Study On Damage Detection Of Arch Dam Shaking Table Model Tests

A large number of high arch concrete dams which have been built and will be constructed in southwest China whose is high intensity earthquake-prone area. That would be a incalculable damage to the downstream areas if the dam have an accident. Therefore, high arch concrete dam health monitoring and damage development under severe earthquakes analysis has become the key technical problems in water conservancy construction. Dynamic model test is dams’ main research method which is used to analysis the dam failure mechanism and evaluate dam seismic safety.Due to the features that fast response, linear correlations, low price, good positive and converse piezoelectric effects, wide frequency range, piezoelectric ceramics has a good driver and sensing function. Piezoelectric ceramics particularly suitable for embedded internal damage detection of concrete structures. So piezoelectric ceramic sensors are widely used in research fields of health monitoring in civil engineering structures. But piezoelectric ceramic stress testing and health detecting based on wave method have never been used in the high arch dam’s dynamic model experiments. This thesis through a series of experiments on the high arch dam simulation model by using piezoelectric ceramic sensors to detect stress and damage. The main contents of the thesis are shown as follows:The piezoelectric ceramic sensors are embedded in the concrete beam. One of the sensors as the actuator and the other end of the sensors as the receivers to detect the beam’s damage by using wave method. The received data are analyzed in time domain, frequency domain and wavelet packet. Experimental results show that the wave method can be used in detect concrete material damage and can effectively reflect the damage state of the structure.In the calibration test, we use electro-hydraulic servo tester to calibrate dynamic stress piezoelectric ceramic sensor. The experiment data are analyzed by method of linear fit and we could obtain a piezoelectric ceramic sensor sensitivity coefficients. The study found that the loaded linear correlation curve and the piezoelectric ceramic sensor output curve is very similar. And piezoelectric ceramic sensor can be used for detecting dynamic stress dam model.Finally, the piezoelectric sensor is embedded in specific locations in the model of high arch dam, while acceleration sensors arranged in specific locations on the surface of the dam model. Stress and injury data are collected in dynamic model test project, and cracks’ development in the model are also recorded. The data received by using wave method are analyzed in the time domain, frequency domain. They are also analyzed by wave method. And the data are compared with stress data, cracks development, acceleration. The test found that changes in stress data and damage data are more sensitive to damage. And this method can detect damage earlier and locate the damage position of the structure.