含水率对黄土高原地区几种主要类型土壤流变特性的影响  

Effect of Water Content on Rheological Properties of Several Major Types of Soil in Loess Plateau Region

作　　者：张亚楠 周琳 许晨阳[1] 杜伟 胡斐南 Zhang Yanan;Zhou Lin;Xu Chenyang;Du Wei;Hu Feinan(College of Resources and Environment,Northwest A&F University,Yangling,Shaanxi 712100,China;State Key Laboratory of Soil Erosion and Dryland Agriculture on the Loess Plateau,Institute of Soil and Water Conservation,Ministry of Water Resources,Chinese Academy of Sciences,Yangling,Shaanxi 712100,China)

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100 [2]中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100

出　　处：《水土保持通报》2024年第4期143-150,共8页Bulletin of Soil and Water Conservation

基　　金：国家自然科学基金项目“有机物质影响黄土区土壤结构稳定性的介尺度调控机理”(42277311)。

摘　　要：[目的]研究含水率对土壤浆体流变特性的影响机理,为黄土高原地区泥浆体流动规律的认识和泥石流防治提供科学依据。[方法]以黄土高原地区4种主要类型土壤为研究对象,通过流变振荡剪切测试,探究含水率对土壤流变特性的影响。[结果](1)[土娄]土、褐土和黑垆土的储能模量、损耗模量、剪切应力随含水率的增加(40%~80%)均呈减小趋势,剪切应力分别从229.85,193.38,96.46 Pa减小到2.25,2.65,2.32 Pa;在含水率较大(>50%)的条件下,黄绵土表现出强应变过冲现象。(2)4种土壤浆体的储能模量随剪切应变的增加出现两个平台区,表现出两步屈服现象;随着含水率的增加,浆体出现两步屈服向一步屈服的转变。第一步屈服与初始网络结构的破坏有关,第二步屈服表明浆体结构被完全破坏。(3)当土壤含水率≤50%,土壤细颗粒可通过形成絮凝体增加絮凝程度从而提高土壤浆体流动点剪切应力;当含水率>50%时,土壤中的粗颗粒通过增加颗粒间摩擦力提高流动点剪切应力,此时黄绵土流动点剪切应力大于其他土壤。[结论]土壤流变特性不仅与其自身性质有关,而且受土壤含水率的重要影响;细颗粒含量较大的土壤,在高含水率条件下其浆体更易发生流动。[Objective] The influence of the soil water content on the rheological properties of the soil slurry was analysed to provide a scientific basis for understanding the flow law of the slurry and the prevention and control of mudflow in the Loess Plateau region.[Methods] Four main types of soil in the Loess Plateau were studied,and the effects of water content on the soil rheological properties were investigated using rheological oscillation shear tests.[Results](1) The storage modulus,loss modulus and shear stress of lou soil,cinnamon soil and dark loessial soil all decreased with the increase of soil water content(40%~80%).The shear stress reduced from 229.85,193.38 and 96.46 Pa to 2.25,2.65 and 2.32 Pa respectively.Under conditions of high water content(> 50%),the loess soil showed a strong strain overshoot.(2) With increased shear strain,the storage modulus of the four types of soil slurry appeared in two plateau areas,showing a two-step yield phenomenon.With increased soil water content,the slurry changed from a two-step to a one-step yield.The first step of the yield was related to the destruction of the initial network structure,and the second step indicated that the slurry structure was completely destroyed.(3) When the soil moisture content was less than 50%,the fine soil particles increase the degree of flocculation by forming flocs,thus increasing the shear stress at the flow point of the soil slurry.When the moisture content was greater than 50%,the coarse particles in the soil increased the shear stress at the flow point by increasing the friction between the particles.[Conclusion] Soil rheological properties are not only related to soil properties but also significantly influenced by soil water content.Soils with a high fine particle content have a slurry that is more susceptible to flow under high-water-content conditions.

关 键 词：振荡剪切 流变特性 储能模量 剪切应力 流动点 

分 类 号：S152.9[农业科学—土壤学]