Article
Construction & Building Technology
Yingchun Li, Yi Tan, Ammar Ahmed, Hao Cheng
Summary: This study investigates the mechanical behavior of fully grouted rockbolts reinforced with steel fiber-reinforced grout (FRG). The results show that FRG significantly enhances the bond strength of rockbolts, with a higher proportion of fibers leading to greater bond strength. Furthermore, under a constant confining pressure, the bond strengths of all grouted rockbolts are significantly elevated, and FRG exhibits less brittle post-peak failure compared to plain grout. The wavy steel fiber performs better in enhancing bond strength and mitigating grout cracking due to its crack bridging effect facilitated by its rough geometry.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Peter Craig, Hamed Lamei Ramandi, Honghao Chen, Damon Vandermaat, Alan Crosky, Paul Hagan, Bruce Hebblewhite, Serkan Saydam
Summary: Premature failure of rockbolts due to stress corrosion cracking (SCC) is a global issue in underground structures, especially in underground mines. This study innovatively used in-situ testing to investigate the behavior of different steel grades under stressed conditions, providing detailed insights into rockbolt SCC in the underground environment.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Metallurgy & Metallurgical Engineering
Qi-feng Guo, Hai-long Liu, Xun Xi, Hong-chi Ma, Ji-liang Pan, Mei-feng Cai
Summary: Corrosion of rockbolt has a significant negative impact on the long-term functionality of anchorage structures in rock engineering. This paper conducts comprehensive experiments to investigate the degradation caused by corrosion in mortar grouted rockbolts, considering natural fractures and continuous loads. Results show that the corrosion reduces the bond strength and critical slip displacement of the rockbolts. The degree of corrosion and the proximity of natural fractures and axial loads have a strong influence on the degradation caused by corrosion.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2023)
Article
Construction & Building Technology
Haiyang Gao, Lianguang Wang, Xue Li, Yaosheng Zhang
Summary: This study investigates the pull-out behaviors of wedge-grouted rockbolts and grouted rockbolts in different weathered rocks. The test results show that the minimum anchoring length varies in strongly weathered and moderately weathered rocks for both types of rockbolts. The effect of wedge head on restraining deformation is related to the anchoring length. Freeze-thaw cycle has little influence on the stiffness and deformation of the rockbolts. The wedge-grouted rockbolts exhibit better deformation performance compared to grouted rockbolts. Furthermore, the calculation models provide reasonable predictions for strain and shear stress development.
INTERNATIONAL JOURNAL OF STEEL STRUCTURES
(2023)
Article
Mechanics
Shadi Ansari, David S. Nobes
Summary: The study developed an algorithm based on the shadowgraph method to evaluate the instantaneous change in pressure of an isolated bubble passing through a confined geometry. Results showed that the pressure across the bubble varies at different locations along the pore, with the critical pressure increasing as the size of the bubble increases.
Article
Chemistry, Multidisciplinary
Youliang Chen, Peng Xiao, Xi Du, Suran Wang, Tomas Manuel Fernandez-Steeger, Rafig Azzam
Summary: This study focused on acid-etched freeze-thaw rock in geotechnical engineering in cold regions, introducing chemical damage variables, freeze-thaw damage variables, and force damage variables. The research derived a damage evolution equation and constitutive model for acid-eroded rock under the coupling action of freeze-thaw and confining pressure, and verified the rationality and accuracy of the model through triaxial compression tests. The damage constitutive model can better reflect the stress-strain peak characteristics of rock during triaxial compression, demonstrating the rationality and reliability of the model and the method for determining the model parameters.
