增减湿条件下喀什地区湿陷性黄土结构强度损伤劣化规律  

Structural Strength Damage and Deterioration of Collapsible Loess in Kashi Area Under Condition of Increasing and Decreasing Humidity

作　　者：李涵 王海娟[1,2] 马红娜 张映珍 LI Han;WANG Hai-juan;MA Hong-na;ZHANG Ying-zhen(College of Water Conservancy&Architectural Engineering,Shihezi University,Shihezi 832000,China;Key Laboratory of Cold and Arid Regions Eco-Hydraulic Engineering of Xinjiang Production&Construction Corps,Shihezi 832000,China;Anhui Province Pishihang Irrigation Area District Administration of Engineering Technology Center,Hefei 230088,China)

机构地区：[1]石河子大学水利建筑工程学院,新疆石河子832000 [2]寒旱区生态水利工程兵团重点实验室,新疆石河子832000 [3]安徽省淠史杭灌区管理总局工程技术中心,安徽合肥230088

出　　处：《水电能源科学》2024年第10期96-100,49,共6页Water Resources and Power

基　　金：新疆叶尔羌河錾高水电站工程渠道结构研究与验证评价技术咨询服务(XHZS-A-JF-2022-011)。

摘　　要：为研究喀什地区湿陷性黄土在增湿减湿作用下结构强度损伤劣化规律,开展了增湿减湿条件下室内常规三轴剪切试验(CU)和电镜扫描试验。结果表明,宏观方面,增湿过程中,增湿前期黄土的结构强度对含水率的变化较为敏感,且粘聚力随含水率的增加逐渐减小;减湿过程中,重塑湿陷性黄土的应力-应变曲线在一定范围内发生变化,粘聚力呈现先减后增的趋势,内摩擦角受含水率变化影响较小。微观方面,增湿过程中重塑湿陷性黄土颗粒连接方式从面面接触为主转变为点点接触和点面接触为主,颗粒接触面积逐渐减小,受外力时颗粒易发生错动;减湿过程中,土样内部产生轻微裂隙,颗粒发生干缩,使土体结构强度有所上升;分析验证了黄土增湿损伤力学本构模型能较好地描述喀什地区湿陷性黄土在增湿作用下的损伤过程。研究结果可为在喀什地区湿陷性黄土地基上修建工程提供相关力学参数和理论支撑。In order to study the law of structural strength damage and deterioration of collapsible loess in Kashi area under the action of humidification and dehumidification,laboratory triaxial shear test(CU)and electron microscope scanning test were carried out under conditions of humidification and dehumidification.The results show that the structural strength of loess is sensitive to the change of water content,and the cohesion decreases with the increase of water content.During the process of dehumidification,the stress-strain curve of remolded collapsible loess changes within a certain range,the cohesion decreases first and then increases,and the internal friction Angle is less affected by the change of water content.From the micro respect,the particle connection mode of the remodeled collapsibility loess changes from surface contact to point contact during the process of humidification.The contact area of the particles decreases gradually,and the particles are prone to dislocation when subjected to external forces.In the process of dehumidification,slight cracks occur inside the soil sample,and the particles shrink,which increases the structural strength of the soil.It is verified that the mechanical model of loess humidification damage can describe the damage process of collapsibility loess in Kashi area under humidification.The research results can provide relevant mechanical parameters and theoretical basis for the construction of collapsion loess foundation in Kashgar area.

关 键 词：增湿减湿 结构损伤 力学特征 电镜扫描 沉降计算 

分 类 号：TV223.2[水利工程—水工结构工程]