• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.475-480
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• 2000

This study was to present the method for estimating the horizontal coefficient of consolidation by using velocity method which was based on the Barren's equation. Horizontal drainage consolidation tests, including a radial drainage consolidation test, a cylindrical consolidation test, and a large soil box test, were performed to examine its validity. Using the velocity method, horizontal coefficient of consolidation was calculated and compared with lost method, √t method, Magnan & Deroy's method, Bergado's method.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.385-391
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• 2000

Velocity method was supposed by Parkin et al.(1985) in order to supplement previous log t and (equation omitted) method. This study was to present the method for estimating the horizontal coefficient of consolidation by using velocity method which was based on the Barren's equation. Velocity method throughly eliminated not only settlement curve which had shape with difficulty in evaluating coefficient of consolidation but also the effect of unknown intial compression, the secondary consolidation and occurrence of unknown point by using velocity instead of settlement. The purpose of this study is to investigate its application in field. Velocity method was used in obtaining horizontal coefficient of consolidation in Kyung-gi area. Horizontal coefficient of consolidation using velocity method was calculated and compared with log t method, √t method Magnan & Deroy's method, Bergado's method.

• Smart Structures and Systems
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• 제7권4호
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• pp.289-302
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• 2011

In marine clay deposits, naturally formed or artificially reclaimed, the evaluation and monitoring of the consolidation process has been a critical issue in civil engineering practices due to the time frame required for completing the consolidation process, which range from several days to several years. While complementing the conventional iconographic method suggested by Casagrande and recently developed in-situ techniques that measure the shear wave, this study suggests an alternative experimental procedure that can be used to evaluate the consolidation state of marine clay deposits using the shear wave velocity. A laboratory consolidation testing apparatus was implemented with bimorph-type piezoelectric bender elements to determine the effective stress-shear wave velocity (${\sigma}^{\prime}-V_s$) relationship with the marine clays of interest. The in-situ consolidation state was then evaluated by comparing the in-situ shear wave velocity data with the effective stress-shear wave velocity relationships obtained from laboratory experiments. The suggested methodology was applied and verified at three different sites in South Korea, i.e., a foreshore site in Incheon, a submarine deposit in Busan, and an estuary delta deposit in Busan. It is found that the shear wave-based experimental procedure presented in this paper can be effectively and reliably used to evaluate the consolidation state of marine clay deposits.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.442-451
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• 2008

The evaluation of field degree of consolidation on soft clays has been an important problem in geotechnical areas. Monitoring either settlements or pore water pressures has been widely applied in the filed, but occasionally they have some problems. This study addresses the suggestion and application of another method for evaluating the degree of consolidation using shear wave velocities. A research site where soft clay layers were consolidated by surcharging loads was chosen. Laboratory tests were performed to determine the relation between shear wave velocity and effective stress. Field seismic tests were conducted several times during the consolidation of the clay layers. The tests results show that the shear wave velocity increased significantly as clays consolidated. The shear wave velocities at each field stress states were derived from the laboratory results and the degree of consolidation was evaluated by comparing the shear wave velocities obtained by laboratory and field seismic methods. In most stress states, the degree of consolidation evaluated using the shear wave velocity matched well with that obtained from field settlement record, showing the potential of applying the method using shear waves in the evaluation of field degree of consolidation on soft clay deposits.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.990-997
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• 2005

In this paper, the measured results obtained from the ground improved by SCP method at quay-wall caisson foundation in Pusan New Port 1-1 phase are analyzed and then compared with the values predicted by a consolidation theory. The measured settlement is generally smaller than the predicted settlement. For consolidation velocity, the measured velocity is later than the predicted value. According to the execution of caisson placing phases, the predicted value shows higher settlement than the measured one with time being.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.51-56
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• 2004

The sand compaction pile (SCP) method, which forms a composite ground by driving sand piles into clay deposit, is the most commonly used soil improvement techniques in many countries for more than 30 years. Installation of sand compaction piles reduces the amount of consolidation settlement and increases the bearing capacity of soft clay deposit. In this paper, field survey conducted to investigated the consolidation behavior of the composite ground improved by SCPs. It is suggested that the measured consolidation velocity is later than design theory, however measured consolidation settlement is higher than design theory.

