A study on the vehicles and construction equipments vibration characteristics of Geomunoreum lava tube system, Jeju Island

이근춘(Geun-Chun Lee),송재용(Jae-Yong Song),안웅산(Ung-San Ahn),박유철(Yu-Chul Park),조경남(Kyoung-nam Jo) 대한지질학회 2021 지질학회지 Vol.57 No.2

밀폐형과 개방형이 결합된 복합지열시스템의 지중열교환기 성능 분석

박영윤,송재용,이근춘,김기준,목종구,박유철,Park, Youngyun,Song, Jae-Yong,Lee, Geun-Chun,Kim, Ki-Joon,Mok, Jong-Koo,Park, Yu-Chul 한국지하수토양환경학회 2017 지하수토양환경 Vol.22 No.5

This study was conducted to evaluate performance of geothermal heat exchanger (GHE) in the combined well and open-closed loops geothermal (CWG) systems. The CWG systems were designed to combine open loop geothermal heat pumps and closed loop geothermal heat pumps for high energy efficiency. GHE of the CWG systems could be installed at pumping wells for agricultural usage. To get optimal heat exchange capacity of GHE of the CWG systems, 4 GHEs with various materials and apertures were tested at laboratory scale. Polyethylene (PE) and stainless steel (STS) were selected as GHE materials. The maximum heat exchange capacity of GHEs were estimated to be in the range of 33.0~104 kcal/min. The heat exchange capacity of STS GHEs was 2.4~3.2 times higher than that of PE GHE. The optimal cross section area of GHE and flow rate of circulating water of GHE were estimated to be $2,500mm^2$ and 113 L/min, respectively. For more complicated GHE of the CWG systems, it is necessary to evaluate GHEs at various scales.

제주 거문오름 용암동굴계에 영향을 미치는 발파진동특성에 대한 연구

송재용 ( Jae-yong Song ),이근춘 ( Geun-chun Lee ),안웅산 ( Ung-san Ahn ),임현묵 ( Hyun-muk Lim ),문성우 ( Seong-woo Moon ),서용석 ( Yong-seok Seo ) 대한지질공학회 2021 지질공학 Vol.31 No.1

본 연구는 제주도 거문오름동굴계 주변 지역을 개발하는 과정에서 발생되는 발파진동이 용암동굴에 미치는 영향에 대해 분석하고, 용암동굴의 효율적인 관리보존 대책을 마련하기 위해 수행되었다. 이를 위해 연구지역에서 11개의 시추공을 천공하고, 공내 지발당 장약량을 0.5 kg에서 최대 10 kg까지 변화시켜가며 현장 발파진동시험을 수행하였다. 진동속도와 진동레벨의 상관관계를 분석하여 진동규제 기준을 만족하는 진동속도를 산정한 결과, 주간 허용 진동레벨을 만족하는 진동속도는 0.276 cm/sec 이하로 평가되었다. 시험결과를 토대로 진동속도 추정식을 도출하였으며, 95% 신뢰구간에 해당하는 입지상수(k, n)에 의한 환산거리식을 통해 도출된 k 값은 자승근식에서 130.04, 삼승근식에서 199.71이며, n 값은 자승근식에서 -1.717, 삼승근식에서 -1.711인 것으로 나타났다. 진동속도 추정식을 바탕으로 진동속도에 부합하는 지발당 장약량을 평가한 결과, 일반적인 문화재 진동기준치인 진동속도 0.2 kine과 진동원과의 거리 20~100 m를 적용할 때 거리와 장약량에 따른 진동속도 추정식에서의 지발당 장약량은 0.57~7.42 kg/delay, 자승근식에서 0.21~5.29 kg/delay, 삼승근식에서 0.04~5.51 kg/delay로 나타났다. 또한, 본 연구에서 도출된 삼승근식과 선행 연구의 결과를 종합하여 0.2 kine 기준에 부합하는 상관관계식을 각각 도출하였다. 관계식을 이용하여 진동속도 0.2 kine을 만족하는 거리에 따른 허용 지발당 장약량을 산정한 결과, 50 m에서 1.07 kg/delay, 100 m에서 5.13 kg/delay, 200 m에서 22.26 kg/delay로 평가되었다. 본 연구를 통해 산출된 진동속도별 상관관계식은 거문오름용암동굴계 주변 지반의 지발당 장약량 산정 근거로 활용이 가능할 것으로 판단된다. For management and preservation measures of lava tube, it is studied how the blasting vibration by constructions near Geomunoreum lava tubes in Jeju affect lava tube. 11 boreholes were drilled in study area, and in-situ blasting tests were conducted by changing from 0.5 kg to 10 kg charge per delay in those boreholes. The vibration velocity, which meets the regulatory vibration criterion during daytime, was estimated as below 0.276 cm/sec by analyzing the relationship between vibration velocity and vibration level. In addition, SRE and CRE were calculated from the results of in-situ blasting tests, and k-values were shown as 130.04 in SRE, 199.71 in CRE, respectively. Also, n-values were shown as -1.717 in SRE, -1.711 in CRE, respectively. Charge per delay were assessed based on these equations, and charges per delay had ranges of 0.57~7.42 kg/delay in estimation equation of vibration velocity, 0.21~5.29 kg/delay in SRE, and 0.04~5.51 kg/delay in CRE, considering the 0.2 kine vibration criterion for cultural heritage and the 20~100 m distance from vibration source. Additionally, the relationships which meet the criteria of 0.2 kine, were calculated by combining CRE in this study with the result of previous study. Allowable charges per delay, which meet the criteria of 0.2 kine, were evaluated as 1.07 kg/delay in 50 m, 5.13 kg/delay in 100 m and 22.26 kg/delay in 200 m distances. These relationships for each vibration velocity are useful to deduce charge per delay for the ground near Geomunoreum lava tube.

