管型座混凝土工作性态及破坏机理研究

Research on Working Behavior and Failure Mechanism of Concrete for Tube Base

灯泡贯流式机组通常以管型座为支撑,将机组所受荷载传递给周围的混凝土基础。以岷江中下游某航电枢纽工程为实例,采用三维非线性有限元方法对管型座混凝土基础在工作荷载及超载作用下的应力应变状态及破坏机理进行研究。结果表明:正常工作时,管型座上下支柱角点以及下游临空面部位拉应力较大,最大拉应力达到2.07MPa,出现于上支柱角点部位,同时在上下支柱角点部位的表层混凝土存在轻微损伤。随着超载倍数的增大,混凝土破坏由内层向外层逐渐发展,最终形成贯通裂缝,此后钢筋自外层至内层开始逐层发生屈服,最终结构整体失效破坏。管型座混凝土基础的超载安全系数为Kp=2.4,满足设计安全要求。

Bulb tubular unit are usually supported by tube base to transmit loads on the unit to surrounding concrete foundations.Taking an aeroelectric complex project in the middle and lower reaches of Minjiang River as an example,the stress-strain state and failure mechanism of concrete foundation with tubular socket under working load and overload are studied by three-dimensional non-linear finite element method.The results show that the tensile stresses at the corner points of upper and lower pillars and the downstream empty face of pipe seat are large during normal operation,and the maximum tensile stress reaches 2.07MPa,which occurs at the corner points of upper pillar.The surface concrete at the corner points of upper and lower pillars is slightly damaged.With the increase of overload multiple,concrete damage gradually develops from inner layer to outer layer,resulting in through cracks.Thereafter,steel bars yield layer by layer from outer layer to inner layer,and ultimately the overall structure fails and destroys.The overload safety factor of concrete foundation of tube base is Kp=2.4,which meets the design safety requirements.