单裂隙低渗透地层原位氧化修复机制与适用性研究  

Mechanism and application of in-situ oxidation in low-permeability strata with a single fracture

作　　者：郑奇腾 张旭[2] 冯世进 陈宏信[2,3] 张晓磊 ZHENG Qiteng;ZHANG Xu;FENG Shijin;CHEN Hongxin;ZHANG Xiaolei(State Key Laboratory of Disaster Reduction in Civil Engineering,Shanghai 200092,China;Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education,Shanghai 200092,China)

机构地区：[1]土木工程防灾减灾全国重点实验室,上海200092 [2]同济大学地下建筑与工程系,上海200092 [3]岩土及地下工程教育部重点实验室,上海200092

出　　处：《岩土工程学报》2025年第5期1036-1044,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家重大科研仪器研制项目(42227804);国家自然科学基金面上项目(42377152)。

摘　　要：低渗透地层具有渗透性差、物质传输困难等特点,传统氧化修复技术(ISCO)难以满足需求,而压裂可以形成优势渗流通道,提升注入氧化剂的影响范围,但目前对压裂协同氧化机制的认识仍不足,相应的设计指南也极为缺乏。因此,考虑复合溶质对流、扩散、反应和天然需氧量(NOD),建立了单裂隙低渗透地层ISCO修复二维轴对称模型,揭示了氧化剂沿孔隙-裂隙多尺度结构的迁移转化与修复机制,研究了注入压力、氧化剂猝灭、污染物非平衡吸附、基质渗透和扩散系数及污染物分布特征对修复效率的影响规律,结果表明压裂ISCO修复技术更适用于基质渗透系数≤10^(-7)m/s且扩散系数≤8.4×10^(-10)m^(2)/s的低渗透污染地层,且裂隙宜布置在污染羽中下层、氧化剂注入后需持续维持水头,否则修复效果欠佳。最后,对比了不考虑和考虑反应条件下氧化剂的径向和垂向影响范围,提出了相应的设计思路,为压裂增渗协同修复技术的完善提供一定的理论依据。The low-permeability strata are characterized by poor permeability and difficulty in substance transport.The traditional in-situ chemical oxidation(ISCO)techniques often fall short in addressing these challenges.Hydraulic fracturing creates advantageous flow channels,enhancing the ranges of injected oxidants.However,the current understanding of the synergistic mechanism between fracturing and oxidation remains limited,leading to a lack of corresponding design guidelines.Thus,this study considers compound solute advection,diffusion,reactions and natural oxidant demand(NOD)to establish a two-dimensional axisymmetric model for ISCO remediation in low-permeability strata with a single fracture.It reveals the migration and transformation mechanisms of oxidants across pore-fracture multiscale structures,investigating the influences of injection pressure,oxidant quenching,non-equilibrium adsorption of contaminants,matrix permeability,diffusion coefficients and pollutant distribution on remediation efficiency.The results indicate that the hydraulic fracturing ISCO is more suitable for low-permeability contaminated strata with matrix permeability≤10^(-7)m/s and diffusion coefficients≤8.4×10^(-10)m^(2)/s.Placing fractures in the lower layer of the contaminant plume is suggested,maintaining hydraulic head post-oxidant injection for optimal remediation.Finally,comparisons of radial and vertical ranges of oxidants between with and without considering reaction conditions are made,proposing the corresponding design strategies to refine synergistic hydraulic fracturing-enhanced remediation technologies based on the theoretical foundations.

关 键 词：低渗地层 压裂氧化 迁移转化 修复机制 适用性 

分 类 号：TU43[建筑科学—岩土工程]