某水电站坝肩堆积体力学参数及滑动边界探讨

Mechanical Parameters and Slip Boundary of Deposit Slope on Dam Abutment of Hydropower Station

堆积体稳定性计算成果直接影响工程的造价和施工方案,计算成果准确与否与两方面因素——堆积体强度参数和边界条件密切相关,而堆积体强度参数和边界条件的研究和确定较为复杂,尤其是这类滑动边界和强度参数不同于滑坡中的滑带易于查明和确定。以大渡河下游某水电站左坝肩堆积体为典型实例,对没有贯通滑带控制的和反演条件不充分的这类堆积体进行了探索性的研究。通过地质分析和滑动边界,采用最大剪应力法进行搜索分析,潜在滑面主要通过中部性状较差的碎石夹粉质黏土层而形成;堆积体强度参数采用工程类比、室内大型试验和反演法综合确定。结果表明,以地质分析为基础进行的数值计算与定性分析较为吻合,可为进一步的工程研究提供依据。

Quantitative calculation of deposit slope stability,which is closely related to the strength parameters and slip boundary,directly determines the cost and planning of the construction.Different from that of the sliding zone,the determination of strength parameter and slip boundary involves great complexity.The deposit slope with neither sliding zone control nor adequate inversion condition is explored.In the study,a deposit slope on the left abutment of a hydropower station in downstream Dadu river is taken as a typical case.Detailed geological data and slip boundary searching by maximum shear stress method show that the potential sliding boundary is formed through the gravel mingled with soft silty clay with unfavorable properties in the middle stratum.The strength parameters are determined comprehensively by engineering analogy,large-scale indoor test and inversion method.Final results reveal that quantitative calculation based on geological data is consistent with the qualitative analysis.