scholarly journals A study of the load transfer behavior of fully grouted rock bolts with analytical modelling

2020 ◽  
Vol 30 (1) ◽  
pp. 105-109 ◽  
Author(s):  
Jianhang Chen ◽  
Fulian He ◽  
Shoubao Zhang
Keyword(s):  
Load Transfer ◽  
Analytical Modelling ◽  
Rock Bolts ◽  
Transfer Behavior ◽  
Grouted Rock Bolts

scholarly journals The Analytical Approach to Evaluate the Load-Displacement Relationship of Rock Bolts

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Jianhang Chen ◽  
Shengli Yang ◽  
Hongbao Zhao ◽  
Junwen Zhang ◽  
Fulian He ◽  
...  
Keyword(s):  
Shear Strength ◽  
Young’S Modulus ◽  
Analytical Model ◽  
Load Transfer ◽  
Young's Modulus ◽  
Peak Load ◽  
Rock Bolts ◽  
Residual Shear Strength ◽  
Grouted Rock Bolts ◽  
Elastic Softening

Fully grouted rock bolts are widely used in civil engineering and mining engineering, playing a significant role in keeping the stability and safety of excavations. In this paper, the load transfer mechanism of fully grouted rock bolts was studied with an analytical model. A trilinear model was used to depict the bond-slip behaviour of the bolt/grout interface. The displacement of the confining medium was involved in this analytical model. Then, the shear stress propagation along the bolt/grout interface was analysed in the elastic, elastic-softening, elastic-softening-debonding, softening-debonding, and debonding stages. Experimental pull-out tests were used to validate this analytical model. There was a good correlation between experimental and analytical results. A parametric study was conducted to evaluate the influence of Young’s modulus of the confining medium, the shear strength of the bolt/grout interface, and the residual shear strength of the bolt/grout interface on the load transfer performance of rock bolts. The results show that increasing Young’s modulus of the confining medium was beneficial for improving the load transfer performance of rock bolts. However, once Young’s modulus of the confining medium was beyond a critical limit, it had marginal effect on the peak load of rock bolts. Furthermore, increasing the shear strength of the bolt/grout interface and the residual shear strength of the bolt/grout interface led to rising of the peak load of rock bolts. However, compared with the residual shear strength of the bolt/grout interface, increasing the shear strength of the bolt/grout interface had more apparent effect in improving the peak load of rock bolts.

scholarly journals Study on Mechanical Characteristics of Fully Grouted Rock Bolts for Underground Caverns under Seismic Loads

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Guoqing Liu ◽  
Ming Xiao ◽  
Juntao Chen ◽  
Hao Zhou
Keyword(s):  
Mechanical Characteristics ◽  
Load Transfer ◽  
Seismic Load ◽  
Seismic Loads ◽  
Stress Distributions ◽  
Rock Bolts ◽  
Pull Out ◽  
Underground Caverns ◽  
Grouted Rock Bolts

This study establishes an analytical model for the interaction between the bolt and surrounding rock based on the bearing mechanism of fully grouted rock bolts. The corresponding controlled differential equation for load transfer is deduced. The stress distributions of the anchorage body are obtained by solving the equations. A dynamic algorithm for the bolt considering shear damage on the anchoring interface is proposed based on the dynamic finite element method. The rationality of the algorithm is verified by a pull-out test and excavation simulation of a rounded tunnel. Then, a case study on the mechanical characteristics of the bolts in underground caverns under seismic loads is conducted. The results indicate that the seismic load may lead to stress originating from the bolts and damage on the anchoring interface. The key positions of the antiseismic support can be determined using the numerical simulation. The calculated results can serve as a reference for the antiseismic optimal design of bolts in underground caverns.

Optimization of the fully grouted rock bolts for load transfer enhancement

2015 ◽  
Vol 25 (5) ◽  
pp. 707-712 ◽  
Author(s):  
Mostafa Ghadimi ◽  
Korosh Shahriar ◽  
Hossein Jalalifar
Keyword(s):  
Load Transfer ◽  
Transfer Enhancement ◽  
Rock Bolts ◽  
Grouted Rock Bolts

scholarly journals Studying the performance of fully encapsulated rock bolts with modified structural elements

2021 ◽  
Author(s):  
Jianhang Chen ◽  
Hongbao Zhao ◽  
Fulian He ◽  
Junwen Zhang ◽  
Kangming Tao
Keyword(s):  
Shear Stress ◽  
Load Transfer ◽  
Maximum Shear Stress ◽  
Coupling Model ◽  
Numerical Approach ◽  
Rock Bolt ◽  
Structural Elements ◽  
Rock Bolts ◽  
Two Stage ◽  
Bolt Diameter

AbstractNumerical simulation is a useful tool in investigating the loading performance of rock bolts. The cable structural elements (cableSELs) in FLAC3D are commonly adopted to simulate rock bolts to solve geotechnical issues. In this study, the bonding performance of the interface between the rock bolt and the grout material was simulated with a two-stage shearing coupling model. Furthermore, the FISH language was used to incorporate this two-stage shear coupling model into FLAC3D to modify the current cableSELs. Comparison was performed between numerical and experimental results to confirm that the numerical approach can properly simulate the loading performance of rock bolts. Based on the modified cableSELs, the influence of the bolt diameter on the performance of rock bolts and the shear stress propagation along the interface between the bolt and the grout were studied. The simulation results indicated that the load transfer capacity of rock bolts rose with the rock bolt diameter apparently. With the bolt diameter increasing, the performance of the rock bolting system was likely to change from the ductile behaviour to the brittle behaviour. Moreover, after the rock bolt was loaded, the position where the maximum shear stress occurred was variable. Specifically, with the continuous loading, it shifted from the rock bolt loaded end to the other end.

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