基于塑性屈服体积-应变增量积的特高拱坝整体稳定性评价

Evaluation of Overall Stability of Extra-high Arch Dam by Plastic Yield Volume Strain Increment Product

坝肩岩体的工作性状是评价拱坝整体稳定性的重要依据,也是特高拱坝设计与安全调控的重点与难点。数值模拟分析中,以拉裂及压剪屈服区域发育范围的传统评价方法无法考虑岩体及结构面损伤屈服程度,且难以准确评判断层等对应力状态敏感材料的工作性态。为此,提出一种基于应变增量判断建坝蓄水后坝肩结构面是否进入屈服状态,采用塑性单元体积与其应变增量的乘积为指标的拱坝整体稳定性评价方法,并采用该方法对ZY特高拱坝展开研究,揭示了其坝肩岩体及结构面在正常运行工况及超载条件下整体稳定特征演化规律,厘清了显著影响坝肩稳定性的断层及结构面,为特高拱坝整体稳定性评估及加固措施优化调控提供了技术支撑。

As an important basis for evaluating the overall stability of arch dam,the work behavior of the abutment rock mass is the key and difficulty of the design and safety control of the extra-high arch dam.In numerical simulation analysis,the traditional evaluation method based on the development range of tensile and compressive shear yield regions cannot consider the degree of damage yield of rock mass and structural planes,and it is difficult to accurately evaluate the working behavior of stress sensitive materials such as faults.In this paper,an evaluation method for the overall stability of arch dam was proposed,which is based on the strain increment to judge the work behavior of structural plane in dam abutment after construction and impoundment,and the evaluation index was the product of the volume of the plastic elements and their strain increment.The method was used to study the ZY extra-high arch dam,revealing the evolution law of the overall stability characteristics of the rock mass and the structural plane under normal working conditions and overload conditions,clarifying the faults that significantly affect the stability of the dam abutment,which provides technical support for the overall stability evaluation of the super-high arch dam and the optimization and control of the reinforcement measures.