公伯峡面板堆石坝面板竖向裂缝机理分析

Mechanism Analysis of Vertical Cracks on Face Slab of Gongboxia CFRD

公伯峡大坝面板在水库运行后出现竖向裂缝,每年寒冬后,裂缝不断增加。根据大坝变形监测成果,反演得到坝体堆石E-B模型参数及流变参数,计算分析和预测面板堆石坝变形、面板结构应力,并针对冬季严寒低温、寒潮温降、昼夜温差等恶劣气候条件,进行面板温度应力变化规律和分布规律以及库水位对面板温度应力敏感性分析,得出温度应力是导致面板产生竖向裂缝的主要因素,堆石体流变增加的结构应力是两侧面板裂缝进一步发展的推动因素。

The vertical cracks are appeared in the face slab of Gongboxia CFRD after the operation of reservoir, and these cracks are growing after every cold winter. Based on the actual monitoring data of dam deformation, the E-B model parameters and rheological parameters of dam are got by inversion analysis. The dam deformation and slab stress of Gongboxia Dam are calculated by above model and parameters. In view of the adverse weather conditions such as low temperature in winter, cold wave and large temperature difference between day and night, the distributions and variations of temperature stress in face slab are analyzed and the sensitivity of reservoir water level on temperature stress of face slab are also studied. The results show that the temperature stress is the primary factor which leading to vertical cracks on slabs and the structure stress caused by the increase of rockfill rheology further promotes the development of cracks in two sides of face slab.