Research On Engineering Rock Damage Acoustic Emission Source Location Optimization

In recent years, the engineering rock mass disasters often happen at home andabroad, causing heavy casualties and economic losses. AE technique is a new type ofdynamic nondestructive testing technology and its demand for checked material is low.Using this technology to detect internal damage condition of rock material isconducive to health monitoring of geotechnical engineering, disaster warning, testingreinforcement and so on.The traditional signal analysis methods are difficult to comprehensiveinterpretation on its main components and can affect the source location accuracybecause AE signal is complex and non-stationary. Source location who is an importantobjective of AE technique can roughly describe internal damage regions of materials.The signal arrival time and location equation algorithm can affect its precision incommonly used time orientation.This paper mainly introduces the basic concepts related to AE, related technology,its main applications and AE properties of rock material damage; Summarized mainresearch direction and the current research status of AE source location technology;Respectively done in-depth research of AE signal pretreatment and source locationtechnology, Summarizing the influencing factors of source localization and elaboratingthe related theory. Putting forward the corresponding solving measures based on aboveresearch foundation and in view of the existing problems of AE signal de-noising andsource location process. The main research works of this paper include:①Aimed at problems of component loss and residual noise in the AE signalde-noising process, using the median filtering and SVD as a prefilter to eliminateinterference pulse and random noise; and using wavelet packet decomposition adoptingadaptive threshold selection method based on scale and improved soft threshold valuede-noising equations for signal de-noising; Studying limestone rock material damageAE signal frequency characteristics, main ingredients and energy distribution,reserving the main components of AE signal and improving the SNR.②Aimed at problems of low source localization accuracy and the number ofiteration steps long, using the method of reading seismic wave arrival time for gettingwindow containing AE signal arrival time, and using the AIC algorithm based on ARmodel for identifying arrival time in this window; Calculating source location by the least square method combined with simplex iterative algorithm, reducing the iterativesteps and improving the location accuracy.③Damage location testing has been carried out and location results andaccuracy have been analyzed according to different materials and differentspecifications of rock. And it’s verified that improved method has achieved goodlocation effect by identifying AE signal effectively and improving location methodthrough test of lead breaking, location correction and numerical simulation.