• 한국지반신소재학회논문집
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• 제15권4호
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• pp.89-96
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• 2016

인천 ${\bigcirc}{\bigcirc}$지역의 연약지반에 시공된 변단면 연약지반보강기초(Variable cross-section soft ground reinforced foundation)의 연직압축거동을 분석하였다. 변단면 연약지반보강기초는 원지반과 고화재를 혼합교반하여 형성되는 고형체의 높은 강성과 강도를 이용하여 상부구조물로부터 유발되는 연약하중을 효과적으로 저항하기 위하여 시공된다. 변단면 연약지반보강기초는 군말뚝 형식으로 시공이 되는데, 정확한 연직거동을 알기 위하여 1개소의 기초에 대한 연직재하시험을 수행하였다. 변단면 연약지반보강기초의 거동을 일반적인 깊은 기초의 거동과 비교하기 위하여 유사한 천층지반조건에 시공된 PHC 파일의 재하시험 결과와 비교하여 재하하중에 따른 침하량 및 하중전이 거동특성을 분석하였다. 연직재하시험결과를 비교분석하였다. 변단면 연약지반보강기초는 제한된 범위의 연직하중에 대하여 천층에서도 효율적으로 저항하는 것으로 분석되었다.

• 한국안전학회지
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• 제23권6호
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• pp.131-137
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• 2008

SCP(Sand Compaction Pile) method that forms a composite ground by driving compacted sand piles into the soft ground. This method is one of the soil improvement techniques for reinforcing and strengthening soft ground deposits. This thesis describes the investigation on the behavior of soft ground reinforced with SCP by low improvement ratio. Direct shear test and consolidation test carried out to verified behavior of composite ground reinforced with SCP. Test results were discussed with reference to the amount of consolidation settlement, variation of shear resistance with area replacement ratio and effect of the stress concentration. And, laboratory model loading test carried out to verified the effect of the location and failure mode of reinforced embankment. Residual shear strength varies with the area replacement and constrict load in the low replacement ratio. Calculated stress concentration ratio overestimate than proposed valve by experimental, theoretical and analytical method. As regards the location, improving right below of the top of the slope was more effective than below of the toe of the slope. This thesis carried out to obtain fundamental information of behavior of the composit ground. Hereafter, centrifuge test that reproduce stress state of the in-situ must be necessary through the further study about pile penetration, reinforce position and construct time.

• 한국지반환경공학회 논문집
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• 제10권4호
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• pp.41-48
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• 2009

표준사로 형성된 지반 10cm아래에 연성관을 매설하여 각각의 상대밀도에서 지반거동에 따른 관의 변형을 관찰을 하였다. 지반보강 상태에서의 관의 거동을 파악하기 위하여 지오그리드를 매설관 하부에 설치한 후 각각 지반에서의 관의 변형을 관찰하였다. 관아래 지오그리드를 설치한 후 보강된 지반의 관 변형형태를 관찰하였다. 지오그리드로 보강한 지반은 수직하중이 높아질수록 보강재에 인장력이 형성되어 보강유무에 따른 동일한 수직하중에서 침하가 감소하였다. 상대밀도 100%지반과 70%지반 변형분포가 차이가 나타났다. 보강 70%지반에서는 최종침하 100mm일 때 무보강 100%지반의 최종침하에서의 지반반력에 가깝게 수렴 하였다. 매설관의 하부 변형 형태에서도 무보강 100% 지반의 매설관 변형 형태와 유사한 것으로 보아 연약지반에서 지오그리드의 보강효과가 기대된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.415-422
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• 1999

The general concept of reinforced roadbed in the high-speed railway is to cope with the soft ground for the bearing capacity and settlement of foundation soil. The cyclic plate load tests were performed to determine the behavior of reinforced ground with multiple layers of geogrid underlying by soft soil. Five series of test were conducted with varying the soil profile conditions including the ground level, type of soil, and the thickness of each soil layer. Based on these plate load tests, laboratory model tests under cyclic loading were conducted to know the effect of geogrid reinforcement in particular for the high-speed rail roadbed. The permanent settlement and the behavior of earth pressure in reinforced roadbed subjected to a combination of static and dynamic loading are presented.

• 지질공학
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• 제17권4호
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• pp.601-613
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• 2007