• 지질공학
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• 제23권4호
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• pp.511-517
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• 2013

Field Velocity Probe (FVP)는 관입형 전단파 탐사 장비로 다양한 현장의 적용성이 날로 증가하고 있다. 본 연구에서는 FVP의 활용성을 증대시키는 측면으로 FVP를 이용하여 연약지반의 압밀 특성을 평가하는 것이다. 대상지반은 국내 대표 연약지반인 인천 송도 지역이며 실내압밀 실험을 수행하기 위하여 시료를 3 m와 6 m에서 채취 하였다. 채취한 시료는 개량된 압밀 시료기에 안착시켜 유효응력 변화에 따른 전단파 속도 경향성을 분석하였다. 현장의 전단파 속도는 FVP를 이용하였으며 매 심도 20 cm 간격으로 상세한 속도 주상도를 도출하였다. 동일 유효응력 조건에서 도출한 실내 전단파 속도와 현장 전단파 속도를 비교하여 연약지반의 압밀 상태를 평가 하였으며 3 m 구간은 과압밀 그리고 6 m 지역은 압밀 진행중인 상태로 나타났다. 본 연구에서는 FVP가 연약지반의 압밀 평가에도 활용될 수 있음을 보여주며 기존 방법의 대체 방법으로 활용성 될 것으로 판단된다.

• 한국지반공학회논문집
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• 제24권8호
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• pp.25-34
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• 2008

연약 지반의 거동 특성 평가를 위하여 전단파 속도와 전기저항을 측정할 수 있는 새로운 압밀셀을 개발하였다. 전단파의 발진과 수신을 위한 벤더엘리먼트는 압밀셀의 상 하부판 및 벽면에 설치하였다. 국부적인 간극비 변화를 평가하기 위하여 이중 쐐기 형식의 전기저항 탐침을 적용하였다. 벤더 엘리먼트와 전기저항 탐침은 나일론 재질의 스크류 안에 고정하였다. 나일론 재질의 스크류는 압밀셀과의 임피던스 차이로 인하여 압밀셀을 통한 파의 직접적 전달을 최소화하며, 고장난 벤더 엘리먼트와 전기저항 탐침을 쉽게 교환하게 해준다. 전기저항-대수 시간 곡선의 기울기 및 전단파 속도의 변화로부터 일차 압밀 시간을 평가하였다. 교란 효과가 적을 경우, 입자 배열은 전단파 속도에 영향을 미치며 이로부터 흙의 고유 이방성을 평가할 수 있었다. 압밀 실험동안 침하량으로 산정한 간극비와 전기저항으로부터 계산된 간극비는 거의 유사한 것으로 나타났다. 본 연구는 전단퐈 속도와 전기저항이 일차 압밀, 고유 이방성, 간극비 등 연약 지반의 압밀 특성 파악을 위한 보완적인 정보를 제공해 줌을 보여준다.

• 한국지반공학회논문집
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• 제16권1호
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• pp.167-178
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• 2000

준설매립 공사시 자중압밀침하량 및 체적변화비 예측을 위해 사용되는 Yano 방법의 단점을 보완하고실제 준설매립 공사시 준설토가 연속적으로 투기되며 퇴적고의 상승이 토층의 증가와 침강 및 자중압밀에 의한 체적감소의 결과로 표현되어지는 것을 고려한 단계투기법에 의한 새로운 해석기법에 대한 시험적 연구를 수행하였다. 단계투기시험에 의해 투기속도와 퇴적고 상승속도의 관계를 측정하여 현장 매립계획고에 소요되는 현장투기 완료일수를 산정하였고 그때 소요되는 전체 투기높이 그리고 이에 해당하는 실질토량고를 산정하여 이를 바탕으로 현장투기완료 후 자중압밀 침하량 및 체적변화비,함수비, 간극비의 변화를 예측하였고, 전체투기 시험을 통한 Yano법에 의한 산정결과와 비교 분석하였다. 자중압밀 침하량의 경우 약 29.8%, 체적비의 경우 31.1%, 공극비 및 함수비가 약 40%정도 전체투기에 의한 Yano 법이 단계투기법에 의한 결과보다 작게 평가되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.1190-1197
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• 2009

Design parameters related to Yano's method(1984, 1985), one of experimental approaches having been used widely in Korea to estimate sedimentation and consolidation of dredged and reclaimed ground, were analyzed and their propriety were reassessed in this paper. Data analyses were performed on the basis of the settling test results using samples from the west coastal area of Korea. From analysis of results, for specific characteristics of these dredged and reclaimed marine soft clays, co-relations of initial water content - coefficient of sedimentation/ consolidation - initial setting velocity were evaluated. Relation between height of soil solid and surface height of slurry at the stages of initiation and termination of consolidation was also assessed. Finally ranges and average values of these design parameters were evaluated and typical empirical equations between these design parameters were also proposed.