大型人字闸门设计计算中的若干问题

在人字闸门设计中,通常将闸门分割为一些平面构件进行计算,难以全面反映闸门的整体性能力。为此,针对人字闸门的构造型式、受力特点和变形规律,提出了分析人字门的组合有限元模型,并据以研制了空间薄壁结构分析程序(TWSAP)。该分析模型在葛洲坝人字门的现场试验中得到了很好的验证。为增加闸门刚度,对大型人字闸门采用增设背拉杆并对其施加预应力,以抵消闸门自重引起的翘曲变形。对于背拉杆预应力的作用及施加条件、预应力施加方法进行了研究,并以三峡人字闸门为例,对两种背拉杆预应力施加方案进行了实例比较。从施工方便及施加预应力较少角度出发,推荐先对主背拉杆再对副背拉杆施加预应力的方案。对于三种不同构造的人字门,分别对其抗扭刚度、用钢量和用钢效率,以及最大位移、背拉杆内力等技经指标进行了比较,从而为选择经济合理的闸门形式提供了依据。

On designing huge miter gates

A miter gate is usually designed by dividing the gate body into a numbr of plane elements for structural analysis, which can not fully reflect the monolithic behaviour of the whole gate. Therefore, in accordance with the type of constitution. stressing features and deformation behavior of the miter gate, a combined finite element model for structurally analysing it has been established; and based on this model, a computer program for analysing three dimensional thin-wall structures (TWSAP) has been developed. This model has been applied to Gezhouba miter gates, and the computed results were confirmed by field observation data. In order to increase the rigidity of a huge miter gate, prestressing tension braces should be provided on the rear of it so as to counteract the deflection caused by the weight of the gate. The effects, prestressing conditions and prestressing method of rear tension braces have been studied, and taking miter gates of Three Gorges project for example, two prestressing alternatives of rear tension braces are compared. From the point of view of convenient construction and small prestresses, the prestressing procedures are recommended as carefully arranged: first prestressing the main rear tension braces and then prestressing the secondary ones. The twisting stiffness, steel demand, efficiency of steel used and maximum displacements of miter gates and internal forces of rear tension braces are compared among three miter gates of different type, which provides a scientific basis for economic and reasonable selection of miter gate structure.