지하수정호와 결합한 복합지열시스템의 열교환 효율에 대한 실험적 연구

송재용(Song, Jae-Yong),이근춘(Lee, Geun-Chun),박남서(Park, Namseo) 대한건축학회 2018 大韓建築學會論文集 : 構造系 Vol.34 No.5

The temperature of underground water generally remains constant regardless of the season. therefore, it is possible to get plenty of energy if we use characteristics of underground water for both cooling and heating. This study evaluates efficiency of real size coaxial and U-tube type complex geothermal system which is combined with underground water well. This study also evaluates relative efficiency/adaptability through comparison with existing geothermal systems(vertical closed loop system, open loop system(SCW)). The heat exchange capacity of complex geothermal system according to temperature difference between circulating water and underground water shows very high significance by increasing proportionally. The temperature change of underground water according to injection energy, shows very high linear growth aspect as injection thermal volume heightens. As a result of evaluation of heat exchange volume between complex geothermal system and comparative geothermal system, coaxial type has 26.1 times greater efficiency than comparative vertical closed type and 2.8 times greater efficiency than SCW type. U-tube type has 26.5 tims greater efficiency than comparative vertical closed type and 2.8 times greater than SCW type as well. This means complex geothermal system has extremely outstanding performance.

골프선수의 불안 원인과 주의집중의 관계

김성준(Kim Sung-Jun),이근춘(Lee Geun-Chun),송선희(Song Sun-Hee) 한국체육과학회 2009 한국체육과학회지 Vol.18 No.2

The purpose of this study was to verify the differences of competitive anxiety causes on sex, golf career, skill level in golf players(KPGA, semipro, university golfer, high school golfer) and to identify the style of attentional focus according to high group/low group of the anxiety causes. The participants was 125 golfers who were athletes of high school, university and semi-pro, KPGA golfers. They have answered the questionnaires about competitive anxiety causes developed by kim ki ung et al.(1986), TAIS developed by Nidiffer(1976). The results were as follows; First, there was significantly differences between male and female on competitive anxiety causes factor depends on lack of confidence. Second, there was significantly differences between career high group and career low group on competitive anxiety causes factors depends on burden on expectancy, unfamiliarity of facilities, discontent of training. Third, there was significantly differences between KPGA golfer and university golfer/high school golfer on competitive anxiety causes factors depends on fear of failure, burden on expectancy, unfamiliarity of facilities. there was differences between semi-pro golfer and high school golfer on competitive anxiety causes factor depends on trouble among round teammates. Fourth, there was significantly differences between competitive anxiety causes high group and competitive anxiety causes low group on attentional focus factors depends on lack of confidence, fear of failure, burden on expectancy, unfamiliarity of facilities, trouble among roud teammates, fear of injury, personality of player.

