天气因素对排土场生态边坡稳定性的影响

Weather factors' influence on the stability of ecological slopes of waste dump

为了研究排土场在天气影响下的稳定性,建立排土场温度-渗流-应力耦合有限元分析模型,研究其饱和-非饱和渗流场、应力场以及稳定性响应规律,然后与排土场典型滑坡特征进行对比验证,并提出采用边坡危险滑动带来分析非均质边坡失稳特征。结果表明:考虑天气影响时,雨水入渗深度范围土体孔隙水压力均会不同程度地低于无蒸散和植物截留时的孔隙水压力,稳定性系数极小值比无蒸散和植物截留时更高,出现时间更晚,表明雨后一段时间内滑坡风险仍在不断增加,能更准确地反映出降雨所致边坡失稳的滞后效应。提出在采用极限平衡法分析非均质边坡失稳特征时,通过递增稳定性系数增量来观察最危险滑动带发展趋势的方法,以便更加全面反映出边坡滑坡类型和特征。

In order to examine the weather effect on the stability of ecological slope of waste dump,a coupled thermo-hydro-mechanical numerical model of waste dump based on finite element method is established to analyze response pattern of seepage field,stress field and stability.Then analysis results are compared with the characteristics of typical landslide and critical slip zone is considered to better describe failure feature of non-homogeneous slope.The results show that when evapotranspiration and canopy interception are considered,pore-water pressure of soil affected by infiltration is lower and the minimum value of stability coefficient appears later with a higher value,which means slope failure risk can still increase within a period of time after rainfall.Hysteresis effect of slope failure is reflected more accurately compared with the results when evapotranspiration and canopy interception aren "t considered.When limit equilibrium method is used in stability analysis of non-homogeneous slope,characteristics of slope failure can be reflected more entirely through watching the scope change of the critical slip zone due to increasing of stability coefficient increment.