A Study On Stress Influence Of The Large Orifice On The Masonry Arch Dam

The masonry arch dam was vital type of local material dam, There are some advantages using masonry arch dam, such as obtaining raw materials locally;coming through flood period easily, construction simply, saving investment and having good safety feature. So such type dam has been widely promoted in the course of dam construction.For the arch dam which reservoir has no suitable breach to build lasher and has mass flood discharge, opening large orifice for flood discharge has great advantage. But the large orifice weakening the whole structure, making the force distribution complex. To carry out the analysis for the arch dam which setting large orifice was a one of the important problems in the arch dam design in home and out.The masonry arch dam was different with the general arch dam on the feature of material and otherwise, it was seldom to setting large orifice on it. So it was necessary to research the influence which large orifice caused to the dam.The paper combined GuTian Shuangkoudu masonry arch dam, aimed at the problem that setting large orifice on mid-small masonry arch dam, apply three-dimension finite element method to analysis the impact of the orifice upon the dam as a whole under the static load, use the method of finite internal force to analysis the dam which has large orifice. Through the static property calculate to the two instances that setting orifice or not, we could find the large orifice on the dam has seldom impact upon the secure working of the dam.The purpose of opening the orifice was to sluice. The influence of fluctuating pressure upon the dam was another problem which was concerned by engineer. The paper analyzed Shuangkoudu masonry arch dam. The result indicated that the dam natural frequencies which consider the dam and the reservoir water interaction have great different from the preponderant frequencies of fluctuating pressure, the dam's first rank of vibration was far away from the high energy region of the fluctuating flow, so the sympathetic vibration would not take place. The dam's stress level was lowness under the fluctuating pressure, the obvious bad influence would not take place while sluicing.In the calculating, the local incompatible mesh was adopted at the joint of the pier and other structure, then apply compatible displacement method of local incompatible mesh to calculate. Consequently the precision could be satisfied while improved the efficiency of the calculate and ensured the stability of the result.