甘肃天水浅表层滑坡易发区滑坡分布与植被根系特征  

Landslide Distribution and Vegetation Root Characteristics in Shallow Landslide-prone Area of Tianshui,Gansu

作　　者：李牧阳 王云琦[1,2] 王玉杰[1,2] 张建华 代智盛 王丽娟 LI Muyang;WANG Yunqi;WANG Yujie;ZHANG Jianhua;DAI Zhisheng;WANG Lijuan(Three-gorgesarea(Chongqing)Forest Eco-system Research Station of Ministry of Education,School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083;Chongqing Jinyun Forest Eco-system Research Station,School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083;Xiaolongshan Forestry Research Institute of Gansu Province,Tianshui,Gansu 741022)

机构地区：[1]北京林业大学水土保持学院重庆三峡库区森林生态系统教育部野外科学观测研究站,北京100083 [2]北京林业大学水土保持学院重庆缙云山三峡库区森林生态系统国家定位观测研究站,北京100083 [3]甘肃省小陇山林业实验局林业科学研究所,甘肃天水741022

出　　处：《水土保持学报》2020年第6期101-109,116,共10页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目“降雨条件下植物根系动态固土效应研究”(31971726);中央高校基本科研业务费专项“山地灾害和植被间的相互响应机制”(2018BLCB03)。

摘　　要：为探究甘肃天水浅表层滑坡易发区滑坡分布特征与植被的关系,选取典型滑坡区域和典型植被类型进行研究。油松、华山松、日本落叶松和锐齿槲栎为研究区内典型乔木类型,针对种间根系分布特征和力学特性展开研究。首先,通过无人机获取区域不同植被类型分布,统计得到不同林分类型下的滑坡密度;其次,通过剖面法调查0-100 cm土层深度内的根系数量与直径分布,进行了单根抗拉试验测得抗拉强度,并分层量化为根系附加黏聚力;最后,结合林分调查结果和岩土体力学性质,计算不同植被类型边坡在不同水分条件下和坡度下的安全系数。结果表明:(1)在滑坡高密度区和滑坡低密度区,油松×华山松林地的滑坡密度均高于日本落叶松×锐齿槲栎林地;(2)锐齿槲栎根系数量、分布深度和单根抗拉强度显著高于油松、华山松和日本落叶松,其根系垂直分布深度超过100 cm,抗拉强度最大可达(32.551±7.551)MPa,0-100 cm土层深度内提供的平均附加黏聚力达9.364 kPa;(3)当岩土体处于饱和的极端降水条件时,油松、华山松、日本落叶松对坡体稳定的作用效果为负,而锐齿槲栎能有效加固边坡,在当地具有防治浅表层滑坡的良好功能。Aimed to analyze the relationship between landslide distribution and vegetation types,typical landslide areas and tree species was chosen in this research.Pinus tabuleaformis,Pinus armandi,Larix kaempferi,and Quercus aliena are 4 typical tree species widespread in the study area,and their root distributions and mechanical characteristics among species were analyzed.The unmanned aerial vehicle images were used to obtain the landslide density in different vegetation areas according to different physiological characteristics of leaves.Root investigation within 100 cm depth soil by soil profile method was used to quantify root number and diameter distribution,indoor experiments were conducted to test the tensile strength of each single root for root additional cohesion evaluation.Finally,the safety factors of slopes with different vegetation types under different water conditions and slopes were calculated combining with forest survey results and the mechanical properties of rock and soil.The results showed that:(1)The P.tabuleaformis and P.armandi forests have higher landslide density than the L.kaempferi and Q.aliena forests in both high and low landslide density areas.(2)The root number,distribution depth,and tensile strength of single root of Q.aliena was significantly greater than those of P.tabulaeformis,P.armandi,and L.kaempferi.The root vertical distribution of Q.aliena was more than 100 cm,the root maximum tensile strength was(32.551±7.551)MPa,and the root average cohesion was 9.364 kPa in 100 cm depth.(3)When the rock and soil were in saturated extreme precipitation condition,the contributions of P.tabuleaformis,P.armandi,and L.kaempferi to slope stability were negative,while Q.aliena could efficiently reinforce the slope and had good function of preventing and controlling the sallow landslide.

关 键 词：浅表层滑坡 根系固坡 生态减灾 边坡稳定 

分 类 号：S714.7[农业科学—林学]