• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.521-528
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• 2002

This paper presents the results of centrifuge model tests on the reinforced slope by pressure grouting. Tests were performed to investigate the reinforcing effect of grouting. In the tests, slopes of scale factor 1/10 were used changing the space and number of reinforcing bar. Test results are as tile follows; 1. The reinforcing effect increase rapidly with reinforcement area ratio at low value of reinforcement area ratio. 2. At high reinforcement area ratio the increase ratio of reinforcing effect decrease. 3. At same reinforcement area ratio, the reinforcing effect of double reinforcing bar was larger than the single reinforcing bar due to arching effect.

• Tunnel and Underground Space
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• v.6 no.2
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• pp.166-174
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• 1996

Stability of rock slope is greatly affected by the geometry and strength of discontinuities developed in the rock mass. In this study an analytical method which is capable of analyzing the effect of relative orientation between the discontinuities and the slope face on the safety of slope by assessing their vector components was used to evaluate the stability and the maximum cut-angle for the proposed slope design. The results of computerized vector analysis revealed that slope area under investigation might be divided into 3 sections of different face directions. The safety factors for benches in each 3 sections were calculated using the limit-equilibrium theory. Then, by utilizing the concept of probabilistic risk analysis, the susceptibility of entire slope failure was estimated. Based on the distribution of safety factor in each bench, the maximum cut angle of each section could be selected differently ot achieve the permanent stability of the entire slope.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.219-222
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• 2003

Even through hundreds of meters high steep slope is stable, only several ten meters high dull slope could be collapsed. This means that stability of slope is depend on the slope of a surface of discontinuity like faults existing in rock floor. The existence and nonexistence of a discontinuity surface have a very important effect to the stability of a rock floor slope, and examination for geologic peculiarity is one of the most important pant for investigation of stabilities. Accordingly, in the study, we extracted three dimension coordinates of slope with close photogrammetry, and through interpretations of three dimensions' position of fault within rock floor slope, we expect this will be use as a important sauces when evaluate stabilities of rock floor slope.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.4
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• pp.273-281
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• 2008

In this study, the effect of slope length and angle at the entrance to fishing pots on the size of captured shrimp was examined to determine the optimal design of pots for use in Hokkaido, Japan. The purpose of the current study was to optimize the design of shrimp pots to allow greater control over the size of captured individuals for the purposes of shrimp resource management. Tank experiments were conducted to determine the optimal slope length and slope angle by analyzing the sizes of shrimp entering 10 model pots with combinations of five different slope lengths on slope angle of current shrimp pot, and five different angles on slope length of current shrimp pot. The results showed that, as the slope length of the pot increased, the size of individuals which entered the pot increased. In addition, as the slope angle was elevated in each of the five different slope angle treatments, the size of individuals entering was also increased.

• Journal of the Korean Geosynthetics Society
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• v.8 no.4
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• pp.47-51
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• 2009

The slope failure in the country is caused by mainly rainfall and its type is reported shallow slope failures in general. To investigate the cause of slope failure, the unsaturated soil slope behavior in accordance with rainfall amount studies actively, but there are little studies related the slope erosion and scour by rainfall. The slope erosion and scour by rainfall cause environmental pollution and slope instability, however there are few methods to effectively control them. This research analyzed experimentally how infinite gradients are infiltrated according to the changes of amount of rainfall and the slope of gradients by manufacturing the model of gradient in order to investigate how rainfall infiltrates regarding homogeneous gradients and slope protection method. For this, this experiment measured and analyzed discharge, storage rate occurring in gradients by going on changing amount of rainfall, slope of gradients.

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.33-41
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• 2017

In this study, the increment effect of safety factor according to increasing of horizontal permeability coefficient is analyzed when geocell is installed on the slope for protection. To evaluate the horizontal permeability and reinforcement effect, the laboratory tests such horizontal permeability test were conducted. According to the laboratory test results, as the porosity rate of geocell increases, the coefficient of horizontal permeability is also increased. And also, regardless of the different types of filled materials, the coefficient of horizontal permeability is improved in a geocell reinforced ground compare with the non-reinforced ground. Laboratory test results and the rainfall intensity were applied to the numerical modeling of slope for seepage analysis and stability analysis of slope by using Soilworks, numerical analysis program. As a result of the slope stability analysis, it is confirmed that the installed geocell on the slope facilitates the drainage of water on the surface of slope. Hence, the ground water elevation is suppressed. Therefore, the safety factor of the slope is increased by the increasing of the internal friction angle, apparent cohesion, and coefficient of horizontal permeability by reinforcing the slope with geocell.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.745-750
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• 2007

