夹竹桃根系拉拔力学试验及计算模型研究  

Study on pull-out mechanical experiment and calculation model of oleander root system

作　　者：杨果林[1] 李亚龙 林宇亮[1] 李琪焕 李海峰[1] YANG Guolin;LI Yalong;LIN Yuliang;LI Qihuan;LI Haifeng(School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075

出　　处：《中南大学学报（自然科学版）》2023年第6期2085-2099,共15页Journal of Central South University:Science and Technology

基　　金：国家重点研发计划项目(2019YFC1509800);国家自然科学基金资助项目(51778641,51878667)。

摘　　要：通过原位拉拔试验测定长江上中游地区温暖湿润气候条件下,龄期为1、2和3 a的夹竹桃的整株拉拔力,分析拉拔力与株高、植株质量、地径、根系质量等生长参数之间的相关关系。为探究根系的分布情况及力学特性,采用整株挖掘法提取不同龄期的夹竹桃完整根系,对其根系质量分布进行统计,然后进行室内单根拉伸试验,探究夹竹桃根系抗拉力和抗拉强度与其根系直径的关系。研究结果表明:夹竹桃根系的整株最大拉拔力随龄期的增加而增加,与株高、植株质量、地径、根系质量均存在正相关关系;夹竹桃根系抗拉强度随直径增大而减小,而抗拉力随直径增大而增大;夹竹桃根系的根系质量随龄期的增加而增加,但根系质量集中于[0~10) cm的埋深范围内。通过理论推导,建立考虑根-土界面摩阻特征的根土复合体拉拔力学模型并给出了模型参数确定方法及模型适用范围。由该模型得到的夹竹桃根系的拉拔力计算值与夹竹桃拉拔力实际值相符,验证了模型的合理性,可为实际工程生态护坡效应评价提供理论参考。In situ pulling tests were conducted to determine the whole-plant pulling force of Oleander at 1,2 and 3 a of age under warm and humid climatic conditions in the upper and middle reaches of the Yangtze River,and to analyze the correlation between pull-out force and growth parameters such as plant height,plant mass,ground diameter and root mass.To investigate the distribution and mechanical properties of the root system,the whole plant excavation method was used to extract intact root systems of oleander at different ages and to count their root mass distribution,and indoor single-root tensile tests were conducted to investigate the relationship between root tensile force and tensile strength and diameter of oleander.Based on the above experimental results,a root-soil composite pullout mechanics model considering the frictional characteristics of root-soil interface was established.The results show that the maximum pull-out force of the intact root system of oleander increases with the increase of the age and is positively correlated with plant height,plant mass,ground diameter and root mass.The tensile strength of the root system of oleander decreases with the increase of the diameter,while the tensile strength increases with the increase of the diameter.The mass of the root system of oleander increases with the increase of the age,but the root mass is concentrated in the burial depth range of[0,10)cm.The theoretical value of the pull-out force of the root system of the oleander is obtained from the model,which is consistent with the actual value of the pull-out force of the oleander,thus verifying the reasonableness of the model and providing a theoretical reference for the evaluation of the effect of ecological slope protection in practical engineering.

关 键 词：夹竹桃根系 拉拔力 抗拉强度 力学模型 

分 类 号：TU43[建筑科学—岩土工程]