Research On Nondestructive Detection In Anchorage Quality Of Rock Bolts

Rock bolts now used widely in the world, such as tunneling, mining, high slope and deep foundation excavation etc. It is used in underground structure from intact wall rock, joint rock to coal seam and soil. But construction of rock bolts is a covert project, which not only lies on the effect of traverse stratum and condition but also decided by construct techniques and management level, it is also the case that some potential flaw makes the quality of construction can't reach design requirement and do a lot of damage in project and economy. As a result, we must emphasize detection in anchorage quality to guarantee the safe mass of projects.Nowadays most detection on anchorage quality and stress is stayed in the step of using fluid pressure operated jacks. Therefore, it is an urgent mission to make a research on nondestructive detection in anchorage quality of rock bolts.The paper based on wave theory and according to variable situation on anchoring state, a lot of research is conducted in the theory on anchorage quality of rock bolts and gets some major achievement as follows:(1) The academic analysis of stress wave spreading is conducted on transmit rule about elasticity wave to offer an important academic base for nondestructive test and evaluation of anchorage system quality.(2) Anchorage system quality can be estimated by concretion wave velocity anchorage length and bolt work load state.(3) To identify bottom reflection signal with wavelet analysis, multi-differentiate analysis and adapt sieve wave. It shows that bottom reflection has been identified well by high frequency signal of decomposed original signal with db4 in 4 scale ; multi-differentiate and wavelet packet are abundant means for wavelet; and several means above have a good coherence.(4) Apply MATLAB to analyze the signal of nondestructive testing and visualization the results in order to improve analysis precision and visualize analytic process.The wavelet analysis used in this paper is also can be used in nondestructive detection at construction of slop engineering and underground engineering, and provide referenced academic evidence for their safety evaluation.