• Tunnel and Underground Space
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• v.11 no.3
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• pp.206-216
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• 2001

Many failures in cut slopes occur during and following road construction. Failures are caused, in part, by a lack of understanding of the characteristics of rock mass including its geologic structure. The stability of rock slopes is closely related to factors that include the type of rock, development of geological structures, weathering, characteristics of rock, and the shape of the geologic features. Therefore, it is very important to consider these characteristics of rock mass in the evaluation of rock slope stability. In spite of investigation from many slope failures, these information data were not systematically stored and not efficiently utilized. In this study, a Database system named DB/SLOPE was developed using Oracle for systematic management of cut slopes. The developed database system can be used to estimate of slope stability and to predict of slope failure.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.561-568
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• 2011

The purpose of this study is to measure displacements that occurs on a surface and interior of slope model and the shape when the slope is destroyed at vibration experiment of the slope model using close range photogrammetry. The circle targets and sphere targets are installed on a chamber and a slope model, while the earthquake wave are applied in regular time interval. The close range photogrammetric images are acquired in each displacements step until the slope model is destroyed. Those photos are processed by image processing method and the center points of targets are automatically extracted. Furthermore, the three-dimensional coordinates of targets are calculated by image orientation and bundle adjustment processing. As a result, amount of displacement at each level is precisely measured and provided the basic information for assessing the slope stability using three-dimensional measurement of the target movement and slope destruction.

• Journal of Korean Society of Forest Science
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• v.96 no.6
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• pp.611-619
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• 2007

This study was carried out to analyze the landslide characteristics and forest environment factors on the landslide area of 7 national parks in korea. The results obtained from this study were summarized as follows; The total number of landslide occurrence was 44 areas. The average length of the landslides scar was 152 m, average width was 17 m. And the average area was $2,818m^2$. The factors influencing landslides were highly occurred in Metamorphic rock, mixed forest type. And also, $30{\sim}35^{\circ}$ in slope gradient, NE in slope aspect, slope higher than 1,000 m, concave (凹) type in vertical and cross slope, 0 ordered stream. The main factors affecting landslide area in stepwise regression analysis were sheet type in landslided shape, NE in slope aspect, 2 ordered stream, SE in slope aspect, slope gradient and complex slope in cross slope type in order of regression coefficient.

• Structural Engineering and Mechanics
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• v.20 no.3
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• pp.313-334
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• 2005

The paper presents a new approach for the analysis of slope stability that is based on the numerical solution of a differential equation, which describes the thrust force distribution within the potential sliding mass. It is based on the evaluation of the thrust force value at the endpoint of the slip line. A coupled approximation of the slip and thrust lines is applied. The model is based on subdivision of the sliding mass into slices that are normal to the slip line and the equilibrium differential equation is obtained as the slice width approaches zero. Opposed to common iterative limit equilibrium procedures the present method is straightforward and gives an estimate of slope stability at the value of the safety factor prescribed in advance by standard requirements. Considering the location of the thrust line within the soil mass above the trial slip line eliminates the possible development of a tensile thrust force in the stable and critical states of the slope. The location of the upper boundary point of the thrust line is determined by the equilibrium of the upper triangular slice. The method can be applied to any smooth shape of a slip line, i.e., to a slip line without break points. An approximation of the slip and thrust lines by quadratic parabolas is used in the numerical examples for a series of slopes.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1161-1170
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• 2009

The Roads in Gangwon Province generally was made on purpose to use the military road. In case of these roads, tremendous dangerous cut slopes do exist and its road linear shape was badly designed. In order to make up for this situation, the government has continuously established the new road or performed the public works such as the straight line of the curved road. Soksil 2 cut slope was made through the road improvement work. This has small surface failures and collapses. In spite of dry season, this slope are leaking lots of groundwater at the unbelievable point. So as to get curious phenomenon right, we performed a detailed field investigation, the geomorphological analysis, the stability analysis considering field characteristic and ultimately proposed the countermeasure to make sure stability of Sokil 2 cut slope.

