• Tunnel and Underground Space
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• v.29 no.5
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• pp.305-317
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• 2019

The RMR and Q-system for characterizing rock mass and drilling core, and for estimating the support and reinforcement measures in mine galleries, tunnels and caverns have been widely used by engineers. SMR has been widely used in the rock mass classification for rock slope, but Q-Slope has been introduced into slopes since 2015. In the last ten years, a modified Q-system called Q-slope has been tested by the many authors for application to the benches in open pit mines and excavated road rock slopes. The results have shown that a simple correlation exists between Q-slope values and the long-term stable and unsupported slope angles. Just as RMR and Q have been used together in a tunnel or underground space and complemented by comparison, Q-Slope can be used in parallel with SMR. This paper introduces how to use Q-Slope which has not been announced in Korea and application examples of Pasir open pit coal mine in Indonesia.

• The Journal of Engineering Geology
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• v.10 no.3
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• pp.205-216
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• 2000

An unstable natural slope located at Icheon-Ri, Dasa-Eup, Dalseong-Kun which has been severely cracked during heavy rain fall in September, 1998, was investigated and analysed for remedial measures. Various geological data were obtained by performing a surface geological survey, a ground penetrating radar(GPR) exploration, four geotechnical borings with field and laboratory tests, and the precipitation records were also reviewed. Based on the these data, the probable sliding plane was determined as a bedding plane with dip angle of 20 to 25 degrees between sandstone and shale layers at depth of 6 to 8 meters. By performing back analyses with the limit equilibrium method, the friction angle and cohesion of the sliding plane were determined as 18$^{\circ}$ and 0, respectively. Based on these results, a series of stability analyses such as stereo-graphic projection method, limiting equilibrium method and numerical method were carried out. The remedial measures for the unstable slope were selected based on the results of the limit equilibrium analyses by considering various conditions expected at the site. Ground grouting or anchoring method with proper surface drainage systems could be employed for the long term safety of the slope.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.1
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• pp.79-90
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• 2002

The structural analysis such as rigid frame analysis has been used for the design of cut and cover tunnel due to its simplicity and convenience. This analysis, however, could not account for the geometrical factors such as interface elements, slope of excavation plane, distance between lining and excavation plane, etc. To develop the analysis technique and design technology for the cut and cover tunnel, in this study, the numerical analyses considering not only geometrical but geotechnical factors are conducted. Especially, the effects on the mechanical behaviors of cut and cover tunnel due to the slope of excavation plane and the distance between lining and excavation plane are mainly focused in this study.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.98-98
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• 2011

중소규모 하천에서 많이 설치되어 있는 경사형보를 대상으로 하류부 세굴에 대한 수리모형실험과 수치모의를 통하여 경사형보 하류부 세굴특성과 세굴영향인자들에 대한 민감도 분석을 실시하였다. 수리모형실험은 폭 0.8m, 길이 20m의 가변경사 직선 개수로에서 1 : 2(H/L)경사를 가지는 경사형보의 높이, 월류수심, 하류부 수심 변화에 따른 최대 세굴심과 세굴길이의 변화를 관측하였고, 수치모의는 유사이동 모의가 가능한 3차원 수치모형인 FLOW-3D를 이용하여 경사형 보의 경사 변화에 따른 하류부 세굴특성을 모의하였다. 수리모형실험 결과 최대 세굴심 및 세굴길이에 가장 영향을 크게 미치는 인자는 월류고이며, 하류부 수심은 최대 세굴심과 세굴길이의 감소효과 뿐만 아니라 세굴공의 형상에도 영향을 미쳤다. 낙하류의 유입 각도가 예연보에 비하여 작은 경사보는 예연보에 비하여 수평방향 유속이 상대적으로 증가하여 세굴길이가 증가하였으며 이로 인하여 세굴공 하류부 천이영역의 사면경사가 상대적으로 완만하게 형성되었다. 세굴공의 상류부에 재순환 영역이 발생되어 천이영역에서 이송되는 유사의 최대세굴심 발생 위치에 퇴적되는 현상을 방해하며 세굴공의 모양은 완전히 발달된 이중(double) 세굴공을 생성하였으며, 특히 낙하류의 유입각도와 하류부 수위의 영향으로 하류수심($h_t$)과 낙차고(H)의 비($h_t/H$)가 1.0 미만인 경우에 이중(double) 세굴공이 발생하였다. 경사형보의 경사각 영향에 따른 하류부 세굴 영향은 3차원 수치모형을 이용하여 모의하였으며, 경사각을 1V/2H, 1V/3H, 1V/4H로 변화시키며 수치모의를 수행하였다. 수치모의 결과 경사각이 증가할수록 최대 세굴심은 증가하는 경향을 보이고 그에 따른 증가율은 감소하였다. 보 높이, 월류고, 하류부 수심, 경사각 변화에 따른 세굴심의 변화는 상대민감도 방법을 이용하여 비교하였으며 주요 영향인자에 대한 민감도비는 월류고가 보 하류부 세굴에 가장 큰 영향을 미치고, 경사각, 보 높이, 하류부 수심 순이다. 특히 보 하류부의 수심은 음의 민감도를 보이며, 이는 보 하류부 수심이 증가할수록 세굴심이 감소하는 것을 의미한다. 추후 보완 실험 및 수치모의를 추가 활용한다면, 경사형보 하류부 물받이 및 하상보호공 설계를 위한 정량적인 기초자료를 제공할 수 있을 것으로 판단된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5115-5122
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• 2013

