多花木蓝根系与土体界面摩阻特征
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摘要
为研究灌木植物根系的固土护坡力学效应,探讨根系与土体间相互作用的特性。以多花木蓝为供试植物,进行植物根系切片并计算根系的表面凹凸度,选取0~0.5,0.5~1.0,1.0~1.5,1.5~2.0mm 4种粒径的粉质黏土,在不同的土体含水率和根径条件下,制备根土复合体扰动试样,进行单根抗拔摩阻试验和直剪摩阻试验,探讨土体含水率、植物根径以及土体粒径对根土界面摩阻特性的影响。结果表明:多花木蓝根系的表面凹凸度随根径变化无显著性差异,根系的拉拔剪应力集中在17.36~32.76kPa,而根土界面的摩擦系数为0.10~0.20;根系拉拔剪应力和根土界面摩擦系数随土体粒径和土体含水率的增加逐渐下降;土体含水率和土体粒径愈低,根系形态特征对根系的拉拔剪应力和根土界面摩擦系数的影响愈显著。研究结果对分析根土界面摩阻特性的影响因素,以及利用灌木植物提高边坡土体结构稳定和防治水土流失、土壤侵蚀等地质灾害具有重大的指导意义。
To study the mechanical effect of shrub plants on slope protection and to investigate the friction characteristics of root-soil interface,the roots of Indigofera amblyantha were sliced and the root surface roughness of this kind of plant were calculated.In order to evaluate the influence of different root diameters,soil moisture content and soil particle size on friction characteristics of root-soil interface,pull-out friction tests and shear friction tests were conducted on the root-soil composites with the particle size of 0~0.5,0.5~1.0,1.0~1.5 and 1.5~2.0 mm which prepared by sieving and remolding.The results showed that there was no significant difference in root surface roughness of I.amblyantha with the gradual increasing of root diameter,the pull-out shear stress of root system was concentrated in 17.36~32.76 kPa,and the friction coefficient of root-soil interface varied between 0.10 and 0.20.The pull-out shear stress of roots and the friction coefficient of root-soil interface in soil-root composites presented a downward trend with the increase of soil moisture content and soil particle size.When soil particle size and soil moisture content were small,the effects of root morphology on the pull-out shear stress of I.amblyantha roots and the friction coefficient of root-soil interface were more significant.These results were great guiding significance to analyze the influence factors of root-soil interface friction characteristics,and use shrub plants to improve the stability of slope soil structure and prevent soil erosion and other geological disasters.
To study the mechanical effect of shrub plants on slope protection and to investigate the friction characteristics of root-soil interface,the roots of Indigofera amblyantha were sliced and the root surface roughness of this kind of plant were calculated.In order to evaluate the influence of different root diameters,soil moisture content and soil particle size on friction characteristics of root-soil interface,pull-out friction tests and shear friction tests were conducted on the root-soil composites with the particle size of 0~0.5,0.5~1.0,1.0~1.5 and 1.5~2.0 mm which prepared by sieving and remolding.The results showed that there was no significant difference in root surface roughness of I.amblyantha with the gradual increasing of root diameter,the pull-out shear stress of root system was concentrated in 17.36~32.76 kPa,and the friction coefficient of root-soil interface varied between 0.10 and 0.20.The pull-out shear stress of roots and the friction coefficient of root-soil interface in soil-root composites presented a downward trend with the increase of soil moisture content and soil particle size.When soil particle size and soil moisture content were small,the effects of root morphology on the pull-out shear stress of I.amblyantha roots and the friction coefficient of root-soil interface were more significant.These results were great guiding significance to analyze the influence factors of root-soil interface friction characteristics,and use shrub plants to improve the stability of slope soil structure and prevent soil erosion and other geological disasters.
引文
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[19]倪九派,袁天泽,高明,等.土壤干密度和含水率对两种紫色土抗剪强度的影响[J].水土保持学报,2012,26(3):72-77.
[20]栗岳洲,付江涛,胡夏嵩,等.土体颗粒对盐生植物根-土复合体抗剪强度影响的试验研究[J].岩石力学与工程学报,2016,35(2):403-412.
[21]胡宁,刘静,姚喜军,等.快剪条件下柠条根对3种土壤土工特性的影响[J].水土保持学报,2014,28(1):106-111.
[2]邢会文,刘静,王林和,等.柠条和沙柳根与土及土与土界面摩擦特性[J].摩擦学学报,2010,30(1):87-91.
[3]邢会文.4种植物根-土界面摩阻特性研究[D].呼和浩特:内蒙古农业大学,2009.
[4]刘小光,赵红华,冀晓东,等.油松和落叶松根与土界面摩擦特性[J].摩擦学学报,2012,32(6):550-556.
[5]周跃,徐强,络华松,等.乔木侧根对土体的斜向牵引效应(I原理和计算模型)[J].山地学报,1999,17(1):4-9.
[6]张云伟,刘跃明,周跃.云南松侧根摩擦型根土粘合键的破坏机制及模型[J].山地学报,2002,20(5):628-631.
[7]赵亚楠.芦苇的快速繁育方法及其根茎抗阻拉力研究[D].长春:东北师范大学,2006.
[8]杨永红,刘淑珍,王成华,等.浅层滑坡生物治理中的乔木根系抗拉实验研究[J].水土保持研究,2007,14(1):138-140.
[9]杨永红.东川砾石土地区植被固土护坡机理研究[D].成都:西南交通大学,2006.
[10]夏振尧,管也锋,牛鹏辉,等.麦冬和多花木蓝根系抗拉拔特性试验研究[J].水土保持通报,2015,35(6):110-113.
[11]李为萍,史海斌,胡斌.沙地柏根系径级对根土复合体抗剪强度的影响[J].土壤通报,2012,43(4):934-937.
[12]逯海叶,李平.地表温度和土壤颗粒组成对抗剪强度的影响[J].内蒙古农业大学学报,2005,26(1):75-78.
[13]余宏明,胡艳欣,唐辉明.红色泥岩风化含砾黏土的抗剪强度参数与物理性质相关性研究[J].地质科技情报,2002,21(4):93-95.
[14]张爱国,李锐,杨勤科.中国水蚀土壤抗剪强度研究[J].水土保持通报,2001,21(3):5-9.
[15]钟守琴,刘波,魏朝富,等.紫色泥岩土壤<2mm岩屑及其对抗剪强度的作用机制[J].中国农业科学,2015,48(23):4846-4858.
[16]江浩浩,董希斌,王海飙.边坡土壤含水率对不同植被土壤抗剪强度的影响[J].森林工程,2009,25(3):77-80.
[17]张存根,张怀静.粉质黏土含水量与抗剪强度参数关系的试验研究[J].华北科技学院学报,2011,8(2):27-29.
[18]王丽,梁鸿.含水率对粉质黏土抗剪强度的影响研究[J].内蒙古农业大学学报,2009,30(1):170-175.
[19]倪九派,袁天泽,高明,等.土壤干密度和含水率对两种紫色土抗剪强度的影响[J].水土保持学报,2012,26(3):72-77.
[20]栗岳洲,付江涛,胡夏嵩,等.土体颗粒对盐生植物根-土复合体抗剪强度影响的试验研究[J].岩石力学与工程学报,2016,35(2):403-412.
[21]胡宁,刘静,姚喜军,等.快剪条件下柠条根对3种土壤土工特性的影响[J].水土保持学报,2014,28(1):106-111.