水位变动速度对某库区岸坡堆积体稳定性的影响

Influence on a Bank Slope Accumulations' Stability of the Rising or Falling Speed of a Reservoir Water Level

水位变动期间库区岸坡堆积体渗流场及稳定性的变化是一个动态过程,如何评价水位变动速度对堆积体稳定性的影响是工程上一个重要课题。采用有限元计算与刚体极限平衡分析相结合的方法,探讨了水位变动速度对堆积体渗流场及稳定性的影响机理和规律,研究成果表明,水位变动速度对堆积体在水位变动期间瞬时渗流场有着较大的影响,较大水位上升速度对堆积体稳定性有利,但水位下降速度增大对堆积体稳定性不利,水位下降速度由0.5增大至5 m/d,堆积体稳定性系数可降低15%～20%,水位下降期间堆积体危险水位往往出现在堆积体坡脚以上1/3～1/5坡高处。

The change of the bank slope accumulations＇seepage and its stability is a dynamic process during the period of rising or falling of reservoir water level.The combination of the FEM method and equilibrium analysis was applied to analyze the action mechanism and laws of the water level＇s rising and falling speed effect on accumulations＇seepage and stability.The analysis results showed that the water level＇s rising and falling speed can influence the congeries＇s transient seepage obviously,and faster rising speed of water level is favorable to the accumulations＇stability.But the faster falling speed is unfavorable,and the stability coefficient will reduce by 15%~20% with the falling speed increased from 0.5 to 5 m/d,and the most dangerous water levels are commonly located at one-third to one-fifth of the congeries＇s height up the accumulations＇ bottom.