根土复合体依赖根系含量的力学特性及非线性破坏准则  

Mechanical Properties and Nonlinear Failure Criteria of Root-Soil Composite Dependent on Root Content

作　　者：程平 李鹏程 钟彩尹 何博 吴礼舟 CHENG Ping;LI Peng-cheng;ZHONG Cai-yin;HE Bo;WU Li-zhou(College of Environment and Civil Engineering,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Mountain Bridge and Tunnel Engineering,Chongqing Jiaotong University,Chongqing 400074,China)

机构地区：[1]成都理工大学环境与土木工程学院,成都610059 [2]重庆交通大学山区桥梁及隧道工程国家重点实验室,重庆400074

出　　处：《长江科学院院报》2023年第12期110-117,共8页Journal of Changjiang River Scientific Research Institute

基　　金：国家自然科学基金重大项目(41790432);成都理工大学“研究生拔尖创新人才培育计划”项目(CDUT2023BJCX006)。

摘　　要：为研究植物根系对根土复合体力学特性的影响,开展不同根系含量下的根土复合体三轴试验,分析了根土复合体依赖根系变化的力学特性,建立了根土复合体非线性破坏准则。研究结果表明:根系通过提供抗拉能力来提高土体抗剪强度,根主要影响土体黏聚力,对内摩擦角影响较小;当根系含量为0.36%时,黏聚力增加了64.91%;主应力差随应变的增加显著,当轴向变形>2%时,主应力差变化缓慢;试样破坏时表现为剪胀破坏,产生纵向裂缝;随着围压的增大,根土复合体破坏的剪胀效应减弱;初始切线模量随围压及含根量的增大而增大;根土复合体破坏应力比最大值为0.99,最小值为0.63;基于含根量的变化,非线性强度破坏准则反映了根土复合体的破坏特性,破坏包络线在低围压下表现为非线性,高围压下为线性,线性与非线性变化的临界应力与围压的大小有关。To investigate the influence of plant roots on the mechanical properties of root-soil composite,triaxial tests were conducted on root-soil composite with varying root content.The mechanical properties dependent on root content and nonlinear failure criterion of the root-soil composite were analyzed.Results demonstrate that roots enhance the shear strength of the soil by providing tensile strength.Roots primarily impact the cohesion of the rooted soil,while slightly affect the internal friction angle of the root-soil composite.At a root content of 0.36%,the cohesion increased by 64.91%.The principal stress difference increases rapidly at the initial stage of strain,but such change slows down when the axial strain is greater than 2%.The specimen failure is characterized by dilative shear and the formation of longitudinal cracks.Increasing the confining pressure weakens the dilative shear effect of the root-soil composite.The initial tangent modulus increases with increasing confining pressure and root content.The maximum and minimum failure stress ratio of the root-soil composite is 0.99 and 0.63,respectively.The nonlinear strength failure criterion reflects the failure characteristics of the root-soil composite with varying root content.The failure envelope is nonlinear at low confining pressure and linear at high confining pressure,with the critical stress correlated to the confining pressure.

关 键 词：根土复合体 根系含量 三轴试验 抗剪强度 破坏准则 

分 类 号：TU43[建筑科学—岩土工程]