降雨下边坡开挖支护离心模型试验

为研究降雨下高速公路高边坡在开挖及运营过程中的变形规律及稳定性，以柳南公路改扩建工程某处典型高边坡为原型，利用大型土工离心机及自主研发降雨装置，开展12组不同开挖-支护时序边坡模型试验，通过对边坡从变形至破坏全过程监测，分析不同支护时序条件对边坡稳定性的影响。结果表明:实时支护能有效抑制边坡在水平和竖向的变形，在边坡开挖至第1级和第6级后，坡顶水平变形分别降低33.9%和30.4%，竖向变形降低54%和11.6%；实时支护对维持降雨下边坡稳定状态非常有利，边坡开挖至第2、4、6级后遭遇降雨，其稳定系数降低了10.1%、5.4%、6.5%；相同降雨量下，无实时支护边坡的稳定系数要比实时支护至少降低50%，说明了实时支护对降雨下边坡稳定性的意义巨大。 

CENTRIFUGE MODEL TEST OF SLOPE EXCAVATION AND SUPPORT UNDER RAINFALL

In order to study the slope stability and deformation characteristics under rainfall during excavation and operation process, the typical high slope of Liu-Nan highway extension project is chosen as the prototype. Using the geotechnical centrifuge of Chang''an University and independently developed rainfall device, 12 groups of centrifuge model tests of different excavation-support sequence were carried out. Through monitoring the whole process of slope from deformation to failure, the effect of different support sequence on the stability of slope was analyzed. The following results are obtained:the horizontal deformation and the vertical deformation of the slope are well restricted by the timely-support method, the horizontal deformations of the 1th and 6th grade excavation are reduced by 33.9% and 30.4%, and vertical deformations are reduced by about 54% and 11.6%; It is extremely favorable to use the timely-support excavation method for the stability of the slope under rainfall condition. The rainfall stability coefficient have a very small drop at 2th, 4th and 6th grade excavation after rainfall and reduce by 10.1%, 5.4% and 6.5% respectively. Under the same rainfall, the stability coefficient of slope without timely-support is at least 50% lower than that of timely-support excavation method, which shows that it is of great significance to slope stability under rainfall.