白鹤滩拱坝底孔应力分析及配筋设计研究

高拱坝孔口周围应力分布复杂,需适当配筋改善孔口结构的受力状态,保证拱坝的安全运行。以白鹤滩拱坝3~#底孔为例,首先对施工期工况下孔口结构进行三维有限元计算,分析孔口周围的应力分布规律和产生机理,然后依据应力图形法对孔口进行配筋设计,最后采用钢筋混凝土有限元法对完成配筋的孔口进行非线性分析。结果表明:在坝体自重的作用下,混凝土泊松比效应是引起孔口顶、底板出现顺河向拉应力的主要原因;钢筋整体应力不高,配筋设计方案有较大的安全裕度,应力图形法偏于保守。但出于安全考虑,仍应采用应力图形法进行配筋设计。

Stress analysis and reinforcement design of bottom orifice of Baihetan Arch Dam

The stress distribution around the orifice of high arch dam is complex, while proper reinforcements is necessary to improve the stress state of the orifice structure and ensure safe operation of arch dam. Taking the No. 3 bottom orifice of the Baihetan Arch Dam as an example, a 3-D finite element calculation was firstly made on the orifice structure under construction condition for analyzing the the stress distribution and mechanism around the orifice. Then the stress graph method was used to obtain a reinforcement design of the orifice. Finally, the non-linear calculation of reinforced concrete was carried out for the orifice with reinforcement. The results showed that the Poisson''s ratio effect of concrete was the main cause of the tensile stress along the river at the top and bottom of the orifice under the action of gravity of dam body. The overall stress of the reinforcement was not high, and the reinforcement design scheme had a great safety margin, which means the stress graph method is conservative. However, the stress graph method should still be adopted for the reinforcement design in terms of safety.