• Journal of the Korean Geographical Society
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• v.28 no.4
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• pp.285-297
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• 1993

For the application of the diffusion equation, slope height and maximum slope angle are calculated from the plotted slope profile. Using denudation rate as a solution for the diffusion equation, an apparent age index can be calculated, which is the total amount of denudation through total time. Plots of slope angle versus slope height and apparent age index versus slope height are useful for determining relative or absolute ages and denudation rates. Mathematical simulation plots of slope angle versus slope height can generate equal denudation-rate lines for a given age. Mathematical simulations of slope angle versus age for a given slope height, for equal denudation-rate at a particular profile site, and for comparing to other sites having controlled ages.

• Journal of the Korean Geosynthetics Society
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• v.22 no.3
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• pp.71-86
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• 2023

Rock blasting tests using underground penetration-type displacement sensors were conducted, and three-dimensional finite element numerical analyses were performed to assess their applicability and mitigate slope hazards during rock blasting. Additionally, parameters influencing vibration velocity were investigated during the tests. The results confirmed that underground penetration-type displacement sensors are suitable for monitoring rock slope behavior, and the numerical analyses revealed that the most influential parameter on vibration velocity during rock blasting is the unit weight. Furthermore, it was observed that vibration velocity decreases significantly with distance from the blast source, and proximity to the source leads to substantial variations in vibration velocity due to differences in elastic modulus and unit weight. Changes in internal friction angle and adhesive strength had minimal impact.

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.137-146
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• 2005

299 railroad slopes were investigated and the failure characteristics and reinforcement patterns were analyzed. Stability analyses on the 14 cut-off soil slopes were carried out. Surficial failures were predicted by infinite slope analyses assuming the temporarily perched ground water table at soil surface during rainfall period. Limit equilibrium analyses were also carried out and the influences of rainfall infiltration on the slope stabilities were taken Into account by seepage analyses using finite element method and by assuming ground water tables to be located adjacent to soil surface. The adequacy of those analyses was evaluated by comparing the slope failure characteristics between analysis results and the past failure records. From the comparison results, it was deduced that the limit equilibrium analyses were not appropriate to estimate the shallow failure that occurred at most of the railroad cut-off soil slopes. For the better estimation of the surficial failure, not only the increase of pore-water pressure (reduction of matric suction), but also the influence of water flows over slope surface which erode soil mass, should be evaluated and considered.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.3
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• pp.48-62
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• 2018

In this study, landslide of debris flow occurred at 51 sites around Daeryounsan located in between Chuncheon-si and Hongcheon-gun during July in 2013 were investigated in field and behavior characteristics of debris flow were analyzed on the basis of records of rainfall and site investigation. According to debris flow types of channelized and hill slope, location and slope angle of initiation and deposit zone, and width and depth of erosion were investigated along entire runout of debris flow. DEM(Digital Elevation Model) of Daeryounsan was constructed with digital map of 1:5,000 scale. Land slide hazard was estimated using SINMAP(Stability INdex MAPping) and the predicted results were compared with field sites where debris flow occurred. As analyzed results, for hill slope type of debris flow, predicted sites were quite comparable to actual sites. On the other hand, for channelized type of debris flow, debris flow occurrence sites were predicted by using stability index associated with topographic wetness index. As analyzed results of 4 different conditions with the parameter T/R, Hydraulic transmissivity/Effective recharge rate, proposed by NRCS (Natual Resources Conservation Service), predicted results showed more or less different actual sites and the degree of hazard tended to increase with decrease of T/R value.

• Journal of the Korean association of regional geographers
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• v.17 no.3
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• pp.297-312
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• 2011

Understanding the distribution and location characteristics of the settlements is preliminary study on discovering the formation and extinction process of the settlements used information of archeological excavation. So far, most researchers have been concerned about the location-environment of the dwelling. However, this study focuses on the understanding of the geomorphological environments in high-density residential zone. The study area is located in Cheonan, Chungnam, South Korea. It is called the Baekseokdong Heritage Group, which has 205 dwelling sites in the bronze age. This study is considered micro-landforms of hillslope, slope, and aspect from a view of geomorphological environments. In the study area, The high-density residential zones, the bronze ages dwelling sites are concentrated, consists mainly of slope land between undulated plain and semi -gentle of crest slope or crest flat, and south-facing aspect(southwest-south-southeast).

• Tunnel and Underground Space
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• v.25 no.1
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• pp.76-85
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• 2015

We have developed a software to predict failure time of the rock slope based on analysis of the data from real time displacement measurements with respect to time. The software consists of four modules that play roles in analytical methods such as inverse velocity method, log time-log velocity method, log velocity-log acceleration method and nonlinear least square method to estimate failure time. VisualBasic.NET on the MS Visual Studio platform was utilized as a development tool to efficiently implement the modules and the graphical user interface of the software. Displacement data obtained from laboratory physical model studies of plane sliding were used to explore the applicability of the software, and to evaluate the possibility of predicting potential slope failure. It seems possible to estimate failure time using developed software for sliding plane having exponential type of deformability.

