斥水膨胀土的水力稳定性  

Hydraulic stability of water-repellent expansive soil

作　　者：杨松 黄英豪 YANG Song;HUANG Yinghao(College of Civil Engineering and Architecture,Beibu Gulf University,Qinzhou 535011 China;State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Nanjing 210024,China;Geotechnical Department,Nanjing Hydraulic Research Institute,Nanjing 210024,China)

机构地区：[1]北部湾大学建筑工程学院,钦州535011 [2]水文水资源与水利工程科学国家重点实验室,南京210024 [3]南京水利科学研究院岩土工程研究所,南京210024

出　　处：《农业工程学报》2023年第24期127-133,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(41867038)。

摘　　要：由于对斥水性黏土的斥水稳定性缺乏认识,斥水土应用仅针对斥水干砂,而干砂的力学性质较差,应用范围非常有限。为充分扩展斥水土的应用范围,该研究用十八胺对吸附性较强的膨胀土进行斥水改性,并分析不同斥水度的松散膨胀土吸附水蒸气后的斥水稳定性,在此基础上进行5种膨胀土击实试样(亲水膨胀土、亲水膨胀土+亲水砂、亲水膨胀土+斥水砂、斥水膨胀土、斥水膨胀土+斥水砂)的水力稳定性研究。结果表明:水气吸附试验前不同斥水度(包括轻微斥水)的膨胀土在吸附稳定后都变成了极度斥水,且各测试点都均匀斥水。击实后的斥水膨胀土与斥水膨胀土+斥水砂试样,在较大的含水率变化范围内均表现出了斥水性。与其他试样相比,斥水膨胀土+斥水砂的水力性能最好,可使膨胀土的膨胀率从33.9%下降为3.45%,收缩裂隙度从18.75%下降为3.6%,与亲水膨胀土相比,斥水膨胀土的基质吸力与强度参数并没有出现明显的改变。膨胀土较强的吸附性及斥水团聚体的存在是斥水膨胀土产生特殊的斥水性与水力特性的主要原因。研究可为斥水性黏土在农业工程中的应用及推广提供思路,同时也为扩展斥水性土壤的应用范围提供相应的理论参考。Water-repellent soil has a very wide application prospect in the field of agricultural engineering.However,it is still lacking in the hydraulic stability of water-repellent clay.The applications are only targeted at water-repellent dry sand so far.In this study,octadecylamine was taken to modify the highly adsorbent expansive soil with water repellency.A systematic investigation was also conducted to explore the water-repellent and hydraulic stability of loose expansive soil with different water repellency after adsorbing water vapor.Five samples were selected as the compacted expansive soil(hydrophilic expansive soil,hydrophilic expansive soil+hydrophilic sand,hydrophilic expansive soil+water repellent sand,water repellent expansive soil,water repellent expansive soil+water repellent sand).The results show that the greater the humidity was,the greater the mass of water vapor adsorbed by different water repellency expansive soil was.At the same humidity,the water repellency shared little effect on the mass adsorbed by soil.The expansive soil with different water repellency(including slight water repellency)was extremely water repellent after adsorption,where all test points were evenly water repellent.The huge specific surface area of water-repellent expansive soil was obtained for the strong adsorption properties.As such,the water repellency of expansive soil further increased to fully adsorb octadecylamine molecules while adsorbing water vapor during adsorption.After compaction,the water-repellent expansive soil and water-repellent expansive soil+water repellent sand samples exhibited water repellency in a large range of moisture content.There was a range of water-repellent moisture content,all of the soil samples were extremely water-repellent.Compared with the rest,the best hydraulic performance was achieved in the water-repellent expansive soil+water-repellent sand mixed sample share.Specifically,the expansion rate of the expansive soil was reduced from 33.9%to 3.45%,and the shrinkage fissure degree was redu

关 键 词：土壤 含水率 裂隙 斥水度 吸附 力学特性 

分 类 号：S278[农业科学—农业水土工程]