• The Journal of Engineering Geology
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• v.21 no.3
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• pp.221-230
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• 2011

The movement of rock cut slopes may result in upheaval of an adjacent road. Because most cut slopes consist of rock, road upheaval due to the movement of a cut slope is a rare phenomenon in Korea. We found that the movement of rock slopes which are heavily weathered and with strongly developed weak zones is governed by circular failure of the overall rock formation rather than by failure along discontinuities. The results of a numerical analysis revealed that the application of a ubiquitous joint model in a continuum analysis is appropriate for anisotropic rocks (e.g., schist) and for slopes for which the stability is influenced by a particular discontinuity. The results of a field investigation and numerical analyses suggest that retaining walls and anchors should be used to stabilize rock slopes and that real-time monitoring equipment should be installed to assess the reinforcing effect of the remedial measures.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.1
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• pp.83-89
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• 2007

As tunnel excavation generats stress release, a stability security of tunnel face is mainly important in case of tunnel excavation in the weak grounds. Using the steel bar or glass fiber pipe which had regular hardness, a face bolt method to reinforce previously is applied to an excavation object tunnel face aspect among measures methods regarding this. Therefore, used $FLAC^{3D}$ Ver. 2.1 on 5 Case of 0.5D (2EA), 1.0D, 1.5D, 2.0D with the length and 6 Case of 0, 20, 40, 60, 80, 100EA with the number of the bolt that a face bolt method was installed at these papers in the necessary weak grounds in order to review applicability of the tunnel face reinforcement method that used these face bolts, and executed three dimension continuous analysis.

• Tunnel and Underground Space
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• v.18 no.2
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• pp.125-133
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• 2008

The rock treatment methods for improving bearing capacity and reducing settlement of the underground roadway structure foundation on fractured rock was studied in this paper. Also, effective reinforcement scheme was evaluated by numerical analysis for the application to the practical construction. Various in-situ and laboratory tests were executed systematically at Yeongi-goon, Ohoongchungnam-do, Korea, for the purpose of defining the physical and mechanical properties of rock. Consequently the effective treatment methods insuring the bearing capacity of fractured rock were proposed. In addition, the adequate reinforcing depth of the comparatives measure, such as double rod, triple rod injection methods and micropile, were investigated from the case study. Finally, the most effective construction scheme with the consideration of safety and economical aspects were proposed by using numerical analysis(Plaxis ver. 8.2).

• Journal of the Korean Geotechnical Society
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• v.22 no.5
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• pp.27-37
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• 2006

Cemented Sand and Gravel (C.S.G) method has become increasingly popular in Japan and throughout the world as a construction method and material. This method is favorably used for cofferdam and large dam because a quarry and aggregate plant facility can be diminished. Also, this method can reduce construction cost, work duration and destruction of environment. In this paper, a methodology for C.S.G mix design based on so-called soil mechanics approach is proposed for trapezoid-shaped dam. The methodology consists of selection of a suitable aggregate, introduction of compaction method, processing to prepare standard specimens, and determination of mix portions. Also, unconfined compressive strength tests and large triaxial compression tests are performed. From the results of the test, correlation equation among strength, elastic modulus and unit cement is proposed.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.217-226
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• 2019

Optimum engineering methods for bank protection were classified based on steepness of bank slope and an existence of waterfront facility in the floodplain, and a new concept of eco-hybrid rolling mat method which could be applicable for the unfitted cases with previously developed countermeasures was suggested in this study. The eco-hybrid rolling mat method can be constructed while maintaining the river environment and ecosystem that does not interfere with the ground and slopes, when bank erosion occurs, it is an economical and efficient construction method that can protect the revetment and the bank slope immediately. The developed eco-hybrid rolling mat method was verified for the designed structure, system, function and effect based on large-scale river experiments including field exposure and decomposition test. As a result, the normal operation and effect of the rolling mat ted under low and high velocity conditions were confirmed with respect to bank protection. The effect of bank erosion prevention was quantitatively validated by sediment concentration monitoring and analysis, and the product specification of the eco-hybrid rolling mat was presented based on the standardized mat applied in real-scale tests.

