Article
Environmental Sciences
Haijian Xie, Hao Ding, Huaxiang Yan, Dandi Yang, Zhanghua Lou, Zhanhong Qiu, Yun Chen
Summary: This study presents an analytical model to investigate the effects of cracks on the migration of organic contaminants in a composite liner system. The results show that the presence of cracks significantly affects the breakthrough curve and bottom concentration of contaminants. Increasing the adsorption factor and degradation rate of contaminants can improve the performance of the composite liner.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Environmental Sciences
Hao Ding, Haijian Xie, Peifu Cai, Liang Wang, Huaxiang Yan, Aimin Jin, Yun Chen
Summary: This study develops alternative formulations for transient analytical modeling of organic contaminant transport in a composite of geosynthetic clay and attenuation layer system. The Laplace transform method is used to derive the solution. The proposed analytical frameworks are validated by benchmark tests and applied to evaluate various cases of organic contaminant transport.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Engineering, Geological
Huaxiang Yan, Jiawei Wu, Hywel R. Thomas, Hao Ding, Liangtong Zhan, Haijian Xie
Summary: This study investigates the behavior of organic chemicals transport in landfill composite liner system. It was found that the triple liner under double drainage boundary condition performs better compared to the case under single drainage boundary condition. Additionally, GCL consolidation can increase the breakthrough time.
GEOTEXTILES AND GEOMEMBRANES
(2021)
Article
Engineering, Geological
Huaxiang Yan, Haijian Xie, Hao Ding, Dandi Yang, Cong Chen, Yunmin Chen, Yun Chen
Summary: A composite liner system consisting of a geomembrane layer, a compacted clay layer, and an attenuation layer is widely used in landfills. Consolidation of the soil liner can have detrimental effects on contaminant breakthrough, particularly under relatively high stress caused by waste placement. This study develops a one-dimensional model to investigate the transport behavior of contaminants in the composite liner system considering consolidation. The results show that the volume compressibility coefficient in the attenuation layer and the thickness of the attenuation layer play important roles in controlling the consolidation induced effects.
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS
(2022)
Article
Computer Science, Interdisciplinary Applications
Huaxiang Yan, Haijian Xie, Jiawei Wu, Hao Ding, Zhanhong Qiu, Zhilin Sun
Summary: An analytical model for transient contaminant transport in clay barriers under the combined effects of diffusion, adsorption, and consolidation processes has been developed. The model was validated using experimental results. The study found that the consolidation model with large displacement induces the shortest breakthrough time and contributes significantly to the contaminant flux.
COMPUTERS AND GEOTECHNICS
(2021)
Article
Computer Science, Interdisciplinary Applications
Jin-Wei Qiu, Lu-Sha Jiang, He-Fu Pu, Ding-Bao Song, Ming Min, Jun Tong
Summary: This study presents analytical solutions for one-dimensional contaminant transport in a saturated double-layer composite liner system. The solutions consider the effects of CCL effective porosity, GMB defects, and thermodiffusion, providing temperature distribution and contaminant concentration distribution for steady state as well as transient-state conditions. The proposed solutions are validated and verified, and parametric studies indicate the importance of considering thermodiffusion and CCL effective porosity in estimating contaminant outflow rate.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Engineering, Environmental
Ming-Qing Peng, Shi-Jin Feng, Hong-Xin Chen, Zhang-Long Chen, Hai-Jian Xie
Summary: A new analytical model for organic contaminant transport through GMB/CCL composite liner was developed, considering adsorption, diffusion, and thermodiffusion processes. The study showed that thermodiffusion has a significant impact on contaminant transport in wet landfills, and neglecting its effect can lead to overestimation of barrier performance. Additionally, thermal conductivity of GMB and CCL has negligible effect on contaminant transport in GMB/CCL composite liners.
