考虑力学-化学荷载下压实黏土垫层中一维非线性固结与污染物运移耦合模型  

Coupled model for one-dimensional nonlinear consolidation and contaminant transport in a compacted clay liner considering mechanical-chemical loading

作　　者：江文豪 李江山[1,3] 冯晨 JIANG Wenhao;LI Jiangshan;FENG Chen(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Science,Wuhan 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Hubei Province Key Laboratory of Contaminated Sludge and Soil Science and Engineering,Wuhan 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：《岩土工程学报》2023年第11期2289-2298,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家重点研发计划课题(2019YFC1804002);国家自然科学基金项目(42177163,51979267)。

摘　　要：针对力学-化学荷载下压实黏土垫层中一维固结与污染物运移耦合过程,考虑了土体压缩性和渗透性的非线性变化,建立了相应的耦合模型,并利用有限差分法对该模型进行了求解。通过与有限元软件COMSOL Multiphysics计算结果和已有解析解计算结果展开对比分析,对所建耦合模型正确性进行了验证。基于所建模型,比较研究了两种假定情况下力学荷载pu和渗滤液中污染物浓度Cb对耦合过程的影响。结果表明:当忽略非线性压缩和渗透特性时,力学荷载pu的增大会使污染物运移速率降低;但当考虑非线性压缩和渗透特性时,pu的增大会使污染物运移速率增大,这主要是由于污染物运移过程会受对流和扩散作用的综合影响。污染物浓度Cb的增大会使沉降量增大,超孔隙水压力值减小,也会使得污染物运移速率降低;相比于忽略非线性的情况,考虑非线性情况下Cb对沉降量、超孔隙水压力和污染物运移速率的影响会减弱。For the coupled process of one-dimensional consolidation and contaminant transport in a compacted clay liner under mechanical-chemical loading,the corresponding coupled model is established by considering the nonlinear changes of compressibility and permeability of soils,and the finite difference method is adopted for solving the model.The correctness of the proposed coupled model is validated by comparing its results with the calculation ones of the finite element software COMSOL Multiphysics and the existing analytical solution.Based on the proposed model,the effects of mechanical loading pu and contaminant concentration Cb in leachate on the coupled process under two assumptions are compared and investigated.The results show that when the nonlinear compressibility and permeability characteristics are neglected,the increase of pu reduces the transport rate of contaminants.However,when the nonlinear compressibility and permeability characteristics are considered,the increase of pu leads to the increase of transport rate,which is mainly due to the comprehensive effects of advection and diffusion on the transport process.The increase of Cb increases the settlement,reduces the excess pore water pressure and decreases the transport rate of contaminants.Compared with the case of ignoring nonlinearity,the effects of Cb on the settlement,excess pore water pressure and transport rate of contaminants are reduced when the nonlinearity is considered.

关 键 词：非线性固结 污染物运移 力学-化学荷载 压实黏土垫层 耦合模型 

分 类 号：TU43[建筑科学—岩土工程] X705[建筑科学—土工工程]