喀斯特地区棕榈根-土复合体抗剪特性  

Shear Resistance Properties of Root-Soil Composite of Trachycarpus Fortunei in Karst Area

作　　者：廖拉拉 唐丽霞[1] 吴文丽 阮仕航 王子杰 LIAO Lala;TANG Lixia;WU Wenli;RUAN Shihang;WANG Zijie(College of Forestry,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州大学林学院,贵阳550025

出　　处：《山地学报》2024年第6期827-837,共11页Mountain Research

基　　金：国家自然科学基金(31960332);贵州省重大专项子项目(黔科合重大专项(2014)6024-2);贵州省基础研究(自然科学)计划项目(QKHJC-ZK[2023]YB65)。

摘　　要：棕榈树根系发达,生命力顽强,是中国西南喀斯特地区生态恢复的优势树种。关于棕榈根系固土的力学特性尚不明确。本文以棕榈根系为研究对象,将根系分为2~3 mm、3~4 mm、4~5 mm三个径级,采用TZY-1型土工合成材料综合测定仪在4种垂直荷载下对棕榈根-土复合体进行直剪试验,探讨不同含根量(2根、4根、9根、16根)和布根角度(0°、30°、60°、90°)下根-土复合体的抗剪特性。研究结果表明:(1)相比素土,根-土复合体的抗剪强度增加,增幅为0.4%~26%,且抗剪强度整体随着含根量和布根角度的增加而增大。当含根量从9根增加到16根时,增幅减小。当根系与剪切面的夹角趋于90°时,根-土复合体抗剪强度最大。(2)抗剪强度比F值随含根量和布根角度的增大分别增加23%和13.1%,且低荷载下的根系有更好的抵抗剪切破坏能力。(3)不同根系含量和分布角度分别使根-土复合体粘聚力增加0.64~2.79 kPa和0.23~1.99 kPa,同比素土提高了2.6%~34%。根系加筋主要是通过提高附加粘聚力进而增强根-土复合体的抗剪强度,对内摩擦角的影响并不显著。本研究成果可为棕榈根系固土效果提供有力的理论技术支撑,为西南喀斯特地区生态恢复提供理论依据。Trachycarpus fortunei has a well-developed root system with resilient vitality,making it an advantageous species for ecological restoration in karst areas.Unfortunately,the mechanical properties of soil reinforcement by its root are not yet clear.In this study,the shear resistance of the root-soil composite of Trachycarpus fortunei with varied root morphology in the karst regions of southwestern China was investigated.It sorted the roots into three diameter classes:2-3 mm,3-4 mm,and 4-5 mm.Direct shear tests were conducted on the root-soil composites under four levels of vertical loads using a TZY-1 Type geosynthetic materials comprehensive tester to figure out the shear properties of the root-soil composite under different root contents(2 taproot,4 taproot,9 taproot,16 taproot)and root stretching angles(0°,30°,60°,90°).(1)Compared with plain soil,the shear strength of the root-soil complex of Trachycarpus fortunei increased by 0.4%to 26%.The overall shear strength increased with the increase in taproot quantity and root stretching angle;however,taproot quantity increased from 9 to 16 roots,the rate of increase decreased.The shear strength of the root-soil composites reached the maximum when the angle between the root stretching and the shear plane approached 90°.(2)The shear strength ratio(F value)increased by 23%and 13%with the increase in root quantity and root stretching angle,respectively,and the root-soil complex had better resistance to shear failure under low load.(3)Different taproot quantities and stretching angles increased the cohesion of root-soil composites by 0.64 kPa to 2.79 kPa and 0.23 kPa to 1.99 kPa,respectively,representing an increase of 2.6%to 34%as compared with plain soil.Root reinforcement primarily enhanced the shear strength of the root-soil composites by increasing additional cohesion,with a non-significant impact on internal friction angle.Generally,the stabilization of root-soil composite depends on the morphological features of a root system.To enhance the strength of root-soi

关 键 词：根-土复合体 根系形态 抗剪强度 粘聚力 棕榈 

分 类 号：S718.3[农业科学—林学]