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| With the Swiss anchorage quality of anchor bar and its application |
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UpdateTime：[2012/8/18 15:48:53] Hits：[2952] From：TONRY MINING SAFETY SUPPORT TECHNOLOGY CO.,LTD
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High strength bolt anchoring quality acoustic detection skills including instrument system and software system in two parts, the acoustic wave detection skill levels by the above two big system constraints. The current domestic and foreign bolt anchoring quality acoustic detecting instrument hardware system is very different, the difference only in the transmission and acceptance. Acoustic source artificial hammer aroused and the transmitter has two kinds, artificial hammer method operation is convenient, the energy than transmitter aroused great. But because the transmitter is the choice of electrical signal control emission, so the emission energy consistency than the artificial hammer is much better. In other words, selection of transmitter has gained waveform repeatability than artificial hammer is much better. Emission source data was divided into the piezoelectric ceramic vibrator and magnetic vibrator, piezoelectric ceramic vibrator signal frequency common a super magnetic source must be high, but its aroused energy than super magnetic source is much smaller, the magnetic source is a larger radiation energy, but the emission signal frequency compared with piezoelectric ceramic vibrator system is much lower. Each one has his good points. Two sources, the former for short bolt testing, the latter for the detection of long anchor.
Mortar saturation detection task in 1978 at the earliest, the Swedish H.F.Thurner[41] proposed by measuring the ultrasonic energy loss principle to detect the anchor system the quality of perfusion, and by the GendynamikAB company accordingly in 1980 launched BoltometerVersion anchoring quality testing instrument. But the approach has aroused conditions harsh and fast attenuation of faults, and the detecting results are for the pullout resistance of anchor bolt. In 1987, China Academy of Railway Sciences railway proposed by with sonic energy approach, i.e. by reflection wave energy ratio to evaluate the mortar saturation. In 1999, the Yangtze River Engineering Geophysical Prospecting Research Institute ( Wuhan ) [15] in Three Gorges permanent lock, use energy comparison method on high strength bolt mortar saturation evaluation have done a lot of test tasks. In 2003, the Yangtze River Scientific Research Institute are made on [42] in Qingjiang Shuibuya project, the use of sonic frequency stress wave method in detection of the construction quality of anchor, proposes the use of amplitude comparison method for mortar saturation evaluation. But from the testing results, the quantitative assessment of error is relatively large, effects are not ideal. Can say, the mortar saturation detection is still qualitative evaluation period, how to correctly evaluate still need to do a lot of research task.
High strength bolt length detection seems very simple, but sometimes the anchor at the bottom end of the reflected signal is often flooded other signals, the useful signal is difficult to identify, which led to this seemingly simple question often make mistakes. Aimed at this problem, many units and individuals in the signal disposal to do effective task. In 2002, Dalian University of Technology [42] using wavelet analysis detection of anchor length and disadvantages, including the extraction of measured signal corresponding to the defect site reflecting characteristics of the stress wave information, reproducing the reflected wave signal on a time axis regularity, the elimination of the measured signal is directly read from the presence of potential fault. In 2004 the Changjiang Engineering Geophysical Exploration Institute ( Wuhan ) [43] using instantaneous spectrum analysis discriminant bolt testing signal reflection characteristics, the measured effects.
The above content provided by http://www.kuangshanzhihu.com |
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