APPLIED SCIENCES-BASEL
(2021)
Article
Chemistry, Multidisciplinary
Eliass El Alami, Fatima-Ezzahra Fekak, Luigi Garibaldi, Hassane Moustabchir, Ahmed Elkhalfi, Maria Luminita Scutaru, Sorin Vlase
Summary: This paper explores the impact of corrosion on the bond strength of reinforced concrete structures using a numerical model. The study investigates the effects of embedment depth, rebar diameter, and concrete cover width on the bond strength. The results are validated with experimental data and the study confirms the relationship between these parameters and bond strength.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Geological
Charlie C. Li, Andreas Aure, Greig Knox
Summary: An inflatable rockbolt is a steel tube that expands through water injection and reinforces the rock mass through friction. This study focuses on quantifying the effects of borehole size, roughness, and water pressure on the bolt's load capacity. Pull tests showed higher load capacity in boreholes close to the bolt's initial or fully unfolded diameter. Additionally, smaller boreholes had enhanced load capacity due to deformation locking, and percussively drilled boreholes had higher load capacity than diamond-drilled ones. Increased installation water pressure also increased load capacity.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Energy & Fuels
Shuisheng Yu, Wancheng Zhu, Leilei Niu
Summary: In this study, the debonding of rockbolts under different pull-out loads was investigated using laboratory experiments and numerical simulations. Ultrasonic guided wave propagation was found to be a sensitive method for detecting and quantifying the debonding. The results showed that the critical bond length could be calculated based on the guided wave propagation in the grouted rockbolt.
INTERNATIONAL JOURNAL OF COAL SCIENCE & TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Yao Huang, Navid Zolfaghari, Andrew P. Bunger
Summary: The numerical analysis in this study explores the growth of cracks from a notched borehole under confinement. A Finite Element framework is used to simulate crack initiation and propagation behavior, which is validated using burst experiments. The study shows that the three-parameter traction-separation law accurately describes crack initiation behavior, eliminating the need for ad hoc stress and size dependence factors. The limitations of traditional burst experiments are also identified, along with a proposed modification to remove ambiguity and enable complete characterization of the traction separation law by pairing it with Acoustic Emission monitoring.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Chemistry, Multidisciplinary
Natnael Tilahun Asfaw, Gang Lei, Mehran Azizian, Arjan Poudel, Laureano Hoyos, Xinbao Yu
Summary: This study tested the ultimate pull-out capacity of percussion driven earth anchors in clayey soil slopes and compared the field experiment results with the calculated capacities. The findings shed light on the performance of these anchors in actual field conditions.
APPLIED SCIENCES-BASEL
(2023)
Article
Mechanics
Yang Liu, Mingxuan Li, Xiaofeng Lu, Qingsheng Li, Xiaolei Zhu
Summary: The study introduced a new type of interference-fit fastener and analyzed its pull-out performance and failure modes through pull-through resistance tests and finite element method. It was found that the length of expansion sleeve, reducer segment, nut extension length, and interference size greatly influenced the performance of the joint. Through optimization using the response surface method, the optimal parameter combination of the interference-fit fastener was obtained.
COMPOSITE STRUCTURES
(2021)
Article
Engineering, Geological
Salem Algarni, Murtada Saleh Aljawad, Haider Al-Majid, Shabeeb Alajmei, Abdulazeez Abdulraheem, Dhafer Al-Shehri
Summary: This study investigates the stability and characteristics of wormholes under high confining pressure. Experimental results show that wormholes in chalk samples tend to close, while those in limestone samples remain mechanically stable.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Engineering, Geological
YangPing Yao, NingBo Wang, Dong Chen
Summary: This study systematically analyzes the mechanical behaviors of granular soils under low confining pressure by introducing compressive hardening parameter and interlocking strength parameter, and establishes a unified hardening model for granular soils. Experimental data show that the UH-L model is capable of uniformly describing the stress-strain relations and strength of granular soils under low confining pressure.
Article
Construction & Building Technology
Bo-Han Xu, Yi-Ge Zhao, Kong-Bin Yu, Abdelhamid Bouchair, Binsheng Zhang
Summary: The corrosion of metal fasteners by water-based preservatives can reduce the service life of preserved timber in outdoor environments. Wooden fasteners, on the other hand, offer resistance against corrosion and better compatibility with timber members. This study examined the performance of dried densified wood dowels embedded into glued laminated timber in different ambient environments.
JOURNAL OF MATERIALS IN CIVIL ENGINEERING
(2023)