• The Journal of Engineering Geology
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• v.32 no.3
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• pp.339-350
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• 2022

There are a variety of types in tafoni formed in Miocene tuff from Golgulsa, Gyeongju. Tuff bearing tafoni was quite weathered, composed of quartz, feldspars, micas, vermiculite, chlorite, smectite, and analcite. In the early stage of the tafoni development, tafoni preferentially formed from cavities where volcanic breccias were removed or from microcavities where microcrystals were chemically altered. Small tafoni grew into large one by merging each other. The orientation of tafoni is inversely arranged to slopes, with slight inclination toward the inner cavity. Height, width, and depth of tafoni are closely interrelated: the correlation coefficients are 0.839 (width-height), 0.900 (width-depth), and 0.856 (height-depth), respectively. Removal of walls between tafoni resulted in lenticular or crescent forms, and small tafoni laterally combined to large tafoni. Large tafoni is weak because of high porosity and low strength compared to normal slope. Therefore, systematic monitoring for slope strength, pore proportion and volume, and growth of cavity needs to secure the slope stability where tafoni in Golgulsa is widespread.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.496-503
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• 2016

To analyze an infinite slope that is reinforced with stabilizing piles, the forces on the stabilizing pile were estimated by the theory of plastic deformation and the theory of plastic flow and the effects of diverse factors on the factor of safety of an infinite slope were investigated. According to the results of the analyses, the factor of the safety of the slope reinforced with stabilized piles were increased tremendously and the factor of safety decreased as the center to center distance of the stabilizing pile increased. The effect of the existence of seepage of the infinite slope with stabilizing piles on the factor of safety appears to be insignificant. Considering the formulated factor of safety of an infinite slope with stabilizing piles, the width and length of the element of the infinite slope and force on the stabilizing pile influence the factor of safety of the infinite slope with a stabilizing pile including the soil strength parameter, inclination of the slope and depth of the slope, which are important for calculating the factor of safety of a non-reinforced infinite slope. The factor of safety of an infinite slope with stabilizing piles derived from the theory of plastic deformation were increased significantly with the internal friction angle of the soil, and the minimum and the maximum factor of safety under the conditions considered in this study were 13.7 and 65.6, respectively. As the diameter of the stabilizing pile increased, the forces on the stabilizing pile also increased but the factor of safety of the infinite slope with stabilizing piles decreased due to the effects of the width and the length of the element of the infinite slope. The factor of safety of the infinite slope with stabilizing piles derived from plastic flow were much larger than that of the non-reinforced infinite slope and the factor safety of the infinite slope with a stabilizing pile increased with increasing product of the flow velocity and plastic viscosity ( ) and the factor of safety of the infinite slope with stabilizing piles decreased with increasing center to center distance of the pile.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.583-594
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• 1994

One of the major elements of a natural landslide is the increase of the pore water pressure in a weakened layer. Therefore, the measurement of the pore water pressure in the layer is important. This work is a laboratory model study of the measurement of the pore water pressure with regard to the confined groundwater level, the permeability of the crack zone and the weathering degree of the weakened layer. By the model of the Tertiary period failure type and the Colluvium failure type, the reactions of the pore air pressure and the pore water pressure were measured in the weakened layer according to the permeability of the filter on the condition of the confined groundwater states. On the reaction phase of the pore pressure according to the during time, the Tertiary period failure type proved to be a step type and the Colluvium failure type turned out to be a wave type. The reaction ratios of the pore water pressure in the Tertiary period failure type are higher than the Colluvium failure type, decrease according to increasing of the weathering degree of the weakened layer.

• Journal of Korean Society of Forest Science
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• v.64 no.1
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• pp.42-46
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• 1984

This study was carried out to obtain the advanced basic data for hillside erosion control works. Recovery of vegetation in the hillside erosion control districts depends on various factors i.e., topographies, soil qualities, rain conditions and erosion control methods. The only relations between topographies and vegetation coverage were surveyed, since the other factors were equal in all those surveyed areas. The results obtained are summarized as follows; 1) Mean coverage values were decreased in order of 80%, 78.7%, 64.0% and 56.5%r in concave slope, uniform slope, compound slope and convex slope respectively. The mean coverage of all aspects was 69.8%. The slope pattern have a influence on formation of coverage. 2) Moisture ratio in soil and mean slope have an effect on the mean coverage value. 3) In the beginning of the hillside erosion control working, coverage (14.8%) by arbor species was too low comparing with that by herb. 4) It is more desirable to recover regetation by artificial planting or seed planting than by the natural vegetation in the barren hillside. In the beginning of the hillside erosion control working, it is difficult to expect vegetation recovery by natural species.