摘要
研究根-土复合体土-水特征曲线与抗剪强度的关系,可为紫色土埂坎根-土复合体强化机理的揭示与埂坎稳定性的维持提供科学依据。选取三峡库区典型紫色土坡耕地埂坎草本植物根—土复合体为研究对象,结合Hyprop2土壤水分特征曲线测量仪、滤纸法与直剪试验,拟合土-水特征曲线,揭示基质吸力对根-土复合体抗剪强度的影响。结果表明:(1)根-土复合体土-水特征曲线明显分为边界效应区、过渡区与非饱和残余区,3种常用模型(B-C、VG、F-X)中F-X模型拟合该曲线效果最好,根-土复合体饱和含水率、进气吸力、残余区含水率以及相同体积含水率下的基质吸力均高于素土。(2)随着体积含水率降低,根-土复合体黏聚力先增大后减小,试验范围内黏聚力最大值51.25 kPa出现在体积含水率约23%时,内摩擦角则线性增大。相同体积含水率下,根-土复合体黏聚力较素土最大增加50%,内摩擦角提升不大。(3)基质吸力对根-土复合体抗剪强度的增强作用具有阶段性特征,各阶段临界吸力值与土-水特征曲线一致,过渡区(基质吸力为3~500 kPa)土体抗剪强度提高明显,进入非饱和残余区后(基质吸力>500 kPa)由于黏聚力下降,土体抗剪强度增速减慢,根-土复合体抗剪强度随基质吸力增大而提升的幅度大于素土。通过建立埂坎根-土复合体土-水特征曲线和抗剪强度的关系,可估测实际工况下的埂坎土体抗剪强度,进而为坡耕地埂坎的建设、维护管理以及坡耕地侵蚀阻控提供理论依据。
Investigating the relationship between soil-water characteristic curve(SWCC)and shear strength of root-soil composites is expected to provide a scientific basis for revealing the strengthening mechanism of purple-soiled root-soil composites and maintaining the stability of soil bunds.The root-soil composites of herbaceous plants on the soil bunds of typical purple-soiled sloping farmlands in the Three Gorges Reservoir region was selected as the research object,and the effect of matrix suction on the shear strength of root-soil composites was constructed by using Hyprop2 soil moisture characteristic curve measuring instrument,filter paper method combined with the direct shear test.Major findings were:(1)SWCC of the root-soil composites could be divided into boundary effect zone,transition zone,and unsaturated residual zone,and the F-X model fitted best among the three commonly used models(B-C,VG,F-X).The saturated water content,air intake suction,residual water content,and suction at the same volumetric water content of the root-soil composites were all higher than those of the plain soil.(2)The cohesion of the root-soil composites first increased and then decreased with the decreasing volumetric moisture content,and the maximum cohesion of 51.25 kPa in the test range occurred at a volumetric moisture content of about 23%.At the same time,the angle of internal friction increased linearly.The cohesion of root-soil composites increased by 50%compared with plain soil at the same volumetric water content,and the internal friction angle was not greatly enhanced.(3)The enhancement effect of matrix suction on the shear strength of root-soil composites and its parameters had a stage-specific characteristic,and the critical suction value of each stage was consistent with the SWCC.The shear strength of soil in the transition zone(where the matrix suction was 3~500 kPa)was most obviously improved.After entering the unsaturated residual zone(matrix suction was greater than 500 kPa),the shear strength of soil increased at a sl
作者
郑文娇
韦杰
唐强
李进林
何颖
ZHENG Wenjiao;WEI Jie;TANG Qiang;LI Jinlin;HE Ying(Chongqing Key Laboratory of Surface Process and Environment Remote Sensing in the Three Gorges Reservoir Area,School of Geography and Tourism,Chongqing Normal University,Chongqing 401331;Chongqing Observation and Research Station of Earth Surface Ecological Processes in the Three Gorges Reservoir Area,Chongqing 401331;Chongqing Jinfo Mountain Karst Ecosystem National Observation and Research Station,School of Geographical Sciences,Southwest University,Chongqing 400715,China;Chongqing Institute of Green and Intelligent Technology,Chinese Academy of Sciences,Chongqing 400714)
出处
《水土保持学报》
CSCD
北大核心
2023年第4期75-82,共8页
Journal of Soil and Water Conservation
基金
重庆市杰出青年科学基金项目(cstc2019jycjjqX0025)
重庆英才青年拔尖人才项目(CQYC201905009)
四川省科技计划项目(2020YJ0202,2021YFS0288)
国家级大学生创新创业训练计划项目(202110637004)。
关键词
根-土复合体
土-水特征曲线
抗剪强度
基质吸力
埂坎
root-soil composites
soil-water characteristic curve
shear strength
matrix suction
soil bunds
