• Journal of Forest and Environmental Science
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• v.17 no.1
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• pp.74-87
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• 2001

When the revegetation of the slopes is required, it is more desirable to consider it from the ecological view point rather than from the disaster-preventive one because the environment is critical for the introduction of pioneer plants to the denuded slopes. The ecological point of view adheres to the maintenance of the present, original ecosystem of the construction area. The new revegetation technology is presented using native microorganisms and its effective usuage was discussed based on the data in the research field. Direct seeding is recommended and explained in detail than planting seedlings. The importance of inclination angle of slope face is shown for the successful revegetation from its relationship with the thickness of soil. It is indicated that the introduction of pilot plants to the slopes should include their ability to ease the acid rain effects as much as possible. Finally every construction may not be desirable for the maintenance and improvement of the global ecosystem without the consideration of the opinions mentioned above.

• Korean Journal of Remote Sensing
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• v.37 no.5_3
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• pp.1425-1434
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• 2021

Continuous and periodic data acquisition must be preceded to maintain and manage the river facilities effectively. Adapting the existing general facilities methods, which include river surveying methods such as terrestrial laser scanners, total stations, and Global Navigation Satellite System (GNSS), has limitation in terms of its costs, manpower, and times to acquire spatial information since the river facilities are distributed across the wide and long area. On the other hand, the Mobile Mapping System (MMS) has comparative advantage in acquiring the data of river facilities since it constructs three-dimensional spatial information while moving. By using the MMS, 184,646,009 points could be attained for Anyang stream with a length of 4 kilometers only in 20 minutes. Levee points were divided at intervals of 10 meters so that about 378 levee cross sections were generated. In addition, the waterside maximum and average slope could be automatically calculated by separating slope plane form levee point cloud, and the accuracy of RMSE was confirmed by comparing with manually calculated slope. The reference slope was calculated manually by plotting point cloud of levee slope plane and selecting two points that use location information when calculating the slope. Also, as a result of comparing the water side slope with slope standard in basic river plan for Anyang stream, it is confirmed that inspecting the river facilities with the MMS point cloud is highly recommended than the existing river survey.

• The Journal of Engineering Geology
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• v.29 no.2
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• pp.123-136
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• 2019

This study examines the effect of collector well installed to reduce groundwater level in the regions with the occurrence of landcreep, a soil mass movement triggered by instability on slopes. Slopes are prone to failure as a result of instability caused by its internal, topographic and geological properties as well as due to external factors such as rainfall and earthquake. In Korea during the rain season, rainfall infiltration affects the groundwater level in soil, building up porewater pressure and load, and finally drives slopes to collapse. Slope failure caused by rainfall infiltration has been leading to a drastic forest degradation. The studied slope is located adjacent to a valley, its terrain corresponds to piedmont gentle slope, while the upper part of the failure surface is steep. After reinforcing the terrain where landcreep had occurred and installing collector well on the slope, we measured the changes in the groundwater level. In order to analyze the relationship between the well and the slope, we calculated the ratio of groundwater level to rainfall before and after the installation of the collector well. As a result, it is confirmed that the ratio increases after the installation of the well, which in turn reduces the groundwater level. Analysis of the change in groundwater level after 3, 7, 15 days antecedent rainfall showed that the higher the overall groundwater level, the less the value ($r_p$) of groundwater level-rainfall ratio is, while the value becomes relatively greater when the groundwater level is low. In particular, if a slope has a large catchment basin as is in the case of the studied site, antecedent rainfall affects groundwater level in the order of 3 < 7 < 15 days.

• Tunnel and Underground Space
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• v.17 no.5
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• pp.350-359
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• 2007

Most large cut slopes of open pit mines, roadways, and railways are steeply inclined and composed with rocks that do not contain soils. However, these rock slopes suffer both weathering and fragmentation. In the case of steep slopes, falling rock and collapse of a slope may often occur due to surface erosion. Cast-in place concrete and rubble work are the most widely used earth structure-based pressure supports that act as restraints against the collapse of the rock slope. In order to overcome the shortcomings of conventional retaining walls, a segmental grid retaining wall is being used with connects precasted segments to construct the wall. In this study, laboratory model test was conducted to estimate deformation behavior of segmental grid retaining wall with configuration of rear strecher, height and inclination of the wall. In order to examine the behavior characteristics of a segmental grid retaining wall, this research analyzes the aspects of spacial displacement through relative displacement according to change in the inclination of the wall. Also, the walls behavior according to the formation and status of the rear stretcher which serves the role of transferring the load from the header and the stretcher which make up the wall, the displacement of backfill materials in the wall, and the location of the maximum load were surveyed and the characteristics of displacement in the segmental grid retaining wall were observed. The test results of the segmental grid retaining wall showed that there was a sudden increase in failure load according to the decrease in the wall's height and the size of the in was greatly decreased. Furthermore, it revealed that with identical inclination and height, the structure of the rear stitcher did not greatly affect the starting point or size of maximum horizontal displacement, but rather had a stronger effect on the inclination of the wall.

