• Journal of the Korean Geotechnical Society
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• v.37 no.7
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• pp.5-12
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• 2021

When drilling investigations for Rock Slopes are not possible, it is often difficult to calculate the Ground Design Constants required for the Limit Equilibrium Analysis. Therefore, the outcrops or partially cutted Rock Slopes were analysed using JRC and JCS that can be easily and conveniently measured. In particular, the effect of the JRC on the Safety Factor or the Rock Slopes was analyzed intensively, and the results were presented as a relationship formula and Table. When the Rock slope was stable, the JRC increased by an average of 9.0% as the slope height increased, and increased by an average of 29.8% as the slope angle increased. JRC was more sensitive to slope angle changes. The Cohesion corresponding to JRC was calculated from JRC-Fs formula. JRC and Cohesion showed a nonlinear relationship, and the Cohesion was about 8.0% more sensitive to slope height changes than slope angle changes.

• 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 Geotechical Society Conference
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• 2008.03a
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• pp.1365-1371
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• 2008

Based on the data obtained from field investigation and soil testing to slope hazards occurrence section and non-occurrence section in gneiss area, a prediction technique was developed by the use of a decision tree model. The slope hazards data of Seoul and Kyonggi Province were 104 sections in gneiss area. The number of data applied in developing prediction model was 61 sections except a vacant value. The statistical analyses using the decision tree model were applied to the entrophy index. As the results of analyses, a slope angle, a degree of saturation and an elevation were selected as the classification standard. The prediction model of decision tree using entrophy index is most likely accurate. The classification standard of the selected prediction model is composed of the slope angle, the degree of saturation and the elevation from the first choice stage. The classification standard values of the slope angle, the degree of saturation and elevation are $17.9^{\circ}$, 52.1% and 320m, respectively.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.73-81
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• 2006

A sensitivity analysis about effects of influencing factors on the stability of Soil cut slope was performed. Slope stability analyses were carried out under dry, rainy and seismic conditions. Dominant factors controlling the slope stability were chosen such as cohesion and internal friction angle, unit weight of soil, water table and seismic horizontal coefficient used for the slope stability during earthquake. Parametric stability analysis with those factors was performed for sensitivity analysis. As results of analyzing the sensitivity of factors under dry and rainy conditions, effects of cohesion, internal friction angle and unit weight of soil on the stability of slope are more critical in the dry condition than in the rainy condition. Cohesion and internal friction angle are more dominant factors influencing the slope stability irrespective of dry or rainy conditions than unit weight of soil and the horizontal seismic coefficient. The unit weight and the horizontal seismic coefficient affects crucially the stability according to conditions of slope formation and dry or rainy seasons. For the effect of horizontal seismic coefficient on stability of slope, safety factor of slope is not affected significantly by dry or rainy conditions. However, increase of the horizontal seismic coefficient under the rainy condition floes reduce the safety factor significantly rather than the dry condition. Therefore, it is needed that the location of the water table is assigned appropriately to satisfy the required safety factor of stability in the case of checking slope stability for the rainy and seismic conditions.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.3
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• pp.121-128
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• 2005

Forest fire is expanded to large-scale forest fire based on topographic characteristics, particularly slope. This report addresses the currently available methods of calculation slope angle from a digital elevation model and develops a new method that circumvents a number of the shortcomings associated with other algorithms. The results of the comparison of five different slope angle calculation algorithms show that maximum uphill slope angle calculation is the proper method for the purpose of predicting forest fire hazard.

• Journal of the Korean Geographical Society
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• v.40
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• pp.15-29
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• 1989

The purpose of this study is to analyze the Slope Angles and Summit Levels in the relation with the geological structures in the Taehwa River Basii where the NNE-SSW trending Yangsan fault and subsiduary fault are well developed. The mean slope angle in the Taehwa river basin is 12.18$^{\circ}$. The mean slope is higher in the volcanic and metamorphic terrain than in the area of granitic and sedimentary rocks. In view of a slope angle, the area can be divided into four categories, that is, low plains (0-5$^{\circ}$), hilly gentle slopes (5-15$^{\circ}$), moderate steep mountain slope (15-25$^{\circ}$), and steep mountain slope (over 25$^{\circ}$). The analysis of summit level exhibits that the mean of the highest points in the Taehwa River Basin composed mainly of the volcanic and metamorphic rocks is 327m.

