摘要
[目的]探究西南山区云南松根土复合体力学特性及其对坡体稳定性的影响,为该区浅层滑坡机理认识,识别预警与防治等提供理论基础与数据支持。[方法]以四川省凉山州中研究极为缺乏且与浅层滑坡密切相关的云南松根系为研究对象,开展根土复合体抗剪强度试验和FLAC 3D边坡安全系数数值模拟,探究了不同根系密度、根系分布方式与土壤含水量组合下乔木根土复合体的力学性质及浅层边坡稳定性。[结果]较高的植物根系密度可明显提高土体的抗剪强度,与素土相比,黏聚力、内摩擦角提高比例分别高达45.5%,9.6%。然而,根径与根系抗拉强度却呈显著的幂函数负相关关系(p<0.05),根径低于2 mm的细根抗拉强度最强;同时,乔木根系水平或垂直分布方式下,土壤含水量的增加均会降低土体的抗剪强度,不利于边坡稳定,而乔木交错分布最有利于提高土壤的抗剪强度和边坡稳定性。[结论]乔木根系的高密度发育,复杂交错分布,细根丛生等特点对提高根土复合体抗剪强度与边坡稳定性具有重要作用,适度地增加边坡植被覆盖是控制浅层滑坡发生的重要措施之一。通过评价地质灾害多发区不同条件下乔木根系护土固坡效应,可为震后地质活跃区开展生态修复提供理论支持。
[Objective]The mechanical properties of the root-soil system of Yunnan pine and its influence on slope stability in the southwestern mountainous area of China were determined in order to provide a theoretical basis and data support for the understanding,identification,early warning,and prevention of shallow landslides in this area.[Methods]Research regarding the root system of Yunnan pine is extremely lacking as it relates to shallow landslides in Liangshan Prefecture,Sichuan Province.The shear strength test of the root-soil system and FLAC 3D numerical simulation were carried out to explore the mechanical properties of tree-root-soil system and shallow slope stability under different combinations of root density,root distribution,and soil water content.[Results]Higher plant root density could significantly improve soil shear strength.Compared with soil without roots,the cohesion and internal friction angle of soil with roots increased by 45.5%and 9.6%,respectively.However,there was a significant negative power function relationship between root diameter and root tensile strength(p<0.05),and the tensile strength of fine roots with diameters less than 2 mm was the strongest.At the same time,under the horizontal or vertical distribution of the root system,an increase in soil water content would reduce the shear strength of the soil,and this situation was not conducive to slope stability.Staggered distribution of trees was most conducive to improving soil shear strength and slope stability.[Conclusion]The characteristics of high density,complex staggered distribution,and clustering of fine roots play an important role in increasing the shear strength of the root-soil system and slope stability.Moderately increasing vegetation coverage is one of the important measures that could be implemented to control the occurrence of shallow landslides.Evaluating the effect of soil protection and slope stabilization provided by tree roots under different conditions in geologically disaster-prone areas could provide theoretical s
作者
李怡帆
张国涛
雷鸣宇
方海燕
李朝月
Li Yifan;Zhang Guotao;Lei Mingyu;Fang Haiyan;Li Chaoyue(Key Laboratory of Land Surface Pattern and Simulation,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Mountain Hazards and Surface Process,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu,Sichuan 610041,China)
出处
《水土保持通报》
CSCD
北大核心
2022年第6期88-96,共9页
Bulletin of Soil and Water Conservation
基金
国家自然科学基金重大项目“青藏高原东缘地形急变带山地生态—水文过程与山地灾害互溃机制及灾害风险调控”(41790432)
中国科学院战略性先导科技专项(XDA23090303)
中国博士后科学基金第70批面上项目(2021M703180)
中国科学院特别研究助理资助项目。
