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为探究结构缝的存在对碾压混凝土拱坝地震破坏机理的影响,在地震模拟系统上进行了拱坝模型动力破坏试验。模型的建立基于弹性力-重力准则,不考虑库水以及坝体-地基相互作用。采用一种新型压电传感器测量模型内部的动态应力,并主动监测模型内部微裂纹的发生和发展过程。横缝的模拟考虑了键槽的影响,诱导缝的模拟基于断裂力学理论。选择模型基频对应的谐波逐级加载来研究拱坝在地震动超载作用下的反应。试验表明,拱坝顶拱的端部与拱冠的破坏均较严重,试验中横缝与诱导缝的先后张开分别释放了拱向端部应力与冠部应力,从而引导了裂纹开裂方向,减轻坝体破坏。通过实际震害与物理模拟的对比验证了试验结果的可靠性,显示本文的物理模拟技术有助于研究结构缝对拱坝地震破坏机理和最终失效模式的影响,可为碾压混凝土拱坝的抗震设计提供科学依据。
In order to investigate the influence of structural joints on the earthquake damage mechanism of RCC arch dam, the dynamic failure test of arch dam model was carried out on the seismic simulation system. The establishment of the model is based on the elastic-gravity criterion, irrespective of reservoir water and dam-foundation interaction. A new type of piezoelectric sensor is used to measure the dynamic stress in the model and the initiative to monitor the occurrence and development of micro-cracks in the model. The simulation of the transverse joint takes into account the effect of the keyway, and the simulation of the induced joint is based on the theory of fracture mechanics. The fundamental frequency of the model corresponding to the harmonic loading step by step to study the arch dam response to earthquakes under the action of overload. The test shows that the failure of the arch arch crown is more serious than the arch crown. In the experiment, the transverse joint and the inducing seam are opened one after another to release the arch stress to the crown and the crown stress respectively, Reduce dam damage. The reliability of the test results is verified by comparing the actual seismic damage with the physical simulation. The results show that the physical simulation technology in this paper is helpful to study the influence of structural joints on the failure mechanism and the final failure mode of arch dam. It can be used for the RCC arch dam Seismic design provides a scientific basis.