• 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 GEO-environmental Society
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• v.23 no.2
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• pp.37-47
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• 2022

Recently, with the establishment of active stabilization measures, large-scale collapse of slopes is decreasing. However, the frequency of rockfalls due to the destabilization of floating stones or boulder within or above the slope has not been decreased significantly. As a measure for stabilizing rockfall and disaster prevention, protection methods such as rockfall barriers and rockfall protection nets are typically applied. However, the approach to catching the rockfall in a catchment area by reducing the energy of the rockfall and changing the rolling condition of the rockfall is relatively insignificant. Therefore, in this study, using a general-purpose rockfall simulation program, the change in the rolling characteristics of rockfall according to the specifications of the ditch installed under the slope was investigated. It is expected that the research results can be used as basic data to determine the specifications of the ditch that can be applied to general roads or trails.

• Journal of the Korean GEO-environmental Society
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• v.12 no.8
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• pp.25-31
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• 2011

In recent rainy seasons, severe rain storms have caused frequent reinforced retaining wall collapses and slope sliding which have lead to casualties. In this paper, investigating cases of reinforced retaining wall failure, the causes of cracks in reinforced retaining wall and slope sliding have been examined, and a finite element analysis considering the construction phase has been done to analyze the cause and characteristics of slope sliding. As a result, reinforced retaining wall displacement has increased due to heavy rain storms and the increase size has been shown to be large. From these results, it has been analyzed that pile driving can have an effect on the collapse of reinforced retaining walls.

• Journal of the Korean Geotechnical Society
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• v.37 no.3
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• pp.5-17
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• 2021

This study aims to investigate the causes and countermeasures for the occurrence of tension cracks in the slope of the rock mass of heavy equipment for road construction. Electric resistivity survey was performed to investigate the expandable tensile crack range. As a result of examining the distribution of soft zones in the rock mass, a low specific resistance zone was found at the bottom of the access road where tensile cracks occurred. It was confirmed that a low resistivity zone was distributed near the top of the excavation slope. Therefore, reinforcements was performed by determining the location of the possible tensile crack as the top of the excavation slope. Two rows of reinforced piles and anchors were proposed as a reinforcement method, and the slope stability analysis showed that the allowable safety factor was satisfied after reinforcements.

• Journal of Korean Tunnelling and Underground Space Association
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• v.2 no.2
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• pp.50-61
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• 2000

The ground around the portal of a tunnel is the most typical part showing the 3-dimensional mechanical behavior in the tunnel. The portal slope is constructed at the weathered soft rock-mass, and remains as a potential sliding mass. The slope failure around the tunnel portal may happen drastically and induce the great disaster; hence, for the permanent stability several special techniques are required. To solve this problem, the ground around the tunnel portal may be excavated in the arch shape to develop the arching effect in horizontal direction. With the arch-type portal slope, one can reduce considerably the excavation mass and the damage of environments. This approach has not been attempted yet due to the lack of understanding and the well-defined analyzing method, so the retaining wall type portal is more universal. The 3-dimensional finite element analyses were carried out to prove that the arch type is more advantageous in safety and cost than the right angle type. The influence of the tunnel construction sequence and the strength of the rock-mass on the slope stability was investigated by focusing on the maximum shear strain in the slope, and the yield zone at the tunnel face.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.239-253
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• 1992

The masonry walls, having the characters of cheap construction materials and relatively easy construction, have been widely used in supporting slopes. However, the necessity of reinforcing methods to improve the stability of masonry walls has been continuously required due to the collapses taken place quite often. In the present study, a new method to improve the stability of masonry walls was developed based on the soil nailing system proven effective in strengthening the surrounding soils. The developed method could be used in reinforcing the old masonry walls structually unsafe as well as in constructing new masonry walls. The effects of pore water pressures due to heavy rainfalls were included in the developed method and also the chart practically applicable to design was presented, together with a design example.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.1
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• pp.21-26
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• 2013

In recent study, infiltration analysis considering rainfall intensity is more economical and practical than existing analysis method. Revised construction slope design standard is also stated to full-fill infiltration analysis considering rainfall for practical stability review. Infiltration analysis considering rainfall for practical stability review. But, to infiltration analysis, the process is complicated by ground impermeability and rainfall intensity. In this study, we perform infiltration analysis to charge infiltration conditions, soil type and rainfall characteristics, for more pratical stability review. Using the result, we can suggest construable condition on the assumption that soil is saturated up to surface zone.

• Journal of the Korean Geotechnical Society
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• v.29 no.12
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• pp.11-24
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• 2013

This study presents a design method for typical rainfall-induced landslide considering in-situ matric suction. Actual landslide data are used to validate the proposed method. The soil-water characteristic curve (SWCC) and unsaturated permeability are experimentally determined to estimate hydraulic properties of testing site. The field measurement of matric suction is carried out to monitor in-situ matric suction in a natural slope subjected to rainfall infiltration, which is incorporated in the landslide analysis. The wetting band depth and safety factor of the slope are assessed to clarify the effect of domestic rainfall pattern. Especially, the effect of antecedent rainfall on the slope stability is investigated and discussed in terms of wetting band depth using parametric study. It is found from the result of this study that proposed design method can consider the characteristic of unsaturated soil and effect of antecedent rainfall. The location of the scarp zone is fairly well predicted by proposed design method. Moreover, heavy rainfall, concentrated in the backward part with time, causes the lowest safety factor of the slope. These results demonstrate that decrease in matric suction due to antecedent rainfall may trigger slope instability. After the antecedent rainfall, additional rainfall may cause the slope failure due to increasing wetting band depth.

• Journal of the Korean Geosynthetics Society
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• v.10 no.1
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• pp.9-18
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• 2011

This paper described that the failure causes of reinforced slope are analyzed based on the effect of geological and rainfall. The analysis result confirmed that the rainfall has effects on the stability of reinforced slope. Therefore, it was applied to the dewatering method using collector well for slope stabilized, and then the analysis of seepage and slope stability were conducted on slope with the applied method. The results of seepage analysis are corresponded with failure cause by rainfall and the results of slope stability, which is applied to dewatering method, are satisfied with safety factor criterion. Therefore, it confirmed that the dewatering method using collector could be possible to apply in field and reasonable method for slope stabilized during heavy rainfall.

• Journal of the Korean GEO-environmental Society
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• v.10 no.7
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• pp.15-23
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• 2009

This research area is a greate section of triple tunnels that passes through the fault fractured zone the in the granite area. In this area, tunnel section, pillar width and overburden height are changed consecutively due to declivity of 1 : 4.5 and slope formation of upper part as changed section. That is, stability estimation for each section varying pillar width can be conducted because tunnel diameter changes gradually from 0.5D to 1.0D according to distance of pillar width. We have estimated the stability of pillar width in triple tunnels with monitoring value, and compared the stability with results of numerical analysis.