边坡降雨和动荷载耦合作用下模型试验研究

Experimental study on slope model considering rainfall and dynamic load effects

在降雨和交通荷载等作用下,边坡经常发生滑坡、崩塌、湿陷等灾害,为此本文通过设计边坡模型试验系统,开展降雨和动荷载两个诱因作用下的模型试验,研究坡内含水率、孔隙水压力和应力的变化规律及动荷载作用下边坡的动力响应,探讨降雨和动荷载对边坡的影响.结果表明:雨水入渗后,较浅土体最快达到饱和,孔隙水压力最先产生响应,应力呈上升趋势,经一段时间降雨后会形成0~50cm的稳态饱和区范围,最大含水率约40.8%;动荷载强度越大,测点距动荷载越近,边坡对动荷载的动力响应越强烈,且动荷载震动频率在50Hz时接近边坡共振频率,使边坡易引发共振现象;降雨与动荷载共同作用下,饱和区会发生下移,且产生超静孔隙水压力,导致抗剪强度进一步降低,对边坡稳定性造成不利影响,导致边坡从坡顶开始滑塌.

Under the action of rainfall and traffic load,landslides,collapses,collapse and other disasters often occur on the slope.The slope model test system is designed in this paper,and the model tests under the inducement of rainfall and dynamic load are carried out to study the change law of moisture content,pore water pressure and stress in the slope and the dynamic response of the slope under dynamic load.Abaqus finite element method is used to simulate the variation of seepage and saturation in the slope during rainfall.The effects of rainfall and dynamic load on the slope are discussed.The results show that after rainwater infiltration,the shallower soil reaches saturation the fastest,pore water pressure responds first,and stress shows an upward trend.After a period of rainfall,a steady-state saturation zone range of 0-50 cm will be formed,with a maximum moisture content of about 40.8%;The greater the strength of the dynamic load,the closer the measuring point is to the dynamic load,the stronger the dynamic response of the slope to the dynamic load,and the vibration frequency of the dynamic load is close to the slope resonance frequency at 50 Hz,making the slope prone to resonance phenomenon;Under the combined action of rainfall and dynamic loads,the saturated zone will move downwards and generate excessive pore water pressure,resulting in further reduction of shear strength and adverse effects on slope stability,leading to slope collapse from the top of the slope.