极端久雨条件下软岩边坡动态稳定性分析  

Dynamic Stability Analysis of Soft Rock Slope Due to Extremely Prolonged Rainfall

作　　者：蒋中明[1,2] 曾铃[3] 付宏渊[3] 熊小虎[1] 

机构地区：[1]长沙理工大学水利工程学院,湖南长沙410114 [2]长沙理工大学水沙科学与水灾害防治湖南省重点实验室,湖南长沙410114 [3]长沙理工大学土木与建筑学院,湖南长沙410114

出　　处：《中国公路学报》2014年第2期27-34,共8页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(51078042;51278067);湖南省交通科技计划项目(2009003)

摘　　要：为探索软岩边坡在极端长期降雨条件下的稳定性,采用饱和非饱和理论获取边坡在降雨过程中渗流场的分布特点及变化规律;将渗流计算结果导入FLAC3D软件平台,应用Fish语言对各单元强度变化的时间效应和重度变化的空间分布特性进行修改;最后采用强度折减法分析了软化效应和渗流场共同作用对软岩边坡动态稳定性的影响。结果表明:长期降雨过程将导致软岩边坡浅层部位出现大面积暂态饱和区,因边坡渗流的集聚效应,坡脚附近将维持较长时间的暂态高水位状态;软岩边坡在降雨过程中安全系数逐渐减小,降雨停止后,边坡安全系数呈现先减小、再增加,继而再减小的变化规律;极端久雨前期,边坡中基质吸力的降低、重度及渗透力的增加是影响边坡动态稳定性的主导因素;极端久雨后期,暂态饱和区内岩石的软化效应对边坡稳定性起控制作用。To explore the stability of soft rock slope influenced by extremely prolonged rainfall, saturated-unsaturated seepage theory was employed to analyze the variation process and distribution characteristics of seepage field in slope. The calculated seepage results were transfered to the software FLAC3D for the modification of material characteristic values with Fish language. The method of shear strength reduction was employed to analyze the influence of softening effect and seepage field on the dynamic stability of soft rock slope. The results indicate that a great extent of transient saturation area appears in slope during long-term rainfall. Transient high water level near the toe of the slope will maintain a long time due to the seepage agglomeration effect. During the whole prolonged rainfall process, the safety factor of soft rock slope decreases gradually. After the rainfall, the safety factor appears a law of deceasing first,then increasing and decreasing again. During pre-stage of the prolonged rainfall process, the decrease of suction and increase of unit weight and seepage force are the key factors for influencing the stability of soft rock slope. At the last stage of the prolonged rainfall, the stability of soft rock slope is mainly controlled by softening effect of rock.

关 键 词：道路工程 软岩边坡 数值计算 动态稳定性 极端久雨 饱和非饱和渗流 软化效应 

分 类 号：U416.14[交通运输工程—道路与铁道工程]