混凝土面板坝面板变形模式与水平向挤压破损研究

Study on conceptualization method of deformation pattern and horizontal breakage of face slab of concrete faced rockfill dam

研究了混凝土面板在横断面内的变形模式和概化方法,探索了面板变形与面板坡向应力的关系和面板坡向应力的产生机制,揭示了时间、库水位等外部条件对面板坡向应力变形的影响模式,发现坝体变形导致的面板顺坡向挤压或拉伸是面板应力的主要来源。以三板溪面板堆石坝为例,研究了面板水平向破损原因,坝体较大的流变变形引起的面板顺坡向变形是面板较大坡向应力的主要来源,面板在库水推力作用下的局部弯曲变形、一期面板先期浇筑后坝体沉降的影响、特殊地形导致的面板水平向高应力以及垫层亏坡等造成的面板既有弯曲等都增大了面板坡向应力,并导致面板在结构存在缺陷的一、二期面板施工缝处发生破损。

The deformation behavior of face slab of concrete faced rockfill dam（CFRD） in the cross section and its conceptualization method was studied. The relationship between deformation behavior of face slab and stress along slope direction in face slab, and the generation mechanism of stress along slope direction in face slab was explored. The effect of the external factor including time and reservoir water level on slab stress along slope direction was also discovered. It is found that the drag effect of dam deformation on face slab along slope direction is the main reason of the stress along slope direction in face slab. The case of Sanbanxi CFRD was employed to investigate the mechanism of horizontal breakage of face slab of CFRD. The results show that the rather big creep deformation of dam embankment and the displacement of face slab along slope direction due to dam deformation is the main source which lead to rather high stress along slope direction in face slab. The regional bending deflection of face slab due to reservoir water pres- sure, the effect of embankment settlement on stress of the frst stage face slab, high horizontal stress of face slab due to special terrain, and the existing bending deflection of face slab due to slope deficiency in- creases stress along slope direction in face slab and eventually result in the face slab breakage in construc- tion joint of the first and the second stage face slab, which has local structural defect.