• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.404-410
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• 2002

Dynamic compaction is an efficient ground improvement technique for loose soils and waste landfill. The improvement is obtained by controlled high energy tamping and its effects vary with the soil properties and energy input. This study demonstrated the application of dynamic compaction method for the improvement of waste landfill in construction site. Various tests and measurements such as standard penetration test, bore hole loading test, crater settlement, ground settlement, pore water pressure were peformed during dynamic compaction field test. From the field test results, the efficiency of dynamic compaction method for the improvement of waste landfill was proved.

• 한국세라믹학회지
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• 제34권3호
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• pp.296-302
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• 1997

SiC휘스커를 첨가한 알루미나 분말 기지 복합체의 치밀화에 미치는 상온 반복 압축의 영향을 조사하였다. 반복 압축 응력과 반복 횟수가 증가할수록, 또한 바이어스 압력이 낮을수록 복합체의 초기 성형 밀도가 증가하였으며 가압 및 제하 속도, 반복 속도는 분말의 미끄러짐과 재배열에 큰 영향을 미치지 않음을 알 수 있었다. 상온 반복 압축으로 인한 SiC 휘스커의 파단은 거의 없었으며 휘스커의 배열 방향은 반복 압축 방향에 관계없이 고른 분포를 나타냄으로써 상온 반복 압축 성형이 SiC 휘스커를 첨가한 알루미나 분말 기지 복합체의 초기 성형 밀도를 높일 수 있는 효과적인 방법임을 알 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 연약지반처리위원회 학술세미나
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• pp.1-13
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• 1999

The use of Compaction Grouting evolved in the 1950's to correct structural settlement of buildings. Over the almost 50 years, the technology has developed and is currently used in wide range of applications. Compaction Grouting, the injection of a very stiff, 'zero-slump' mortar grout under relatively high pressure, displaces and compacts soils. It can effectively repair natural or man-made soil strength deficiencies in variety of soil formations. Major uses of Compaction Grouting include densifying loose soils or fill voids caused by sinkholes, poorly compacted fills, broken utilities, improper dewatering, or soft ground tunneling excavation. Other application include preventing liquefaction, re-leveling settled structures, and using compaction grout bulbs as structural elements of minipiles or underpinning. The technique replaced slurry injection, or 'pressure grouting', as the preferred method of densification grouting. There are several reasons for the increased use of Compaction Grouting which can be summarized in one word: CONTROL. The low slump grout and injection processes are usually designed to keep the grout in a homogeneous mass at the point of injection, while acceptable in some limited applications, tends to quickly get out of control. Hydraulic soil fracturing can cause extensive grout travel, often well beyond the desired treatment zone. So, on the basis of the two case history constructed in recent year, a study has been peformed to analyze the basic mechanism of the Compaction Grouting and verify the effectiveness of the ground improvement using some test methods.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.347-351
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• 2007

The influence of compaction pressure and sintering temperature on the hydraulic cylinder block fabricated by powder metallurgy is investigated in this study. The cylinder block is powder compacted under various compaction pressures and sintered under various sintering temperatures, and its density and dimensions are measured to reveal the relation of the process condition with the product quality. Moreover, finite element analyses of the density distributions are conducted under the same conditions with the experiments and the predicted results are compared with the measured ones.

• 지질공학
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• 제29권4호
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• pp.367-381
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• 2019

We investigate pore pressure conditions and reservoir compaction associated with oil and gas production using 3 different permeability models, which are all based on one-dimensional radial flow diffusion model, but differ in considering permeability evolution during production. Model 1 assumes the most simplistic constant and invariable permeability regardless of production; Model 2 considers permeability reduction associated with reservoir compaction only due to pore pressure drawdown during production; Model 3 also considers permeability reduction but due to the effects of both pore pressure drawdown and coupled pore pressure-stress process. We first derive a unified stress-permeability relation that can be used for various sandstones. We then apply this equation to calculate pore pressure and permeability changes in the reservoir due to fluid extraction using the three permeability models. All the three models yield pore pressure profiles in the form of pressure funnel with different amounts of drawdown. Model 1, assuming constant permeability, obviously predicts the least amount of drawdown with pore pressure condition highest among the three models investigated. Model 2 estimates the largest amount of drawdown and lowest pore pressure condition. Model 3 shows slightly higher pore pressure condition than Model 2 because stress-pore pressure coupling process reduces the effective stress increase due to pore pressure depletion. We compare field data of production rate with the results of the three models. While models 1 and 2 respectively overestimates and underestimates the production rate, Model 3 estimates the field data fairly well. Our result affirms that coupling process between stress and pore pressure occurs during production, and that it is important to incorporate the coupling process in the permeability modeling, especially for tight reservoir having low permeability.

