• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.972-978
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• 2008

Quality Assurance of Deep Mixing to fulfill the requirements of geotechnical design cannot be achieved only by the process control During production conducted by the deep mixing contractor but it should involve relevant activities that are carried out prior to, during and after the construction by all the parties involved in a deep mixing project. The requirement is different for different application, and hence, QA/QC method/procedure and verification technique may be different for different application. In order to maintain the high quality of deep mixing work in the global market, it is necessary to conduct a research project, such as investigation of illustrations, the variety of existing QA/QC methods/procedures, the correlation between the outcomes of different QA/QC methods. In these reason, it has been held the international meeting to discuss them, in that kind of activities in 2009 it will be held Symposium. Also Collaborative study for QA/QC is on goin, and conduction by all participated members. The subject for collaborative study are, task 1 : investigation of laboratory tests procedures, task 2 : comparing of different laboratory tests procedures, task 3 : QA/QC method/procedures, task 4 : integrated Task1 ~task 3. The discussion of the results in all task will be held in the Symposium separately. In this paper, it was presented four tasks. Also the results in task 1 and 2 conducting domestically until now, such as investigation of laboratory test procedures, effect on the unconfined compressive strength by aging temperature and by delayed time.

• 한국지반공학회논문집
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• 제27권1호
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• pp.65-76
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• 2011

본 논문에서는 보강토 구조물의 장기거동에 관한 수치해석 내용을 다루었다. 본 연구는 사용연한동안 지속하중을 받는 보강토 구조물의 장기 변형 관련 메카니즘을 고찰하는데 주 목적을 두었다. 연구를 위해 먼저 Singh-Mitchell 크리프 모델과 멱함수(Power law) 크리프 모델을 이용하여 각각 뒤채움흙과 보강재의 크리프 변형을 모델링하는 방안을 구축하였으며 이를 토대로 뒤채움흙과 토목섬유 보강재의 크리프 특성에 대한 매개변수 연구를 수행하였다. 해석결과 외부하중을 받는 보강토 구조물이 세립분이 많이 포함되어 있는 흙으로 뒤채움이 될 경우 뒤채움흙과 토목섬유 보강재로부터 발생하는 크리프 효과로 인해 상당한 크기의 장기 변형이 발생할 수 있는 것으로 나타났다. 본 논문에서는 외부하중을 받는 보강토 구조물에 있어서 크리프 효과가 구조물의 사용성에 미치는 영향을 집중적으로 고찰하였다.

• 한국지반공학회논문집
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• 제25권11호
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• pp.75-86
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• 2009

본 논문에서는 쇄석말뚝의 하중 지지력 향상을 위해 지오그리드를 이용하여 주면을 감싸는 일명 "지오그리드 보강 쇄석말뚝"의 하중지지특성에 관한 내용을 다루었다. 이를 위해 지오그리드 감쌈 쇄석말뚝의 근본적인 기능인 배수 효과와 지오그리드 보강 효과를 현실적으로 모사할 수 있는 3차원 응력-간극수압 수치해석 모델을 이용하여 재하하중에 대한 다양한 시공조건에 대한 매개변수 해석을 수행하고 그 결과를 분석하였다. 그 결과, 기존의 연구에서 발표된 성토 하중 조건에서 확인할 수 있었던 장기 하중지지력 향상 효과와 유사하게 재하하중 조건에서도 지지력이 현저히 향상하는 결과를 확인할 수 있어 지오그리드 보강 쇄석말뚝 공법은 연약지반 성토시 적용성 뿐만 아니라 구조물 기초로도 활용성을 확보할 수 있는 것으로 검토 되었다. 해석 결과는 지오그리드 보강 쇄석말뚝의 하중지지력과 영향 인자간의 관계 설정이 가능하도록 제시하였으며 현장적용성 측면에서의 고찰을 시도하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제9권4호
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• pp.252-260
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• 2005

