【摘要】 黄土边坡的变形破坏多发生于降雨期间,由此也造成了大量的损失。为减小降雨诱发黄土滑坡的影响,开展降雨型滑坡现场实验研究,具有现实意义。本文选取泾阳一天然黄土边坡为研究对象,利用自行设计的模拟降雨系统,设计并进行了3组不同雨强下的大型黄土边坡人工模拟降雨试验,旨在研究不同雨强条件下天然黄土边坡的入渗规律及变形破坏模式。通过对边坡内埋设的土壤水分传感仪、土压力盒和张力计管的读数变化及试验现象进行分析,进而得出降雨条件下大型黄土边坡现场试验的变形破坏规律,总结出该类边坡的水分入渗规律和变形破坏模式。试验结果表明,边坡入渗呈现一定的规律:降雨条件下,坡肩入渗深度和速率最大,坡脚次之,坡面最小;同时,降雨强度越大,雨水入渗速率越快,入渗时间越长,边坡相同位置处体积含水率和土压力增大幅度越大,基质吸力减小的幅度越大。降雨条件下天然黄土边坡的变形破坏模式为:坡肩侵蚀及侵蚀扩展→坡面裂隙形成扩展→坡肩裂隙形成扩展→局部滑塌;若继续降雨,则坡肩局部裂隙逐渐贯通进而形成滑面,最终导致滑坡发生。更多还原

【Abstract】 The deformation and failure of the loess slopes is more likely to occur during the rainfall,and have caused significant losses. In order to reduce the impact of loess landslides induced by rainfall,it is of practical significance to carry out the field experimental study on rainfall-induced landslides. The natural loess slope chosen in this article is located at Jingyang. Based on the rainfall simulation system designed by us,we designed andconducted three groups of field tests of loess slope with different rainfall intensities,aiming at investigating osmotic law and deformation and failure mode of the natural loess slopes under the different rain fall intensity. By analyzing the changes of readout of soil moisture sensors,earth pressure cells and tensiometers buried in the slope and experimental phenomenon,we obtained the deformation and failure law of field test of large loess slope under the artificial rainfall condition,and the law of water infiltration,and meanwhile we summarized deformation and failure mode of this kind of slopes. The experimental results show that,the rainfall infiltration on the loess slope present certain rules during the tests,which are : the infiltration depth and seepage rate of slope shoulder are the largest under rainfall condition,followed by slope toe,and that of middle slope location are the smallest. Moreover,the greater the rainfall intensity is,the lager the infiltration rate of loess is,the longer the infiltration time is,and the bigger the increasing range of the soil pressure and volume moisture at the same position and the decrease magnitude of the matrix suction are. Under the condition of rainfall,the deformation and failure mode of natural loess slope is:(1) formation and extension of erosion at the shoulder of slope;(2) emergence and development of fractures in the slope surface;(3)occurrence and growth of fissures at the shoulder of slope;(4)local caving of the slope. If it continues to rain,some cracks at the shoulder of slope will penetrate each other gradually,the sliding surface can be subsequently formed,and landslide can occur eventually.更多还原