Study on the Performance of Full-Length Pre-Stressed Anchor Bolts

Abstract:

In order to reveal the the performance of full-length pre-stressed anchor bolts, and research the rock pressure behavior law, a combination method of FLAC3D 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 anchoringthe 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.

• Periodical: Advanced Materials Research (Volumes 639-640)
• Pages: 765-769
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.639-640.765
• Online since: January 2013
• Authors: Da Sai Wang, Ai Qing Liu
• Keywords: Bolt Prestress, Full-Length Anchor, Instrumented Rockbolt, Neutral Point

References

[1] The pretension of the fully encapsulated rockbolts distributed evenly in the lag anchoring section, while it decayed in the form of negative exponential in the preload anchoring section.

[2] The position of neutral point of the highly prestressed bolt moves deeply to the surrounding rock as the rock strength reduction, and the neutral point moving deeply will accelerate the destruction of the deep rock in the anchorage zone.

[3] The instrumented rockbolt and the newly developed sleeve have a better response to the stress distribution of full-length pre-stressed bolts in site, and meet the requirements of imposing high pretension .