三峡库岸红层土体饱水失水过程中水土化学作用研究  

Study on chemical reactions during red soil soaked and dehydrated processes in Three Gorges Reservoir area

作　　者：彭三曦[1,2] 单慧媚 梁和成 蔡鹤生[1] 李义连[1] 

机构地区：[1]中国地质大学(武汉)环境学院,武汉430074 [2]桂林理工大学地球科学学院,广西桂林541004 [3]桂林理工大学广西环境污染控制理论与技术重点实验室,广西桂林541004 [4]桂林理工大学岩溶地区水污染控制与用水安全保障协同创新中心,广西桂林541004

出　　处：《桂林理工大学学报》2017年第3期444-450,共7页Journal of Guilin University of Technology

基　　金：国家自然科学基金青年基金项目(41502232;407002059);广西矿冶与环境科学实验中心项目(KH2012ZD004);广西高等学校高水平创新团队及卓越学者计划项目(002401013001)

摘　　要：三峡库区水位波动下,岸坡广泛分布的红层土体长期处于"饱和-失水-再饱和"过程,边坡稳定性受到显著影响,其中复杂的水土化学作用被认为是引起土体结构和力学变化的关键因素。选取石榴树包滑坡红层土体为研究对象,设计反复饱水-失水试验,分析水、土化学成分和土体矿物组成变化特征,结合热力学模拟,揭示其反复饱水-失水过程中水土化学作用规律。结果发现:饱水-失水过程显著影响库岸边坡水土化学作用,饱水过程主要发生方解石矿物溶解,该作用随着饱水-失水过程次数的增加而增强;其次该过程发生阳离子交换,以溶液中Ca^(2+)、Mg^(2+)置换出红层土体中Na^+,溶液中K^+置换出红层土体中Mg^(2+)反应为主,其中Ca^(2+)与Na^+的交换反应随饱水-失水过程次数的增加而减弱。In the Three Gorges Reservoir area,red soil is widely distributed and its stability is significantly influenced by fluctuation of river water level.Complicated chemical reactions between water and red soil are the key factors caused changes of soil structure and mechanical property.In this study,red soil samples were collected from the Shiliushubao landslides of the Three Gorges Reservoir area.They were repeatedly soaked by water and dehydrated for three times.In these processes,water samples were collected for analysis of conventional anionic and cationic contents,and soil samples were collected for analysis of mineral and chemical compositions and contents.Thermodynamic models were then established to identify the critical chemical reactions of red soil and water.Results show that in the soil soaked（SS） and soil dehydrated（SD） processes,the major chemical reaction is calcite dissolution and will be enhanced with the increased SS and SD processes.Then follows the cation exchange reaction,mainly including of Ca2＋ and Mg2＋ exchanged Na＋ from red soil,K＋ exchanged Mg2＋ from red soil,in which,Ca2＋ and Na＋ will be weakened with the increased SS and SD processes.

关 键 词：红层土体 饱水-失水过程 热力学模拟 水土化学作用 

分 类 号：P641.3[天文地球—地质矿产勘探]