基于连续断裂过程的根系黏聚力Wu氏模型修正系数的确定

发布时间：2018-02-01 02:58

  本文关键词： 浅表层滑坡 根系黏聚力 Wu氏模型 断裂修正系数 根截面积比　出处：《林业科学》2017年11期 　论文类型：期刊论文

【摘要】：【目的】研究根系黏聚力Wu氏模型的修正系数,可提高Wu氏模型的精确度,进而提高造林边坡稳定性评价的准确性。【方法】针对Wu氏模型对根系黏聚力的高估问题,以刺槐和侧柏根系为研究对象,应用复合材料学的连续破坏理论,阐述根系的渐进失效过程,提出基于连续断裂过程的根系黏聚力Wu氏模型修正系数,即断裂修正系数,并研究不同算法间修正系数的差异性以及修正系数与根截面积比之间的关系。【结果】根系断裂修正系数随算法(P0.001)、树种(P0.001)和土层深度(P0.001)的变化而有显著差异;位移控制式算法引入的修正系数显著高于由拉力控制式算法引入的修正系数(P0.001);断裂修正系数随深度的增加而增加,表层30 cm内的修正系数显著低于深层根系(P0.001);根截面积比与断裂修正系数的负相关性存在阈值,当根截面积比小于阈值时(刺槐0.14,侧柏0.11),断裂修正系数随着根截面积比的增加而减少;当根截面积比大于阈值时,断裂修正系数的根截面积比效应不显著。【结论】根系断裂修正系数随算法和树种不同而变化,随土壤深度增加而增大,且在根截面积比阈值范围内(刺槐0.14,侧柏0.11)与根截面积比呈负相关关系。研究结论能为评价造林边坡的稳定性、揭示植物护坡的力学机理提供理论基础,并为水土保持工程植物措施的选择提供科学依据。
[Abstract]:[objective] to study the correction coefficient of Wu's model of root cohesion, which can improve the accuracy of Wu's model. In order to improve the accuracy of evaluation of afforestation slope stability. [methods] aiming at the problem of overestimation of root cohesion by Wu's model, Robinia pseudoacacia and Platycladus orientalis roots were studied, and the theory of continuous destruction of composite materials was applied. The progressive failure process of root system is expounded, and the modified coefficient of Wu's model of root cohesion based on continuous fracture process is proposed, which is called fracture correction coefficient. The difference of correction coefficient between different algorithms and the relationship between correction coefficient and root cross-sectional area ratio were studied. [results] the correction coefficient of root fracture with algorithm P0.001). There were significant differences between P0.001) and P0.001 (soil depth). The correction coefficient introduced by the displacement control algorithm is significantly higher than that by the tension control algorithm. The correction coefficient of fracture increased with the increase of depth, and the correction coefficient in surface 30 cm was significantly lower than that in deep root system (P 0.001). The negative correlation between root cross-sectional area ratio and fracture correction coefficient existed threshold, when root cross-sectional area ratio was less than threshold value (Robinia pseudoacacia 0.14, Platycladus orientalis 0.11), fracture correction coefficient decreased with the increase of root cross-sectional area ratio. When the root cross-sectional area ratio was greater than the threshold value, the root cross-sectional area ratio effect of the fracture correction coefficient was not significant. [conclusion] the root fracture correction coefficient varied with the algorithm and tree species, and increased with the increase of soil depth. And in the threshold range of root cross-sectional area ratio (Robinia pseudoacacia 0.14, Platycladus orientalis 0.11) there was a negative correlation between the root cross-sectional area ratio and the root cross-sectional area ratio. To reveal the mechanical mechanism of plant slope protection provides a theoretical basis and provides a scientific basis for the selection of plant measures for soil and water conservation engineering.
【作者单位】： 北京林业大学水土保持国家林业局重点实验室;宁夏大学农学院;
【基金】：国家自然科学基金项目(31400616;31560232)
【分类号】：S157
【正文快照】： 山体滑坡易造成人员伤亡和大量财产损失。以往地质学家常采用土木工程措施防治滑坡,随着人类对生存环境的要求越来越高,对生态文明的可持续发展越来越重视,生态和生物技术专家开始研究并应用植物根系来加固边坡的“生态工程”措施(Coppin et al.,1990;Cammeraat et al.,2015;S，

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