• Ocean and Polar Research
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• v.36 no.1
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• pp.59-69
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• 2014

The long-term mooring performed at a KOGA station, located at about $30^{\circ}20^{\prime}N$, $126^{\circ}12^{\prime}E$ in the East China Sea shelf, shows some different behaviors between "semi-diurnal" and "diurnal currents" defined as the currents with periods around, respectively, a half day and a day. They appear to be predominantly tidal having significant coherences with sea level changes around the semi-diurnal and diurnal frequencies. The "semi-diurnal current" is strongly barotropic all year round. However, contrastingly, it is largely baroclinic in summer in the area about 70 km nearer to the continental slope, referred to as the "slope-area", as was found in previous current observations. The "diurnal current" of tidal origin is strongly barotropic in winter. In spring and summer, however, it becomes more baroclinic although it still remains largely barotropic, also showing more of its barotropic nature than in the "slope-area". The inertial oscillation contributing to the "diurnal current" appears to be more prominent when the current is baroclinic, indicating the important role played by stratification in generation of inertial oscillations. Downward energy propagation of inertial oscillation is not observed, suggesting that it is not created at the surface by wind. Considering that the study area is both near a critical latitude and proximity to the continental slope, it is suggested that parametric subharmonic instability (PSI) plays a significant role in creating the baroclinic inertial oscillation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2D
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• pp.191-198
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• 2010

The displacement of slope is a key factor in predicting the risk of a landslide. Therefore, the slope displacement should be continuously observed with high accuracy. Recently, high-tech equipment such as optical fiber sensor, GPS, total station and measuring instrument have been used. However, such equipment is poorly used in fields due to economics, environment, convenience and management. Because of this, development of substantial observational techniques for varied slope observation and field applications is needed. This study analyzed the possibility of terrestrial LiDAR for slope monitoring and suggested it as information-obtaining technique for slope investigation and management. For that, this study evaluated the monitoring accuracy of terrestrial LiDAR and performed GRID analysis to read the displacement area with the naked eye. In addition, it suggested a methodology for slope monitoring.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.302-311
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• 2008

There have been repetitive landslides and debris flows on natural terrain induced by intensive rainfalls which have never been experienced during the last a few decades in Korea. Frequencies and magnitudes of landslides and debris flows are steeply increased after 2000 resulting in huge damages of human beings and facilities. According to a statistical data from NEMA, the human deaths induced by landslides and slope hazards occupies 22.3% of the total human deaths by all the natural hazards in Korea during the last 30 years. Among the human deaths by landslides and slope hazards, 85% of the damages were caused by landslides and debris flows on natural hazards. Therefore, this paper summarizes important events of landslides and debris flows, their characteristics, and suggests some methods of damage mitigation.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.663-671
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• 2020

Recently, there have been many natural disasters in Korea, not only in forest areas but also in urban areas, and the national requirements for them are increasing. In particular, there is no pre-disaster information system that can systematically manage the collapse of the slope of the national highway. In this study, big data analysis was conducted on the factors causing slope collapse based on the detailed investigation report on the slope collapse of national roads in Gangwon-do and Gyeongsang-do areas managed by the Cut Slope Management System (CSMS) and the basic survey of slope failures. Based on the analysis results, a slope collapse risk prediction model was established through Adaboost, a classification-based machine learning model, reflecting the collapse slope location and weather information. It also developed a visualization map for the risk of slope collapse, which is a visualization program, to show that it can be used for preemptive disaster prevention measures by identifying the risk of slope due to changes in weather conditions.

• Journal of the Korean Geotechnical Society
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• v.27 no.12
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• pp.39-52
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• 2011

This paper describes a new numerical analysis technique in stability analysis for a slope reinforced with pressure grouted soil nails. The installing effect of pressure grouted soil nails can be simulated in this method. Shear strength reduction method associated with finite element method is used for slope stability analysis. Factors of safety for a slope reinforced with pressure grouted soil nails are compared with those for a natural slope and a slope reinforced with gravity grouted soil nails in order to investigate their reinforcing effects. More than 50% increase in the factor of safety is obtained when the slope is reinforced with pressure grouted soil nails compared to the one with gravity grouted soil nails. The reinforcing effects of pressure grouted soil nails become obvious with increase in their length. The reinforcing mechanism of the pressure grouted soil nails for the slope stability can be explained by the slope failure surface expanding gradually toward the backfill. The increased stability of the slope reinforced with pressure grouted soil nails results mainly from their improved pull-out resistance.

