Chapter 13 - Experimental study of dynamic and static damage failure of concrete dam based on acoustic emission technology

Abstract

The stress of the high arch dam is very complicated under earthquakes. When an earthquake occurs, the interaction strength has great randomness. The acoustic emission (AE) technique is the effective means of detecting damage conditions and studying the failure mechanism of the internal concrete, which achieve the global continuous monitoring of internal damage of the internal material. Especially because acoustic emission testing has the characteristics of the condition of real-time monitoring, studying on dynamic mechanical properties of dam concrete is particularly important. The research of the dynamic damaging process and the failure mechanism of dam concrete is less by using acoustic emission technology at present. Therefore, in view of the stress characteristics of the high arch dam are complex, the relation between mechanical properties of the concrete and acoustic emission parameters by using different loading ways is analyzed, which provides an important reference value for the seismic safety of high arch dams. In this chapter, the main contents are as follows: the effects of the whole graded and wet-sieved concrete on the AE parameters and strain rate in the bending tensile failure process of the dynamic and static bending test; the recognition and regularity of AE parameters of each concrete component in the failure process of the uniaxial tension tests, especially for the measuring of AE parameters of the softening part of the stress–strain curves of concrete under uniaxial tension test and the discovery of the “strain Kaiser effect” in the process of unloading and reloading. Beside the analysis of AE source location, the numbers of hits measured by comparing the different position of the AE sensor (independent channel localization approach) can roughly determine the distribution region of the AE source. The test results show that using the AE characteristic parameters can more intuitively and accurately response mechanical properties and crack development of materials under different loading conditions. It is of significance to study the internal damage process, the failure mechanism, the effect of strain rate of concrete, which provides theory support for the current seismic design and safety evaluation of high arch dam engineering, and it has the broad application prospect in future.