본 연구에서는 ${\bigcirc}{\bigcirc}$지역에서의 터널 간섭사례에 따른 적정 지반 구역화 및 각 구역별 특성치 분석을 수행하였다. 본 대상 지역은 호상흑운모 편마암 및 흑운모 편암, 화강 편마암이 심도와 평면상에서 불규칙하게 분포하고 있는데, 전반적으로 풍화대가 깊게 분포하고 있으며, 단층대 및 파쇄대가 깊은 심도에서도 대규모로 분포하고 있었다. 본 사례에서와 같이 특정 간섭부분의 공간적 지층특성 구분이 향후 안정성 분석 및 설계반영에 매우 중요하게 작용하는 경우, 기존 터널설계시의 지층구분 및 대표 특성치 산정 방식은 적정 지층특성 분석에 많은 한계점을 지니고 있었다. 본 연구결과, 각종 지반조사 결과의 종합 및 분석을 통해 공간적 지층구분 및 적정 특성치 산정이 향후 안정성 검토 등에 있어 매우 유효하게 적용됨을 알 수 있었다.

• 자원환경지질
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• 제41권5호
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• pp.635-644
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• 2008

물리탐사는 측정점에 대한 정보에만 국한하는 다른 조사방법과는 달리 지반내부에 대한 영상 및 정보를 제공할 수 있으므로 환경오염부지 평가 및 감시, 지반조사, 지질재해 등에서 중요한 기술로 활용되고 있다. 본 연구에서는 상기물리탐사 요소기술에 관한 특허분석을 실시하였다. 1976년부터 2005년까지 출원된 특허의 요약문, 청구항, 도면 검색 등을 통해 총 904건의 관련 특허를 추출하였다. 추출된 특허를 대상으로 국가별, 연도별, 출원인별, 그리고 기술 분야별 출원동향을 분석하였다. 또한 미국특허 분석을 통해 국가별 기술수준을 비교 분석하였다. 상위 5위의 출원국가는 미국, 영국, 일본, 노르웨이 그리고 프랑스 순이었으며, 특히 미국과 영국 출원인의 특허건수가 663건(73.3%)으로 이 분야 기술개발을 주도하고 있는 것으로 파악되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 가을 학술발표회 논문집
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• pp.29-62
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• 2001

Based on the results from investigation of behaviour of pulverized fly ashes (PFA) at laboratory and field, the way how to reduce the environmental impacts to geotechnical practices Is considered and described. In order to reduce discharged industrial by-products, it should primarily be emphasized that an effort are made as much as possible not to put into homing. Secondarily, an effort must be made to increase amount of utilization to geotechnical engineering practices. In addition, from an environmental point of view, we should challenge to create innovative materials which are eligible for controlling other wastes and remedying contamination m soils by using industrial byproducts which belong to wastes This Is a new concept in which the polluting materials can be eliminated by making use of wastes. Based on the above-stated concept, the previous and possible utilization of PFA is classified into: (1 ) reclamation, embankment or backfill material, (2) light weight geo-material, (8) soil stabilization/improvement, and (4) environmental material. The reason why PFA, in particular, slurry PFA has been used and will possibly be used more widely is due to the fact that PFA has the advantages : (i) low specific gravity leading to a light weight geomaterial, (ii) high pozzolanic activity enhancing strength, especially due to cement addition, and (iii) spherical shape of particles producing isotropy and then pumpability. As well as the concept of reducing geo-environmental impacts, the present text mainly describes the successful results at laboratory and field which have been obtained by the authors. The most important issue hi application of byproducts including PFA for geotechnical practices is to prevent leakage of polluted substances from sedimentary deposits, ground and earth structures. As one of possible techniques far achieving this purpose, a method of washing off the polluted substances by hot water is described.

