北方5种常见乔木根-土摩擦锚固性能研究  

Tribological properties between roots and soil of five common tree species in North China

作　　者：韩朝[1] 冀晓东[1] 刘小光[1] 张晓 赵东晖 Han Chao;Ji Xiaodong;Liu Xiaoguang;Zhang Xiao;Zhao Donghui(Key Laboratory of Soil and Water Conservation of State Forestry Administration,Beijing Forestry University,Beijing 100083,China)

机构地区：[1]北京林业大学水土保持国家林业局重点实验室,北京100083

出　　处：《北京林业大学学报》2020年第9期80-91,共12页Journal of Beijing Forestry University

基　　金：国家自然科学基金项目(31570708)。

摘　　要：【目的】油松、白桦、蒙古栎、华北落叶松和榆树作为在北方广泛生长及种植的树种,其根系在锚固土壤和防止滑坡方面起着重要作用,因此研究其根-土界面摩擦性能具有科学意义。【方法】本文将挖自于木兰围场县木兰林管局北沟林场的5种乔木树种根系按不同直径分成若干小段,并将单根埋入干密度为1.52 g/cm^3、含水率为12.72%的土壤试件盒中。通过北京林业大学植被力学实验室自主研发的根系拉拔试验机对埋入土壤的单根进行拔出试验,探究单根拔出的作用机理并从不同树种、不同直径两方面分析影响其摩擦力的因素。【结果】(1)单根在被拔出的过程中会发生两种破坏模式,当根的最大抗拉力小于根-土界面最大摩擦力时发生拔断破坏,反之则发生拔出破坏。(2)单根的最大摩擦力随直径以幂函数关系增长且拟合度很高,树种对于最大摩擦力的增幅具有明显的影响。(3)蒙古栎、榆树根-土界面最大剪应力随直径的增长而减小,白桦、华北落叶松、油松根-土界面最大剪应力随直径的增长而增大。(4)5种树种根-土界面剪应力与位移曲线可以用改进的双曲线模型进行拟合,各树种剪应力均在位移量为总值的6%时达到峰值。【结论】研究表明不同树种及直径对其根系固土效果会产生较大的影响,传统的固土效果预测方法会高估根系的固土作用,因此在进行人工防护林建设过程中应综合考虑根系的影响。[Objective]Pinus tabuliformis,Betula platyphylla,Quercus mongolica,Larix principisrupprechtii and Ulmus pumila are widely grown and planted in the North China.Their roots play an important role in anchoring soil and preventing landslides.Therefore,it is of scientific significance to study their root soil interface friction performance.[Method]In this paper,the roots of five tree species dug from the Beigou Forest Farm of Mulan Forest Administration Bureau in Mulan Weichang County of Hebei Province,northern China were divided into several small sections according to different diameters,and the roots were buried in the soil specimen box with a dry density of 1.52 g/cm^3 and a moisture content of12.72%.The root pulling test machine developed by the plant mechanics laboratory of Beijing Forestry University was used to pull out the roots embedded in the soil,to explore the mechanism of root pulling out and analyze the factors affecting the friction force from different tree species and varied diameters.[Result](1)There were two failure modes in the process of root pulling out.When the maximum tensile strength of root was less than the maximum friction between root and soil,the root pulling off failure will occur,otherwise,the root pulling out failure will occur.(2)The maximum friction of root system increased as a power function with the diameter increasing and the fitting degree was very high.(3)The maximum shear stress of root soil interface of Q.mongolica and U.pumila decreased with the increase of diameter,while that of B.platyphylla,L.principis-rupprechtii and P.tabuliformis increased with the increase of diameter.(4)The shear stress and displacement curve of the root soil interface of five tree species can be fitted by the improved hyperbolic model,and the shear stress of each tree species reached the peak value when the displacement was 6%of the total value.[Conclusion]The results show that different vegetation types and diameters have great influence on the soil consolidation effect of roots.The traditional pr

关 键 词：根系 树种 摩擦性能 固土 模型 

分 类 号：S781.2[农业科学—木材科学与技术] S781.3[农业科学—林学]