• Geomechanics and Engineering
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• v.11 no.4
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• pp.457-469
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• 2016

Steep rock slope with water-filled tension crack will happen to overturn around the toe of the slope under seismic loading. This failure type is completely different from the common toppling failure occurring in anti-dipping layered rock mass slopes with steeply dipping discontinuities. This paper presents an analytical approach to determine the seismic factor of safety against overturning for an intact rock mass slope with water-filled tension crack considering horizontal and vertical seismic coefficients. This solution is a generalized explicit expression and is derived using the moment equilibrium approach. A numerical program based on discontinuous deformation analysis (DDA) is adopted to validate the analytical results. The parametric study is carried out to adequately investigate the effect of horizontal and vertical seismic coefficients on the overall stability against overturning for a saturated rock slope under two water pressure modes. The analytical results show that vertically upward seismic inertia force or/and second water pressure distribution mode will remarkably decrease the slope stability against overturning. Finally, several representative design charts of slopes also are presented for the practical application.

• Journal of Coastal Disaster Prevention
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• v.1 no.1
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• pp.1-9
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• 2014

In order to examine the characteristics of tsunami run-up heights on impermeable/permeable slope, a numerical wave tank by upgrading LES-WASS-3D was used in this study. Then, the model were compared with existing hydraulic model test for its verification. The numerical results well reproduced experimental results of solitary wave deformation, propagation and run-up height under various conditions. Also, the numerical simulation with a slope boundary condition has been carried out to understand solitary wave run-up on impermeable/permeable slope. It is shown that the run-up heights on permeable slope is 52.64-63.2% smaller than those on the impermeable slope because of wave energy dissipation inside the porous media. In addition, it is revealed that the numerical results with slope boundary condition agreed well with experimental results in comparison with the results by using stair type boundary condition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.6 s.237
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• pp.895-903
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• 2005

In this paper, we present a cutter location (CL) surface deformation approach for constant scallop height tool path generation from triangular mesh. The triangular mesh model of the stereo lithography (STL) format is offset to the CL surface and then deformed in accordance with the deformation vectors, which are computed by the slope and the curvature of the CL surface. In addition, the tool path which is computed by slicing the deformed CL surface is inversely deformed by those same deformation vectors to a tool path with a constant scallop height. The proposed method is implemented, and a tool path generated by the proposed method is tested by simulation and by numerical control (NC) machining. The scallop height was found to be constant over the entire machined surface, demonstrating much better quality than that of mesh slicing, under the same constraints for machining time.

• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.151-160
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• 2004

This research addresses the experimental application of the digital close-range photogrammetric technique for 3D deformation measurement and visualization of road slope. The 3D displacements were extracted by the photo-triangulation based on the bundle adjustment method using the digital imagery. In addition, we produced the digital elevation models, the digital orthorectified images and the 3D perspective view images of the slope employing a digital photogrammetric workstation. Also the inclination map of the slope was generated as the data for monitoring and managing dangerous slopes.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1139-1146
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• 2009

Collapse of cut slope includes many uncertainties in view of the reason and time. So, in the past, risky cut slopes have been dealt after they've been collapsed through post-management measures. But recently, advanced disaster prevention system is required, and as a part of that RTMS(Real-Time Monitoring System) was developed. In this study, stability of risky cut slope was evaluated by site investigation. To grasp deformation behavior characteristics of slope, numerical analysis based on FEM was performed and using results of that, specific standards for installation of Real-Time Monitoring System were suggested.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.643-650
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• 2002

It is necessary, in the light of the importance of long-term slope stability problem, to develop a simple method or tool which can figure out the possible failure zone resulted from weathering effect and other factors. The FBG sensor system is used to estimate the correlations between the temperature and the slope in Yunhwajae, and to find a failure zone in slopes effectively. This research is to seek for the correlation between the soil temperature distribution and the strain distribution in a active zone by analyzing the data from the in-situ measurement so that the possible failure zone should be well defined based on the correlation. The zone of high temperature fluctuation can be regarded as one of the possible sliding zone due to the weathering effect while the constant temperature depth of the ground, if exists, would not be relatively affected by the weathering process.