Article
Environmental Sciences
Shaymaa Mustafa, Arifah Bahar, Zainal Abdul Aziz, Mohamad Darwish
Summary: This article presents several analytical solutions for three-dimensional contaminant transport in a homogeneous and isotropic aquifer using Green's function and groundwater flow in three directions. The study confirms the influence of groundwater velocities and the geometrical shape of contaminant sources on the spreading and concentration of contaminants.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Engineering, Environmental
Lee Li Yong, Vivi Anggraini, Mohd Raihan Taha, Mavinakere Eshwaraiah Raghunandan
Summary: This study investigates the transport behavior of heavy metals (cadmium, copper, lead, and zinc) through an earthen liner and determines the optimum thickness of the liner to prevent breakthrough. Results show that the migration of heavy metals is greater in silty sand due to its higher porosity and lower adsorption capacities. Numerical simulations reveal that the optimum thickness for clayey and silty sand liners to retain the studied heavy metals within regulatory threshold values for 100 years is 1 m and 1.9 m, respectively. Cadmium can serve as a key indicator of early heavy metal contamination in landfill leachate migration from Malaysian municipal solid waste landfills.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2022)
Article
Engineering, Geological
Zhang-Long Chen, Jun Liu, Chuang Yu, Shun Wang, Wei Wu
Summary: This study presents an exact solution to the thermal gradient enhanced diffusion of organic contaminants through unsaturated composite liners, considering the existence of the capillary fringe. The results show that the capillary fringe has a significant influence on contaminant diffusion and the thermal effects. A simplified solution is proposed and evaluated for engineering practice. These findings are important for analyzing organic contaminants diffusion in unsaturated composite liners with the consideration of the capillary fringe and thermal effects.
Article
Multidisciplinary Sciences
Shujie Tu, Xiaoming Liu, Hongjiang Cai
Summary: A mathematical model of colloidal particle migration in saturated porous media with the gravity effect is established in this paper. The study shows that gravity is an important mechanism of particle migration in saturated porous media and its effects are influenced by the particle size, density, and seepage velocity.
Article
Engineering, Civil
Junqi Huang, John Christ, Mark N. Goltz
Summary: An analytical solution for modeling contaminant transport in fractured-rock matrix systems was developed in this study, explicitly simulating Poiseuille flow in the fractures. The model includes contaminant diffusion, aqueous phase decay, and sorption onto matrix solids. Simulation results suggest that the dispersion approximation may not be sufficient in certain scenarios.
JOURNAL OF HYDROLOGY
(2021)
Article
Engineering, Geological
Haijian Xie, Jiawei Wu, Hywel R. Thomas, Peifu Cai, Huaxiang Yan, Yun Chen
Summary: This study investigates the effects of leachate head variations on contaminant transport in landfill sites. The results show that variations in leachate head can cause time-dependent changes in seepage velocity and alter the transport mechanisms of contaminants. Considering the effects of leachate head variations is critical in designing a stable and reliable landfill liner.
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS
(2023)
Article
Engineering, Geological
Lin Han, Zhihong Zhang
Summary: This paper proposes novel analytical solutions to solve the non-zero initial concentration (NZIC) problem for a fully-coupled hydraulic-mechanical-chemical (HMC) model by Fourier transform, which are highly competent and efficient compared with existing solutions. The solutions are applied to investigate the long-term contaminant transport behavior and consequent deformation of clay liner under NZIC conditions. Neglecting the NZIC of contaminant can lead to an overestimation of performance efficiency of clay liners in practical engineering.
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS
(2023)
Article
Environmental Sciences
Akhilesh Paswan, Pramod Kumar Sharma
Summary: A mathematical model has been developed to study the effect of stagnant zones on the transport of contaminants with colloids in groundwater flow systems. The model simplifies the mobile-immobile (MIM) model and considers the equilibrium approach for mobile-immobile regions. Results show that the presence of stagnant zones enhances contaminant transport and increases the velocity in mobile regions, leading to augmented breakthrough curves.
WATER RESOURCES RESEARCH
(2023)
Article
Engineering, Geological
Qiao Wang, Shuangke Fei, Liang Wang, Abdelmalek Bouazza, Siliang Shen, Haijian Xie
Summary: Methane emissions from the Jiangcungou landfill in China were examined and compared with the results obtained from the Calmim model. The study found that methane emissions from the temporary cover were significantly higher than those from the final cover and working face. The observed fluxes were lower than the predicted values by Calmim, which can be attributed to the transient nature of field monitoring and the neglect of lateral gas migration in the model.
