Numerical modelling of failure propagation in fully grouted rock bolts subjected to tensile load

Nemcik, Jan; Ma, Shuqi; Aziz, Naj; Ren, Ting X; Geng, Xueyu

doi:10.1016/j.ijrmms.2014.07.007

Cited by 90 publications

(39 citation statements)

References 18 publications

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“…He established that load-displacement distribution at the interface of the bolt and anchor could be a solution [7]. In Nemcik's study, the nonlinear bond-slip constitutive model is combined with FLAC2D to simulate the failure transmission law of a full-length anchored rock under tension [8]. Hu reported a low-viscosity and highstrength anchoring agent using fine stone powder as an aggregate, increasing the amount of resin to improve the consistency of the anchoring agent and compensating for the decrease in resin strength due to a lack of coarse aggregates by increasing the degree of polymerization of the resin [9].…”

Section: Introductionmentioning

confidence: 99%

Development, Performance, and Microscopic Analysis of New Anchorage Agent with Heat Resistance, High Strength, and Full Length

Liu

Yao

Xue

et al. 2019

Advances in Materials Science and Engineering

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To solve the difficult problems of failure of pretensioned bolt supports under high ground pressure and temperature, a new kind of anchorage agent with excellent performance is developed. First, the selection and compounding of raw materials were conducted. The new anchorage agent was obtained by modifying the PET resin by mixing with a phenolic epoxy vinyl ester resin (FX-470 resin) and adding a KH-570 silane coupling agent. Then, the viscosity, thermal stability, compressive strength under different temperatures, and anchorage capacity of the new anchorage agent were tested. Moreover, the best proportion ratio of anchorage agent by mixing resin : coarse stone powder : fine stone powder : accelerator : curing agent : KH-570 = 100 : 275 : 275 : 1 : 32.5 : 1 is obtained. The test results showed that, with the addition of a KH-570 silane coupling agent, the viscosity decreased significantly, thereby solving the difficult technical problems of pretensioned bolt supports in full-length anchorage support. Compared with the conventional anchorage agent, the compressive strength of the new anchorage agent increased by 20.4, 82.5, 118.2, and 237.5% at 10, 50, 80, and 110°C, respectively, and the anchorage capacity increased by 4.7, 8.7, 40.2, and 62.9% at 30, 50, 80, and 110°C, respectively. Finally, the enhancement in compressive strength and heat-resistant mechanism are revealed through microanalysis.

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Section: Introductionmentioning

confidence: 99%

Development, Performance, and Microscopic Analysis of New Anchorage Agent with Heat Resistance, High Strength, and Full Length

Liu

Yao

Xue

et al. 2019

Advances in Materials Science and Engineering

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“…Curves 1 and 1 in Figure 1(a) show the interfacial stress distribution mode; the former indicates a case that the pullout load is relatively low, whereas the latter indicates a case that the overlarge pullout load leads to certain amount of interfacial bonding failure. It has been completely testified that the peak bonding shear stress will gradually move from loading end to the free-loading end for a bolt subjected tensile load [10]; then a complete bonding failure should firstly occur at a section close to the loading end, causing a zero shear stress at the beginning of curve 1 , which is then followed by certain range of partial bonding failure towards the peak stress point. Beyond the section, the shear stress decreases exponentially to the free-loading end in accordance with Farmer's solution [7].…”

Section: Mechanical Differences Between Bolt In Pullout Test and Boltmentioning

confidence: 99%

“…Generally, laboratory pullout test is utilized to investigate the reinforcement effects of bolts. Regardless of the great number of pullout tests conducted around the world in various types [7][8][9][10][11][12][13], certain mechanical differences between bolt in pullout test and bolt in situ should be noted.…”

Section: Introductionmentioning

confidence: 99%

Pullout Test on Fully Grouted Bolt Sheathed by Different Length of Segmented Steel Tubes

Feng

Zhang

et al. 2017

Shock and Vibration

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In order to evaluate the anchorage performance of rebar bolt sheathed by different length of segmented steel tubes, a total of eight groups of pullout tests were conducted in this study. The steel tubes, segmented by 5 cm, 7 cm, 9 cm, 10 cm, and 15 cm, utilized in current study were bonded together by a high performance two-component adhesive to form standard 30 cm long steel tube. Unlike axial stress distribution in bolt, the axial stress distribution in steel tube showed exponential decrease trend from tube-clamp end to bolt-clamp end; thus a series of interesting results were observed. For instance, the sequence for segments detachment had its specific order of priority; the failure form of bolting system, the load oscillation characteristics, and the final displacement were highly determined by the length of the last segment, namely, the one fixed by clamp of testing machine. Moreover, the loaddisplacement relationship for some particular samples was further investigated from the perspective of energy transformation, and the disequilibrium extension of interfacial decoupling was also discussed. This paper, from a relatively idealized perspective, presents a laboratorial solution to interpret the mechanical performance of the bolt installed in layered strata; so far at least it demonstrates that a bolt installed in comparatively thicker layer of strata can last more durable and stable.

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“…The shear stress on anchor surface in the pull-out process can be divided into three parts: cohesion, mechanical self-locking force, and friction force [3]. Many mechanical models have been proposed: the shear lag model for an anchoring system based on the condition of considering bonding conditions of different interfaces [4], the simple trilinear constitutive model that describe the shear slip of the bonding interface between the anchor cable and grouting body [5], the stick-slip relationship and the trilinear stick-slip model established through pull-out tests on anchor bolts [6,7], the three-parameter and two-parameter combined-power models of the distribution of axial force within the anchorage zone [8], the hyperbolic function model of load transfer by using mathematical-mechanical methods [9]. Zhu(2009) derived a function describing the distribution of frictional resistance on anchor bolts in an elastic homogeneous rock mass [10].…”

Section: Introductionmentioning

confidence: 99%

Load transfer mechanism and critical length of anchorage zone for anchor bolt

Xu¹,

Tian²

2020

PLoS ONE

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The length of anchorage zone of an anchor bolt affects the distribution of axial force and shear stress therein. Based on a shear-displacement model, the load distribution of anchor bolts in the elastic deformation stage was analysed. Moreover, the mechanical response of threaded steel anchor bolts with different anchorage lengths was explored through pull-out test and numerical simulation. The results showed that axial force and shear stress were negatively exponentially distributed within the anchorage zone of anchor bolts in which there were the maximum axial force and shear stress at the beginning of the anchorage zone. In the elastic deformation stage of the anchorage, the longer the anchorage length, the more uniformly the shear stress was distributed within the anchorage zone and the larger the ultimate shear stress; however, there was a critical anchorage length, which, when exceeded, the ultimate shear stress remained unchanged. The calculation formula for the critical anchorage length was deduced and a reasonable anchorage length determined. The research result provides an important theoretical basis for rapid design of support parameters for anchor bolts.

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Numerical modelling of failure propagation in fully grouted rock bolts subjected to tensile load

Cited by 90 publications

References 18 publications

Development, Performance, and Microscopic Analysis of New Anchorage Agent with Heat Resistance, High Strength, and Full Length

Development, Performance, and Microscopic Analysis of New Anchorage Agent with Heat Resistance, High Strength, and Full Length

Pullout Test on Fully Grouted Bolt Sheathed by Different Length of Segmented Steel Tubes

Load transfer mechanism and critical length of anchorage zone for anchor bolt

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