• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6C
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• pp.313-319
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• 2009

In this study, field pull-out test and 3-D FEM analysis have been performed for examining and reflecting the behavior of steel pipe nailing installed foldable wedge. Field pull-out test was performed under various conditions. As a result, the steel pipe nailing installed foldable wedge has an effect of pull-out resistance increased about 30% in comparison with non-wedge type steel pipe nailing. Through back analysis in 3-D FEM for behavior of non-wedge type steel pipe nailing, friction characteristics between nail to soil was analyzed and obtained first consistent with field pull-out behavior. Then, the frictional characteristic was used for analyzing the behavior of the steel pipe nailing installed foldable wedge. The result was compared with the test results. Consequently, friction coefficient (${\mu}$) of about 1.2 between grout to soil leads to good agreement with analysis results and test results. And a limited pull-out resistance, $$T_L{\sim_=}32$$ tonf is similar to field pull-out test result which is improved about 33% in comparison with non-wedge type steel pipe nailing's $$T_L{\sim_=}24$$ tonf.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.1
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• pp.71-82
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• 2011

This paper presents the tensile strength of shotcrete steel fibers depending on the shape of steel fiber. The experimental and numerical analyses are performed in this study. In experimental study, a series of laboratory pullout tests are carried out by changing both the angle and the length of the embedded steel fiber according to the corresponding type of steel fiber in order to derive the optimal type of steel fiber. Results obtained from the experimental work are evaluated and compared with the numerical analysis results. The results clearly show that the pull-out strength of the steel fiber are increased with increasing the hook angle and embedded angle of steel fiber. It is also found that the pull-out strength of the steel fiber is larger in case of the short steel fiber body length.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.167-173
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• 2014

The embedded suction anchor, ESA, is one type of mooring anchor systems which utilizes the suction pile or caisson to penetrate the anchor into the sea bed and develops its capacity under pullout load. In this study, the numerical analysis using ALE (Arbitrary Lagrangian Eulerian) Adaptive Meshing technique was performed to simulate the pullout behavior of the ESA, and the results were compared to those of the previous research, centrifuge model tests and the analytical method based on limit equilibrium theory. The pullout behaviors of the ESA under horizontal, vertical, and inclined loading were evaluated. The analysis results showed that the maximum horizontal pullout load was developed when the location of loading point was at the mid-point, and the each vertical pullout load gave the similar value regardless of the locations of the loading points. The pullout load decreased as the load inclination angle increased at the mid-point of the anchor.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.2
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• pp.69-76
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• 2010

This study is an numerical study of predicting the behavior of anchor embedded in weathered rocks, subjected to uplift loads, about ultimate pullout capacity and the failure mechanism. Factors influencing the behavior of anchors were investigated by reviewing the data about in-situ anchor tests performing numerical modelling with changing the bondage length of anchor, diameter of anchor body and diameter of tendon, and by correlations between those factors were evaluated to apply them to predict the behavior of anchors. As results of numerical analysis, a linear relationship between bondage length, diameter of anchor body and diameter of tendon with ultimate pullout capacity was obtained on the one hand, from the result of numerical analysis changing the Young's modulus of weathered rock, this parameter was found to influence to load-displacement and ultimate pullout capacity within the range of 10%, which was not so significant to affect.

• Land and Housing Review
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• v.7 no.4
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• pp.281-289
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• 2016

Structural experiment result showed that PHC(d=600mm) Pile used as a common compression member could resist 83.6 ~ 91.6 tonf of ultimate tension force, if the adhesion of P.C. bar of PHC pile to the concrete foundation is strengthened. Considering a proper safety factor to ultimate tension strength, PHC pile can substitute the anti-floating anchor, or reduce the number of anchors. For this purpose, pullout resistance behavior of a Bored pile embedded in real ground as well as structural tension strength of PHC pile must be evaluated. This study performed the static pullout tests to evaluate the pullout behavior of bored pile, and compared the test results with design value of side resistance. To evaluate the pullout resistance easily, static pullout test results were compared with dynamic loading test results using PDA. As a result, cement paste of the bored pile was hardened which is after 15 days, LH side resistance design value corresponded well to the Static pullout test results, also to the side resistance evaluated by dynamic loading test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2797-2803
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• 2012

