• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.443-446
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• 2004

이동장수 먹는샘물 공장부지내에 파쇄대에 위치한 관정에서 인공수압파쇄 및 인공함양 시험을 실시하여 대수성 산출 증대효과와 저장 증대효과를 살펴보았다. 인공수압파쇄 시험은 두개의 관정(MW-2, O-7)에 실시하였고, 마찬가지로 인공함양 시험도 다른 두개의 관정(O-7a, MW-7)에 대해서 실시하였다. 또한 대수성 산출능의 효과를 살펴보기 위하여 인공수압파쇄 및 인공함양시험 전후에 각각 양수 시험을 실시하여 비양수량, 투수계수, 및 수위강하를 구하였다. 따라서 사전 사후 대수성 시험 비교 결과 인공수압파쇄 시험에서는 평균적으로 약 367 %의 투수계수의 증가율과 271 %의 비양수량의 증가를 나타내었다. 마찬가지로 인공함양 시험 결과 O-7a는 약 110%의 투수계수의 증가와 약 75%의 비양수량의 증가를 보였다. 반면에 MW-7는 거의 변화가 없었다. 인공함양시험은 인공수압파쇄시험보다 낮은 투수계수 증가율을 보이거나 거의 변화를 일으키지 못했지만 주변에 있는 관정에 주입압과 비슷한 양상를 갖는 수위변화를 일으키는 것으로 보아서 함양된 주입수가 주변의 대수층에 널리 퍼져 있을 것으로 추측된다.

• 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.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.267-268
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• 2013

본 논문에서는 아날로그 필터회로의 신호 증폭비에 따른 센서리스 각추정 성능에 대해 분석 하였다. 신호 주입 센서리스에서 높은 주파수 신호 주입 방법이 선호되는데, 주입 주파수가 커질수록 시스템 임피던스가 증가한다. 따라서 낮은 주파수 주입방법과 동일한 각추정 성능을 얻기 위해서는 상대적으로 큰 주입전압이 필요하다. 특히 전동기의 돌극성이 작거나 ADC의 정밀도가 낮으면 각추정이 불가능한 경우도 존재 한다. 하지만 아날로그 필터회로를 이용하여 주입 주파수 신호를 증폭할 경우 작은 크기의 전압주입으로 각추정이 가능하다. 아날로그 대역통과필터의 신호 증폭비에 따른 최대 각에러 값을 모의 실험을 통해 비교하고, 실제 회로를 설계하여 센서리스 각추정 성능을 시험평가 하였다.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.115-127
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• 2019

The low-flow grouting injection technique, the target construction method for this study, is a method of pouring mortar into the ground by non-emission replacement principle, which can be expected to increase the density of the ground, and, in some cases, be used as a base file using the strength of the high injection solids, along with low noise, low pollution, and high durability. To verify that the dynamic characteristics of the ground are improved by the low-flow injection technique, the test work was conducted on the site and physical tests were performed, and the quality of the improvement formed in the ground was verified through the indoor test on the core and core recovery rate was analyzed. The density logs test layer calculated the volume density of the ground layer by using the Compton scattering of gamma-rays, and the sonic logs was tested on the ground around the drill hole using a detector consisting of sonar and receiver devices inside the drill hole. As a result of the measurement of the change in physical properties (density and sonic logs) before and after grouting, both properties were basically increased after infusion of grout agent. However, the variation in density increase was greater than the increase in speed after grouting, and the ground density measurement method was thought to be effective in measuring the fill effect of the filler. Strength and core recovery rates were measured from specimens taken after the age of 28 days, and the results of the test results of the diffusion and strength test of the improved products were verified to satisfy the design criteria, thereby satisfying the seismic performance reinforcement.

• Journal of the Korean GEO-environmental Society
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• v.9 no.2
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• pp.61-65
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• 2008

In this study, a newly modified soil nailing technology named as the PGSN (Pressurized Grouting Soil Nailing) system is proposed. Effects of various factors related to the design of the pressurized grouting soil nailing system, such as the length of re-bars and type of reinforcement materials, were examined throughout a series of the displacement-controlled field pull-out tests. 9 displacement-controlled field pull-out tests were performed and the ratio of injected grout volume to grout hole volume were also evaluated based on the measurements. In addition, short-term characteristics of pull-out deformations of the newly proposed PGSN system were analyzed and compared with those of the ordinary soil nailing system by carrying out field pull-out tests. The test results were shown that the displacements of pressurized grouting soil nailing system were decreased 30~36% in comparison with using gravity grouting soil nailing system by the pressurized effect. The displacements of steel tube were diminished 31~32% comparison with using deformed bar by the reinforcement type change from the field pull-out tests.

