摘要
黄土结构疏松,水敏性强,干黄土遇水易崩解、湿陷。选取工业副产品木质素作为改良材料,以达到增强黄土持水性和水稳性的效果。基于土-水特征曲线试验和湿化崩解试验,研究不同掺量木质素改良黄土的持水性和水稳性,并结合扫描电镜测试探讨掺入木质素导致黄土水稳性改善的内在机制。研究结果表明:1%~2%掺量木质素改良黄土土-水特征曲线较为平缓,且随基质吸力的增加,体积含水率损失较小,持水性最强。不同体积含水率条件下改良黄土的基质吸力均随木质素掺量增加先增后减,反映出改良黄土强度也呈现先增后减的趋势,掺量1%的改良黄土强度达到最优。改良黄土水稳性并非随掺量持续增加而单调增强,1%~2%掺量的改良黄土水稳性最佳。在此基础上分析木质素改良黄土持水性和水稳性的内在微观作用机制,主要表现在有效填充土体孔隙、胶结颗粒和疏水基斥水作用。
Loess has a loose structure and strong water sensitivity,and dry loess is easy to disintegrate and collapse when meeting water.The industrial by-product lignin is used as a modified material to effectively improve the water holding capacity and water stability of loess.Based on a series of soil-water characteristic tests and disintegration tests,the water holding capacity and water stability of lignin-modified loess were studied.Combined with the imagines obtained by scanning electron microscope tests,the microscopic mechanism of lignin improving water stability of loess was analyzed.The results show that the soil-water characteristic curves of the modified loess with a lignin content of 1%–2%are relatively smooth,and that,with increasing the matric suction,the volumetric water content loss is small and the water holding capacity is the strongest.Under different volumetric water contents,the matric suction of the modified loess increases first and then decreases with increasing the lignin content,and reaches the highest as the lignin content is equal to 1%,showing that the strength of the modified loess also increases first and then decreases.The water stability of the modified loess is not continuously enhanced with continuously increasing the lignin content,and the water stability of the modified loess with a lignin content of 1%–2%is the best.Based on these studies,the microscopic mechanism of lignin improving water holding capacity and water stability of loess,mainly represented by the effective filling of soil pores,cementing particles and hydrophobic repellence,was analyzed.
作者
刘钊钊
王谦
钟秀梅
刘富强
梁收运
高中南
LIU Zhaozhao;WANG Qian;ZHONG Xiumei;LIU Fuqiang;LIANG Shouyun;GAO Zhongnan(Key Laboratory of Loess Earthquake Engineering,China Earthquake Administration and Gansu Province,Lanzhou,Gansu 730000,China;Department of Civil Engineering and Mechanics,Lanzhou University,Lanzhou,Gansu 730000,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2020年第12期2582-2592,共11页
Chinese Journal of Rock Mechanics and Engineering
基金
中国地震局地震科技星火计划项目(XH20057)
国家自然科学基金资助项目(51778590)。
