• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.427-434
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• 2000

When a large number of hazardous road cut-slopes are spreaded in widely scattered areas, the effective investigation and evaluation method that is able to decide the risk of hazardous road cut-slopes, is required. Many different evaluation techniques were suggested by many different researchers based on their demands, but there are the limited researches on the experimental evaluation technique which can be utilized by personnel who does not have much experiences on the road cut-slopes. In this study, the appropriate and effective evaluation method of the dangerous slope is suggested and this method can be used by both inexperienced and experienced persons. Therefore, this is the one of the effective ways that can mitigate the possibility of landslides.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.502-513
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• 2007

This paper describes the rainfall-induced slope failures caused by infiltration due to prolonged rainfall. The emphasis was on quantifying the effect of fine-grained contents which are influencing on the infiltration rate in the wetting front of initially unsaturated slopes during rainfall. Suction tests by tensiometer were performed for five mixture specimens with varying fine-grained contents and then, numerical analyses for the stability of unsaturated slopes are carried out for different relative densities and mixture portions based on the soil water characteristic curves obtained by GCTS pressure plate. It is shown that the fines are highly influenced on wetting front suction of unsaturated soil slopes. Based on the results, it is found that until 15% fine content is the limit showing different wetting front suction, beyond which the wetting band depth do not affect considerably the stability of unsaturated slopes.

• Geomechanics and Engineering
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• v.23 no.5
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• pp.481-491
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• 2020

Piles installed in row(s) are used as an effective technique to improve the stability of soil slopes. The analysis of pile-stabilized slopes require a reliable prediction of lateral resistance offered by the piles. In this work, an analytical solution is developed to estimate the lateral resistance offered by the stabilizing piles in sand and c - 𝜙 soil slopes considering soil arching phenomenon. The soil arching in both horizontal direction (between the neighboring piles) and vertical direction (in the active wedge in front of the pile row) are studied and their effects are incorporated in the proposed model. The shape of soil arch is assumed to be circular and principal stress trajectories are defined separately for both modes of arching. Experimental and numerical studies found in literature were used to validate the proposed method. A detailed parametric analysis was performed to study the influence of pile diameter, center-to-center spacing, slope angle and angle of internal friction on the lateral pile resistance.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.5
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• pp.22-29
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• 2002

This study was conducted to suggest develop revegetation methods and to classification of cutting-rock slopes revegetation type. The data was collected from pre-experienced data, reports and journal. Also research result was reflected from field research for the conditions of construction, vegetation types and field conditions. As the result of analyze, the factors affecting the plant coverage rates of cutting-rock slopes were period of construction, revegetation methods, slope gradient and slope length. Classification of cutting-rock slopes revegetation type was fourth from material of revegetation measures and spray type. It is recommended to adjust the proposed factor as environment, field condition and characteristic related with revegetation measures on slopes for the presentation of revegetation standard.

• Geomechanics and Engineering
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• v.16 no.5
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• pp.513-525
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• 2018

Slope stability of sensitive clayey soils is particularly important when subjected to strength loss and deformation. Except for progressive failure, for most sensitive and insensitive slopes, it is important to review the feasibility of conventional analysis methods based on peak strength since peak strength governs slope stability before yielding. In this study, as a part of efforts to understand the behavior of sensitive clay slopes, a total of 12 centrifuge tests were performed for artificially sensitive and insensitive clay slopes using San Francisco Bay Mud (PI = 50) and Yolo Loam (PI = 10). In terms of slope stability, the results were analyzed using the updated instability factor ($N_I$). $N_I$ using equivalent unit weight to cause a failure is in reasonable agreement shown in the Taylor's chart ($N_I$ ~ 5.5). In terms of dynamic deformation, it is shown that two-way sliding is a more accurate approach than conventional one-way sliding. Two-way sliding may relate to diffused shear surfaces. The outcome of this study is contributable to analyzing stability and deformation of steep sensitive clay slopes.