ENVIRONMENTAL GEOTECHNICS
(2023)
Article
Engineering, Geological
Xinru Zuo, Yunmin Chen, Liang Wang, Haijian Xie, Siliang Shen
Summary: This study investigated the mechanism of multicomponent landfill gas transport in loess through soil column tests and numerical modeling. The results showed that ordinary diffusion played a key role in the gas transport, while Knudsen diffusion had a relatively weak effect. Increasing influent flux could enhance the methane oxidation rate.
ENVIRONMENTAL GEOTECHNICS
(2023)
Article
Engineering, Mechanical
Junting Lu, Haibo Xie, Yunmin Chen, Huayong Yang
Summary: In this paper, a flow-reduced double valve actuation strategy is proposed to improve the performance of electro-hydraulic servo drives by reducing the flow and enhancing the dynamic response of the servo valve. Simulation and experimental results demonstrate that the proposed strategy outperforms the conventional single valve actuation in terms of dynamic performance.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE
(2023)
Article
Engineering, Geological
Junchao Li, Kaiwen Yang, Yubing Wang, Ruoxi Chen, Yunmin Chen
Summary: The slope on coastal soft soil ground poses a high risk of landslide and settlement during earthquakes, leading to damage to structures above. Soil replacement is an effective method to improve the seismic stability of coastal soft soil ground. Centrifuge shaking table tests were carried out to investigate the seismic response and stability of soft soil ground and slopes before and after replacement. The results indicate that the acceleration response of the backfill slope increases after the soft soil is replaced, while the post-earthquake settlement significantly decreases. The study also found that replacing the soft soil foundation can enhance drainage, accelerate the dissipation of excess pore pressure, and reduce post-earthquake settlement.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2023)
Article
Energy & Fuels
Qingdong Li, Zexu Ning, Jia Liu, Wenjie Xu, Liangtong Zhan, Jiqin Liu, Yunmin Chen, Xilin Shi, Xiangsheng Chen, Jinlong Li
Summary: This paper investigates the impact of step distance on the stability and economy of multi-step horizontal salt caverns (MSHSCs) for energy storage. The study uses a solution mining model to determine the geometry of MSHSCs with different step distances and conducts static creep analyses to assess stability risks. Results show that smaller step distances increase stability risks but also lead to increased cavern volume and expected revenue. Economic analysis is conducted to find a balanced step distance, and a medium step distance of 100 m or 125 m is recommended for MSHSC design.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Engineering, Geological
Yuan Cao, Yuhei Kurimoto, Yan-Guo Zhou, Akira Ishikawa, Yunmin Chen
Summary: This study investigates the seismic response and liquefaction mitigation effect of soil-cement grid improved ground subjected to large earthquake loadings through dynamic centrifuge tests. The results show that the soil-cement grid effectively mitigates soil liquefaction and post-shaking settlements, even under very strong shakings. The interaction between the soil and the cement grid plays a significant role in reducing dynamic shear strain and enhancing the overall performance of the improved ground.
BULLETIN OF EARTHQUAKE ENGINEERING
(2023)
Article
Computer Science, Interdisciplinary Applications
Chuang Zhao, Jiaming Liu, Hongming Liu, Xuecheng Bian, Yunmin Chen
Summary: Soft soils under transportation infrastructures subjected to high-frequency and high-cycle traffic loads exhibit shakedown deformation development. A conceptual model was proposed to describe the behavior of soft soils under such loads, taking into account the weakening effect of excess pore water pressure increase and the hardening effect of contractive plastic deformation. The model incorporates a mapping ratio and a one-time calculation approach to consider the effect of loading frequency and improve calculation efficiency. Validation tests and parametric analyses were conducted, demonstrating the feasibility and reliability of the proposed model.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Engineering, Geological
Huaxiang Yan, Haijian Xie, Hamid Rajabi, Xiting Gu, Yun Chen
Summary: This study proposes an analytical solution for a one-dimensional and steady-state model to analyze the diffusion of VOCs within landfill capillary cover systems under unsaturated water flow and stable conditions. The research examines the impact of evaporation rate and clay thickness on coupled water flow and VOCs diffusion. The findings reveal the importance of considering unsaturated water flow in assessing VOC emissions in the cover system.
