• 한국도로학회:학술대회논문집
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• 2008.10a
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• pp.265-268
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• 2008

• Journal of the Korean Geotechnical Society
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• v.17 no.5
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• pp.107-114
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• 2001

비검측공 시험법을 현장타설말뚝의 건전도 평가 목적으로 적용함에 있어서 시험법의 적용성을 향상시키기 위한 연구가 진행되어 오고 있다. 본 논문에서는 같은 맥락에서 수행되어 온 일련의 해석적 연구 결과 중 시험법의 해상도에 관한 문제와 말뚝 주변 및 선단지반의 강성이 비검측공 시험결과에 미치는 영향에 관해 다루었다. 본 논문에서 수행한 연구결과에 의하면 충격응답기법의 해상도를 평가하기 위해서는 말뚝재료에 대한 지반의 강성비($V_{s}$ /$V_{c}$)와 말뚝의 길이에 대한 직경의 비(L/D)에 의존하는 기존 평가기준에 부가하여 말뚝의 상대적인 체적변화가 필히 고려되어야 한다는 결론을 얻었다. 한편, 말뚝이 수평으로 층이 진 주변 지반을 통과하여 말뚝선단부를 지지하는 지반(선단지반)에 근입되거나 지지되는 경우에 말뚝의 자유단 혹은 고정단 경계 조건은 주변 지반과 선단 지반의 강성비와 선단 지반에 대한 말뚝의 근입깊이에 따라 변화한다는 사실을 규명하였다. 말뚝의 건전도 평가 시에 사용하게 되는 말뚝의 공진주파수가 이들 조건에 따라 변화하므로 결과적으로 시험결과분석에 있어서 이들 영향이 필히 고려되어야 한다는 결론을 얻었다.

• Journal of the Korean Geotechnical Society
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• v.17 no.4
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• pp.331-339
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• 2001

인산석고(phosphogypsum)는 비료생산과정에서 발생되는 산업부산물로, 주요구성성분은 이수석고(CaSO$_4$.2$H_2O$)의 성분이 대부분이고 여기에 인(P$_2$O$_2$), 철(F)와 유기물질 등으로 이루어져 있다. 전 세계적으로 인산석고 발생량은 현재 1억8천만톤이고 향후 약 3억8천만톤 발생될 것으로 추정되며, 국내에는 약 157만톤이 발생되고 있다. 본 연구는 성토재료로 인산석고를 활용할 경우 이에 대한 물리적 환경적 특성을 분석하였다. 이를 위하여 인산석고와 화강토 혼합비율에 따른 입도분석, 비중시험, 다짐시험, CBR시험, pH시험 및 용출시험 등 일련의 실험을 실시하였다. 실험결과, 인산석고 혼합재료를 성토재료로 활용할 경우 환경적으로 유해한 영향이 적으며, 산업부산물의 자원화 차원에서 대체 성토재료로 활용이 가능한 것으로 나타났다.

• Journal of the Korean GEO-environmental Society
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• v.9 no.2
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• pp.15-22
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• 2008

Recently loess are used as design and construction materials in some construction sites. However, many problems have come to the fore because the loess was considered merely as ordinary soil, not taking the engineering characteristics of loess into account at all. The purpose of this study is to effectively mix and use the oyster shell-which is the byproduct of oyster farming in the clean and pure water zone of Southwestern region-with loess in a bid to increase the utility, considering that loess itself has the limit for civil engineering purpose, and research the usability of oyster shell as an alternative material for construction.

• Journal of the Korean GEO-environmental Society
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• v.3 no.4
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• pp.67-79
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• 2002

The purpose of this study is to present criteria of selection of optimum grout materials through analyzing the limitation of permeability of each materials(MSG-N, OPC), in various ground conditions by comparing presentation of strength and permeability of MSG method and LW method(or SGR method). To do that, physical and chemical characteristics of grout materials were analyzed and compressive tests of homogel, mixed coagulation materials and hardening materials in certain mixing ratio, and of milk paste. In addition, permeability tests for each ground soil, each injection pressure, and each materials in combined stratum were performed with massive chamber. The results of tests showed that ultra fine grout materials like grout of MSG is necessary to construct effective grouting in sand and silty sand ground. Also, it is expected to become chemical grouting guide data to layout construction engineers because presented proper injection pressure by kind of object ground in case using ultra-fine grout material.

