农业环境科学学报2024，Vol.43Issue(7)：1503-1511,9.DOI:10.11654/jaes.2024-0008
镉污染红黏土强度劣化机理分析
Strength degradation mechanism analysis of cadmium-contaminated laterite
摘要
Abstract
In this study,we revealed the strength degradation mechanism of cadmium-contaminated laterite to investigate how cadmium-contaminated laterite microstructure evolution influences the shear strength of the soil.We studied the shear and microstructure characteristics of cadmium-contaminated laterite using direct shear tests,X-ray diffraction(XRD)analysis,and scanning electron microscopy.Our results demonstrated the following:Cohesion decreased by 25.5%and the internal friction angle increased by 21.1%on average with the increasing cadmium content.Therefore,the shear strength tended to deteriorate,and the shear failure surface shapes became more evident.The microstructure of cadmium-contaminated laterite underwent significant restructuration with the particle erosion phenomenon,coupled with pore development and honeycomb formation based on the microscopic image analysis.Honeycombed pore development increased by 11.8%on average.The soil particle contact modes changed from the angle-side,edge-side,face-face to angle-side,and point-face.The microstructure indices(particle abundance,orientation frequency,and pore fractal dimension)reflected the change soil particle characteristics from strong to weak contact.Due to the strong adsorption capacity of clay particles to cadmium ions,the diffusion electrical double layer was compressed and hydrolysis occurred between the cadmium ions and carbonates in the clay.Therefore,the binding force of the water film between the clay particles was reduced and the cohesive structural function gradually weakened.In summary,cadmium contamination exerts a deterioration effect on laterite shear strength to worsen soil erosion in the cultivated land layer under the surface runoff effect easily.关键词
红黏土/镉污染/抗剪强度/微观结构/劣化效应Key words
laterite/cadmium contamination/shear strength/microstructure/degradation effect分类
农业科技引用本文复制引用
陈小双,徐兴倩,刘剑,赵熹,尹亚敏,王海军,王能龙..镉污染红黏土强度劣化机理分析[J].农业环境科学学报,2024,43(7):1503-1511,9.基金项目
国家自然科学基金项目(42367025) （42367025）
云南省基础研究计划面上基金项目(202101AT070271) （202101AT070271）
云南省农业联合专项(202301BD070001-171) （202301BD070001-171）
云南省高层次人才培养支持计划"青年拔尖人才"专项(YNWR-QNBJ-2020-030)Special Funds of the National Natural Science Foundation of China(42367025) （YNWR-QNBJ-2020-030）
Yunnan Provincial Research Foundation for Basic Research(202101AT070271) （202101AT070271）
Yunnan Agricultural Joint Special Project(202301BD070001-171) （202301BD070001-171）
Yunnan Province High Level Talent Training Support Program"Youth Top Talents"Special Project(YNWR-QNBJ-2020-030) （YNWR-QNBJ-2020-030）
