• The Journal of Engineering Geology
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• v.19 no.4
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• pp.517-528
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• 2009

Statistical analyses of cut-slope stability were performed over approximately 5.7 km section along the National road No. 25, which cross-cuts in NW-SE direction the Cheongwon and Boeun-Gun area, Chungbuk. A measure of slope-stability was established by using direct reinforcement and indirect protection methods in whole section. Orientations(dip/dip direction) of the slopes, foliations(bedding), cleavages and joints were measured in total of 30 slope sites. The results analyzed using stereographic projection indicate that major directions of the slopes come out predominantly in three directions: 1) $58^{\circ}/095^{\circ}$, 2) $60^{\circ}/296^{\circ}$ and 3) $59^{\circ}/212^{\circ}$. In analyses of dip direction and frequency of cut-slopes established by reinforcement and protection methods, slopes with dip direction of $80-120^{\circ}$ and $280-320^{\circ}$ mostly occur. However, slopes with dip direction of $0-80^{\circ}$(N and NW) and $120-160^{\circ}$(SE) are not distributed in the study area. Failure aspects were analyzed for three major directions of the slopes, respectively. The results of failure aspects analyzed indicate that slopes in the study area could generate various failures as the results of intersection and/or intersection combination among joints, foliations(bedding) and cleavages. However, possibility of failure in a slope of major direction No. 3 is statistically very low because of low frequency in total number of slopes with the direction and of formation of small scale-slopes geographically, although the slope might generate all aspects of failure-modes.

• Journal of the Korean GEO-environmental Society
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• v.11 no.2
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• pp.53-60
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• 2010

Considering environmental issues and lack of space, it is a necessity to minimize the amount of excavation. Various types of excavation methods are being used in practice. This study proposes a reasonable method for estimating the earth pressure acting on a reinforced wall in front of a excavated slope. The measured data in the field and numerical analyses were used. Results of the study shows that the earth pressure acting on the excavated wall is less than that estimated by Rankine's equations. It was shown that when the excavated slope is used with the reinforced wall, the pressures acting on the reinforced wall can be greatly reduced.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.420-423
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• 2001

토목합성재료(Geosynthetics) 중 직포매트는 i) 분리, ii) 보강/보호 등의 기능을 가지고 있으며 연약지반 보강, 도로포장, 간척지 지반 공사 및 해안지역 LNG 저장고 공사, 폐기물 매립지의 사면 및 저면 보호재 등 기초 보강재료로 널리 이용되고 있다. 그러나 현재 토목건설공사에 사용되고 있는 직포매트용 봉합사는 타이어 코드 제조용 폴리에스테르 고강력사이며, 봉합할 경우 원통형 관입에 의한 인장신도가 커지게 되어 변형에 의한 파괴가 쉽게발생한다. (중략)

• Journal of Korean Society of Disaster and Security
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• v.17 no.2
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• pp.1-11
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• 2024

Most reservoirs in South Korea are earthen dams, mainly because they are cost-effective and easy to construct. However, earthen dams are highly vulnerable to seepage and overtopping, making them prone to sudden failure during excessive flooding. Such sudden failures can lead to a rapid increase in flood discharge, causing significant damage to downstream rivers and inhabited areas. This study investigates the effect of riprap placement on the slopes of earthen dams in delaying dam failure. Delaying the failure time is crucial as it allows more time for evacuation, significantly reducing potential casualties, which is essential from a disaster response perspective. Hydraulic experiments were conducted in a straight channel, using two different sizes of riprap for protection. Unlike previous studies, these experiments were performed under unsteady flow conditions to reflect the impact of rising water levels inside the dam. The target dam for the study was a cofferdam installed in a diversion tunnel. Experimental results indicated that the presence of riprap protection effectively prevented slope failure under the tested conditions. Without riprap protection, increasing the size of the riprap delayed the failure time. This delay can reduce peak discharge, mitigating damage downstream of the dam. Furthermore, these findings can serve as critical reference material for establishing emergency action plans (EAP) for reservoir failure.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.06a
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• pp.67-78
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• 2001

지금까지의 하천 사면보호공법은 돌망태, 사석, 호안블럭(Con'c Block), 재래형 섬유대공(Ordinary Fabric Form) 등을 주로 사용하여 왔다. 그러나, 이들 공법은 자연재료인 돌이나 사석 등이 이미 고갈되어 취득이 매우 어렵고, 콘크리트 제품은 인공구조물 일색의 보호공으로서 자연환경에 어울리지 않거나 인력을 이용한 고가의 공사비가 요구되므로 이를 개량하여 본 환경친화형 섬유대공을 개발하기에 이르렀다. 본 공법은 홍수나 수해로부터 토사제방의 침식 및 세굴방지는 물론 중간에 자연환경 적인 잔디나 조경식재를 하여 환경친화적 호안공을 형성하는 공법으로서 침식방지와 환경친화 효과를 동시에 만족시키기 공법이다.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.162-166
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• 2011

