Acoustic Emission testing

Acoustic emission monitoring and positioning of rock mass st

Update time：2007-06-13 14:50　　　 Viewed：次

There is acoustic emission and micro vibration phenomenon before rock mass is damaged. The state of instability of rock mass and its location can be determined by the instrument monitoring acoustic emission and micro seismic.

Occurrence of rock burst in coal mine, coal and gas outburst, water and other geological disasters, have inevitable connection with the micro seismic phenomenon in rock mass. Firstly, this paper introduces the mechanics mechanism of acoustic emission under the microscopic scale. Secondly the location on the phenomenon of micro seismic and some parameters such as frequency, energy, and fractal dimension analysis explains their role in the disaster forecast. The existing observation results show that the low frequency and large energy incident and fractal dimension reduction are heralds the geological disaster will happen; Then it sums up mechanical generating mechanism rock failure of micro seismic caused by mining activity of vertical stress ,which can be divided into four kinds of shear types :high and low lateral pressure, high side pressure, low vertical stress ;

Micro seismic fracture monitoring technique is the main basis in the process of hydraulic fracturing, the fracture around the weak aspects of the stability of the affected, shear sliding occurs, has a similar to occur along the fault of "earthquake", micro seismic radiation from elastic wave frequency is quite high, generally at the frequency range of sound waves. The elastic wave signal can be used well and adjacent well detection precision of the sensors in construction, and through the analysis of the data processing about the source of information. Currently in construction well receive information technology in the further development of it, and the acoustic emission microseismic monitoring technology has grown up. In the process of fracturing, as the production of small earthquakes in time and space, fracture test results continuously updated, formed a fracture extension "dynamic demonstration figure", the picture get the fracture azimuth and length of the flat view, can be directly to get the top and bottom of the crack depth, the extension of the azimuth and the length of the two wings of a crack. Construction and observation Wells located on the same wellblock, distance within the effective monitoring of distance. Fracturing Wells fracturing construction process, micro seismic signals travel through formation, receiver micro seismic signals and to travel to the surface monitoring processing equipment. In the process of using microseismic fracture monitoring technology, construction well and the distance of the observation well each are not identical in different strata.
(Editor：admin)

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