摘要
因干湿、冻融等作用导致黄土强度降低,形成的黄土滑坡是新疆伊犁河谷地区最主要的地质灾害,而矿物成分是岩土体性质变化的主控因素之一,从矿物成分角度分析土体力学性质变化能更深入地认识土体强度变化规律和滑坡成因。本文以伊犁黄土为研究对象,利用三轴压缩和扫描电镜试验,探究不同云母含量(1.8%、3.8%、5.7%和7.7%)的黄土,在不同干湿循环次数(0、1、3、5、10、15、20)下,其抗剪强度及微观结构的变化规律。试验结果显示:云母含量对黄土的抗剪强度存在劣化作用,在相同干湿循环次数下,随着云母含量增加,伊犁黄土抗剪强度呈先增加后减小,总体下降趋势,特别是在第3次干湿循环中表现最为明显。云母含量对抗剪强度参数的影响是不一致的,对粘聚力影响较大,随云母含量的增加,逐渐减少;对内摩擦角影响较小,随着云母含量的增加有波动性的降低。随云母含量增加,黄土微结构逐渐由凝块、圆球状、面胶结、附着型转变为粉粒、似长柱状、点接触、角砾型。
Due to the effects of moisture,freeze-thaw cycles,and other factors,the strength of loess decreases,leading to loess landslides,which are the primary geological hazards in the Ili River Valley region of Xinjiang.The mineral composition is one of the main controlling factors for changes in soil properties.Analyzing the mechanical properties of soil from a mineral perspective can provide deeper insights into the patterns of soil strength changes and the causes of landslides.This paper takes Ili loess as the research object,Using triaxial compression and scanning electron microscopy tests,this study investigates the changes in shear strength and microstructure of Ili loess under different mica contents(1.8%,3.8%,5.7%,and 7.7%)and various numbers of moisture cycles(0,1,3,5,10,15,and 20).The experimental results show that mica content has a detrimental effect on the shear strength of loess.Under the same number of moisture cycles,as the mica content increases,the shear strength of Ili loess first increases and then decreases,showing an overall downward trend,particularly evident during the third moisture cycle.The impact of mica content on shear strength parameters is inconsistent;it significantly affects cohesion,gradually decreasing with increasing mica content;it has a minor effect on internal friction angle,which fluctuates with increasing mica content.As the mica content increases,the microstructure of loess gradually changes from clumps,spherical shapes,surface adhesion,and attachment types to powder particles,elongated columns,point contact,and angular gravel types.
作者
史光明
张艾
薛元
郭泽坤
王定宇
Shi Guangming;Zhang Ai;Xue Yuan;Guo Zekun;Wang Dingyu(School of Geology and Mining Engineering,Xinjiang University,Urumqi,Xinjiang,830017,China)
出处
《新疆地质》
2025年第2期355-362,共8页
Xinjiang Geology
基金
新疆维吾尔自治区自然科学基金(2021D01C111)
自治区高校基本科研业务费项目(XJEDU2025J006)联合资助。
关键词
伊犁黄土
干湿循环
抗剪强度
微观结构
Yili loess
Dry and wet circulation
Shear strength
Micromechanism