• Journal of Forest and Environmental Science
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• v.39 no.1
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• pp.13-19
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• 2023

We investigated Soil respiration in Bluepine forest of western Bhutan, in relation to soil temperature, moisture content and soil pH and it was aimed at establishing variability in space and time. The Bluepine forest thrives in the typical shallow dry valleys in the inter-montane Bhutan Himalaya, which is formed by ascending wind from the valley bottom, which carries moisture from the river away to the mountain ridges. Stratified random sampling was applied and the study site was classified into top, mid, low slope and further randomized sample of n=20 from 30 m×30 m from each altitude. The overall soil respiration mean for the forest was found 2248.17 CO₂ g yr^-1 and it is ~613.58 C g yr^-1. The RS from three sites showed a marginal variation amongst sites, lower slope (2,309 m) was 4.64 μ mol m^-2 s^-1, mid slope (2,631 m) was 6.78 μ mol m^-2 s^-1 and top slope (3,027 m) was 6.33 μ mol m^-2 s^-1 and mean of 5.92 μ mol m^-2 s^-1, SE=0.25 for the forest. Temporal distribution and variations were observed more pronounced than in the space variation. Soil respiration was found highest during March and lowest in September. Soil temperature had almost inverse trend against soil respiration and dropped a low in February and peak in July. The moisture in the soil changed across months with precipitation and pH remained almost consistent across the period. The soil respiration and soil temperature had significant relationship R²=-0.61, p=0.027 and other variables were found insignificant. Similar relationship are reported for dry season in a tropical forest soil respiration. Soil temperature was found to have most pronounced effect on the soil respiration of the forest under study.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.1 no.1
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• pp.95-101
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• 1998

In order to seek a efficiency of site cooperation and slope stabilization in a rock sloping work, it would rather take into consideration, in its importance, a concurrent performance of civil works and landscaping works than give any part a special priority. It can enable us to achieve an expanded scope of landscaping works and improvement of slope scenery via this sort of cooperation. However, this can not be achieved without assurance on the slope stabilization and scenic view of the project owner, and further via this cooperation, environmentally familiar works can be performed, becoming natural environment and minimizing damages on surrounding scenery and environment. It is foreseeable that improvement of functions of civil equipment, introduction of technology and development of landscaping materials can facilitate an improvement in the betterment of slope scenery. Landscaping related parties need to enhance their understanding of rock sloping and scenic view based on knowledge on the fundermental understanding of slope stabilization and on the base rock characteristics.

• Journal of Industrial Technology
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• v.31 no.A
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• pp.87-94
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• 2011

This paper is results of analyzing characteristics of landslides occurred in Wonju, Gangwondo, around July, 16 in 2006, caused by heavy rainfall and antecedent precipitation by two typhoons of Ewiniar and Bilis. The main causes of landslides were antecedent precipitation during July 8 to 15, resulting in weakening grounds by increasing the degree of saturation previously, and the heavy rainfall during July 15 to 16. Most of landslides in natural slopes were transitional failures occurred along the boundary between the residual weathered soil in shallow depth and the hard mother rock. From results of conclusive analyses regarding 28 sites in Wonju region where landslides occurred, the slope length of landslide, the slope width, and the slope area were less than 50m with 71% of frequency, 20m with 79% of frequency and $300m^2$ of 64% of frequency respectively. The average value of slope angle was $35^{\circ}$. The most probable direction of slope was found to be north because of topography and advancing direction of seasonal rain front.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.6 s.113
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• pp.127-139
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• 2006

Mt. Yokmang landscape design awarded first in [North container terminal site furtherance construction in Busan new port], design competition sponsoring in the Korea Container Terminal Authority in 2005. Design guideline was to propose the symbol of new port and to establish landscape plan in consideration of view and geological location. Because landscape plan required establishment of restoration plan for cutting slope, Mt. Yokmang became the major object. The purpose of planning are as follows. The first purpose is to minimize existent natural environment damage, and the second, to connect with ambit and create new image. The third is to provide place of rest and interchange for local resident. Reflecting stratum structure and landscape characteristics, cutting slope consisted of [utilization slope], [presentation slope], [landscape slope], and [ecological slope]. Vegetation design applied ecological restoration method through restoration of stratum, and eve environment-friendly afforestation, planned program that can connect area with existing ecosystem. In process that decides form of the cutting slope, analyze view structure and visual exposure in various access routes, sensitivity etc. was accomplished. Also, symbolic tower(Ocean Polaris) that presents in architecture and landscaping features, night landscape planning could gain synergy effect by keeping consistence with landscape and ecological planning. Passing through final design and construction process, I expect that the Mt. Yokmang will be a new landmark in Busan new port.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.5
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• pp.115-127
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• 2012

This study was conducted on the measurement of soil hardness through a hardness testing machine in slopes of natural environments and artificial environments which is generally known as slope revegetation. The soil hardness as one of physicochemical soil properties is significantly associated with plant growth. Although another studies related to the slope revegetation was focused on herbaceous plants, studies related to soil properties for arbor appearance is lack. It was focused on the correlation analysis between the soil hardness and the plant appearance. the results were as follows : The higher the soil hardness is, the less the appearance of plants is as a result of survey. Species appearing in the high levels of the soil hardness represented mugwort and grass. The levels of the soil hardness in the slope of natural environments was good environmental conditions with various plants in the range of 6 to 12mm. The levels of the soil hardness in the slope revegetation was in the 6.88-30mm range. The soil hardness below 21mm showed a variety of plants with arbors and herbaceous plants, whereas it above 21mm represented a monotonous style of plant structure including Artemisia princeps, Lolium perenne, Poa pratensis L and Setaria viridis. The result of the correlation analysis between the soil hardness and the plant appearance was negatively correlated with justifiable significance levels. The result of a logistic regression analysis for tree appearance was statistically proved when the numerical value of the soil hardness is lower.