Study on the performance of full-length pre-stressed anchor bolts

摘要

In order to reveal the performance of full-length pre-stressed anchor bolts, and research the rock pressure behavior law, a combination method of FLAC~(3D) and situ tests were presented, the conclusions were drawn as following: the prestress of full-length pre-stressed anchor bolt was approximately uniform distribution along the slow anchoring section of the rod, while in the fast anchoring the segment showed a negative exponential or linear form of attenuation, and the bolt axial load was biggest in the neutral point; the neutral point of full-length pre-stressed anchor bolt move to deeper of the drill hole with the reduction of rock strength, while neutral point shifting deeper would accelerate the destruction of the anchorage zone in deep rock formations, deteriorating the anchoring effect. The methods of pre-grouting and grouting bolt (or cable) should be taken to improve the anchoring force.