• The Journal of Engineering Geology
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• v.24 no.3
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• pp.333-341
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• 2014

The construction of roads, tunnels, and bridges results in changes to the local terrain that may influence the ground safety factor, which represents the stability of geotechnical structures. In this study, we assessed construction sites that had collapsed as a result of terrain change, and then simulated variation in the ground safety factor with respect to terrain change caused by road construction. We assumed steep slopes to simulate changes in terrain in a mountainous area and assumed that earthworks took place for road construction by cutting a platform into the slope and altering the slope angle of the terrain both above and below the road. We calculated values of the ground safety factor through a stability analysis of the slope both above and below the road, and examined the variation in the safety factor of the above- and below-road slopes with respect to changes in road width. We found that if the slope angle was the same above and below the road, then the change in the ground safety factor during/after road construction occurred in the slope below the road, and if the slope angle above the road differed from that below, then the change occurred in both the above- and below-road slopes. Furthermore, the ground safety factor was essentially constant for road widths exceeding 2-6 m, depending on both above- and below-road slope angle. The findings of this study can be used to guide the management of construction sites and to assess changes in ground stability during road construction work, particularly in the early stages of earthworks, when the road width is narrow.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1467-1470
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• 2008

An upper tibial opening wedge osteotomy is an operation to cure a malalignment and a degenerate arthritis. To prevent the postoperative malalignment caused by the upper tibial opening wedge osteotomy, the research to define the relationship between a Hinge Axis Angle and a Posterior Slope Angle is needed. The effect of the relationship between the hinge axis angle and the gap angle on the posterior slope angle is studied. After 3-D Compute Tomography (CT) scanning image is reconstructed, the virtual surgery is performed by the reconstructed 3-D tibia model. It was proved that the relationship between the hinge axis angle and the gap angle were constant and the simple mathematical model could be derived. To verify the suggested mathematical model, it compared with the measured data from the virtual surgery. In conclusion, while the deviation between the data from the virtual surgery and ones of the mathematical model under the gap angle<$10^{\circ}$ was less than 1%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.955-956
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• 2009

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.2
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• pp.2980-3001
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• 1973

Nozzle is a part of sprayer and is consists of several elements; swirl plate, vortexchamber, cap and body. The travelling distance of sprayed particles is important in the wide reach nozzle. The factors to influence the travelling distance of the sprayed particles may be the helical angle of swirl plate, the distance of vortex hamber, the slope and the size of cap hole. The study was conducted to examine the effects of these factors on the travelling distance. The results of this study are summarized as follows; 1) There was higher positive correlation(+0.96) between the maximum travelling distance for which amount of sprayed particles was 5cc/cm min. and centro-position of the travelling distance. 2) There was a higher positive correlation(+0.85) between total discharge of sprayed particles and the centro-position of the travelling distance. 3) Main effects and interaction effects of helical angle, pressure, vortex chamber distance and cap slope were significantly affected the travelling distance of sprayed particles. 4) Main effects of helical angle, pressure and cap slope were especially highly significant to influence the travelling disance. 5) Helical angle, pressure, vortex chamber distance and cap slope influenced spraying forward velocity of dise hole, among which cap slope and pressure of nozzle was the most important factors. 6) Effect of change of helical angle on the travelling distance of sprayed particles, was generally a quadratic, the least value of the distance being showed about $45^{\circ}$ and the largest at about $15^{\circ}\;and\;55^{\circ}$, the decreasing rate of the change between $15^{\circ};and\;25^{\circ}$ was very small. 7) Effect of change of pressure on the travelling distance sprayed particles was generally a linear, the increasing rate of the charge was about 1.68, which was the most effective compared to the change of the other factors. 8) Effect of change of vortex chamber distance on the spraying distance was also generally a linear, the increasing rate being about 0.16, which was the least effective. 9) Effect of change of cap slope on the travelling distance was also generally a linear, the increasing rate was about 0.61 and its effect was about medium.