제주 거문오름 용암동굴계의 진동영향에 관한 실험적 연구

송재용 ( Jae-yong Song ),이근춘 ( Geun-chun Lee ),안웅산 ( Ung-san Ahn ),임현묵 ( Hyun-muk Lim ),서용석 ( Yong-seok Seo ) 대한지질공학회 2020 지질공학 Vol.30 No.3

본 연구는 제주도에서 각종 개발과정 중 발생되는 지반진동이 용암동굴에 미치는 영향에 대해 분석하고, 용암동굴의 효율적인 관리보존 대책을 마련하기 위해 수행되었다. 이를 위해 제주도 거문오름동굴계 분포지역에서 암질별 RMR과 Q-system 암반분류를 통해 지반상태를 평가하였고, 시추공 내에서 발파를 수행하여 만장굴 및 용천동굴에서 진동속도를 측정하였다. 암반분류 결과와 진동속도를 분석한 결과 암질이 좋을수록 진동의 영향이 크고, 암질이 불량할수록 진동영향이 작게 나타나는 경향을 보였으나 지반 불균질성 등의 이유로 선형관계가 뚜렷하게 나타나진 않았다. 진동시험 결과를 토대로 진동속도(PPV)와 진동레벨(dB(V))의 상관관계식을 도출하였으며, 생활진동규제기준(진동레벨 주간 65 dB(V), 야간 60 dB(V))을 만족하려면 진동속도가 주간 0.371 cm/s, 야간 0.285 cm/s인 것으로 계산된다. 야간 진동기준이 더 보수적인 값이므로 허용진동기준은 0.285 cm/s 이하로 설정될 필요가 있다. 연구지역에서의 발파진동추정식 결정을 위하여 자승근 환산거리 및 삼승근 환산거리에 대해 선형 회귀분석을 수행한 결과, 결정계수(R2)가 0.76 이상으로 나타나 양호한 신뢰성을 가지는 것으로 평가되었다. 도출된 발파진동추정식의 자승근 관계식을 적용하여 문화재 진동기준치인 0.2 cm/s를 만족하는 장약량을 산정하였고, 동굴에서 50 m 이격된 경우 2.88 kg, 100 m 이격된 경우 11.52 kg으로 계산되었다. The effects of ground vibration on lava tubes during construction were studied to aid design of management and preservation measures for lava tubes. Ground conditions were assessed by RMR (Rock mass rating) and Q-system classifications for the Geomunoreum lava tubes, and vibration velocity was measured during in situ blasting tests in the Manjanggul and Yongcheondonggul lava tubes. Results indicate that the higher the rock quality, the greater the effect of vibration, although there is no clear linear relationship due to ground heterogeneity. A relationship derived between vibration velocity (PPV) and intensity (dB(V)) on the basis of blasting tests indicates that a vibration level of < 0.285 cm/sec meets the regulatory limit of 0.371 cm/sec and 65 dB(V) during daytime, and 0.285 cm/sec and 60 dB(V) during night. For blasting vibrations, square- and cube-root scaled distances are linearly correlated, with R² ≥ 0.76. On the basis of this correlation, explosive-charge weights meeting the 0.2 cm/sec vibration criterion for cultural heritage were estimated to be 2.88 kg at 50 m distance, and 11.52 kg at 100 m.