연약지반에 보강토옹벽을 시공 시 거동에 영향을 주는 인자로 기본적인 물성뿐만 아니라 보강토옹벽에 의한 하중증가와 압밀기간, 간극수압 등의 영향을 받는 것으로 보고되고 있다. 본 연구에서는 보강토옹벽과 연약지반의 거동해석에 지반해석 프로그램인 SAGE CRISP를 이용하여 수행하였다. 첫 번째로 보강토옹벽의 과도변위를 개선하기 위한 치환공법의 거동 개선 효과를 검토하였으며, 두 번째로 치환공법을 적용 후 보강토옹벽의 배면에 보강재 수직설치간격이 지반의 거동에 미치는 영향을 비교 분석하였다. 마지막으로 치환공법을 적용 시 적정 치환 폭과 깊이를 제안하고자 하였다. 치환공법이 보강토옹벽의 거동 개선에 상당한 효과가 있음을 알 수 있었으며, 보강재 수직설치간격은 옹벽상단의 수평변위 개선효과가 있는 것으로 나타났으나 하단의 수평변위와 옹벽배면의 수직변위 개선효과는 미소한 것으로 나타났다. 또한 치환폭의 증가에 따른 수평 수직변 개선효과는 크지 않은 것으로 나타나 치환폭의 증가는 불필요함을 알 수 있었으며, 적정 치환깊이는 연약층의 두께에 대한 옹벽높이의 비(H/T)에 따라 옹벽높이에 대한 치환깊이의 비(D/H)로 제안하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.145-152
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• 1999

In the applying of the reinforced soil method, it would be possible to obtain reinforcement effect more than before in terms of economic if high water content clayey soils could be used as embanking material. Futhermore it would be possible to expect the expansion of the applying field of reinforced soil method too. In this study, the authors describe the analysis results on the behavior of 5 meter high walls reinforced with nonwoven geotextile having the permeability and woven geotextile or geogrid having large tensile strength on the soil ground. The behavior of the walls were investigated for about 100 days after construction and the deformations of reinforcements, lateral soil pressures, vertical and horizontal displacements of the walls were examined by automatical measuring system. It was found that this kinds of reinforcing system might effectively improve the performance of the steep walls by virtue of the reciprocal action between soil and reinforcements, and it might be concluded that construction of the clayey reinforced soil walls with three kinds of geotextiles could be done successfully even on the comparative weak ground.

• Structural Engineering and Mechanics
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• 제54권6호
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• pp.1111-1133
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• 2015

Rebar corrosion in concrete is one of the main causes of reduction of service life of reinforced concrete buildings. This paper presents the influence of rebar corrosion on the structural behavior of reinforced concrete (RC) buildings subjected to strong earthquake ground motion. Different levels of rebar corrosion scenarios were applied on a typical four story RC frame. The deteriorated conditions as a result of these scenarios include loss in cross-sectional area and loss of mechanical properties of the reinforcement bars, loss in bond strength, and loss in concrete strength and its modulus of elasticity. Dynamic analyses of the frame with different corrosion scenarios are performed with selected strong earthquake ground motion records. The influences of degradation in both concrete and reinforcement on structural behavior are investigated by comparing the various parameters of the frame under different corrosion scenarios with respect to each other. The results show that the progressive deterioration of the frame due to rebar corrosion causes serious structural behavior changes such as change in failure mode. The intensity, propagation time, and extensity of rebar corrosion have very important effects on the level of degradation of steel and concrete, as well as on the earthquake behavior of the structure.

• 한국철도학회논문집
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• 제3권2호
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• pp.84-91
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• 2000

The general concept of reinforced roadbed in the high-speed railway is to cope with the soft ground for the bearing capacity and settlement of foundation soil. The cyclic plate load tests were performed to determine the behavior of reinforced ground with multiple layers of geogrid underlying by soft soil. With the test results, the bearing capacity ratio, elastic rebound ratio, subgrade modulus and the strain of geogrids under loading were investigated. Based on these plate load tests, laboratory model tests under cyclic loading were conducted to estimate the effect of geogrid reinforcement in particular for the high-speed rail roadbed. The permanent settlement and the behavior of earth pressure in reinforced roadbed subjected to a combination of static and dynamic loading are presented.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.838-845
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• 2006

Recently construction work in Korea, demands of favorable condition ground had been increased with industrialization acceleration and economic growth. However, because of limited land space, it was so hard to ensure favorable condition grounds that construction work proceeds until soft ground area on plans of road, railroad and industrial complex. In this case, soft ground improvement was required such as a stone column method. Stone column method, making a compaction pile using crushed stone, is a soft ground improvement method. However, stone column method is difficult to apply to the ground which is not mobilized enough lateral confine pressure because no bulging failure resistance. Hence, in present study, evaluates the stone columns reinforced by geogrid for settlement reduction and wide range of application of stone columns. Triaxial compression tests were conducted for evaluation which is about behavior characteristics of stone column on replacement rate. Then, 3-dimensional numerical analysis were conducted for application of stone column reinforced by geogrid as evaluate behavior characteristics and settlement reduction effect of stone column reinforced by geogrid on reinforcing depth change of geogrid.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 가을 학술발표회 논문집
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• pp.285-292
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• 1999

The cyclic plate load test were peformed to determine the behavior of reinforced soft ground with multiple layers of geogrid. Five series of test were conducted with varying the soil profile conditions which including the ground level, type of soil, and the thickness of each soil layer. The plate load test equipment was slightly modified to apply the cyclic load. Based on the cyclic plate load test results, the bearing capacity ratio(BCR), subbase modules, shear modules, the elastic rebound ratio, and reinforcing parameters are presented.