This paper presents the pull-out behaviors of headed glass fiber reinforced polymer (GFRP) rebar embedded in mortar under tension loading. Five specimens with headed GFRP rebars that were anchored in the center of mortar bases were constructed and the pull-out test was conducted. To verify the test results, the finite element analysis was conducted and the results were compared with the FE analysis using ANSYS software package. Based on the test results it was indicated that the CCD(concrete capacity design) failure theory should be adopted and not to use the 45o cone failure theory as the breakout capacity in the headed GFRP rebar embedded in mortar.

• Tunnel and Underground Space
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• v.21 no.5
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• pp.377-385
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• 2011

In order to prove the applicability of rock bolts with compressible spacers, laboratory model tests and large scale model tests were conducted. Laboratory model tests were performed in various distance of compressible spacers to determine the optimal distance of compressible spacers. The optimal distance of compressible spacers was found that is 1/4 of rock bolts unit length. Large scale model tests that the size was 0.6 m (diameter) ${\times}$ 4.45 m (length) were conducted. Test results showed that pull out resistance could be increased up to 15% larger than that of unused case by using compressible spacers.

• Journal of the Korean Geotechnical Society
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• v.34 no.10
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• pp.61-74
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• 2018

In this study, the pull-out behavior of tunnel type anchorage of suspension bridges was analyzed based on results from laboratory size model tests and numerical analysis. Tunnel type anchorage has found its applications occasionally in both domestic and oversea projects, therefore design method including failure mode and safety factor is yet to be clearly established. In an attempt to improve the design method, scaled model tests were conducted by employing simplified shapes and structure of the Ulsan grand bridge's anchorage which was the first case history of its like in Korea. In the model tests, the anchorage body and the surrounding rocks were made by using gypsum mixture. The pull-out behavior was investigated under plane strain conditions. The results of the model tests showed that the tunnel type anchorage underwent wedge shape failure. For the verification of the model tests, numerical analysis was carried out using ABAQUS, a finite element analysis program. The failure behavior predicted by numerical analysis was consistent with that by the model tests. The result of numerical analysis also showed that the effect of Poisson's ratio was negligible, and that a plugging type failure mode could occur only when the strength of the surrounding rocks was 10 times larger than that of anchorage body.

• Geotechnical Engineering
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• v.3 no.3
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• pp.31-48
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• 1987

The vertical pressure due to soil prism load and surface surcharge load acts on buried pipe, and occasionally uplifting force due to earthquake or differential settlement acts on it. In this paper, study was performed to estimate the pressure acting on the buried pipe due to soil prism load through analyzing Marston-Spangler theory by new method. And loading tests on the buried flexible pipe were performed to study on the response of the pipe due to surface surcharge load. Also, through the estimation of uplifting resistance theory and uplifting test for buried pipe, the method to determine the maximum uplifting resistance of buried pipe was proposed.

• Journal of the Korean GEO-environmental Society
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• v.24 no.4
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• pp.13-22
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• 2023

In this paper, through experimental research, the period when rock bolts exert support effects is presented as grout strength and through numerical analysis, the rock bolt pull-out behavior according to ground conditions and strength reduction factors is analyzed. As a result, it is determined that rock bolts exhibit their reinforcing effect at a grout strength of 5 MPa (cured for 18 hours). The influence of the boundary interface strength reduction factor was found to be significant for rock bolt displacement in weak ground conditions, for shear stress between grout and ground in highly elastic ground conditions, and for grout stress in all ground conditions. These findings are expected to contribute to the establishment of specific standards for rock bolt testing and numerical analysis, and to facilitate improved design and implementation of rock bolt reinforcement.