• Proceedings of the KSR Conference
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• 2002.10a
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• pp.608-613
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• 2002

This study was under taken as an analysis of failure mode in a railroad bed reconstructed with miniaturized Geotextile Container after being destroyed by heavy rain. It assesses the practical use of the bag shaped Geotextile Container method in the rehabilitation of destroyed roadbeds. The failure mode was assessed using the laboratory model tests to determine the following criteria: Strain of Geotextile Container, Vertical ＆ Horizontal displacements of Geotextile Container layer, and the transmitting load effects due to the applied load. The Geotextile Container layer was failed as a Block Failure type, although there was some variation in the results between the saturated and unsaturated conditions. The main failure was caused by the reduction of the interface friction between Geotextile Containers. The result of this mobilizes the significant horizontal displacement and the ultimate failure of the Geotextile Container layer. The strain on the wet Geotextile Container was occurred about two times greater than that of dry condition.

• Ocean Systems Engineering
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• v.3 no.2
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• pp.79-95
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• 2013

Suction anchors are widely adopted in mooring systems. However there are still challenges in predicting the failure mode and ultimate pullout capacity of the anchor. Previously published methods for predicting the inclined pullout capacity of suction anchors are mainly based on experimental data or the FEM analysis. In the present work, an analytical method that is capable of predicting the failure mode and ultimate pullout capacity of the suction anchor in clay under inclined loading is developed. This method is based on a rational mechanical model for suction anchors and the knowledge of the mechanism that the anchor fails in seabed soils. In order to examine the analytical model, the failure angle and pullout capacity of suction anchors from FEM simulation, numerical solution and laboratory tests in uniform and linear cohesive soils are employed to compare with the theoretical predictions and the agreement is satisfactory. An analytical method that can evaluate the optimal position of the attachment point is also proposed in the present study. The present work proves that the failure mode and pullout capacity of suction anchors can be reasonably determined by the developed analytical method.

• Journal of the Korean Geosynthetics Society
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• v.7 no.3
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• pp.9-16
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• 2008

This paper is concerned with the numerical evaluation of the failure behavior of reinforced soil walls based on the elasto-plastic theory. At first, the basic analysis on the failure behavior of reinforced soil walls are discussed. Parametric study of the major factors influencing the failure behavior is conducted by FEM. The objectives are to identify and evaluate the major facts influencing the failure mode of reinforced soil walls. The results of the parametric study on the failure behavior due to soil friction angle, reinforcement type, and reinforecement length are analysed.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.6
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• pp.73-80
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• 2010

Conventional slope stability analysis is focused on calculating minimum factor of safety or maximum probability of failure. To minimize inherent uncertainty of soil properties and analytical model and to reflect various analytical models and its failure shape in slope stability analysis, slope stability analysis method considering simultaneous failure probability for multi failure mode was proposed. Linear programming recently introduced in system reliability analysis was used for calculation of simultaneous failure probability. System reliability analysis for various analytical models could be executed by this method. Optimum design to determine angle of a simple slope is executed for multi failure mode using linear programming. Because of complex consideration for various failure shapes and modes, it is possible to secure advanced safety by using simultaneous failure probability.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.409-416
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• 2005

Design analysis for underground spaces requires evaluating stability related to tunnel collapses. A failure mode is one of the critical factors in the conventional methods of stability analysis. Therefore identification of failure modes is essential in securing safe construction in the phase of design analysis, instrumentation planning and implementation of reinforcing measures. In this study failure modes at the tunnel heading in granular soils are investigated using physical model tests and numerical simulation for various tunnel depths and ground surface inclinations. Test results indicated that the effect of depth and inclination of ground surface on a failure mode are significant. It is identified that, with an incase in depth, failure modes become localized in a region close to the tunnel. It is also known that an increase in the inclination of ground surface results in inclined and wide failure modes.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.61-65
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• 2005

Existing test methods for thick-section specimens ( 4mm) have not provided precise compressive properties to date for the analysis and design of thick structure. A survey of the failure behaviour of such thick specimens revealed that the failure initiated at the top corner of the specimen and propagated down and across the width of the specimen as premature failure, not typically reported for thin compression specimens. In the current study, the premature failure was successfully avoided during compressive testing and the failure mode was quite similar regardless of increasing specimen thickness and specimen volume. Failure mode was similar regardless of increasing specimen thickness and specimen volume, i.e. brooming failure mode combined with longitudinal splitting, interlaminar cracking, fibre breakage and kinkband formation (fibre microbuckling). Nevertheless, average failure strengths of the specimens decreased with increasing specimen thicnkiness from 2mm to 8mm with the T800/924C system (36% strength reduction) and specimen volumes from scaling factor I to scaling factor 4 with the IM7/8552 system (46% strength reduction). It was revealed from the literature$^{11}$ that the thickness effect and scaling effect arc caused by manufacturing defects such as void content and fibre waviness.

