A Study On Nondestructive Detection Theory And Intelligent Diagnosis Technology Of Rockbolt Anchorage Quality

A study on nondestructive detection theory and intelligent diagnosis technology of rockbolt anchorage quality has been carried out systematically in this paper.The mathematics model of the transient responds of rockbolt and wall rock system have been studied and its numerical value solution of wave equation have been analyzed.On the basis of study on the principle and technology of the sonic reflection detection method and detection practicing,a kind of special sensor for rockbolt detection has been developed,Combining with model rockbolt testing and actual project detection practice in site, an evaluation standard for rockbolt anchorage quality of nondestructive detection has been put forward.The reflected wave containing the information of rockbolt defect was obtained on the dissertation firstly by means of sonic reflection, decomposing of the wavelet packet for the reflected wave and calculation of the decomposed waveform fractal dimension were then conducted, the characteristic vectors indicating rockbolt quality were accordingly achieved;based on the overall analysis of the factors which influence the rockbolt quality diagnosis, intelligent diagnosis model of rockbolt quality has been put forward based on the BP neural network,which has created a complete set of practicable, shortcut and convenient detection method and technology for the anchorage system, and has significant application value on the quality detection for the rockbolt works.The main achievements of study works and some innovations are as follows.1.The mathematics model of the wave equation of transient responds of rockbolt and wall rock system have been studied and its numerical value solution of wave equation have been analyzed.2.The principle of the sonic reflection of rockbolt detection;reflection analyse in time and frequency field and the method of signal fitting have studied.3.Principle and technology of the sonic reflection detection method have been studied. A kind of special sensor has been developed on the basis of detection practice, this sensors device has original creation, it has won the national practical and new-type patent.4.Combining with model rockbolt testing and actual project detection practice in site, an evaluation standard for rockbolt anchorage quality of nondestructive detection has been put forward.It has definite original creation and utility.5.Using the powerful decomposing tools of the wavelet packet, decomposing of the wavelet packet is carried out for the reflected wave according to the waveform nature of various frequency band , which has provided in-depth analysis of information for the reflected waveform detection, and also increase the accuracy of analysis by broadening and deepening the evaluation scope of rockbolt defect.6.It is the first time to apply the analysis method of fractal dimension to nondestructive detection of anchorage system. As the dimension calculation can better show the total information of the wave form,the defect of the anchorage system can be more accurately and comprehensively analyzed by employing the wavelet fractal dimension as the characteristic vector of rockbolt defect,this has original creation.7.As for the nonlinear relation between the obtained characteristic vector representing rockbolt defect and rockbolt density,BP neural network model is introduced by means of artifical neural network technique.The factors which would affect quality evaluation of the rockbolt have been analysed, the input and output parameters of the BP neural network finalized, and the computation method and formulas for learning and training purpose given on this dissertation.Upon learning, trying and verifying of this model, forecasting of the rockbolt quality has been conducted, and the forecasted results satisfactorily coincide with the measured data,it is illustrated that the developed model has better accuracy on intelligentized nondestructive detection of the anchorage system,can cater to the requirements of rockbolt detection,and thus is valuable to extensively apply on the engineering practice.