模拟自然降雨条件下植物根系增强边坡土体抗剪强度特征  

Characteristics of slope soil shear strength reinforced by vegetation roots under artificially simulated rainfall condition

作　　者：李华坦[1] 李国荣[1] 赵玉娇[1] 胡夏嵩[1,2] 刘昌义[1] 朱海丽[1] 

机构地区：[1]青海大学地质工程系,西宁810016 [2]中国科学院青海盐湖研究所,西宁810008

出　　处：《农业工程学报》2016年第4期142-149,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(41162010);教育部"长江学者和创新团队发展计划"创新团队研究计划资助项目(IRT13074);青海省重点科研攻关资助项目(2003-N-134)

摘　　要：该研究以位于青藏高原东北部黄土区的西宁盆地作为试验区,采用柠条锦鸡儿（Caragana korshinskii Kom.）、霸王（Zygophyllum xanthoxylon（Bunge）Maxim.）、垂穗披碱草（Elymus nutans Griseb.）、细茎冰草（Agropyron trachycaulum（Linn.）Gaertn.）的单播种植,以及柠条锦鸡儿分别与细茎冰草、垂穗披碱草混播种植等2种方式,开展了原位模拟降雨试验并采用直接剪切试验,系统分析了模拟降雨试验前后试验区边坡表层以下3个不同位置处复合体抗剪强度大小及其随深度变化规律。结果表明：模拟降雨试验前,由柠条锦鸡儿与细茎冰草、垂穗披碱草混播的边坡a层（0~20 cm）根-土复合体黏聚力分别为19.5、18.9 k Pa,均较相同条件下单播边坡a层复合体黏聚力大;混播种植边坡各层根-土复合体黏聚力均较模拟降雨试验后裸坡a层土体黏聚力大,其中柠条锦鸡儿与细茎冰草混播边坡、垂穗披碱草混播边坡模拟降雨试验后,a层复合体黏聚力分别较裸坡a层黏聚力的增幅为30.65%~56.45%;柠条锦鸡儿、霸王、垂穗披碱草、细茎冰草单播边坡b层复合体黏聚力增幅为4.17%~38.89%;柠条锦鸡儿分别与细茎冰草、垂穗披碱草混播边坡b层黏聚力增幅为29.17%~34.72%;边坡c层土体黏聚力增幅相对不及a层、b层显著,反映了草本起到浅层加筋作用,灌木则起到深部锚固作用。Xining Basin which is located at the conjunction of the Loess Plateau and the Qinghai-Tibet Plateau is selected as the testing area, and the artificially simulated rainfall test and the washout test are carried out on the slopes with the monocultures ofCaragana korshinskiiKom.,Zygophyllum xanthoxylon （Bunge） Maxim.,Elymus nutans Griseb, and Agropyron trachycaulum （Linn.） Gaertn, separately, and with the mixed planting ofC. korshinskii andA. trachycaulum, as well asC. korshinskii andE. nutans. And there are denuded slopes there. Based on the artificially simulated rainfall test, the direct shear test is carried out systematically to analyze the influence of the rainfall on the shear strength and the corresponding shear strength variation regularity of 3 different soil layers. The result shows that before the artificially simulated rainfall test, the cohesion force of the soil in layer a（0-20 cm） mixing planted withC. korshinskii andA. trachycaulum, as well asC. korshinskii and E. nutans is 19.5 and 18.9 kPa respectively, which is larger than that for the soil layera on the slope planted with the single plant under the same condition. The cohesion force for the soil in layerb （20-40 cm） on the slope planted with vegetation is larger than that of the denuded slope. And the difference of the cohesion force for the soil layerc（40-60 cm） between the planting slope and the denuded slope is not significant. After the artificially simulated rainfall test, the composite cohesion force of soil layera on the mixed planting slopes is greater than that of the bare slopes. The composite cohesion force amplitude of the soil layer a on the 2 kinds of mixed planting slopes is greater than that of bare slopes, with an increase of 30.65%-56.45%. The increased cohesion force amplitude of soil layer a with the monocultures is 4.17%-38.89%, and that of layer b on the slopes with the mixed planting is 29.17%-34.72%. The cohesion force increased amplitude of soil layerc is significantly less than that of layera and la

关 键 词：土壤 生长 降水 寒旱环境 植物边坡 模拟降雨 复合体抗剪强度 根-土复合体 

分 类 号：S157[农业科学—土壤学]