基于改进Sarma法的倾倒变形体蓄水稳定性评价

库区强倾倒变形体常在蓄水期以特定模式发生失稳破坏。根据现场强倾倒变形体蓄水失稳特征,分析其破坏模式为"上拉下剪"式破坏,破坏面具有明显分段性。在传统Sarma法基础上,考虑饱和岩体强度降低及所受静水压力,通过调整岩层面强度折减系数改进了Sarma法。以Fortran为平台编写强倾倒变形体稳定性分析程序,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。最后进行参数分析,研究结果表明边坡自然坡角对倾倒变形体稳定性影响比较大,坡角越陡稳定性越低,同时软岩较多的边坡蓄水后稳定性将大大降低,得出的结论和规律符合工程实际。

Stability Evaluation of Toppling Deformation Body During Reservoir Impoundment Based on Improved Sarma Method

Strong toppling deformed bodies in reservoir area often destabilize in a specific mode during storage period. According to the instability characteristics of site slope,the failure mode is analyzed as "upper tension-lower shear" failure and sliding surface obviously segmented. Based on the traditional Sarma method,considering the strength reduction of saturated rock mass and hydrostatic pressure,the Sarma method is improved by adjusting the strength reduction coefficient of rock strata. Fortran is used as a platform to compile a program for stability analysis of strongly toppling deformed bodies. The mechanical model and analysis method are validated by a slope example of Miaowei Hydropower Station,and its accuracy is verified by comparing with the results of discrete element simulation. The parameter analysis results show that the stability of the toppling deformation body is negatively correlated with natural slope angle and the stability of the slope with more soft rock will be greatly reduced after impoundment.