하천제방은 가장 치수효과가 높은 홍수방어시설로서 홍수 시 유수를 원활하게 소통시키고 제내지를 보호하기 위해 하천을 따라 축조한 시설이다. 누수에 의한 제방파괴는 제내지 제체에 드러난 포화표면이 결정적인 요인이 되므로 침윤선을 낮추어 제체하부에 위치하도록 해야 하며 누수가 발생한 제방에 대해서는 적절한 보강기법을 적용해야 한다. 본 연구에서는 하천제방 축조 또는 보강 시 누수에 의한 파괴를 방지하기 위한 방법으로 미국 공병단과 일본 국토기술연구센터에서 사용하는 기법 중 하나인 배수공을 두어 침윤선을 조절하는 방법을 적용하였다. 구체적으로 공병단과 일본 국토기술연구센터에서 제시하는 배수공을 가지는 경우의 제방 실험 및 수치 모형 보정 결과를 비교하였다. 침투 수치 모의는 SEEP/W 프로그램으로 검토하였다. 실험에 적용한 제방의 규격은 제방폭 2.6 m, 둑마루폭 0.4 m, 사면경사 1:2, 제방 높이 0.55 m, 수위 0.5 m이다. 배수공이 없는 제방은 사면에서 누수가 발생하였으며, 배수공 바닥폭이 0.4 m인 공병단과 일본 국토기술연구센터에서 제시하는 배수공을 설치하였을 때는 누수가 발생하지 않았다. 같은 배수공 바닥폭을 가지는 공병단과 일본 국토기술연구센터식 배수공을 설치한 제방의 실험을 비교한 결과, 일본국토기술연구센터식 배수공을 설치한 제방의 침윤선이 공병단식 배수공을 설치한 제방보다 낮았다. 즉, 일본 국토기술연구센터식 사각형 배수공이 다소 안정한 것으로 분석되었다.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.681-692
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• 2017

In recent years, large-scale construction projects such as road pavement construction and new city construction have been carried out nationwide with by the expansion of social overhead facilities and base on the economic development planning, resulting in a rapid increase in artificial slope damage. The existing vegetation-based re-installation method of the slope surface greening method reveals various problems such as lack of bonding force, drying, and lack of organic matter. In this study, research was carried out using vegetation-based material and environmentally friendly soil additives, were are used in combination with natural humus, Bark compost, coco peat, and vermiculite. Uniaxial compressive strength was measured according to the mixing ratio of soil additives and the strength was analyzed. Experiments were carried out on the characteristics of the soil material to gauge the slope protection properties by using the soil compaction test method wherein the soil and the soil additive materials are mixed in relation to the soil height, the number of compaction, the compaction method (layer) and the curing condition. As a result of the experiment, excellent strength performance was demonstrated in soil additives using gypsum cement, and it satisfied vegetation growth standards by using performance enhancer and pH regulator. It was confirmed that the strength increases with the mixing of soil and soil additive, and the stability of slope protection can be improved.

• Journal of the Korean Geotechnical Society
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• v.29 no.1
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• pp.49-59
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• 2013

Heavy rainfall intensity may cause shallow slope failures and debris flow by rill erosion and scour on land surface. The paper represents the difference between native soil (weathered soil) and reinforced soil, which is mixed by hardening agent with flyash as main material, for investigating experimental findings of rill erosion and erosion. Results obtained from artificial rainfall simulator show that erosion rate of reinforced soil mixed with hardening agent is reduced by 20% because an amount of eroded soil on slope surface is inversely proportional to the increase of soil strength. For example, rainfall of 45mm (at the elapsed time of 25mins in rainfall intensity of 110mm/hr) triggers rill erosion on native soil surface, but the rill erosion on reinforced soil surface does not even occur at 330mm rainfall (at the elapsed time of 3hrs in rainfall intensity of 110mm/hr). As a result of slope stability analysis, it was found that the construction method for reinforced soil surface would be more economical, easy and fast construction technology than conventional reinforcement method.

• The Journal of Engineering Geology
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• v.24 no.3
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• pp.383-396
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• 2014

The condition, characteristics, and stability of slopes, as well as the consequences of slope failure, need to be understood for the proper stabilization of slopes and preclusion of potential disasters arising from slope failure. Here, a slope code system (SCS) that succinctly and accurately reflects the various conditions of a slope is proposed. The SCS represents the condition, characteristics, and geotechnical stability of slopes, as well as the consequences of slope failure, and the method is quickly and easily applied to a given slope. The SCS comprises five elements: 1) the slope material; 2) the genetic origin (rock type) and geological structure of the slope; 3) the geotechnical stability of the slope; 4) the probability of failure and remedial works made upon the slope; and 5) the consequences of failure. A letter code is selected from each element, and the result of the evaluation and classification of the slope is given as a five-letter code. Because the condition, characteristics, and geotechnical stability of a slope, as well as the consequences of slope failure, are provided by the SCS, this system will provide an effective mechanism for the maintenance and management of slopes, and will also allow more informed decision-making for determining which slopes should be prioritized for remedial measures.

• The Journal of Engineering Geology
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• v.17 no.3
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• pp.393-404
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• 2007

The purpose of this study is to capture the essentials in survey and evaluation scheme which are able to assess the hazard of a rock slope systematically. Statistical analysis are performed on slope instability parameters related to failure of the rock slope. As the slope instability parameters, twelve survey items are considered such as tension crack, surface deformation, deformation of retaining structures, volume of existing failures, angles between strike of discontinuity and strike of cut slope face, angles between dip of discontinuity and dip of cut slope face, discontinuity condition, cut slope angle, rainfall or ground water level, excavation condition, drainage condition, reinforcement. A total of 233 road cut slopes located in Gyeongnam were considered. The stability of the road cut slopes were evaluated by estimating the slope instability index(SII) and corresponding stability rank. 126 rock slopes were selected to analyze statistical relation between SII and slope instability parameters. The multiple regression analysis was applied to derive statistical models which are able to predict the SII and corresponding slope stability rank. Also, its applicability was explored to predict the slope failures using the variables of slope instability parameters. The results obtained in this study clearly show that the methodology given in this paper have strong capabilities to evaluate the failures of the road cut slope effectively.