摘要
为了研究植物根系在阻止边坡土体开裂中的作用机理,通过自主研制的一套单轴拉伸试验装置(由加载模块、数字控制模块、数据采集模块、制样模具4部分组成,可准确地获取测试材料的全过程位移-拉应力关系曲线和抗拉强度)定量地研究根系对土体抗拉强度的增强作用.使用所研制的拉伸装置开展了不同含根量下灌木植物胡枝子根-土复合体的直接拉伸试验,分析根-土复合体的拉伸破坏机理,试验结果表明:素土的位移-拉应力曲线表现为单峰型,而根-土复合体的曲线表现为双峰型;随着含根量的增加,根-土复合体的抗拉强度呈非线性增大特征,相较于素土增加28.01%~142.15%;根-土复合体的抗拉强度可用本文提出的计算模型进行估算,当含根量为1~3根时平均误差为12.12%.胡枝子根-土复合体的拉伸破坏过程可以分为4个阶段:应力增加阶段、土体破坏阶段、应力再增加阶段和根系滑移阶段,且根系主要在第一阶段和第三阶段起到贡献作用.
In order to study the mechanism of plant roots in preventing slope soil cracking,a self-developed uniaxial tensile test device was used to quantitatively study the strengthening effect of roots on the tensile strength of soil and analyze the tensile failure mechanism of root-soil composite.The test device consists of a loading module,a digital control module,a data acquisition module,and a sample making mold,which can accurately obtain the entire process displacement-tensile stress relationship curve and the tensile strength of test material.A series of direct tensile tests were carried out on the root-soil complex of the shrub plant Lespedeza bicolor under different root contents by the developed tensile device.The results show that the displacement-tensile stress curve of pure soil is unimodal,while the curve of root-soil complex is bimodal.The tensile strength of root-soil composite increases nonlinearly with the increase of root content,which is 28.01%−142.15%higher than that of plain soil.The tensile strength of root-soil complex can be estimated by the calculation model proposed in this paper.When the root content is 1−3,the average error is 12.12%.The tensile failure process of the root-soil complex can be divided into four phases:stress increase phase,soil failure phase,secondary increase stage,and root slip phase.The root system mainly contributes to the first and third stages.
作者
牛家永
周永毅
张建经
段达
陈克朋
NIU Jiayong;ZHOU Yongyi;ZHANG Jianjing;DUAN Da;CHEN Kepeng(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Henan Provincial Communications Planning&Design Institute Co.,Ltd.,Zhengzhou 450018,China)
出处
《西南交通大学学报》
EI
CSCD
北大核心
2022年第1期191-199,共9页
Journal of Southwest Jiaotong University
基金
国家重点研发计划(2017YFC0504901)。
关键词
单轴拉伸试验
试验装置
根-土复合体
抗拉强度
含根量
uniaxial tension test
test device
root and soil composite
tensile strength
root content
