污染场地地下水曝气修复微观机理研究

Site remediation technology is one of the hot and front research areas in the fields of geology, environmental and geotechnical engineering currently. In this research project, the in-situ groundwater air-sparging technology for VOCs contaminated site is systemetically investigated by theorerical anaylysis, physical modeling, and numerical simulation. The remediation mechanism will be analyzed at pore scale, and the theoretical model based on the micro-mechanics will be established to describe the coupling process of multi-phase flow in porous media and contaminant transport, and to study the characteristics of air movement and micro-channel development during air sparging process. The physical modeling tests such as soil column and geotechnical centrifuge models will be conducted to further investigate the features of air micro-channel distribution and zone of influence during air sparging and the effect of complicated hydro-geology condition on remediation process, verifying the theoretical model. The representative element volume (REV) will be proposed to reflect the micro-mechanism at pore scale, and the numerical simulation software by finite element method will be developed to simulate the multi-field couping process and tempo-spatial distribution of contaminants via the multi-scale coupling technique and the characteristics of REV. Based on the results of theorerical anaylysis, physical modeling, and numerical simulation, the relationship among the design parameters such as sparging pressure, air flow rate, zone of influence, and required remediation time will be analyzed, and the generized design criteria will be proposed. The research has important academic value as well as wide application prospects. The research will be helpful to improve the environmental remediation technology, and promote the sustainable development of geological environment.

污染场地原位修复技术是当今地质、环境与岩土工程研究的热点和前沿课题。本项目以挥发性有机物污染场地原位曝气修复方法为对象，在孔隙水平深入研究其修复机理，建立多孔介质多相渗流与污染物运移传质转化耦合过程的微观力学理论模型，分析气体运动和气流微通道发展特征；通过一维土柱和土工离心模型试验研究气流微通道分布特征和曝气影响区域三维特征，探讨复杂水文地质条件对曝气修复过程的影响，对理论模型进行分析验证；建立反映孔隙尺度微观特征的表征体元模型，采用多尺度耦合技术，开发基于表征体元性质的多场耦合有限元数值分析软件，模拟修复过程中污染物时空分布特征。根据理论分析、模型试验和数值模拟成果，分析曝气修复系统中曝气压力、气体流量、影响区域和修复时间等重要设计参数的相关关系，提出具有普遍意义的设计准则。项目研究具有重要的学术价值和广泛的工程应用前景，有助于推动环境修复技术水平的提高，促进我国地质环境的可持续发展。

污染场地原位修复技术是当今地质、环境与岩土工程研究的热点和前沿课题。本项目以挥发性有机物污染场地原位曝气修复方法为对象，在孔隙水平深入研究其修复机理，基于孔隙空间结构的网络模型建立多孔介质多相渗流与污染物运移传质转化耦合过程的微观力学理论模型，分析气体运动和气流微通道发展特征；通过土工离心模型试验研究曝气影响区域特征，探讨复杂水文地质条件对曝气修复过程的影响，对理论模型进行分析验证；建立反映孔隙尺度微观特征的表征体元模型，采用多尺度耦合技术，开发基于表征体元性质的多场耦合有限元数值分析软件，模拟修复过程中污染物时空分布特征。根据理论分析、模型试验和数值模拟成果，分析曝气修复系统中曝气压力、气体流量、影响区域和修复时间等重要设计参数的相关关系，提出具有普遍意义的地下水曝气修复工程设计准则。项目研究具有重要的学术价值和广泛的工程应用前景，在理论模型、物理模型试验和数值分析等方面均有创新性的研究成果，推动多孔介质多相渗流理论发展，有助于环境修复技术水平的提高，促进我国岩土地质环境的可持续发展。