碾压混凝土拱坝封拱温度场的仿真分析

Simulation analysis of arch-closure temperature of RCC arch dam

混凝土坝的裂缝是一个带有普遍性的现象,因此有"无坝不裂"的说法。在大坝裂缝事故中,除少数裂缝是因结构不合理或地基不均匀沉降引起之外,大部分是由温度应力引起的。目前,普遍采用的拱梁分载法计算拱坝温度荷载难以描述拱坝在荷载作用下开裂状态。基于这一点,本文采用ANSYS有限元数值仿真技术、考虑混凝土材料的非线性,对某处于初设阶段的碾压混凝土拱坝采用混凝土多参数强度准则(非线性有限元法)进行计算。根据初设阶段资料和混凝土拱坝设计规范的要求对大坝关键部位进行等效应力计算并分析坝基面开裂状况,并对大坝封拱温度取值进行专门分析。在满足应力控制标准和施工可行的情况下提出合理的特征拱圈封拱温度值,以供设计人员参考。

Crack in concrete dam is a universal phenomenon,so there is a say that ＂no dam did not crack＂.Cracks in the dam accident,only a few cracks are due to unreasonable structure or uneven foundation settlement,most of them are caused by temperature stress.At present,it is difficult to describe the arch dam cracking state under the widely used arch-cantilever method to calculate arch dam temperature load.For this reason,the article used the ANSYS finite element simulation technology,thought about non-linear concrete material and carried on the computation of RCC arch dam which was at the beginning of the preliminary design phase by concretes multi parameter intensity criterion（the nonlinear finite element method）.According to preliminary design data and specifications of concrete arch dam design,the paper calculated equivalent stress in the key parts of the dam and cracking conditions on dam foundation surface,and analyzed arch-closure temperature data of arch dam specially.At the case of meeting stress control standards and construction feasibility,it proposed the reasonable arch-closure temperature data of feature arch which can be refered for designer.