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS
(2023)
Article
Engineering, Environmental
Haijian Xie, Cong Chen, Yanghui Shi, Zijing Zheng, Yun Chen, Huaxiang Yan
Summary: Phthalic acid estes (PAEs) are common organic contaminants in landfill leachate, but can be effectively controlled by loess-bentonite cut-off walls modified by hexadecyltrimethylammonium chloride (HTMAC-B). Through adsorption batch tests and numerical transport simulations, it was found that the HTMAC-B modified loess-bentonite can enhance the adsorption capacity for mixed solutions of dimethyl phthalate (DMP) and diethyl phthalate (DEP), thus increasing the breakthrough time of PAEs. The Toth model was found to better capture the adsorption behavior induced by the heterogeneous surface morphology.
JOURNAL OF ENVIRONMENTAL ENGINEERING
(2023)
Article
Engineering, Civil
Xuecheng Bian, Zelei Gao, Xue Luo, Degou Cai, Yunmin Chen
Summary: This study establishes a discrete element method (DEM) model of asphalt track bed to investigate the effect of asphalt layer on the dynamic response and cyclic settlement of ballasted track bed under high-speed train moving loading. Results show that the asphalt layer reduces vibration, cumulative settlement of the ballast layer, and improves the uniformity of the force chain network inside the ballast layer. Parameter analysis indicates that the required thickness of the ballast layer in the asphalt track bed could be reduced by approximately one-third without changing the bearing capacity of the subgrade, making it a more economical and effective track form for high-speed or heavy-haul railway lines.
JOURNAL OF TRANSPORTATION ENGINEERING PART B-PAVEMENTS
(2023)
Article
Engineering, Geological
Han Ke, Chen Sheng Zhang, Mei Lan Zhang, Xing Xu, Xu Liang, Dian Kun Xiao, Ji Wu Lan, Yun Min Chen, Ji Tang, Jie Hu
Summary: Aeration is an effective technique for stabilizing municipal solid waste (MSW) landfills. This study investigated the distribution of oxygen during air injection in an MSW landfill in Shanghai. Results showed that the methane concentration decreased and the oxygen concentration increased rapidly after air injection. A dual-porosity model was proposed to simulate the rapid diffusion and advection of air. The study also observed competitive air injection and uneven increase in waste resistivity during multiple-well injection.
JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING
(2023)
Article
Engineering, Geological
Zhangbo Wan, Weichang Xu, Xuecheng Bian, Yunmin Chen
Summary: This paper presents a full-scale physical modeling investigation on mud pumping in ballastless trackbed. The study found that high-speed train passages caused a separation between the track structure and the underlying roadbed, allowing rainwater to intrude into the roadbed. This intrusion led to saturation of the roadbed and the formation of excess pore water pressure. The study also revealed that mud pumping was driven by hydraulic gradients and amplified by the excess pore water pressure induced by high-speed train passages. Mud pumping resulted in a decrease in trackbed stiffness and an increase in vibration velocity of the track slab.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2023)
Article
Engineering, Environmental
Ke Li, Wenjie Xu, Yunmin Chen, Liangtong Zhan, Han Ke, Hui Xu, Diankun Xiao
Summary: This study investigates the complex process of thermal-hydro-mechanical-biochemical coupled degradation in high food waste content municipal solid waste (MSW) and proposes a THMBC coupled degradation model. The results show that recharging heated mature leachate accelerates the degradation process and settlement, and intraparticle water release contributes to half of the settlement. The research provides theoretical support for the design, construction, and management of landfills.
Article
Materials Science, Multidisciplinary
Zhehui Zhao, Haoran Fu, Ruitao Tang, Bocheng Zhang, Yunmin Chen, Jianqun Jiang
Summary: The rapid evolution of flexible electronic devices holds great potential, but their reliability needs improvement. Understanding failure mechanisms is crucial for enhancing reliability. Various failure modes have been identified and characterized using different methods.
INTERNATIONAL JOURNAL OF SMART AND NANO MATERIALS
(2023)
Article
Environmental Sciences
Hao Ding, Haijian Xie, Peifu Cai, Liang Wang, Huaxiang Yan, Aimin Jin, Yun Chen
Summary: This study develops alternative formulations for transient analytical modeling of organic contaminant transport in a composite of geosynthetic clay and attenuation layer system. The Laplace transform method is used to derive the solution. The proposed analytical frameworks are validated by benchmark tests and applied to evaluate various cases of organic contaminant transport.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
