拉拔作用下护坡植物香根草根系的力学性能  

Mechanical properties of roots of Vetiveria zizanioides as protection slope plants under tensile and pullout conditions

作　　者：肖海 张千恒[1] 夏振尧 胡欢[1] 朱庆文 闫茹冰 张伦 杨悦舒 Xiao Hai;Zhang Qianheng;Xia Zhenyao;Hu Huan;Zhu Qingwen;Yan Rubing;Zhang Lun;Yang Yueshu(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education,Yichang 443002,China;College of Civil Engineering&Architecture,China Three Gorges University,Yichang 443002,China)

机构地区：[1]三峡库区地质灾害教育部重点实验室,宜昌443002 [2]三峡大学土木与建筑学院,宜昌443002

出　　处：《农业工程学报》2022年第11期91-97,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(U21A2031,41807068,U2040207);土木工程防灾减灾湖北省引智创新示范基地项目(2021EJD026)。

摘　　要：植物根系受拔时存在拔断破坏和拔出破坏两种破坏形式,而关于根系倾角对根系受拔力学性能和破坏形式的影响尚不清楚。该研究以香根草作为研究对象,分析不同直径(0.20~1.40 mm)根系单根抗拉性能。并设置不同受拔倾角(0°、15°、30°、45°、60°、75°和90°)的根系进行单根抗拔试验,分析不同生长倾角下单根抗拔性能及其破坏形式,以明确植物根系生长倾角对根系受拔时力学性能和破坏形式的影响。结果表明:香根草根系的最大抗拉力和最大抗拔力随根系直径呈幂函数关系增加,而抗拉强度和抗拔强度则随根系直径呈幂函数关系减小。在受拔倾角为0°、15°、30°、45°、60°、75°和90°时,根系受拔力分别为0.48~2.71、0.59~4.16、0.79~4.08、0.95~4.47、1.86~5.39、2.20~6.39和2.95~7.46 N。随着根系受拔倾角的增加,根系最大抗拔力和抗拔强度增加。植物根系破坏形式受到根系直径和受拔倾角影响,根系直径越小越可能出现拔断破坏,而根系受拔倾角越大,受拔发生拔断破坏的根系数目越多,被拔断的临界根径越大。研究结果表明根系直径和受拔倾角明显影响根系力学性能及拔破时的破坏形式,这对深入理解根系固土机理具有重要意义。Root anchoring in the soil can provide significant resistance for plants to erosion and potential soil shear failure on a slope.Typical failures of plant roots can be found under the pullout and tensile conditions.The pullout angle varies greatly for the different roots,where the root penetrates various directions in the soil.However,the influence of pullout angle on the characteristic of mechanical properties and failure types of plant roots under tensile and pullout conditions can still far from being fully understood so far.Among them,Vetiveria zizanioides has been widely used for ecological slope protection,and soil and water conservation,due to its excellent adaptability,strong resistance,and well-developed root system.Taking the Vetiveria zizanioides as the study material,a series of tensile and pullout tests were conducted to determine the mechanical properties and failure types of roots.The roots were also planted in a plant groove of 100 cm in length,40 cm in width,and 50 cm in depth.A single root tensile test was firstly performed on the roots with different diameters(0.20-1.40 mm).A pullout test was used to simulate the root in different directions in the soil,particularly with the different pullout angles(0°,15°,30°,45°,60°,75°,and 90°).Some parameters were recorded,including the tensile stress-strain curves,the maximum tensile force,and tensile strength for the tensile test,while the pullout force,the pullout displacement curves,the maximum pullout force,and pullout strength for the pullout test.The failure types were identified,according to the resulting relations of the maximum tensile force,tensile strength,the maximum pullout force,and pullout strength to the root diameter.The results indicated that the maximum tensile and pullout force increased,with the increase of root diameter,whereas,the tensile and pullout strength decreased,indicating the power function of the relationships(R2≥0.75,P<0.001).The maximum pullout force increased in the range of 0.48-2.71,0.59-4.16,0.79-4.08,0.95-4.47

关 键 词：根系 力学 坡面 破坏形式 固土 拉拔 香根草 

分 类 号：S157.9[农业科学—土壤学]