基于改进Goodman-Bray法的库区反倾边坡稳定评价

库区岩质反倾边坡常在蓄水期发生失稳破坏,其存在特定的破坏模式。在中国水利水电科学研究院改进的Goodman-Bray算法基础上,考虑岩柱间水压力及库水压力对岩柱产生的倾倒力矩以及饱和区岩土体的强度降低,改进该算法对库区反倾边坡蓄水期稳定性进行评价。以Fortran为平台编写岩质反倾边坡稳定性分析程序,通过苗尾水电站工程实例边坡对所提力学模型和分析方法进行验证,并与离散元模拟结果进行对比验证其准确性。反倾边坡失稳模式为“滑动—倾倒—稳定”三段式,坡形隆起处倾倒变形程度更加强烈。蓄水后饱和岩土体抗剪性能变弱,导致坡脚处失稳模式由倾倒转变为滑动,锁固段岩体失去阻滑力后引起边坡整体失稳。

Reservoir RegionAnti-dip Slope Stability Assessment Based on Modified Goodman-Bray Method

The reservoir region anti-dip rock slope has frequently happened instability failure during impounding period under specially appointed failure mode.Based on the Goodman-Bray method modified by the China Institute of Water Resources and Hydropower Research,considered water pressure between rock pillars and reservoir hydrostatic pressure generated overturning moment and saturated area rock and soil masses strength reduction carried out reservoir region anti-dip slope impounding period stability assessment.Through the FORTRAN has programmed rock anti-dip slope stability analysis,then carried out verification for proposed mechanical model and analysis method through the Miaowei hydropower station slope cases and compared with results from discrete elements simulation to verify the accuracy.The instability mode of anti-dip slope is a“sliding-overturning-stable”three-phase mode;the slope protuberating part has stronger overturning deformation.After impounding,shear strength of saturated rock and soil masses will be weaker,caused slope toe instability mode from overturning changed into sliding,locking section rock mass lost its sliding resistance and made whole slope instable.