土壤含水量和容重对砂姜黑土抗剪强度的影响及其传递函数构建  

Influence of Soil Water Content and Bulk Density on Shear Strength of Shajiang Black Soil and Its Pedo-transfer Function Construction

作　　者：张红霞 彭新华[1,2] 郭自春 高磊 陈月明[1,2] 邵芳荣 ZHANG Hong-xia;PENG Xin-hua;GUO Zi-chun;GAO Lei;CHEN Yue-ming;SHAO Fang-rong(Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing,100049,China;Longkang Farm Co.Ltd.,Anhui State Farms Group Huaiyuan,Anhui 233426,China)

机构地区：[1]中国科学院南京土壤研究所,江苏南京210008 [2]中国科学院大学,北京100049 [3]安徽省农垦集团龙亢农场有限公司,安徽怀远233426

出　　处：《土壤通报》2022年第3期524-531,共8页Chinese Journal of Soil Science

基　　金：国家重点研发计划项目课题(2016YFD0300809);国家自然科学基金项目(41930753,41725004)资助。

摘　　要：目的砂姜黑土湿时泥泞,干时僵硬,难耕难耙,适耕期短,研究砂姜黑土抗剪强度对于确定土壤适耕性具有重要意义。方法以砂姜黑土为研究对象,土壤容重设置1.2、1.4和1.6 g m^(-3)共3个水平,土壤含水量设置田间持水量的100%、85%、70%、55%和40%共5个水平,采用直剪仪测定土壤抗剪强度参数(黏聚力,c;内摩擦角,ϕ),分析土壤剪切特性随土壤含水量(θ)和容重(ρ)的变化规律,并利用多元回归拟合建立土壤抗剪强度(τ)的传递函数。结果砂姜黑土黏聚力随土壤含水量增加呈现指数减小趋势,随土壤湿容重(ρ')增加呈线性增加趋势,三者关系能够用回归方程c=a1e(b1ρ´−c1θ)表示(R^(2)=0.984,P<0.001)。内摩擦角随土壤含水量增加先减小之后趋于稳定,随土壤湿容重增加而增加,表现出φ=a2e(b2ρ´/θ)(R^(2)=0.856,P<0.001)的规律性变化。参照Mohr-Coulomb抗剪强度公式,建立砂姜黑土的抗剪强度传递函数τ=a1e(b1ρ′+c1θ)+σtan(a2e(b2ρ′(θ)),该函数能够很好地表示砂姜黑土的抗剪强度变化规律(R^(2)=0.870,P<0.001)。结论土壤含水量和容重是砂姜黑土抗剪强度的两个重要影响因素,在此基础上构建了以土壤含水量和湿容重为自变量的砂姜黑土抗剪强度传递函数。本研究结果可为砂姜黑土结构和耕性改良提供科学依据。Objective Shear strength can reflect the stability of the cultivated soil structure as well as its suitability for work.When soil overburden pressure exceeds shear strength,soil structure is severely damaged,resulting in decreased farmland productivity.Shajiang black soil has a high soil bulk density,a high clay content and swelling clay minerals,and is classified as a Vertisol in USDA soil classification.It’s typically characterized by structural obstacles like poor workability,which are closely related to soil shear strength.The key influencing factors of shear strength were investigated for establishing its pedo-transfer function to improve soil structure and workability given various undesirable traits of Shajiang black soil.Method Typical Shajiang black soil was selected to study the two key factors that affect the soil shear strength:the soil bulk density(ρ)was set at 1.2,1.4 or 1.6 g m^(-3) and soil water content(θ)was set at 100%,85%,70%,55%,or 40%of field capacity,respectively.The Mohr-Coulomb formula was used to calculate shear strength parameters such as cohesive force(c)and internal friction angle(φ)using a direct shear apparatus.The effect of soil bulk density and water content on soil shear characteristics were investigated,and the pedo-transfer function of soil shear strength was established by multiple regression fitting.Results Our results indicate that:(1)The cohesive force(c)of Shajiang black soil decreased as the water content increased,but increased as the bulk density increased.The shrinkage and swelling properties of Shajiang black soil have been considered sufficiently,and the wet bulk density(ρ')is used as one of the independent variables to establish Pedo-transfer functions.The relationship was well fitted by the regression equation c=a1e(b1ρ′−c1θ)(R^(2)=0.984,P<0.001).(2)With increasing water content,the internal friction angle(φ)decreased at first and then stabilized.It showed that bulk density had a linear relationship with it.The relationship betweenφ-θ-ρ'was well fit

关 键 词：砂姜黑土 剪切特性 黏聚力 内摩擦角 土壤传递函数 

分 类 号：S152[农业科学—土壤学]