• 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 Korea Water Resources Association
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• v.34 no.2
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• pp.141-154
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• 2001

An experimental study was performed to investigate the effects of levee crest width and the slope steepness on levee break due to overtopping flow. The phenomenon of bank failure can be described in 4 stages. In this study, the magnitudes of breach width, breach depth peak discharge, and scouring shape at the break site were measured, and the result shows that peak discharge will be reduced and breach duration extended by widening the crown width and lessening the levee slope steepness. The breach width was narrower and the breach depth deeper, as the levee crest width become wider or the slope steeper. And, the bed scour depth was deeper and steeper, as the levee crest crest width become narrower or the slope milder.

• Phonetics and Speech Sciences
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• v.1 no.3
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• pp.133-144
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• 2009

Pharyngeal flap surgery changes the space and shape of the oral cavity and vocal tract, and these changing conditions bring resonance change. The purpose of this study was to determine the most reliable and valuable parameters for evaluating hypernasality to distinguish two patients before and after pharyngeal flap surgery. Each patient was asked to clearly speak the vowels /a/, /i/, /u/, /e/, /o/ for voice recording. There were nine parameters: Formant (F1, F2, F3), Bandwidth (BW1, BW2, BW3), LPC energy slope ($\Delta$ |A2-A1/F2-F1|), and Band Energy (0-500 Hz, 500-1000 Hz) by each vowel. From the results of discrimination analyses on acoustic parameters, the vowels /a/, /e/ appeared to be insignificant but vowels /i/, /u/, /o/ appeared to be efficient in the separation. A 95%, 100%, and 100% recognition score could be reached when vowels /i/, /u/, and /o/ were analyzed. The results showed that F2, BW3, and LPC slope are more important parameters than the others. Finally, there is a relation between perceptual evaluation score and LPC energy slope of acoustic parameters by least square slope.

• Journal of Industrial Technology
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• v.3
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• pp.53-63
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• 1983

The probability of failure is used to analyze the reliability of three dimensional slope failure, instead of conventional factor of safety. The strength parameters are assumed to be normal variated and beta variated. These are interval estimated under the specified confidence level and maximum likelihood estimation. The pseudonormal and beta random variables are generated using the uniform probability transformation method according to central limit theorem and rejection method. By means of a Monte-Carlo Simulation, the probability of failure is defined as; Pf=M/N N : Total number of trials M : Total number of failures Some of the conclusions derived from the case study include; 1. Three dimensional factors of safety are generally much higher than 2-D factors of safety. However situations appear to exist where the 3-D factor of safety can be lower than the 2-D factor of safety. 2. The F3/F2 ratio appears to be quite sensitive to c and ${\phi}$ and to the shape of the 3-D shear surface and the slope but not to be to the unit weight of soil. 3. In cases that strength parameters are assumed to be normal variated and beta variated, the relationships between safety factor and the probability of failure are fairly consistent, regardless of the shape of the 3-D shear surface and the slope. 4. As the c-value is increased, the probability of failure for the same safety factor is increased and as the ${\phi}-value$ is increased, the probability of failure for the same safety factor is decreased.

• The Journal of Engineering Geology
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• v.32 no.2
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• pp.209-219
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• 2022

To experimentally investigate the variation of soil characteristics in slope during rainfall and the shape of slope failure, the model test was performed using soil box and artificial rainfall simulator. The model test of slope formed by the homogenous sand was performed, and the saturation pattern in the model slope due to rainfall infiltration was observed. The slope model with the inclination of 35° was set up on the slope of 30°, and the rainfall intensity of 50 mm/hr was applied in the test. The soil depth of 35 cm was selected by considering the size of soil box, and the TDR (time domain reflectometry) sensors were installed at various depths to investigate the change of soil characteristics with time. As the result of model test, the slope model during rainfall was saturated from the soil surface to the subsurface, and from the toe part to the crest part due to rainfall infiltration. That is, the toe part of slope was firstly saturated by rainfall infiltration, and then due to continuous rainfall the saturation range was enlarged from the toe part to the crest part in the slope model. The failure of slope model was started at the toe part of slope and then enlarged to the crest part, which is called as the retrogressive failure. At the end of slope failure, the collapsed area increased rapidly. Also, the mode of slope failure was rotational. Meanwhile, the slope failure was occurred when the matric suction in the slope was reached to the air entry value (AEV) estimated in soil-water characteristic curve (SWCC).