混凝土重力坝受水位变化影响的有限元分析

Finite Element Analysis of Concrete Gravity Dam Affected by Water Level Change

为了分析蓄水运行期少横缝设计堆石混凝土重力坝的各项性能,判断少横缝设计是否合理,以某大坝为例,通过有限元模拟计算的方式进行了研究。结果表明,堆石混凝土重力坝选择超长坝段的方式时,坝体在蓄水运行期的应力状态是能够达到应力要求的;蓄水运行后的大坝温度分布状态基本不会受到横缝的影响;在水位到达运行水位后,顺河方向大坝位移分布规律为对称状;不同的横缝条件会使顺河方向河床中间部位坝段位移的分布情况出现变化,普通坝工况变形量与超长坝段相比更高;温度改变沿顺河向形成的拉应力大多数分布在坝体内部强约束位置;蓄水使用时要对横河向温降荷载重点关注,因为在冬季混凝土会发生较大程度的收缩,产生较高的应力水平,会导致上下游面裸露位置出现较高的拉应力,从而使混凝土表面出现斜向或从上向下的裂缝,破坏大坝的整体性。

In order to analyze the performance of the rockfill concrete gravity dam designed with few transverse joints during the impoundment operation period and judge whether the design with few transverse joints is reasonable,this paper takes a dam as an example,and conducts an in-depth study by means of finite element simulation calculation.The research results show that the stress state of the dam body during the impoundment operation period can meet the stress requirements when selecting the super long dam section;the temperature distribution of the dam after impoundment is basically not affected by the transverse joints;after the water level reaches the operating water level,the dam displacement distribution along the river is symmetrical;different transverse joint conditions will change the displacement distribution of the dam section in the middle of the riverbed along the river,and the deformation of the ordinary dam is higher than that of the super long dam section;the tensile stress formed along the river direction by temperature change is mostly distributed in the strong constraint position inside the dam body;during the use of water storage,attention should be paid to the temperature drop load along the river,because the concrete will shrink to a large extent in winter,resulting in a high stress level,which will lead to high tensile stress in the exposed positions of upstream and downstream surfaces,so that the concrete surface will appear inclined or upward downward cracks,damaging the integrity of the dam.