,而孔隙结构的影响则相对减弱。同时,存在一个临界渗流速度值。当渗流速度超出该值时,悬浮颗粒迁移要快于示踪剂,而且临界渗流速度对于玻璃球和石英砂两种多孔介质是不同的;其次,在两种介质中,随渗流速度增大,弥散度增加,回收率和回收悬浮颗粒粒径增大,沉积系数先增大后减小。此外,在孔隙比相近的情况下,悬浮颗粒在玻璃球介质中的回收率要大于其在石英砂中的。可见,孔隙结构和渗流速度是影响饱和多孔介质中颗粒输运的重要因素,渗流速度越大,孔隙结构的作用越明显。

英文摘要：

To investigate the effects of pore structure and hydrodynamic forces on the particle transport and deposition, the penetration processes of a typical silica powder （suspended particles） and fluorescein （as the dissolved tracer） in saturated porous media is studied through a series of column tests. Two kinds of porous media （i.e.,quartz sand and glass beads） and 5 seepage velocities （i.e., 0.033, 0.066, 0.132, 0.199, 0.265 cm/s） are considered, and twenty breakthrough curves are obtained. Based on the experimental results, the influence of pore structure and seepage velocity on the hydrodynamic mechanism, dispersion effects and accelerated effects are analyzed during deposition and migration processes of suspended particles in saturated porous media. It is shown that, the breakthrough curves （BTCs） are well described by an analytical solution of the advective-dispersive equation with a first-order deposition kinetics. In contrast with the effect of pore structure, the effect of hydrodynamics processes on particle transport increases significantly with the increase of seepage velocity. There exists a critical seepage velocity, beyond which suspended particles travel faster than the dissolved tracer, and the critical velocity is different for glass beads and quartz. In addition, the mean diameter of the recovered particles, the longitudinal dispersivity and recovery rate increase with the seepage velocity, and a decrease of the deposition rate of particles beyond the critical seepage velocity is also observed in two porous media. Furthermore, the recovery rate of suspended particles is higher in the glass beads even if the porosities are similar. Overall, the study highlights the effect of pore structure and seepage velocity on the transport of particles in saturated porous media, and the pore structure even plays a greater role in high seepage velocity conditions.