만성요통환자의 심폐기능에 관한 비교 연구

황명훈(Hwang Myoung-Hoon),김건도(Kim Kun-Do),이근춘(Lee Geun-Chun) 한국체육과학회 2006 한국체육과학회지 Vol.15 No.1

The purpose of this study was to investigate of cardiorespiratory function on low back pain's patients. Subject were consist of low back pain patients(13), sedentary(13), athlete(13) who participated in this experiment voluntarily. The subjects in the exercise performed by arm ergometer. Statistical techniques for data analysis were One-way ANOVA and significance level was 5%. This study following result was low back pain is a problem that is common and costly to society, and its effective management remains a challenge. Therefor low back and abdominal exercise and aerobic exercise are prescribed for a injury of low back pain. Also aerobic exercise are beneficial for low back pain' patients.

8주간의 Circuit weight training 다이어트 프로그램이 비만여대생들의 신체조성에 미치는 영향

황명훈(Hwang Myoung-Hoon),김건도(Kim Kun-Do),이근춘(Lee Geun-Chun) 한국체육과학회 2006 한국체육과학회지 Vol.15 No.4

The purpose of this study was to investigate the body composition of fifteen college-age women participated who over 30% body fat ratio during 8 weeks circuit weight training. The result of body weight, body fat weight, % body fat, abdomen fat after six weeks training were decreased, there were significant differences(p<.05). Lean body mass was no significant differences. In conclusion, it can the referred that the circuit weight training are valid in the body composition of college-age women. Restricted diet should be applied more long term and various program.

취수정에서 필터층이 미치는 영향에 대한 실험적 연구

송재용 ( Jea-yong Song ),김기준 ( Ki-joon Kim ),오삼주 ( Sam-ju Oh ),이근춘 ( Geun-chun Lee ),정교철 ( Gyo-cheol Jeong ) 대한지질공학회 2016 지질공학 Vol.26 No.3

본 연구는 실내시험을 통해 필터층을 가진 충적층 지하수 정호에 대한 효율을 평가하기 위해 수행하였다. 이중필터층과 단일필터층을 모사한 시험장치를 제작하여 시험 및 분석을 수행하여 초기취수량, 취수효율, 장기적인 안정성에 대해 평가하였다. 시험결과 초기 60분 이내 취수량을 분석하면, 이중필터를 설치한 경우에는 그렇지 않은 경우보다 초기 취수량이 약 19.4% 증가하는 것으로 분석되었으며, 시험 후 24시간이 경과한 후 취수량을 분석한 결과 이중필터취수정이 단일필터 취수정에 비해 68.9% 높은 것으로 분석되었다. 또한, 시험결과를 토대로 취수량이 50% 이하로 저감되는 시점을 유추해 보면 단일필터의 경우 약 1.35일의 시간이 경과하는 것으로 분석되었으며, 이중필터의 경우 38.66일 소요되어 장기적인 안정성 면에서 이중필터를 설치하는 것이 매우 유리한 것으로 평가되었다. This study was performed in order to evaluate the efficiency of groundwater well installed in alluvial aquifer that has filter layers, using laboratory experiment. We manufactured test equipment that can simulate dual filter layer and single filter layer and evaluated the initial volume of water intake, pumping efficiency, and long term stability using the experiment and analysis. In an early stage within 60 minutes, the case that took the dual filter showed an increase of 19.4 % in the initial volume of water intake compared to the case without it. It was found that after 24 hours of the test, the well installed with the dual filter showed higher than 68.9% compared to the well with single filter. It was calculated that it took 1.35 days to reach the point corresponding to the half of the water intake in case of single filter while it took 38.66 days to do so in case of dual filter. Therefore, it is highly recommended that the well with dual filter is much more favorable in the long term stability.

