考虑界面吸力的根-土界面剪切强度模型及影响因素研究  

Shear-strength Model of Root-soil Interface Considering Interfacial Suction and Its Influencing Factors

作　　者：欧阳淼 蓝日彦 张红日 王桂尧 覃冠华 郭鸥 李臣光 OUYANG Miao;LAN Ri-yan;ZHANG Hong-ri;WANG Gui-yao;QIN Guan-hua;GUO Ou;LI Chen-guang(School of Civil Engineering,Changsha University of Science&Technology,Changsha 410114,Hunan,China;Guangxi Xinfazhan Communication Group Co,Ltd.,Nanning 530001,Guangxi,China;Guangxi Transportation Science and Technology Group Co,Ltd.,Nanning 530007,Guangxi,China;Department of Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Guangxi Road Construction Engineering Group Co,Ltd.,Nanning 530001,Guangxi,China)

机构地区：[1]长沙理工大学土木工程学院,湖南长沙410114 [2]广西新发展交通集团有限公司,广西南宁530001 [3]广西交科集团有限公司,广西南宁530007 [4]上海交通大学土木工程系,上海200240 [5]广西路建工程集团有限公司,广西南宁530001

出　　处：《中国公路学报》2025年第1期108-118,共11页China Journal of Highway and Transport

基　　金：国家重点研发计划项目(2019YFC1509800);国家自然科学基金重点项目(42330701);国家自然科学基金项目(51878071,52178416,42477143);湖南省研究生科研创新项目(QL20220195);2022年度广西高校中青年教师科研基础能力提升项目(2022-MS5-125);2022年度广西交通运输行业重点科技项目清单-创新研发项目;2020年度广西交通运输行业重点科技项目清单项目;广西重点研发计划项目(桂科AB23075184)。

摘　　要：根-土界面含水率是影响根系加筋锚固效果的重要因素,为量化界面含水率对根-土界面剪切强度的影响,以非饱和有效应力原理为基础,建立了考虑界面吸力的根-土界面剪切强度模型。该模型将根-土界面剪切强度分为两部分,一部分剪切强度由净法向应力引起,另一部分剪切强度由界面基质吸力和张力吸力引起。通过室内单根拉拔试验测定了多花木兰、小叶女贞、香根草和刺槐4种植物根系在不同界面吸力、不同法向荷载条件下的根-土界面剪切强度,将试验值与模型值对比,相对误差在9%以内,验证了模型的准确性和可靠性。此外,分析模型影响因素发现,根-土界面摩擦因数与根系表面粗糙度存在显著的相关性,其中根系表面粗糙度指标中轮廓平均高度与根-土界面摩擦因数的关联性最大,关联度为0.96,权重达到0.35;有效应力参数和弯液面半径、饱和半径、填充角、接触角密切相关,且随着界面体积含水率的增加而增大;界面吸应力取决于基质吸力和有效应力参数的相对大小,其随着界面体积含水率的增加呈先增后减的变化趋势。上述研究成果可为进一步探讨根-土界面相互作用力学机制,以及优化边坡生态防护设计提供参考。Water content at the root-soil interface is often unsaturated due to transpiration and water absorption in plants.To quantify the contribution of interfacial suction to the shear strength of the root-soil interface,a shear-strength model of the root-soil interface considering interfacial suction was developed based on the principle of unsaturated effective stress.The model divides the shear strength of the root-soil interface into two parts:one caused by the net normal stress,and the other by the interfacial matric and tension suctions.The root-soil interface shear strength of the roots of four plants,Magnolia multiflorum,Privet microphylla,vetiver,and Robinia pseudoacacia,was measured under different interfacial suction and normal load conditions using a single pull test.The relative error of the test and model values was less than 9%,verifying the accuracy and reliability of the model.The root-soil interface friction coefficient was significantly correlated with root surface roughness by analyzing the influencing factors of the model.Among them,the average height of the root surface roughness index had the largest correlation with the root-soil interface friction coefficient,with a correlation coefficient of 0.96 and a weight of 0.35.The effective stress parameters were closely related to the bending surface radius,saturation radius,and filling and contact angles,and increased with the increase in interfacial volume water content.The interfacial suction stress depends on the relative magnitude of the matrix suction and the effective stress parameter;it increased first and then decreased with the increase in the interfacial volume moisture content.The above results provide reference for further exploring the mechanical mechanism of root-oil interface interaction and optimizing the ecological protection design of slope.

关 键 词：路基工程 根-土界面剪切强度 拉拔试验 界面吸力 粗糙度 

分 类 号：U416[交通运输工程—道路与铁道工程]