Research on the Mechanism and Application of High Pre-Tension on the Crack-Arresting Effect of Rockbolt Anchorage

Bowen Wu; Jucai Chang; Xiangyu Wang; Wenbao Shi; Chuanming Li; Dingchao Chen

doi:10.3390/buildings14082584

Buildings (Aug 2024)

Research on the Mechanism and Application of High Pre-Tension on the Crack-Arresting Effect of Rockbolt Anchorage

Bowen Wu,
Jucai Chang,
Xiangyu Wang,
Wenbao Shi,
Chuanming Li,
Dingchao Chen

Affiliations

Bowen Wu: School of Mining Engineering, Anhui University of Science and Technology, Huainan 232001, China
Jucai Chang: School of Mining Engineering, Anhui University of Science and Technology, Huainan 232001, China
Xiangyu Wang: School of Mines, China University of Mining and Technology, Xuzhou 221116, China
Wenbao Shi: School of Mining Engineering, Anhui University of Science and Technology, Huainan 232001, China
Chuanming Li: School of Mining Engineering, Anhui University of Science and Technology, Huainan 232001, China
Dingchao Chen: School of Mines, China University of Mining and Technology, Xuzhou 221116, China

DOI: https://doi.org/10.3390/buildings14082584
Journal volume & issue: Vol. 14, no. 8
p. 2584

Abstract

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In order to investigate the effect of pre-tension on the anchoring and crack-arresting effect of rockbolts, a theoretical model of stress intensity factor at the crack tip in anchored surrounding rock was established using fracture mechanics theory. An expression for the difference in stress intensity factor due to axial force on the rockbolt was derived, exploring the influence of pre-tension on the stress intensity factor of cracks. A numerical model of anchored crack specimens was developed using UDEC (V6.0) software to simulate and analyze the mechanical performance and damage characteristics of specimens anchored with different pre-tension. The results indicate that the difference in stress intensity factor of cracks is positively correlated with pre-tension. High-pre-tensioned rockbolts can effectively reduce the stress intensity factor of cracks. Prestressed rockbolts can alter the failure mode of rock masses from shear failure along pre-existing cracks to tensile splitting failure. The application of high pre-tension significantly enhances the strength of the rock mass, reducing both the damage degree and the number of internal cracks. After anchoring with high-pre-tensioned rockbolts, the peak strength and elastic modulus of the crack specimens increased by 22.5% and 31.9%, respectively, while damage degree decreased by 17.4%, the number of shear cracks decreased by 22.6%, and the number of tensile cracks decreased by 42.9%. The pre-tensioned rockbolt method proposed in this study was applied to the support of roadway widening. Field monitoring data indicated that the axial force of the rockbolts in the test section generally exceeded 60 kN, effectively controlling the deformation of the roadway surrounding the rock. The convergence of the two sides decreased by 22%, and borehole inspections showed a significant reduction in internal cracks. The research results provide a theoretical basis for controlling the discontinuous deformation of deep broken surrounding rock roadways.

Published in Buildings

ISSN: 2075-5309 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Building construction
Website: https://www.mdpi.com/journal/buildings

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