Study On The Nondestructive Testing Method Of The Rock Bolt Bearing Based On Grey Theory

With the rapid development of China’s economy, more and more anchoring geotechnical has been widely used in highway slope, mine shaft, underground railway tunnel, cavern support and other projects. Anchor technology used in geotechnical can give full play to its own inherent energy of rock, strengthen self-supporting and self-stability and to ensure construction safety and stability. As the rock bolt is the core of the anchor project, the quality of the rock bolt plays a crucial role in engineering constructs stability, so anchoring quality testing has a very important role in anchoring geotechnical engineering, and bolt bearing capacity detection is one of the most important qualities of testing part. Aiming at this part, the studies are as follows:(1)As for the impact for prestress, experimental error and anchoring quality,analyze the rock bolt P-S curve shape obtained from the pull-out test.(2)On the basis of simulating the traditional analog of anchor P-S curve model,exponential model has been improved; put forward an improved means-hybrid power function model; for the impact of prestress and experimental error, modified the traditional model, and introduce of the cubic polynomial model are modified; for affect to the quality of rock bolt, propose segmented GM(1,1) model and the GM(1,1) model based on function transformation to simulate the rock bolt P-S curve.(3)When measuring P-S curve modeling to predict the ultimate bearing capacity,the less of elastic stage data and richer of the destruction stage data, the higher the accuracy of prediction is. From the perspective of practical engineering, taking not accurately distinguish between elastic and elastic-plastic stage data and less measurement data of destruction stage into account, analysis usability of each model in engineering trial.(4)For the shortcoming of “High single model can not predict the ultimate bearing capacity of the full shape of the P-S curve accurately”, introduce the idea of combined model, put forward a method based on D-S evidence theory to predict theultimate bearing capacity of rock bolt, hence the accurate has been greatly improved.