• Journal of Korean Society for Geospatial Information Science
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• v.13 no.1 s.31
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• pp.3-10
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• 2005

This study attempts to measure effectively three dimensional deformation in road slopes using digital close-range photographs. After the still video images were acquired respectively on the same multi-station geometric configuration in two epoches, photo-triangulation was rallied out respectively by conventional standard bundle adjustment and free-net bundle adjustment and the computed results were compared with those of geodetic method by total station. Three dimensional coordinates and deformation amounts were able to be derived with the RMSE of sub-millimeter and the relative accuracy of $1/30,000{\sim}1/35,000$. It was shown that free-net bundle adjustment is about 13% higher than standard bundle adjustment in the accuracy of photo-triangulation. It was ascertained that the free-net technique is able to promote fast and accurate deformation surveying without the necessity of geodetic control survey in complicated industrial sites.

• Journal of the Korean Society of Safety
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• v.22 no.4
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• pp.57-65
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• 2007

Effects on the stiffness of the embankment and sandmat on the construction safety of road embankment was investigated in this study by the numerical experiments using FEM. Two points was mainly focused in this study especially. First the deformation characteristics by the change of the stiffness of sand mat and embankment was investigated by the analyzing the consolidation settlement at the center of the embankment and the lateral displacement at the toe of the embankment. And, the effect of the stiffness on the stress distribution characteristics was also investigated in this study. Furthermore, slope stability analysis was carried out to gain the safe factor by change the stiffness of the sandmat and the embankment. The objective of the study is supplying the result of the numerical experiments for the geotechnical engineers who use the FEM for the safety design of the soil structures. As a result, the stiffness of the superstructures greatly affects on the deformation characteristics both in consolidation settlement and lateral displacement. However, it can be aware that it is not dominants to the stress distribution in the aspect that the no changes in the residual excess pore water pressure. Therefore, the decision of the stiffness has to be carried out deliberately considering not only the consolidation the magnitude of the settlement and the lateral displacement, but the slope stability.

• International Journal of Highway Engineering
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• v.6 no.3 s.21
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• pp.37-46
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• 2004

This study was performed to establish valid methodology for determining dynamic stability(DS) of deformation-cycle curve which is obtained through wheel tracking(WT) test, the most widely used method for forecast of rutting tendency of asphalt mixture. Existing Korean and Japanese methods for DS are unrealistic and do not really reflect characteristics of rut resistance of asphalt concretes especially when the slope of deformation-cycle curve is stabilized at the end. It was proved that the new DS developed in this study reflected rut resistance characteristics better than existing methods. It is especially effective to distinguish the mixtures with high DR(depth of rut) but stable slope at the end of curve from the mixture with lower DR and continuous slope. The field evaluation must be followed to prove whether the mixture which shows a high DS value this method perform well in the filed.

• Journal of the Korean Geotechnical Society
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• v.31 no.2
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• pp.5-11
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• 2015

Slope stability is affected by duration of precipitation, probable rainfall intensity, unsaturated soil property, and soil strength. The recent analyses of slope stability tend to include unsaturated analysis based on infiltration properties of soil, while researches of unsaturated soil slope tend to include the analysis of deformation and stress distribution of soil over time. However, infiltration property of unsaturated soil slope depends not only on intensity or duration of precipitation, but also on relief and surface condition, which is not considered in status quo. This research uses hydrologic model parameters of soil in order to consider effects of inclination on filtration, and carries out analysis of unsaturated soil slope to confirm the effects according to slope inclination and surface condition. In conclusion, using slope stability analysis, the need to consider infiltration rate according to inclination and surface condition was confirmed even under the same precipitation conditions.