紫色土坡耕地生物埂土壤抗剪强度对干湿作用的响应  

Response of soil shear strength of bio-embankments for slope farmland to drying-wetting effect in Purple Hilly Area

作　　者：史东梅[1] 蒋平 何文健 丁文斌[1] 汪三树 彭旭东[4] Shi Dongmei Jiang Ping He Wenjian Ding Wenbin Wang Sanshu Peng Xudong(College of Resources and Environment, Southwest University, Chongqing 400715, China Chongqing Surveying and Design Institute of Water Resources, Electric Power and Architecture, Chongqing 400020, China Chongqing Eco-environment Monitoring Station of Soil and Water Conservation, Chongqing 401147, China College of Forestry, Guizhou University, Guiyang 550025, China)

机构地区：[1]西南大学资源环境学院,重庆400715 [2]重庆市水利电力建筑勘测设计研究院,重庆400020 [3]重庆市水土保持生态环境监测总站,重庆401147 [4]贵州大学林学院,贵阳550025

出　　处：《农业工程学报》2016年第24期139-146,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：公益性行业(农业)科研专项"坡耕地合理耕层评价指标体系建立(201503119-01-01)";重庆市水利局"重庆市水力侵蚀监测点背景侵蚀环境调查(2016)"

摘　　要：生物埂土壤水分在次降雨中存在＂干-湿-干＂变化过程,这对生物埂土壤抗剪强度具有削弱作用。该文以紫色丘陵区花椒埂（HJ）和桑树埂（SS）为研究对象,通过根系现场挖掘法和土壤物理、力学性质测定等综合方法,研究生物埂土壤水分及抗剪强度在天然降雨干湿作用下的衰减-恢复效应。结果表明：1）生物埂土壤含水率随干湿作用表现出＂急剧增加-急剧降低-稳定波动＂趋势,小雨条件下生物埂0~20 cm土壤含水率变化明显;而在大雨和暴雨条件下,生物埂0~30 cm土壤含水率均变化明显,且分别在3种降雨发生后第5、7、9天土壤含水率趋于稳定;2）生物埂土壤黏聚力和内摩擦角均呈现＂急剧衰减—相对稳定—逐渐恢复＂趋势,小雨条件下生物埂对土壤黏聚力和内摩擦角具有增强效应且随垂直深度呈降低趋势;3）花椒埂、桑树埂在暴雨条件下能显著削弱干湿作用对土壤抗剪强度的劣化效应,2种生物埂的土壤黏聚力劣化率较对照埂分别降低44.03%、65.05%,而内摩擦角劣化率分别降低42.47%、45.70%。研究结果可为紫色丘陵区坡耕地生物埂措施设计和坡耕地耕层水土资源保护利用提供技术支持。As a typical agroforestry system,bio-embankments formed by planting trees,shrubs or herbaceous in terrace ridge are effective farming measures for soil and water conservation in Purple Hilly Area.Bio-embankments not only could prevent soil erosion from slope farmland,but also greatly improve the soil quality and agricultural production conditions for cultivated land.The bio-embankment of slope farmland is often prone to collapse under heavy rainfall condition,which mainly attributed to the deformation and failure of slope caused by soil drying-wetting effect during the continuous raininginfiltration-evaporating process.Soil shear strength is one of the important determinants for slope stability of bio-embankments,which mainly influenced by soil structure,soil particle morphology and soil moisture content.The soil moisture of bio-embankments is often constantly changing along with the drying-wetting-drying circulation under a single rainfall condition,which would greatly weaken stability of bio-embankments.Recently,soil shear strength mainly focused on indoor simulation experiment conducted under such single factor as soil water content,soil bulk density,root system,soil particle composition,and some multi-factor combination experiments were also carried out.However,the changing characteristics of soil content and soil shear strength under drying-wetting-drying circulations caused by a natural raining and evaporating effect is unclear.The study mainly discussed the following facts as： 1） the variation trend of soil moisture for different bio-embankment layers under three-types natural rainfall condition; 2） the effects of different bio-embankment types on soil moisture variation; 3） the response characteristics of soil cohesion and soil internal friction angle of different bio-embankments on wetting-drying effect of rainfall and evaporation.Taking the bio-embankments with mulberry（SS） and zanthoxylum（HJ） planted in terrace ridge of slope farmland in purple hilly area of Southwest University,Chongqi

关 键 词：土壤 抗剪强度 降雨 生物埂 衰减—恢复效应 坡耕地 紫色丘陵区 

分 类 号：TU416[建筑科学—岩土工程] S157.1[建筑科学—土工工程]