基于现场原型测试的乔木覆盖滑坡区根-土复合体力学性能研究  

Mechanical properties of root-soil composite in tree-covered landslide area based on field prototype test

作　　者：林昀昭 简文彬[1,2] 赖增荣 钟鑫 张骏逸 夏昌 LIN Yun-zhao;JIAN Wen-bin;LAI Zeng-rong;ZHONG Xin;ZHANG Jun-yi;XIA Chang(Institute of Geotechnical and Geological Engineering,Fuzhou University,Fuzhou,Fujian 350108,China;Geological Engineering Research Center of Fujian University,Fuzhou University,Fuzhou,Fujian 350108,China;Fuzhou Planning Design and Research Institute,Fuzhou,Fujian 350108,China)

机构地区：[1]福州大学岩土与地质工程系,福建福州350108 [2]福州大学地质工程福建省高校工程研究中心,福建福州350108 [3]福州市规划设计研究院,福建福州350108

出　　处：《岩土力学》2024年第11期3423-3434,共12页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.U2005205,No.41861134011);福建省自然科学基金(No.2023J01423)。

摘　　要：为揭示乔木根系力学特性及其对斜坡的力学效应,选取福建武平高植被覆盖区滑坡为研究点,对研究区典型乔木根系按径级分类后进行根系抗拉力学特性测试,并在滑坡现场进行不同根系横截面积比(rootcross-sectionalarearatio,简称RAR)、含水率下的根-土复合体原位直剪试验以及剖面根系分布特征调查,对根系在浅层滑坡的力学效应展开探究。研究结果表明:(1)1~7径级下马尾松、杉木抗拉力范围为12.45~673.09 N,抗拉力与根径呈幂函数正相关;抗拉强度范围为7.16~60.95MPa,抗拉强度与根径呈幂函数负相关。杉木根系平均抗拉力与抗拉强度均大于马尾松。(2)乔木根系显著提高了土体抗剪强度,根系对土体提供的附加黏聚力与剪切面RAR显著正相关。杉木根系构型更接近R型,马尾松为VH型,相近RAR下杉木对土体的加固作用优于马尾松。(3)随着含水率增加,马尾松、杉木根-土复合体抗剪强度显著下降,水分入渗使根系对土体提供的附加黏聚力受到削减。(4)基于Wu模型,考虑水分对土体黏聚力与根系附加黏聚力的影响,建立了考虑含水率的根-土复合体抗剪强度值估算模型,经检验,精度高于Wu模型,结果较为合理。(5)根系对浅层滑坡虽然具有加固作用,但受到根系分布深度、密度以及降雨等因素限制,强降雨作用下根系对浅层滑坡稳定性贡献具有局限性。In order to understand the mechanical characteristics of tree roots and their mechanical effects on slopes,the landslide in Wuping high vegetation coverage area of Fujian province was selected as the research site,and the root tensile mechanical properties of typical tree roots in the study area were tested after classification by diameter class.Furthermore,in-situ direct shear tests of root-soil composites under different root cross-sectional area ratios(RAR)and moisture content were conducted at the landslide site,and investigations were made into the distribution characteristics of roots in the profile to explore the mechanical effects of roots on shallow landslides.The results showed as follows:(1)The tensile force of Pinus massoniana and Cunninghamia lanceolata ranged from 12.45−673.09 N in 1−7 diameter class,and the tensile force was positively correlated with the root diameter by power function;The tensile strength ranges from 7.16 MPa to 60.95 MPa,and the tensile strength is negatively correlated with the root diameter as a power function.The average tensile force and tensile strength of Cunninghamia lanceolata root were higher than those of Pinus massoniana.(2)Tree roots significantly improved the shear strength of soil,and the additional cohesion provided by roots to soil was significantly positively correlated with the shear plane RAR.The root structure of Cunninghamia lanceolata is closer to R type,and that of Pinus massoniana is VH type.Under similar RAR,Cunninghamia lanceolata roots has a better reinforcing effect on the soil than Pinus massoniana.(3)With the increase in moisture content,the shear strength of the root-soil composites of Pinus massoniana and Cunninghamia lanceolata significantly decreases,as water infiltration diminishes the additional cohesion provided by the root systems to the soil.(4)Based on the Wu model,considering the influence of moisture content on soil cohesion and additional root cohesion,an estimation model for the shear strength value of root-soil composites consider

关 键 词：乔木根系 原位直剪 抗拉强度 根-土复合体 浅层滑坡 

分 类 号：TU411[建筑科学—岩土工程]