This paper presents investigation of topographic effects over isolated 3-dimensional hills through wind tunnel experiments in a boundary layer wind tunnel. Topographic models having five different slopes of $5.71^{\circ},\;11.31^{\circ},\;16.70^{\circ},\;21.80^{\circ}$, and $26.57^{\circ}$, which were based on KBC(2005), were taken into account in the study. The maximum topographic factor and the range of topographic effect from the experiment were compared with those from worldwide major codes and standards, such as ASCE-7-02, AS/NZS-1170.2:2002, ISO4354(1997), and KBC(2005). From the comparison of major codes and standards, in the vertical region of topographic effect, the gentler the slope was. the more different the topographic factors and ranges of topographic effect were, but the steeper the slope was, the more similar they were. It was found from the experimental study that the region of topographic effect in the slope in the across wind direction was greater than the regions of major codes and standard. Also, the gentler the slope was. the larger the topographic factor from the experiment was than the factors of major codes and standards.

• Geomechanics and Engineering
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• v.23 no.4
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• pp.313-325
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• 2020

Slope displacement and factor of safety (FOS) of a slope are two aspects that reflect the stability of a slope. However, the traditional limit equilibrium (LE) methods only give the result of the slope FOS and cannot be used to solve for the slope displacement. Therefore, developing a LE method to obtain the results of the slope FOS and slope displacement has significance for engineering applications. Based on a force-displacement coupled mode, this work expands the LE Morgenstern-Price (M-P) method. Except for the mechanical equilibrium conditions of a sliding body adopted in the traditional M-P method, the present method introduces a nonlinear model of the shear stress and shear displacement. Moreover, the energy equation satisfied by a sliding body under a small slope displacement is also applied. Therefore, the double solutions of the slope FOS and horizontal slope displacement are established. Furthermore, the flow chart for the expanded LE M-P method is given. By comparisons and analyses of slope examples, the present method has close results with previous research and numerical simulation methods, thus verifying the feasibility of the present method. Thereafter, from the parametric analysis, the following conclusions are obtained: (1) the shear displacement parameters of the soil affect the horizontal slope displacement but have little effect on the slope FOS; and (2) the curves of the horizontal slope displacement vs. the minimum slope FOS could be fitted by a hyperbolic model, which would be beneficial to obtain the horizontal slope displacement for the slope in the critical state.

• Geomechanics and Engineering
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• v.17 no.2
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• pp.181-194
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• 2019

Due to the seepage of groundwater, the resisting force of slopes decreases and the sliding force increases, resulting in significantly reduced slope stability. The instability of most natural slopes is closely related to the influence of groundwater. Therefore, it is important to study slope stability under groundwater seepage conditions. Thus, using a simplified seepage model of groundwater combined with the analysis of stresses on the slip surface, the limit equilibrium (LE) analytical solutions for two- and three-dimensional slope stability under groundwater seepage are deduced in this work. Meanwhile, the general nonlinear Mohr-Coulomb (M-C) strength criterion is adopted to describe the shear failure of a slope. By comparing the results with the traditional LE methods on slope examples, the feasibility of the proposed method is verified. In contrast to traditional LE methods, the proposed method is more suitable for analyzing slope stability under complex conditions. In addition, to facilitate the optimization of drainage design in the slope, stability charts are drawn for slopes with different groundwater tables. Furthermore, the study concluded that: (1) when the hydraulic gradient of groundwater is small, the effect on slope stability is also small for a change in the groundwater table; and (2) compared with a slope without a groundwater table, a slope with a groundwater table has a larger failure range under groundwater seepage.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1027-1035
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• 2013

In this study, two rainfall patterns are utilized for practical consideration of rainfall phenomena in unsaturated soil slope design. One is the I.D.F (Intensity-Duration-Frequency) method which is an existing design rainfall method and ignores the effect of the variation of the rainfall according to the time. The other is the Huff method which considers this effect oppositely. First, the safety of factor of the slope according to the variation of an initial suction which means the precedent rainfall effect was examined by means of the application of the I.D.F method. Through the application of two rainfall patterns, it was discussed how the rainfall pattern affects the factor of safety of the slope. As a result, it is found that the Huff method is more practical on the evaluation of the slope stability than the I.D.F method.