• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.598-606
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• 2015

This study analyzed the characteristics of the disaster occurrence and disaster-prone zones on the 85 forest roads in the Jeollabuk-do area by referring to their forest environment factors. The on-site survey reveal the types of forest road disasters as follows: erosions of cutting slopes 54.1%, erosions of the filling slope 35.3%, collapses of cutting slopes with filling slope 9.4%, and erosions of road surface 1.1%. Disasters most frequently occurred in the vertical location (the hillside) and the horizontal location (the slope), and the forest factors affecting the road disasters were degree of cutting slopes in $31^{\circ}{\sim}40^{\circ}$, degree of filling slopes in $21^{\circ}{\sim}30^{\circ}$, and the soil texture of SiL. The most significant factors on the most frequent occurrence of forest road disasters were forest type of coniferous, slope aspect northeast, forest age of plantation and felling area, and rainfall in 1601~1700. An analysis of the occurrence of the forest road disasters in the Jeollabuk-do area showed a positive correlative relationship with the following factors of the forest environment within a 1% error: degree of cutting slope in $31^{\circ}{\sim}40^{\circ}$, annual accumulation rainfall in 1601~1700. and showed a positive correlative relationship with the following factors of the forest environment within a 5% error: horizontal location of valley, forest type of coniferous, length of slope more than 20 m, forest age of plantation and felling area, soil texture of SiL.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.296-296
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• 2008

국내 절토비탈면은 이상 기후 및 건설공사의 증대로 인해 증가하고 있는 추세이며 장마철 및 태풍으로 인해 비탈면의 붕괴로 많은 인명 및 재산피해가 발생되고 있는 실정이다. 국내에서 사용되고 있는 기존의 비탈면의 설계기준은 암반의 불연속면에 대한 조사를 실시하고는 있지만 주로 암반의 굴착난이도를 토층, 리핑암, 발파암으로 구분하여 각각의 비탈면 절취경사를 결정하여 사용하는 방법을 사용하였으며 이러한 기준은 단순히 암석의 강도를 기준으로 설정되어 있으므로 암석의 공학적 특성 즉, 암반내 불연속면 방향성, 연속성, 충진물질, 마찰각, 풍화속도 등의 영향으로 공용후 비탈면 구배의 재조정 및 보강이 빈번하다. 국내외 절토비탈면의 설계기준은 각 기관별로 산재되어 있었으며 비탈면에 대한 설계 및 시공 등에 관한 기준은 도로와 철도 설계기준에 일부 반영되어 있을 뿐 항만, 댐, 택지조성 등 기타 시설 설계기준에는 비탈면에 대한 기준이 마련되어 있지 않아 표준적인 비탈면 설계기준 및 유지관리지침이 등이 필요하였다. 이러한 문제점을 보완하기 위해 2004년부터 2006까지 한국시설안전공단, 한국도로공사, 대한주택공사가 협동으로 연구한 건설공사 비탈면 설계 시공 및 유지관리에 관한 연구의 결과로 2006년도에 "건설공사 비탈면 설계기준"이 수립되었다. 이 설계기준은 건설공사에서의 기존 상이한 기준들을 정리하고 동일화하는 작업을 수행하였으며 지반의 조사에서부터 대책공까지를 막나하여 정리하였다. 그러나 최근에 급격한 기후변화로 인한 비탈면붕괴 빈번함에 따라 과거 적용되어 왔던 이들 기준을 적용하는 경우, 특히 상부 토층 및 풍화암 구간에서 많은 설계안전율을 만족하지 못해 많은 보강을 수반해야 하는 문제가 발생되고 있어 그 원인에 대한 분석을 수행하고자 하였다. 2006년도 정리된 기준은 과거에 적용하여 온 유기시의 안전율 조건을 Fs > 1.1~1.2을 적용하였던 것을 Fs > 1.2로 통일하였으며 지하수위 조건은 지표면에 위치하도록 하였다. 지하수위 조건은 풍화암 및 토층의 경우, 과거 지표면에 -3m를 적용한 시기가 있었으나 지표면에 지하수위를 적용하는 것이 일반적인 해석방법이다. 이러한 결과의 원인을 검토해 보면 다음과 같다. 첫째, 풍화암 및 토층에 적용되어 온 지반강도 정수가 과거 적용한 값보다 최근에는 작아지는 경향을 보이고 있다. 둘째, 지하수위 적용문제로 현재 지표면에 지하수위를 두어 안전율을 감소시키는 문제로 이는 최근 들어 많은 연구기관에서 강우시 간극수압의 증가에 대한 연구가 활발하게 진행되고 있다. 그러나 침투수 해석은 현행 기준에도 강우의 침투를 고려한 해석을 실시하는 경우 FS > 1.3 적용하는 것으로 되어 있으나 대부분의 해석에서는 적용이 되지 못하고 있는 실정이다. 셋째, 안전율이 과거에 주로 적용된 Fs > 1.1에서 Fs > 1.2로 상향 조정되어 우기시의 설계안전율 만족시키지 못하는 문제이다. 그러므로 이러한 문제점을 개선하기 위한 검토가 필요하며 장기적으로 이에 대한 합리적인 기준을 개정하는 작업이 추후에 수행되어야 할 것으로 판단된다.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.515-523
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• 2020

