强降雨入渗下临海软土开挖边坡稳定性分析  

Stability analysis of excavation slope of coastal soft soil under heavy rainfall infiltration

作　　者：黄泰坤[1,2] 王元战[1] 姜金勇 贾晗 刘少增 HUANG Tai-kun;WANG Yuan-zhan;JIANG Jin-yong;JIA Han;LIU Shao-zeng(Civil Engineering School,Tianjin University,Tianjin 300072,China;CCCC First Harbor Consultants Co.,Ltd.,Tianjin 300222,China;Nantong Port Group Construction Investment Co.,Ltd.,Nantong,Jiangsu 226000,China)

机构地区：[1]天津大学建筑工程学院,天津300072 [2]中交第一航务工程勘察设计院有限公司,天津300222 [3]南通港集团建设投资有限公司,江苏南通226000

出　　处：《中国港湾建设》2020年第6期19-24,共6页China Harbour Engineering

摘　　要：临海开挖工程地基土体较差,常需历经雨季,研究强降雨对边坡开挖稳定性的影响,对其边坡设计及防护具有重要意义。以某工程为例,采用雨水入渗模型,建立了非饱和软土边坡开挖渗流-应力耦合的有限元模型。经与野外现场监测数据、GEO-SLOPE极限平衡法计算结果相互对比,验证了模型的有效性。分别计算了无降雨和强降雨情况下的孔隙水压力、土体饱和度、边坡位移、塑性应变、安全系数等变化情况。研究结果表明:1)强降雨入渗下,边坡安全系数较大幅度减小,降低了边坡稳定性,是危险工况;2)强降雨作用下,竖向位移较小且变化不大,雨水对位移影响主要集中于水平位移变位,这是导致边坡局部开裂的重要原因;3)在降雨入渗区域,孔压会随着降雨强度的增大而增大,并趋向于饱和,从而使得浸润线往上移动。建议在开挖交界面处设置防渗土工布等措施进行防渗加固,减少雨水入渗影响。Due to the poor foundation soil and the need to cross the rainy season,it is important to study the influence of heavy rainfall on slope excavation stability for slope design and protection.Taking a practical project as an example,a finite element model of seepage-stress coupling for unsaturated soft soil slope excavation was established by using rainwater infiltration model.The validity of the model was verified by comparison with field monitoring data and GEO-SLOPE limit equilibrium method calculation results.The variation of pore water pressure,soil saturation,slope displacement,plastic strain and safety factor under the conditions of no and heavy rainfall were calculated respectively,the results show that:1)Under the heavy rainfall infiltration,the slope safety factor is greatly reduced,which reduces the slope stability and it is a dangerous working condition;2)The vertical displacement is small and little changed under the heavy rainfall,and the influence of rainfall on the displacement is mainly concentrated on the horizontal displacement,which is an important cause for the local cracking of the slope;3)In the rainfall infiltration area,the pore pressure will increase with the increase of rainfall intensity and tend to be saturated,which makes the infiltration line move upward.It is suggested to set anti-seepage geotextile and other measures at the excavation interface for anti-seepage reinforcement to reduce the impact of rainwater infiltration.

关 键 词：强降雨 边坡稳定 大面积开挖 软土 孔压 

分 类 号：U652.74[交通运输工程—港口、海岸及近海工程]