• Journal of Korean Society of Forest Science
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• v.86 no.4
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• pp.476-488
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• 1997

The purpose of this study was to figure out the suitable field standards for revegetation measures on cut-slopes in consideration of the environmental factors. The field survey was conducted from 1995 to 1996 on highway cut-slopes. The results obtained could be summarized as follows; The major revegetation measures surveyed were 5 major measures as a whole in descending order of seed-spraying measures, block-sod pitching measures, latticed block pitching measures, hydro-seeding measures with seed-fertilizer-soil materials, and several netting measures on highway cut-slopes. According to the analysis of the environmental factors, the plant coverage was affected several major environmental factors which were soil factors(soil hardness, soil texture, soil and rock condition), and site factors(slope gradient, slope length). From a viewpoint of optimum selection, the major 3 factors(soil factors, slope gradient factors, slope length factors) should be considered for selection of revegetation measures on highway cut-slopes.

• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.109-115
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• 2014

The purpose of this study is to estimate the sediment volume concentration of the liquified-solid mixture which is included fine sediment fractions, according to the variance of the channel slope and the water supply. The numerical model was performed by using the Finite Differential Element Method (FDM) based on the equation for the mass conservation, momentum conservation and the equation of coarse sediment an fine sediment. In comparison of varying the channel slope, the deeper the channel slope, the inflection point of the sediment concentration was occurred rapidly. In comparison of variance of the water supply, as the water supply increases fluctuation with high sediment concentration. In this situation, debris flow changes to the turbulent flow and the sediment becomes to be floated. In comparison varying the length paved saturated sediment, the longer the length, the high concentration of sediment occurred, for the safety of the slope it is needed to check the possibility of the erosion in the slope by debris flow. The results of this study will provide useful information in predicting of the disaster by the liquified-solid mixture and in prevention of the debris flow with various the slope in the mountain side.

• The Journal of Engineering Geology
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• v.34 no.2
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• pp.193-206
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• 2024

A standard slope stability analysis was undertaken for new railway sections, based on the slope of sedimentary rock layers and filling material (sand), to evaluate the stability of the cut-off slope in the section passing through a zone of sedimentary rock. The stability analysis was undertaken during the dry and rainy seasons, accounting for earthquake occurrence, based on slope design criteria. It was found that if the slope of the sedimentary rock formation was <10°, the effect on the safety rate of the cut-off slope was insignificant. Furthermore, a slope relief of 1:1.0 or more should be applied with slopes of 10~20°, and 1:1.2 or more with >20°. This study provides an important reference for evaluation of slope stability when railway and road construction is undertaken in areas of sedimentary rock.

• Journal of the Korean GEO-environmental Society
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• v.24 no.8
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• pp.5-11
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• 2023

Due to frequent occurrences of concentrated heavy rainfall caused by abnormal climate conditions in recent years, collapses of steep slopes have been occurring frequently due to surface erosion and increased pore water pressure. Various methods are being applied to prevent slope collapses, such as increasing the resistance to movement and reducing pore water pressure. Research on these methods has been consistently conducted as they provide an efficient response to slope collapses by satisfying both the conditions of resistance to movement and pore water pressure simultaneously. Therefore, in this study, we propose an upward slope reinforcement method by burying drainage materials with an upward slope inclination, instead of the conventional horizontal application. This approach aims to satisfy both slope reinforcement and drainage functions effectively, offering a comprehensive solution for slope stabilization. Furthermore, to determine the optimal burial angle that exhibits the most effective reinforcement and drainage effects of the proposed method, we investigated the reinforcement and drainage effects under conditions where the horizontal drainage materials were set at angles ranging from 0° to 60° in increments of 10° on a representative cross-section. Additionally, indoor model experiments were conducted under the conditions of 40°, which showed the most outstanding drainage effect, and 20°, which exhibited the highest safety factor, to validate the numerical analysis results. The results showed that the burial angle of 40° exhibits a relatively higher drainage effect as with the numerical analysis results, while the angle of 20° results in inadequate drainage and observed slope collapse.

• The Journal of Engineering Geology
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• v.23 no.3
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• pp.257-269
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• 2013

Prevention plans for landslide and slope disasters should be appropriate for a country's budget when considering a systematic investment plan. The systematic management of slopes adjacent to national highways should incorporate reasonable investment risk and the expected degree of damage should be calculated by considering the investment priorities. In terms of priority of investment, the major factors used to determine the degree of hazard are gradient, soil characteristics, RMR (Rock Mass Rating), stability interpretation, type of discontinuities, and history of collapse, among others. The likely consequences of slope failure can be determined by considering traffic volume, the number of lanes, and average vehicle risk. We performed such calculations regarding the priority of investment and performed a regression analysis for 392 slopes located in Yeongseo region, Gangwon province. The calculation results show that collapsed slopes have a higher priority for investment, as do slopes with a high proportion of dangerous sections and locations in valleys.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.1
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• pp.109-115
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• 2008

Malfunction of gutter systems in the slope area accelerate to percolate surface flow into underground and to cause the decrease of soil strength, Overflowing from gutter causes soil erosion from slope surface, secondary it is one of the main reasons to cause disaster in the hillside area. Much researches were reported and are undergoing about flood disaster in the down stream area, but rare in the upper reach(hillside). It is considered that improving function of gutter in the hillside is very important to prevent the disaster caused by rainfall. In this paper, After analyzing relationship between rainfall and disaster on the hillside in Busan, researches about having surface flow run into gutter effectively and preventing from overflowing outside of gutter on the hillside in Busan were carried out. Improved design methods of gutter are suggested to mitigate disaster in the sloping area by analysis of collected data and hydraulic model test.