• Geomechanics and Engineering
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• 제29권4호
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• pp.391-405
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• 2022

A newly proposed grouting simulation method, the sequential diffusion solidification method was introduced into the numerical simulation of combined bi-borehole grouting. The traditional, critical and difficult numerical problem for the temporal and spatial variation simulation of the slurry is solved. Thus, numerical simulation of grouting and blocking of flowing water in karst conduits is realized and the mechanism understanding of the combined bi-borehole technology is promoted. The sensitivity analysis of the influence factors of combined bi-borehole grouting was investigated. Through orthogonal experiment, the influences of proximal and distal slurry properties, the initial flow velocity of the conduit and the proximal and distal slurry injection rate on the blocking efficiency are compared. The velocity variation, pressure variation and slurry deposition phenomenon were monitored, and the flow field characteristics and slurry outflow behavior were analyzed. The interaction mechanism between the proximal and distal slurries in the combined bi-borehole grouting is revealed. The results show that, under the orthogonal experiment conditions, the slurry injection rate has the greatest impact on blocking. With a constant slurry injection rate, the blocking efficiency can be increased by more than 30% when using slurry with weak time-dependent viscosity behavior in the distal borehole and slurry with strong time-dependent viscosity behavior in the proximal borehole respectively. According to the results of numerical simulation, the grouting scheme of "intercept the flow from the proximal borehole by quick-setting slurry, and grout cement slurry from the distal borehole" is put forward and successfully applied to the water inflow treatment project of China Resources Cement (Pingnan) Limestone Mine.

• 토지주택연구
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• 제8권1호
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• pp.13-22
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• 2017

In this study, triggering mechanism of ground sinking was analyzed through groundwater flow analysis on the basis of a case of the ground sinking occurred in Yongsan in 2015. The results of geotechnical investigation performed before and after the ground sinking were analyzed for the accurate understanding of geological features in the study area. The numerical groundwater flow analysis was performed to evaluate the influence of the flow behavior from the surrounding area toward the excavated site using software of Visual MODFLOW. As a result, it was found from the geotechnical analysis that the strata of sedimentary layer along the sunken area in the vertical direction was mixed significantly after the ground sinking compared with the status of the soil condition before the ground sinking. Piping was occurred at the toe of cut-off wall in the sandy gravel layer, and this phenomenon was predicted by the numerical flow analysis. Sequential ground displacement scenario of the ground sinking was derived from the geotechnical in situ test and numerical flow analysis performed in this study.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.521-528
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• 2005

The evaluation process of rock mass properties intrinsically contains some uncertainty due to the inhomogeneity of rock mass and the measurement error. Although various empirical methods for the determination of rock mass properties were suggested, there is no way of integrating various information on rock mass properties except averaging. For these reasons, this research introduces evidence theory which can model epistemic uncertainty and yield reasonable rock mass properties through combining various information such as empirical equations, in-situ test results, and so on. Through the application of evidence theory to the real site investigation and in situ experiment results, an interval of deformation modulus, cohesion and friction angle of rock mass were obtained. The ratios between lower and upper bound of those properties ranges from 1.6 to 3.6. Numerical analyses of circular hole using the properties for TYPE-2 rock mass were carried out. The magnitude or size of plastic region and radial displacement in case of lower bound properties is about 4 times larger than that of upper bound properties.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.338-345
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• 2005

Recently, surface-wave methods have been widely used for site investigation due to economic advantage and improved reliability. Specially, the Spectral-Analysis-of-Surface-Wave (SASW) method has been used to evaluate soil properties in geotechnical engineering. In determination of subgrade stiffness by SASW measurements, only the vertical Rayleigh waves have been used. This study proposed a framework to determine shear-wave velocity profiles by using vertical and horizontal Rayleigh waves and Love wave all together. In addition, the Common-Array-Profiling(CAP) SASW method was employed, which subgrade stiffness of profile the local material under two fixed receivers. The procedure proposed in this study was verified by comparing the shear-wave velocity profiles with the shear-wave velocity profiles of downhole testing at two geotechnical sites.