裂隙宽度空间变异性和泄漏条件对网络裂隙中DNAPLs运移影响研究  

Effects of spatial variability of fracture width and leakage conditions on the migration of DNAPLs in network fractures

作　　者：常兴 骆乾坤[1] 邓亚平 马雷[1] 钱家忠[1] CHANG Xing;LUO Qiankun;DENG Yaping;MA Lei;QIAN Jiazhong(School of Resources and Environmental Engineering,Hefei University of Technology,Hefei,Anhui 230009,China)

机构地区：[1]合肥工业大学资源与环境工程学院,安徽合肥230009

出　　处：《水文地质工程地质》2022年第3期174-181,共8页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金项目(41502226,41831289,41772250);中央高校基本科研业务费(JZ2018HGTB0251)。

摘　　要：DNAPLs本身的化学性质、裂隙的几何性质以及泄漏条件等影响重非水相流体(DNAPLs)在裂隙介质中的运移和分布。针对DNAPLs的运移规律研究多集中在孔隙介质和单裂隙中,在随机网络裂隙中的研究较少。本研究生成随机网络裂隙是基于蒙特卡罗方法,运用像素扫描识别并输出裂隙的坐标和宽度,然后采用PetraSim模拟四氯乙烯(PCE)在随机网络裂隙中的运移,探讨裂隙宽度空间变异性和泄漏条件(包括泄漏速率和泄漏位置)对DNAPLs运移的影响。数值模拟结果表明:DNAPLs的空间展布和运移路径受裂隙宽度空间变异性影响,随着网络裂隙中裂隙宽度空间变异性增大,出现优势通道,DNAPLs运移的速率加快,DNAPLs的质心位置和饱和度空间分布发生明显变化;DNAPLs的运移速率和空间展布受泄漏速率影响,泄漏速率越大,DNAPLs运移速率越快,模型底部蓄积的DNAPLs的饱和度越大,DNAPLs的空间展布也越大;同一网络裂隙中,泄漏位置不同,导致DNAPLs的运移路径及分布范围不同,不同的泄漏位置重力方向裂隙空间变异性不同,导致DNAPLs运移路径和空间展布各不相同。研究结果可以丰富裂隙介质中DNAPLs运移机理研究,为裂隙介质中DNAPLs污染修复提供模型参考。The migration and distribution of dense non-aqueous phase liquid(DNAPLs)in fractured media are affected by many factors,including the chemical properties of DNAPLs,geometric and chemical properties of fractures and leakage conditions.Previous studies were mostly conducted in a single fracture,while the migration of DNAPLs in stochastic network fracture were seldom examined.In this paper,stochastic network fractures are generated using the Monte Carlo method.The coordinates and apertures of fractures are identified and output by pixel scanning. The migration of Perchloroethylene (PCE) in the stochastic network fractures is simulated by PetraSim. The effects of the geometric properties of the fractures and the leakage conditions (including the leakage rate and the leakage location) on the migration of DNAPLs are discussed. The numerical simulation results show that the spatial variability of fractures also affects the migration path and spatial distribution of DNAPLs. With the increase of spatial variability of fracture width in the network fractures, dominant channels appear, the migration rate of DNAPLs accelerates, and the location of DNAPLs centroid and the spatial distribution of saturation change significantly. The leakage rate affects the migration range and spatial distribution of DNAPLs. The higher the leakage rate is, the faster the migration rate of DNAPLs will be. The more saturated the accumulated DNAPLs at the bottom of the model, the greater the spatial distribution of DNAPLs is. In the same network fracture, different leakage locations will also lead to different migration paths and distribution ranges of DNAPLs. The spatial variability of fractures in the gravity direction at different leakage locations is different, leading to different migration paths and spatial distribution of DNAPLs.

关 键 词：随机网络裂隙 蒙特卡罗 像素扫描 重非水相流体 PetraSim 

分 类 号：X523[环境科学与工程—环境工程]