Numerical simulation to examine accuracy of AE source location and its applications to in-situ rock monitoring

The location of an AE event is the most useful information obtained by AE monitoring. The accuracy is important for not only reliability of the source location itself, but also the analysis of crack mechanism depends on an accurate source location. In order to examine an arrangement of sensor positions based on the iterative method with the least-square principle, a simple simulation method using a random number is proposed. In addition, the method is applied to two cases where the sensor network cannot enclose a monitoring region three-dimensionally due to respective monitoring restrictions. The first case is the monitoring of in-situ direct shear test of rock in underground chamber that we actually made. The second is a case to examine an arrangement of drilling holes in advance to monitor hydraulic fracturing in deep underground. Through the examples, advantage and applicability of the method are elucidated for three-dimensional monitoring in a semi-infinite medium, which we often encounter in in-situ rock monitoring. Keywords: Source location, accuracy, sensor arrangement, numerical simulation, in-situ direct shear test, hydraulic fracturing.