This paper has studied about the development and application of landslide collapse prediction real-time monitoring system based on USN to detect and measure the collapse of landslide. The rainfall measuring sensor, gap water pressure sensor, indicator displacement measuring sensor, index inclination sensor, water content sensor and image analysis sensor are selected and these are applied on the test bed. Each sensor's operation and performance for reliability verification is tested by the instrument which is installed in the field. As the result, u-IT based real-time landslide monitoring system which is developed by this research for landslide collapse detection could minimize life and property damages because it makes advance evacuation with collapse risk pre-estimate through real-time monitoring on roadside cut and bedrock slopes. This system is based on the results of this study demonstrate the effect escarpment plan are spread throughout.

• The Journal of Engineering Geology
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• v.25 no.2
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• pp.299-304
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• 2015

Slope stability analysis of unsaturated soil slopes due to rainfall infiltration is an important issue in evaluating landslide analysis and stability assessment. The purpose of this study is to establish the critical depth considering weathered soil of parent rock and rainfall intensity at main scarp in national landslide. Based on the analytical results, it is found that as rainfall duration and Slope angle increased, the critical depth of gneiss-weathered soil increased from 3.00 m to 3.77 m, the critical depth of granite weathered-soil increased from 1.75 m to 2.40 m, and the critical depth of mudstone-weathered soil increased from 3.00 m to 4.15 m, respectively. The critical depth of granite-weathered soil with low cohesion and high internal friction angle is much lower than those of other soils. It is interestingly shown that a decrease in the safety factor is highly significant, much affected by the slope increase rather than the rainfall intensity.

• The Journal of the Korea Contents Association
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• v.16 no.7
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• pp.457-464
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• 2016

The analysis for stability of slope reinforced with soil nails need professional knowledge and skilled technology for program. So we spend a lot of money and time. In this study, we try to save it. After we analyzed the stability of reinforced slope with MIDAS GTS using shear strength reduction technique, we made charts by result. Charts created in the stydy can be used rapidly in slope disaster prevention. We try to analyze stability of slopes when we changed nail spacing, nail angle, slope type, properties of soil. We obtained relationship as follows; 1) The safety factor appears effectively when the nail angle is $10{\sim}20^{\circ}$. 2) The safety factor appears effectively when the nail spacing is 0.8~1.2m. 3) The error of Singh's and suggested chart are 3.45, 8.65, 4.35% when the slope are 1:0.5, 1:1, 1:2.

• 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.

• Journal of the Korean Geotechnical Society
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• v.19 no.3
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• pp.53-64
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• 2003

Many transmission towers, high-rise buildings and bridges are constructed near steep slopes and are supported by large-diameter piles. These structures may be subjected to large lateral loads, such as violent winds and earthquakes. Widely used types of foundations for these structures are pier foundations, which have large-diameters with high stiffness. The behavior of a pier foundation subjected to lateral loads is similar to that of a short rigid pile because both elements seem to fail by rotation developing passive resistance on opposite faces above and below the rotation point, unlike the behavior of a long flexible pile. This paper describes the results of several numerical studies performed with a three-dimensional finite element method (FEM) of model tests of a laterally loaded short pile located near slopes, respectively. In this paper, the results of model tests of single piles and pile groups subjected to lateral loading, in homogeneous sand with 30$^{\circ}$ slopes and horizontal ground were analyzed by the 3-D FE analyses. The pile was assumed to be linearly elastic. The sand was assumed to have non-associative characteristics, following the MC-DP model. The failure criterion is governed by the Mohr-Coulomb equation and the plastic potential is given by the Drucker-Prager equation. The main purpose of this paper is the validation of the 3-D elasto-plastic FEM by comparisons with the experimental data.

• Geotechnical Engineering
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• v.13 no.4
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• pp.37-54
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• 1997

This paper is to investigate the bearing capacity and the failure mechanism of slope subjected to strip surcharges adjassent to embankment slope of sandy soil. Parametric model tests under plain strain condition were performed by changing width of footing, relative density of slope materials, and position of footing from the crest of slopes. For model tests, Jumunjin standard sand was used as the slope material and its relative density was 45% and 70%, respectively. The angle of slope was formed with 1 : 1.5 and 1 2. Rigid model footings, made of aluminuu were used with their widths of 4, 7, 10 and 12cm. For the position of model footing, position ratios, distance of model footing from the crest of slope divided by footing width, were 0, 0.5, 1, 2, 3, 4, 5. Failure mechanism was observed by using ink colored sands and markers inserted in model slopes. Ultimate bearing capacity obtained from tests was analyzed and compared with limit equilibrium method, limit analysis method and empirical equation. Characteristics of load-settlement curves and failure mechanism were also analyzed and compared with the existing theories. Thus, their effects on ultimate bearing capacity of model footing adjacent to slope were assessed.