• Journal of Acupuncture Research
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• v.24 no.2
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• pp.39-49
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• 2007

목적 : 봉독으로 유발된 통각수용의 강도와 봉독으로 나타나는 항통각수용(통각억제성)의 강도를 쥐의 포르말린 테스트를 통해 상호관련됨을 확인하고 capsaicin과 bradykinin으로 통증 유발된 쥐의 자발적인 통증행동(핥기횟수측정; LN), 꼬리경타시험(TFL)과 열판시험(HPL)을 통해 봉독의 항통각수용(통각억제)작용을 재확인 하고자 하였다. 방법 : 쥐의 뒷다리에 통증유도 물질인 Capsaicin 또는 Bradykinin을 20${\mu}l$를 주사하여 동통을 유발하고 자발적 통증행동인 핥기횟수측정(LN), 꼬리경타기간(TFL)과 열판 위에서의 온도자극에 쥐가 반응하는 시간을 측정(HPL)하는 실험을 봉독을 주입하거나, 몰핀을 주입하거나, 아무것도 주입하지 않고 통증유발만 시킨 이후에 각각 시행하였다. 결과: 1. Capsaicin 또는 Bradykinin으로 동통유발 후 LN은 두드러증가를 보임, HPL은 감소를 TFL은 두드러진 감소를 나타내었다. 2. 봉독이나 몰핀 주입 30분 후에 Capsaicin으로 동통유발 이후 LN은 봉독과 몰핀에서 모두 현격한 감소를, HPL은 봉침은 현격한 증가를, 몰핀에서는 감소를, TFL은 봉침과 몰핀에서 모두 현격한 증가를 나타내었다. 3 봉독과 몰핀주입 30분후에 Bradykinin으로 동통유발 이후 LN은 봉독은 증가 몰핀은 현격한 감소를, HPL은 봉침은 증가 몰핀에서는 현격한 증가를, TFL은 봉침과 볼핀에서 모두 증가를 나타내었다. 결론 : 봉독은 Capsaicin 또는 Bradykinin으로 동통유발된 통각수용행동을 감소시키는 결과를 나타내었는데 이것은 기존의 연구결과들에서의 봉독의 항통각수용(통각억제성)의 효과를 입증하였고 봉약침은 염증의 개선이나 암과 관련된 동통에 유효한 방법임을 시사하는 것이다.

• Journal of the Korean GEO-environmental Society
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• v.23 no.9
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• pp.5-16
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• 2022

In recent years due to the development of urban and underground space, the number of ground disasters is increasing, and it is also leading to social problems. To solve the problem, a grouting method is generally used. However, the grouting method has material (grout) limitations in permeability, gelation properties and tensile resistance. Therefore, research on grout materials mixed with fibers is actively carried out to improve the problems. However, in the actual ground injection process, many difficulties have been faced causing the blockage of the inlet port and the injection tube. In this study, 'CNT-mixed grout material' was developed using CNT powder that can reinforce the tensile strength of soils. The uniaxial compressive and tensile strength tests were performed to obtain the optimal content and mechanical properties of the CNT Powder-mixed grout. It was found that the optimal CNT powder content is 0.5% that gives the average maximum strength. A one-dimensional injection test and the bulb formation test were carried out, and it was identified that the injection rate and bulb form could be controlled by pressure and mixing ratio. Field application of the CNT-Mixed grout is simulated using numerical analysis of slopes, foundations, and tunnels reinforced in several types. The positive effect of reducing plastic ranges and settlements was confirmed.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.185-191
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• 2016

The Hybrid Safety Injection Tank is a passive safety injection system that enables the safety injection water to be injected into the reactor pressure vessel throughout all operating pressures by connecting the top of the SIT and the pressurizer(PZR). In this study, the condition for balancing the pressure between the Hybrid SIT and PZR was derived theoretically. The pressure balancing condition was set at the point where the velocity of the Hybrid SIT coolant injected into the Direct Vessel Injection(DVI) line was at or above zero. If the condition was derived from a pressure network for the Hybrid SIT, pressurizer, and reactor pressure vessel, the pressure difference between the pressurizer and SIT is less than 0.07 MPa.

• Journal of the Korean Geosynthetics Society
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• v.12 no.4
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• pp.99-107
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• 2013

In order to investigation Lateral bearing capacity of bored-precast pile, we carried out the analysis of the relationship between Lateral load and horizontal displacement using the result of horizontal pile load test. The six piles injected cement milk of 50%, 70% and 100% of the embedded length of pile were used in the horizontal pile load test. The horizontal displacement, yielding load and horizontal bearing capacity are mainly affected by The injecting ratio of cement milk (injected length of cement milk/embedded length of pile). As the injecting ratio of cement milt is increased, the starting point of horizontal displacement in piles become close to the ground surface and the amount of horizontal displacement is decreased. Also, the horizontal bearing capacity and yielding load are highly increased with increasing the ration of cement milk. The horizontal bearing capacity and yielding load of bored pile with 1 of cement milk ratio are about two or three times those of pile with 0.5 of cement milk ratio.

• Journal of the Korean Geotechnical Society
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• v.27 no.6
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• pp.27-37
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• 2011

Recently, pressure grouting is widely being used in construction site for strength improvement of ground and water proof, reinforcement and so on. It is necessarily required to estimate an appropriate injection pressure and injection time for economical and reasonable construction in the site through the size and shape of the hardened grout measured according to ground condition. However, sampling for the hardened grout is time-consuming and needs high cost on preliminary test in the site. The system which could predict the size and shape of the hardened grout does not exist until now. Thus, numerical method based on VOF method and porous model was used for the calibration chamber injection test with injection pressure (50 kPa, 100 kPa, 150 kPa) in this study. The results indicate that the numerical technique based on VOF method and porous model among CFD analysis is expected to be a basic study for the prediction of the behavior and solidification of pressure grouting.