• Journal of the Korean Institute of Landscape Architecture
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• v.19 no.2
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• pp.75-91
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• 1991

This study is one of studies on the analysis of vegetation spatial image and visual preference of roadside slopes in Chi-Ri Mt. national park. In this article, we analized the soil characteristics and the actual vegetation within slopes and forest lands contiguous to those. The results obtained were summarized as follows; The physical and chemical properties of soil in forest lands were better than slopes and Cheoneun temple - Seongsam pass was the best fertilized among 3 sector. In the structure of woody plants in forest lands, the high importance value species were Pinus denciflora, Quercus aliena within Ukmojeong-Deokdong sector, Q. aliena, Q. varabilis, Q. serrata within Banseon-Seongsam pass sector, and P. denciflora, Q. dentata within Cheoneun temple-Seongsam pass sector. And also, Aster scaber, Arundinella hirta, Pteridium aquilinum were the high importance value herbs within all sector. In slopes, the species diversity indices of woody plants were low, but that of herbs showed slightly high. By the cluster analysis used in similarity index, it was observed that woody plants structure between slopes and forest lands made little, but the herbs made slightly higher than woody plants.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.4
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• pp.32-42
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• 2005

To investigate the plants invasion process and dominant species in large-scale cutting slopes, slopes elapsed one year to thirteen years after construction had been selected in five counties. The obtained results are summarized as follows : The species of high appearance frequency were Alnus firma, Arundinella hirta, Miscanthus sinensi var. purpurascens, Erigeron cancdensis, Artemisia princeps var. orientalis, Oenothera odorata, Lactuca raddeana, Lactrca indica var. laciniata, Lespedeza bicolor, Youngia sonchifolia, Populus albaglandulosa, and so on. The biological type of identified vascular plants was $Ch-D_1-R_{5-e}$. In time, plant coverage was increased gradually and average of plant coverage was 1.17% in slopes which elapsed one year, 42.44% after six years, 56.67% after eight years, and 69.17% after ten years. The dominant species in the surveyed slopes were covered with Alnus firma, Artemisia princeps var. orientalis, Erigeron cancdensis, Miscanthus sinensi var. purpurascens, Arundinella hirta, Lactuca raddeana, Oenothera odorata, Boehmeria spicata, Kummerowia striata and Artemisia montana of the 59 species. The conditions of location in large-scale cutting slopes are hard to fix and germinate of seeds, and extend plant roots in the slope soil. Hence, the highly appearance species and dominance species of the area will make plant coverage quick and slope stable.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.527-534
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• 2000

136 cut slopes which extends from Namyangju to Chunchon city along the 46th national highway were investigated to analyze the influence factors affecting slope instability. Geologic and geotechnical conditions were examined and the detailed investigation were carried out for fifty five failed slopes. failure mode (wedge failure, planar failure, circular failure, sheet eroison and rock falls) are examined with respect to slope inclination, rock type, weathering grade and discontinuity patterns. It is suggested that the failure modes and their dimensions have relations to the morphology and geologic conditions of the slopes. Wedge failure has highest is the most frequent failure mode and falls, sheet erosions, planar failures and circular in descending order of failure percentage. Wedge failure is most dominant failure type over all lithology except quartzite formation. In slopes of well foliated and banded gneiss, failure ratio of wedge is up to 50% ca. Failure ratio(number of rock fall/number of total failure) of rock fall increases with increase fo slope inclinations and decrease of weathering grade. Dimension analyses of failed slopes shows wedge and circular failure has higher value of D/L and D/H than planar failure and sheet erosion.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.652-661
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• 2006

The cut slopes in Jinju area constitute the Cretaceous Sedimentary rock which is one of the most poor ground conditions. The geological rocks of the cut slopes are correlated with Jinju Formation. Most of the rocks consist of Black Shale layer, but the lower parts consist of Alkorsic White Sandstone. So, It is characteristic of the differential weathering due to the difference of rock species. Moreover, vertical joints which concentrate on the released rock and weak rock fragments are accompanied with minor faults. We make out face mapping about each slopes through the detailed field-study and deduce RMR and SMR from the field data. The strength properties of rocks were obtained from references, indoor tests, and Back Analysis method. And, choosing properties were used in the stability analysis as stereographic projection and limit equilibrium analysis and we establish the countermeasures for the cut slopes.

• The Journal of Engineering Geology
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• v.10 no.2
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• pp.1-17
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• 2000

In this study, 270 cut-slopes are investigated and statistical analyses are performed. More than 84% of unstable slopes are rock slopes or rock-soil mixed slopes, and 72% of the slopes have 10 to 30 meter in height. And in order to clarify the cause of failure, 3 slopes which have been failed are back-analysed by using the computer programs such as DIPS, UDEC and PCSTABL5M. A heavy rainfall during rainy season is a main cause of slope failure, and a blasting vibration during construction could also give a significant influence on the slope instability.