• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.174-187
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• 2005

Recently, because of environment, cost, supply and demand factors, though applying sea-sand as horizontal drains is getting difficult that usage of Gravel has been growing in large size of construction sites, Study on engineering properties and behavior characteristics of Gravel stratum is not thoroughgoing enough. We have applied Gravel Mat as the horizontal drains in O O construction site. We also conducted several field tests such as Material property test, Geosynthetics damage test with Repeated load, Discharge capacity test performed by inflow of upper soil and In-situ PBD Penetration test to review the application of Gravel Mat. Test results show that Gravel Mat is not only advantageous in Trafficability and Water drainage by Consolidation due to its great Internal friction angle and Permeability, but also easy to penetrate with Mandrel and has great discharge capacity and guarantee of the stability against geosynthetics damage at the same time. With these benefits Gravel Mat shows great application in fields.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.293-299
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• 2008

If a conventional type of Plastic Board Drain (PBD) is installed to the deep clay deposit, it is subjected to a high lateral earth pressure. a flow channel of PBD may be reduced by the collapse of cores and clogged by the intrusion of filter into the space between cores which are made by lateral pressure. It could decrease the ability of initial discharge capacity and the reliability of long term discharge capacity. A cylindrical plastic board drain (C-PBD) considered in this study consists of cylindrical core and several supports so that it can prevent the reduction of area of flow channel from the higher lateral earth pressure effectively. The discharge capacity of C-PBD was compared to that of a conventional PBD through performing experiments using the composite discharge capacity apparatus which can consider in-situ condition such as penetration of drains, ground settlement and discharge capacity. As a result, C-PBD showed much better performance than PBD in the ability of discharge. It was observed that the C-PBD was folded whereas the conventional PBD was folded after the experiment.

• 한국항해항만학회지
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• 제33권2호
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• pp.119-125
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• 2009

The effect of plastic board drains (PBDs)on ground improvement was checked out considering three crucial factors: ground settlement, undrained shear strength, and residual water head. First, the settlement analysis including initial settlement induced by reclamation of sand mat was conducted by back calculation analysis with measured data. Its result showed toot the PBDs used for this site worked well on improving soft ground. Secondly, the undrained shear strength was investigated by laboratory and in-situ tests including unconsolidated-undrained triaxial compression (UU) tests, unconfined compression tests, in-situ vane tests, and cone penetration tests. From the test results, they showed that the undrained shear strength of the improved ground by PBDs was significantly increased as well as the strength increasing ratio especially $10{\sim}15m$ below the ground surface on site. Thirdly, the residual water head measurement from the in situ dissipation test was found the same as the static water head, which indicated primary consolidation was completed and the effect of soil improvement with PBDs can be confirmed.

• 대한토목학회논문집
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• 제28권6C호
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• pp.339-347
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• 2008

현장 관입 실험은 프로브 관입에 따라 주변 지반을 의도적으로 파괴시켜 지반특성을 파악할 수 있다. 본 논문의 목적은 현장 점토지반에 서로 다른 크기의 프로브 관입으로 인한 간극 수압 소산 특성을 이용하여 파괴에 따른 교란 효과를 분석하는 것이다. 현장 실험을 수행하기 위해 콘관입 시험(CPT), 딜라토미터 시험(DMT) 그리고 현장 속도 프로브 장비(FVP: Field Velocity Probe)가 사용되었다. 샌드 매트(sand mat), PBD 그리고 사석을 이용한 지반 개량 중인 부산 북컨테이너 현장에서 실험이 진행 되었으며, 샌드 매트(sand mat)공법 이후 실내 실험을 수행하기 위해 시료가 채취 되었다. 실내에서는 물성치 실험 및 압밀 실험을 수행하여 지반 특성과 수평압밀계수 값을 도출하였다. 현장 실험은 지반 개량 후 압밀도 90% 시점에서 사석 제거 후 케이싱을 통해 CPT, DMT 그리고 FVP 순서대로 실험이 수행 되었다. 관입에 따른 영향 범위를 최소화 시키기 위해 각각의 실험은 3m 간격을 유지 하였으며, 매 심도 24m에서 관입을 멈추고 시간에 따른 간극 수압 변화 양상을 측정하였다. 실내 압밀 실험을 통해 수평 압밀 계수$(C_h)$를 산정하였으며, 현장 실험을 통해 각 프로브에 따른 $t_{50}$ 값을 계산 하였다. $t_{50}$값을 이용하여 산정된 등가 유효 반경은 FVP가 가장 작게 그리고 DMT가 가장 크게 산정되었다.