考虑固结作用下非均质隔离墙系统中重金属污染物二维运移特性研究  

Study on the two-dimensional transport characteristics of heavy metal pollutants in a non-homogeneous cutoff wall system considering the consolidation effect

作　　者：江文豪 黄啸 冯晨 李江山[1,2,3] JIANG Wenhao;HUANG Xiao;FENG Chen;LI Jiangshan(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Hubei Province Key Laboratory of Contaminated Sludge and Soil Science and Engineering,Wuhan,Hubei 430071,China)

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]中国科学院大学,北京100049 [3]污染泥土科学与工程湖北省重点实验室,湖北武汉430071

出　　处：《岩石力学与工程学报》2024年第7期1722-1735,共14页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点研发计划(2019YFC1804003)。

摘　　要：固结行为会使隔离墙的工程性质沿深度呈非均质性,影响墙体中重金属污染物的运移规律,但相关研究较少。首先,建立非均质隔离墙系统(由缓冲层、非均质隔离墙和含水层组成)中重金属污染物二维运移模型,该模型考虑了固结作用和Langmuir吸附特征。随后,利用数值方法对该模型进行求解,并通过与试验测定结果及其他2种计算方法所得结果对比,验证了模型合理性。在此基础上,开展重金属污染物运移特性研究。结果表明,与忽略固结作用相比,考虑固结作用下隔离墙上部区域的浓度会增大,底部区域的浓度会降低。考虑Langmuir吸附场景下重金属污染物的运移速率高于考虑线性吸附场景下,且2种场景下相对浓度的差异随污染源浓度升高而更显著。进一步,防渗效果评价显示,缓冲层厚度增大有利于延长隔离墙的服役寿命,但鉴于“围护式”隔离墙被广泛应用于实际工程,因而其厚度不应太大。此外,相较于考虑固结作用场景,忽略固结作用场景可能会高估隔离墙的防渗性能。隔离墙厚度及其吸附能力的增大均可提高墙体防渗性能,工程实践中可综合二者开展防污屏障设计。所建模型及研究结果可为隔离墙的有效设计和服役性能评价提供指导。Consolidation behaviour results in non-homogeneous engineering properties of the cutoff wall along the depth,thus affecting the transport characteristics of heavy metal pollutants(HMPs)in the cutoff wall.However,the associated studies are limited.In this paper,a two-dimensional transport model for HMPs in a non-homogeneous cutoff wall system(consisting of a buffer layer,a non-homogeneous cutoff wall and an aquifer)is developed,where the consolidation effect and the Langmuir adsorption features are considered.Then,the proposed model is solved through a numerical approach and its validity is verified by comparing with the experimental measurements and the calculation results of the two other calculation methods.On such basis,a study on the transport characteristics of HMPs is performed and the results show that the concentration in the upper zone of the cutoff wall increases and the concentration in the bottom zone reduces when the consolidation effect is considered compared to it is neglected.The transport rate of HMPs in the Langmuir adsorption scenario is higher than that in the linear adsorption scenario,and the difference in relative concentrations between the two scenarios becomes more significant with growing concentration of the pollution source.Furthermore,the evaluation of barrier performance reveals that the increase of the buffer layer's thickness is beneficial in prolonging the cutoff wall's service life.Nevertheless,the buffer layer's thickness should not be too large given that the“enclosure”cutoff wall is widely applied in practical engineering.Besides,ignoring the consolidation scenario may overestimate the barrier performance of the cutoff wall compared to considering the consolidation scenario.Both the increase in the cutoff wall's thickness and its adsorption capacity can improve its barrier performance,and the two aspects can be combined to conduct the design of anti-fouling barriers in engineering practice.The proposed model as well as the obtained laws in this paper can provide guidance f

关 键 词：环境科学 固结 非均质隔离墙 缓冲层 重金属污染物 二维运移 LANGMUIR吸附 

分 类 号：X53[环境科学与工程—环境工程]