• Journal of the Korean GEO-environmental Society
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• v.13 no.6
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• pp.41-50
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• 2012

In general, it is critical that grout consistency permit the complete filling of void space without segregation of ingredients. Recently, the antiwashout agent is used on underwater grout materials for preventing the grout from the segregation in water. This study introduces a new type of antiwashout underwater and flowable grout material using viscous modifiers and its characteristics comparing with conventional grout materials in fresh and sea water. It is found that the antiwashout underwater grout both in fresh and sea water has enough strength and good resistance to segregation.

• Journal of the Korean Geosynthetics Society
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• v.17 no.1
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• pp.55-64
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• 2018

The purpose of this study is to evaluate the suitability of emergency underground cavity restoration method filling cavity with expansive material based on numerical analysis. For the numerical analysis, experiments were conducted to evaluate properties of expansive material. Based on the measured expansion pressure of the expansive material from the experiment, behavior of underground cavity restoration with various cavity dimensions (variation of height and width of rectangular-shape cavity) was numerically assessed. As a result of analysis, the vertical displacements of the top and bottom of cavity were significantly influenced by the cavity width and lateral displacements of cavity sides were highly dependent on cavity height. These vertical and lateral displacements were increased with increasing expansion pressure of expansive material. Also, when the expansion pressure was applied, the vertical displacement of the upper surface layer of the road was less dependent on cavity height, and was greatly influenced by cavity width.

• Journal of the Korean GEO-environmental Society
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• v.14 no.10
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• pp.29-37
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• 2013

In this study, we constructed the test embankment with four kinds of sections(2 kinds of bottom ash; tire shred-bottom ash mixture, weathered soil) in field and had been monitoring the behaviour of the test embankment and change of ground water quality for 1 year. In the geotechnical aspects, there was no relative difference of deformation in 4 test materials section and we could not see the possibility of the strength-reduction of coal ash materials by freezing inside of the embankment. In addition, no settlement was observed in the test sections because the base soil of the test sections was rigid enough that no consolidation was occurred. In the examination of water quality, all of the heavy metals and negative ions were detected below the drinking water standards except for sulfate($SO_4^{2-}$). In the beginning of measurement, higher concentrations of sulfate from 4 test sections were detected than drinking water standard for 20 days after beginning of the test but the concentrations decreased below the drinking water standard after 50 days after the tests.

• Explosives and Blasting
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• v.40 no.2
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• pp.1-14
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• 2022

Numerical simulation is the most widely used methods for evaluating blasting performance. This study, conducted the numerical analysis of shock chamber model to evaluate the pressure confine effect of the stemming material and plug device. The stemming effect was compared and evaluated with that of the STF-based stemming material currently under development and sand, which is a commonly used blast stemming material. Furthermore, to verify of enhancement the confine effect inside blast hole pressure, three types of stemming plugs were adopted for the numerical analysis. The numerical simulation results revealed that the STF-based stemming materials were superior to the general stemming material. Also, It is evaluated that the STF-based stemming and Plug system can not only prevent detonation gas from overflowing the borehole prematurely, but also prolong the action time and scope of detonation gas in the borehole effective.

• Journal of the Korean Geosynthetics Society
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• v.13 no.2
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• pp.11-20
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• 2014

To create a large-scale complex, it is often the case to perform ground improvement by using vertical drain method after the reclamation of coastal soft ground, for construction period shortening and stable site renovation. During this process, the pore water migrates to the horizontal drainage layer of the ground surface through the vertical drain installed in the soft ground and discharged out to the open. In the past sand was used as the material for the horizontal drainage layer in numerous cases, however recently, due to material shortage and high pricing, the use of crushed stones has increased. To prevent mixing of the materials between the horizontal drainage layer and the upper landfill, geosynthetics (PPMat) are installed. However, the use of geosynthetics results in high additional cost for material purchase and installation, therefore it is necessary to examine the validity of the installation itself. In this study, to verify the necessity, model tests were performed. Results from the model tests indicate that the drainage ability of the horizontal drainage layer is barely affected by the application of geosynthetics.