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.103-111
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• 2017

Saudi Arabia coastal area is highly valuable construction as a flat area covered by sabkha deposit. However, sabkha deposit has some geotechnical problems because of high groundwater level, high salt contents in groundwater, loose density, and possibility of collapsible settlement due to presence of crystals vulnerable to moisture, and ground improvement is needed to improve the bearing capacity. In this study, the characteristics of the sabkha soils in the coastal area of Saudi Arabia were analyzed and the applicability of dynamic compaction method was evaluated. Parametric study was conducted to analyze the behavior of sabkha deposit during dynamic compaction. The appropriateness of the proposed analytical solutions to estimate the depth of improvement was evaluated, and the troubles and notes in applying dynamic compaction in sabkha deposit were discussed.

• Korean Journal of Construction Engineering and Management
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• v.9 no.4
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• pp.57-65
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• 2008

As the society is being developed, the desire about life quality is also growing. Even though the process of waterproof work has very close relation with these life quality, we always focus on management after problem than the precaution of problem. So this process has the highest rate of mengel. We develop LCC analysis model considering the precaution and try to show the necessity of the precaution by comparing and analyzing every alternative proposal during LCC. By studying of the previous work and the result of questionnaire, we deduce the problem of waterproof work in construction area. By discussion with an expert in this process and research, we make solutions about precaution and set the cost items in every alternative proposal about these solutions. We understand the effect of each elements through sensitive analysis of the cost items, and find the economically best suited solution.

• The Journal of Engineering Geology
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• v.14 no.1
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• pp.71-80
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• 2004

The failure of cut slopes frequently occurs particularly during the thawing season and the rain season in summer. This study interpreted data collected from site to which a real-monitoring system was applied in order to analyze the causes of ground behaviors and to forecast future slope failure. As for research methods, this study analyzed the size and mechanism of failure by integrating the results of field surveys and measurements. Furthermore, it analyzed data transmitted by the monitoring system installed in the a result, three times of ground displacement occurred as well as a number of partial tension cracks. The cut slope composed of sandstone and siltstone started its initial behavior as a result of torrential downpour and the loss of support of the substructure. For quantitative analysis of the characteristics of ground behavior, this study measured 5 lateral lines. According to the result of the measurement, displacement happened little in the section to which countermeasure had been applied, but displacement of maximum 400mm happened in the section to which countermeasure had not bee applied. The analysis of data on displacement and rainfall suggested a close relationship between ground behavior and rainfall. According to the result of stability interpretation along with the change of ground saturation, stability rate appeared to be less than 1.0 when ground saturation is over 55%. Although the current trend of ground behavior is at a stable stage falling within the range of tolerance, it is considered necessary to continue monitoring and data analysis because ground displacement is highly possible with the change of temperature during the winter.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.586-591
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• 2004

매년 발생되는 절토사면의 붕괴를 사전에 방지하기 위하여 절토사면에 상시 계측시스템을 설치하고 지반의 거동분석을 실시한다. 본 현장의 절토사면 붕괴 규모와 메카니즘을 분석하고 계측 결과와 상호 비교 분석한다. 본 현장은 상시계측시스템 운용 확대 실시에 따른 시험 설치 현장으로 2003년부터 운용 중에 있다. 계측결과에 의하면 강우량과 지반의 거동이 밀접한 관계가 있는 것으로 사료된다. 본 현장의 경우 크게 3번의 지반이동이 있었으며 현재는 안정화 단계에 있는 것으로 사료된다. 그러나, 향후 동절기의 외분 온도 변화와 동반하여 지반의 변동이 우려됨으로 인하여 지속적인 관찰과 자료 분석이 수행되어야 할 것으로 본다.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.392-401
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• 2006

In the July of 2006, devastating rainfalls ravaged the terrain in the province of Kangwon. These rainfalls resulted in debris flows, landslide and overflow over the habitat. Following these events, the urgent field study and countermeasures were to be needed and several methods were indicated. At each site, field observations were made and the properties of the channel and debris flow were broadly characterized. Debris flows are a natural hazard which looks like a combination of flood, land and rock slide. The same goes for that case, debris flow has been reported frequently overseas and the extent of damages has been increased. But the hazards "debris flow" is still insufficiently researched and futhermore debris flows are very hard to predict. In this paper, the general overview of the debris flow problem and the mitigation method will be presented