• Journal of Biosystems Engineering
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• 제26권3호
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• pp.245-252
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• 2001

This study was carried out to investigate the effect of three factors(dynamic load, inflation pressure and multiple passes of the tire) on the contact pressure and the soil stresses under the tire. A series of soil bin experiment was conducted with a 6.00R14 radial-ply tire for sandy loam soil. Tire contact pressure at soil surface and soil stresses at 10cm and 20cm soil depth were measured for the three levels of dynamic load(1.17kN, 2.35kN and 3.53kN), for the three levels of tire inflation pressure(103.42kPa, 206.84kPa and 413.69kPa), and for five different number of passes(1, 2, 3, 4 and 5 pass). The following results were drawn from this study 1) As dynamic load, inflation pressure and number of passes of the tire increased, tire contact pressure at soil surface and soil stresses at 10cm and 20cm soil depth increased accordingly. Thus increased in dynamic load, inflation pressure and number of passes of the tire would increase soil compaction. 2) The effect of three different factors, or dynamic load, inflation pressure and number of passes of the tire, decreased as the soil depth increase. Consequently, it was found that the soil compaction at a shallow depth in soil is larger than that at deep place in soil. 3) The increase of dynamic load and number of passes increased soil stress exponentially, but the increase of inflation pressure increased soil stress linearly. The effect of tire inflation pressure on soil stress was relatively less than that of the dynamic load. Therefore, it was concluded that dynamic load is more important factor affecting soil compaction in comparison to the inflation pressure of tire.

• 한국분말재료학회지
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• 제12권1호
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• pp.24-29
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• 2005

Nano Fe-6.5wt%Si powders have been synthesized by mechano-chemical process (MCP) for an application of soft magnetic core. Owing to hard and brittle characteristics of Fe-6.5Si nano powders having large surface area, it is very difficult to reach high density more than 70% of theoretical density (~7.4 g/$cm_3$) by cold compaction. To overcome such problem a magnetic pulsed compaction (MPC), which is one of dynamic compaction techniques, was applied. The green density was achieved about 78% (~5.8 g/$cm_3$) by MPC at room temperature.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 연약지반처리위원회 학술세미나
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• pp.1-11
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• 2000

The use of Compaction Grouting evolved in 1950's to correct structural settlement of buildings. Over the almost 50 years, the technology has been developed and is currently used in wide range of applications. Compaction Grouting, the injection of a very stiff, 'zero-slump' mortar grout under relatively high pressure, displaces and compacts soils. It can effectively repair natural or man-made soil strength deficiencies in variety of soil formations. Major applications of Compaction Grouting include densifying loose soils or fill voids caused by sinkholes, poorly compacted fills, broken utilities, improper dewatering, or soft ground tunneling excavation. Other applications include preventing liquefation, re-leveling settled structures, and using compaction grout bulbs as structural elements of minipiles or underpinning. In this paper, on the basis of the case history constructed in this year, a study has been performed to analyze the basic mechanism of the Compaction Grouting. Also, the effectiveness of the ground improvement and the bearing capacity of the Compaction Pile has been verified by the Cone Penetration Test(CPT) and Load Test. Relatively uniform Compaction grouting column could be maintained by planning the Quality Control in the course of grouting. And, the Quality Control Plan has been conceived using grout pressure, volume of grout and drilling depth.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.394-397
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• 2008

In this research, the fine-structure TiO2+Ti bulks have been fabricated by the combined application of magnetic pulsed compaction (MPC) and subsequent sintering, and their densification behavior was investigated. The obtained density of $TiO_2$+Ti bulk prepared by the combined processes was increased with increasing MPC pressure from 0.7 to 1.7 GPa. Relatively higher density (88%) in the MPCed specimen at 0.7Gpa was attributed to the decreasing of the inter-particle distance of pre-compacted component. High pressure and rapid compaction by Magnetic Pulsed Compaction could reduce shrinkage rate (about 10%) of the sintered bulks compared to that of general processing (about 20%). Mixing conditions of PVA, water, Ti and $TiO_2$ nano powder for compaction of $TiO_2$ nano powder did not affect on density and shrinkage of the sintered bulks due to high pressure of MPC.

• 한국지반공학회논문집
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• 제19권6호
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• pp.107-114
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• 2003

국내에서는 조립토를 이용한 연약지반 처리공법 중 모래다짐말뚝공법이 많이 활용되고 있으나, 모래자원의 고갈과 단가상승으로 인해 적용이 제한되고 있어 대체공법이 필요한 실정이다. 본 연구에서는 육상부 현장에 시험시공된 쇄석다짐말뚝에 대한 정재하시험을 수행하였으며, 쇄석다짐말뚝과 연약지반의 응력분담비를 규명하고 성능을 평가하였다. 임의 압력에서 치환율이 증가할수록 침하량이 작아지는 경향을 보였다. 치환율 20%일 때의 항복압력은 치환율 30%, 40%일 때 보다 작았다. 치환율 30%와 40%일 때의 항복응력과 침하량은 비슷하였다. 응력분담비는 1.7∼-3.0의 범위에 있었으며, 치환율이 증가할수록 응력분담비가 증가하는 경향을 보이고 있었다.