• Structural Engineering and Mechanics
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• v.75 no.1
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• pp.123-131
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• 2020

The bond performance of glass fibre reinforced polymer (GFRP) bars and that of steel bars embedded in Alkali Activated Cement (AAC) concrete are analysed and compared using pull-out specimens. The bond failure modes, the average bond strength and the free end bond stress-slip curves are used for comparison. Tepfers' concrete ring model is used to further analyse the splitting failure in ribbed steel bar and GFRP bar specimens. The angle the bond forces make with the bar axis was calculated and used for comparing bond behaviour of ribbed steel bar and GFRP bars in AAC concrete. The results showed that bond failure mode plays a significant role in the comparison of the average bond stress of the specimens at failure. In case of pull-out failure mode, specimens with ribbed steel bars showed a higher bond strength while specimens with GFRP bars showed a higher bond stress in case of splitting failure mode. Comparison of the bond stress-slip curves of ribbed steel bars and GFRP bars depicted that the constant bond stress region at the peak is much smaller in case of GFRP bars than ribbed steel bars indicating a basic bond mechanism difference in GFRP and ribbed steel bars.

• Journal of the Korean Society for Railway
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• v.14 no.1
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• pp.24-30
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• 2011

Conventional slope stability analysis is focused on calculating minimum factor of safety or maximum probability of failure. To minimize inherent uncertainty of soil properties and analytical model and to reflect various analytical models and its failure shape in slope stability analysis, slope stability analysis method considering simultaneous failure probability for multi failure mode was proposed. Linear programming recently introduced in system reliability analysis was used for calculation of simultaneous failure probability. System reliability analysis for various analytical models could be executed by this method. For application analysis for embankment, the results of this method shows that system stability of embankment calculate quantitatively.

• Journal of the Korean GEO-environmental Society
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• v.17 no.5
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• pp.5-16
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• 2016

A rainfall induced slope failure is a common natural hazard in mountainous areas worldwide. Sudden and rapid failures which have a high possibility of occurrence in a steep slope are always the most dangerous due to their suddenness and high velocities. Based on a series of experiments this study aimed to determine a critical angle which could be considered as an approximate threshold for a sudden failure. The experiments were performed using 0.42 mm mean grain size sand in a 200 cm long, 60 cm wide and 50 cm deep rectangular flume. A numerical model was created by integrating a 2D seepage flow model and a 2D slope stability analysis model to predict the failure surface and the time of occurrence. The results showed that, the failure mode for the entire material will be sudden for slopes greater than $67^{\circ}$; in contrast the failure mode becomes retrogressive. There is no clear link between the degree of saturation and the mode of failure. The simulation results in considering matric suction showed good matching with the results obtained from experiment. A subsequent discarding of the matric suction effect in calculating safety factors will result in a deeper predicted failure surface and an incorrect predicted time of occurrence.

• Geomechanics and Engineering
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• v.13 no.3
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• pp.431-446
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• 2017

Rock bridges in rock masses would increase the bearing capacity of Non-persistent discontinuities. In this paper the effect of ratio of rock bridge surface to joint surface, rock bridge shape and normal load on failure behaviour of intermittent rock joint were investigated. A total of 42 various models with dimensions of $15cm{\times}15cm{\times}15cm$ of plaster specimens were fabricated simulating the open joints possessing rock bridge. The introduced rock bridges have various continuities in shear surface. The area of the rock bridge was $45cm^2$ and $90cm^2$ out of the total fixed area of $225cm^2$ respectively. The fabricated specimens were subjected to shear tests under normal loads of 0.5 MPa, 2 MPa and 4 MPa in order to investigate the shear mechanism of rock bridge. The results indicated that the failure pattern and the failure mechanism were affected by two parameters; i.e., the ratio of joint surface to rock bridge surface and normal load. So that increasing in joint area in front of the rock bridge changes the shear failure mode to tensile failure mode. Also the tensile failure change to shear failure by increasing the normal load.