大尺度预应力混凝土蜗壳模型试验研究

Experimental study on large scale pre-stressed concrete spiral case

为研究某水电站大型钢筋混凝土蜗壳结构在设计内水压力以及超载工况下的承载力和整体安全性以及预应力锚索的加固效果,开展了几何比尺为1∶20的大型仿真材料结构模型试验。试验结果表明,不采用预应力锚索加固时,在设计内水压力下蜗壳结构能够满足承载力和正常使用设计要求,但蜗壳左侧墙外表面中部混凝土的竖向拉应力已接近混凝土的抗拉强度标准值,临近开裂;在左侧墙1#、2#断面间外侧设置竖向预应力锚索后,可使左侧墙外侧中部混凝土竖向拉应力有所降低,左侧墙外表面开裂荷载超过设计内水压力33.3%,加载至1.48倍设计内水压力时,结构仍可满足承载力要求。

In order to study the bearing capacity and overall safety of large reinforced concrete spiral case structure of a hydropower station under the design internal water pressure and overload conditions, as well as the reinforcement effect of pre-stressed anchor cable, a large simulation material structure model test with a geometric scale of 1∶ 20 was carried out. The test results show that the spiral case structure can meet the bearing capacity and normal use design requirements under the design of internal water pressure without the pre-stressed anchor cable, but the vertical tensile stress of the concrete on the outer surface of the left wall of the spiral case has reached the standard value of tensile strength of concrete, which is close to cracking;when the vertical pre-stressed anchor cable is arranged on the outside of the cross section 1 # and 2 # in the left wall, the tensile stress of vertical reinforcement in the middle of the outer side of the left wall can be reduced, the cracking load on the outside surface of the left wall exceeds the design water pressure 33.3%, and when loaded to 1.48 times designing internal water pressure, the structure can still meet the bearing capacity requirements.