库水位升降对桥区岸坡稳定性的影响分析

Influence of reservoir water level rise and fall on stability of bridge bank slope

为研究水位升降对桥区岸坡稳定性的影响,以西南地区某桥区岸坡为研究对象,基于饱和-非饱和渗流理论,采用geostudio软件系统分析了桥区岸坡在水位升降过程中渗流场、位移场与稳定性的变化规律,并探讨了桥基水平位移的变化规律。结果表明,在水位升降时,岸坡渗流场具有明显的滞后效应。初蓄水与高水位工况下,坡面监测点的水平位移在正常蓄水位以下先增大后减小,在正常蓄水位以上逐渐增大;水位骤降工况下,坡面监测点的水平位移迅速增大。初蓄水与水位骤降工况下,桥基水平位移迅速增加;高水位工况下,桥基水平位移在坡内浸润线以上时持续增加,在坡内浸润线以下时逐渐减小。较陡的桥区岸坡水平位移较大,应采取相应的加固措施。桥区岸坡的稳定性系数在水位骤降时迅速减小,且在水位骤降约21.32 m后桥区岸坡的稳定性已不满足工程要求。

To study the influence of water level fluctuations on the stability of bridge bank slope,a bridge bank slope in the southwest region was selected as the research object.Based on the saturated-unsaturated seepage theory,the geostudio software system was used to analyze the variations of seepage field,displacement field,and stability of the bridge bank slope during water level fluctuations.The changing law of horizontal displacement of the bridge foundation was also discussed.The results show that during water level fluctuations,the seepage field of the slope exhibits a significant lag effect.Under initial impoundment and high water level conditions,the horizontal displacement of the slope monitoring points increases first and then decreases below the normal impoundment level,and gradually increases above the normal impoundment level;under sudden water level drop conditions,the horizontal displacement of the slope monitoring points increases rapidly.Under initial impoundment and sudden water level drop conditions,the horizontal displacement of the bridge foundation increases rapidly;under high water level conditions,the horizontal displacement of the bridge foundation continues to increase when above the infiltration line within the slope,and gradually decreases when below the infiltration line within the slope.Steeper bridge bank slopes exhibit larger horizontal displacements,requiring corresponding reinforcement measures.The stability factor of the bridge bank slope rapidly decreases during sudden water level drops,and the stability of the bridge bank slope no longer meets the engineering requirements after a water level drop of approximately 21.32 m.