플라즈마 발파를 이용한 토양 내 유체의 침투 효율 개선

백인준 ( In-joon Baek ),장현식 ( Hyun-shic Jang ),송재용 ( Jae-yong Song ),이근춘 ( Geun-chun Lee ),장보안 ( Bo-an Jang ) 대한지질공학회 2021 지질공학 Vol.31 No.3

고전압 아크 방전에 의한 플라즈마 발파의 유체 침투 효율을 검증하기 위해 실험실 규모의 토사 시료에 대하여 발파 시험을 실시하였다. 이 연구를 위해 대용량 축전기가 포함된 플라즈마 발파 장치와 직경 80 cm, 높이 60 cm 크기의 컬럼형 토사 시료를 제작하였다. 토사 시료로는 사질토와 실트를 7:3 비율로 섞은 A 시료 7개와 9:1 비율로 섞은 B 시료 3개가 제작되었다. A 시료에 플라즈마 발파 없이 수압만으로 유체를 주입했을 때는 시추공 주변으로 국소적인 침투만 발생되었고 침투면적비는 5% 이하로 분석되었다. 플라즈마 발파에 의한 유체 침투 시험은 1 kJ, 4 kJ 그리고 9 kJ의 방전 에너지로 실시되었다. A 시료에 대한 플라즈마 발파 시험에서 유체의 침투면적비는 1회만 발파하였을 때는 16~25% 이고 5회 연속 발파 시에는 30~48%로 분석되어, 수압만으로 유체를 주입했을 때보다 침투면적이 최대 9.6배까지 넓어졌다. B 시료에 대한 5회 연속 플라즈마 발파 시험에서 유체의 침투면적비는 33~59%로 분석되어 동일 조건의 A 시료 시험에 비해 침투면적이 1.1~1.4배 정도 넓어졌다. 이러한 결과는 플라즈마 발파 시에 방전 에너지가 클수록, 발파 횟수가 증가할 수록 유체의 침투면적이 증가하며, 투수성이 큰 토양에서 플라즈마 발파가 더욱 효과적임을 보여준다. 유체 침투 효과를 삼차원적인 부피로 분석하기 위해 유체 침투반경을 계산하였다. 수압으로만 유체를 주입했을 때의 침투반경은 9 cm인 반면에, 9 kJ의 에너지로 5회 발파 시에는 침투반경이 27~30 cm로 계산되어 유체 침투 효과가 최대 333%까지 증가되었다. 이러한 연구결과는 투수성이 낮은 실제 오염토양에서 원위치 토양 세정을 실시할 때 플라즈마 발파 기술을 적용하면, 세정제의 전달범위가 증가되어 정화효율이 개선될 수 있다는 것을 보여준다. Plasma blasting by high voltage arc discharge were performed in laboratory-scale soil samples to investigate the fluid penetration efficiency. A plasma blasting device with a large-capacity capacitor and columnar soil samples with a diameter of 80 cm and a height of 60 cm were prepared. Columnar soil samples consist of seven A-samples mixed with sand and silt by ratio of 7:3 and three B-samples by ratio of 9:1. When fluid was injected into A-sample by pressure without plasma blasting, fluid penetrated into soil only near around the borehole, and penetration area ratio was less than 5%. Fluid was injected by plasma blasting with three different discharge energies of 1 kJ, 4 kJ and 9 kJ. When plasma blasting was performed once in the A-samples, penetration area ratios of the fluid were 16-25%. Penetration area ratios were 30-48% when blastings were executed five times consecutively. The largest penetration area by plasma blasting was 9.6 times larger than that by fluid injection by pressure. This indicates that the higher discharge energy of plasma blasting and the more numbers of blasting are, the larger are fluid penetration areas. When five consecutive plasma blasting were carried out in B-sample, fluid penetration area ratios were 33-59%. Penetration areas into B-samples were 1.1-1.4 times larger than those in A-samples when test conditions were the same, indicating that the higher permeability of soil is, the larger is fluid penetration area. The fluid penetration radius was calculated to figure out fluid penetration volume. When the fluid was injected by pressure, the penetration radius was 9 cm. Whereas, the penetration radius was 27-30 cm when blasting were performed 5 times with energy of 9 kJ. The radius increased up to 333% by plasma blasting. All these results indicate that cleaning agent penetrates further and remediation efficiency of contaminated soil will be improved if plasma blasting technology is applied to in situ cleaning of contaminated soil with low permeability.