If the safety factor does not secure the safety factor suggested in the design standard at the slope design stage, the safety factor is secured by installing an anchor. Stability analysis is used to verify the effect of reinforcing the slope of the anchor, but in this process, most of the anchor construction intervals are assumed to be equal and analyzed. For economical and effective slope reinforcement, stability analysis is required by adjusting the anchor construction interval. In this study, the effect of the anchor construction interval on the change of the safety factor of the slope was identified. Stability analysis was performed by setting a virtual slope with two berms and different anchor construction intervals. As a result of the analysis, the stability of the slope is secured when the anchor spacing of the lower surface is narrowed and the anchor gaps of the upper and middle surfaces are wider than when anchors are installed at the same intervals on the upper, middle, and lower surfaces of the slope. The result was a 15% reduction in the amount of anchors. This means that, rather than reinforcing anchors at the same intervals, it is economical and effective to have an economical and effective reinforcement effect to vary the anchor construction intervals according to the slope characteristics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2828-2836
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• 2015

Evaluation items were deducted by based on literature materials to supplement the evaluation system of rock cut-slope in national road. Delphi survey of experts were conducted to review the final evaluation items. As a result of reviewing the significance through stepwise multiple linear regression, all of deducted items were statistically significant because these had lower P-value than 0.05. And It was confirmed that the items were selected appropriately as they had relatively similar levels of the weight. In consideration of CVR and reliability both suggested items and existing items, the exclusible items was selected and new items can complement existing evaluation system were added. Finally 18 rock cut-slope evaluation items was deducted.

• Journal of the Korean GEO-environmental Society
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• v.13 no.3
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• pp.13-19
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• 2012

Due to recent climate change, big typhoon and heavy rainfall happen frequently not only in Korea but also all over the world. It leads to collapse of levee by extraordinary flood. It lead to collapse of levees by extraordinary flood. These natural disasters give the life and property damages in near region. In this study, it was performed that a stability in levee using seepage analysis. It has been evaluated hydraulic gradient of exit zone according to variations in levee crest width, gradient. As a result, it showed that hydraulic gradient of exit zone was decreased due to increase of levee crest width and gradient, and it was evaluated that vertical hydraulic gradient was decreased than that of the horizontal hydraulic gradient.

• Tunnel and Underground Space
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• v.26 no.5
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• pp.431-440
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• 2016

This study aims to suggest the detailed evaluation criteria based on performances for rock slopes. Using the previous research result, final evaluation items are proposed considering characteristics and similarities of each evaluation item. Weight for each evaluation item is deducted using AHP method, verification for suggested evaluation criteria is conducted based on correlation analysis. The research results as follows. All evaluation items have a high statistical correlation with final evaluation result(safety rating). Especially, items of the "rockfall", "ground deformation", "discontinuity characteristic", "instable lithology" were shown the highest in relative correlation coefficient(R), It is judged that items and weight presented in this study well reflect characteristics of rock slopes.

• The Journal of Engineering Geology
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• v.27 no.4
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• pp.417-427
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• 2017

This study aims to present cases of rock slope failures caused by geological structures. Status of slope failures, results of cause analysis and stabilizing methods are introduced, focusing primarily on rock slope failures caused by specific geologic structures, such as intersection of faults infilled with clay, foliation and fault shear zone by dike intrusion and deep-seated clayey layer along lithologic boundary. Detailed geological survey, geophysical exploration and boring survey were conducted for cause analysis. Stabilizing method to prevent further slope failures and to ensure long-term stability of slopes were established, considering characteristics of geological structures, types of failure and geological conditions.

• 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.

• Journal of the Korean Geotechnical Society
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• v.33 no.4
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• pp.5-15
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• 2017

Three-hinge failure occurs in a jointed rock slope with a joint set parallel with slope and a conjugate joint set. Limit Equilibrium Method (LEM) and Finite Element Method (FEM) which are commonly used for slope design, are not suitable for evaluating stability against three-hinge failure, and this study performed parametric study to analyze the failure mechanism and to find influence factors causing three-hinge failure using UDEC which is a commercial two-dimensional DEM based numerical program. Numerical analyses were performed for various joint structural conditions and joint properties as well as ground water conditions. It was found that pore water pressure is the main factor triggering the three-hinge failure and the mode of failure depends on friction angle of basal joint and bedding joint set. The results obtained from this study can be used for adequate and economic footwall slope reinforcement design and construction.

• 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.