• 한국재난정보학회 논문집
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• 제18권4호
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• pp.769-777
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• 2022

연구목적: 본 연구에서는 제주 지역 지반의 특성을 분석하여 연구함으로써 향후 개발사업 진행시 공법설계등의 기초자료로 활용한다. 연구방법: 제주 지역에서 진행된 공사의 지반조사 데이터를 기반으로 심도, 상대밀도, N치, 함수상태, 색조, 지하수위, 압축강도를 분석하고 연구하였다. 연구결과: 본 연구로 부터 제주지역이 고대부터 진행된 화산활동과 인근의 해수에 의한 급속한 냉각으로 이루어진 주상절리와 해안부에서 두텁게 발견된 모래층, 그리고 수성화산활동에 의해 형성된 클링커층 및 서귀포층이 존재함을 알 수 있었다. 결론: 제주지역의 특수한 지반 형태를 이해하고 공사 설계시 그 특성을 잘 반영하여 기초 설계 및 기초 공법 선정의 자료로 쓰여지길 기대한다.

• 대한토목학회논문집
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• 제39권3호
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• pp.419-429
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• 2019

시험발파를 통해 제주 남부지역(현무암과 클링커 층상구조 지반)의 지반진동 특성을 분석하였다. 지반진동의 주요 성분을 파악하고 지반진동추정식을 도출함으로써 제주 남부지역의 지반진동의 전파 특성을 국내 설계지침과 비교하였다. 층상구조 지반에서의 지반진동은 근거리에서는 진동의 크기가 작으나 원거리로 갈수록 지반진동의 감쇠가 적어 진동에너지를 멀리까지 전달하는 것으로 나타났다. 그리고 주파수는 저주파수 대역으로 확인되었다. 이는 공극이 큰 클링커층이 고주파의 발파에너지 탄성파를 파형의 주기가 긴 저주파 형태로 바꿔 전달하기 때문으로 판단된다. 또한, 기반암이 다른 지역과의 지반진동을 비교하여 설계지침의 한계를 확인함으로써, 지역 특성이 반영된 설계 지반진동추정식 개발의 필요성을 제시하였다.

• 한국환경과학회지
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• 제27권8호
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• pp.677-688
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• 2018

The purpose of this study was to minimize salt water intrusion into freshwater aquifers and limit the development of freshwater aquifers, by selecting an appropriate excavation depth of in the western coastal area of Jeju Island. The study site was mostly basaltic lava, which was mainly composed of trachy basalt. A vertical logging test was conducted to investigate the vertical distribution of the groundwater and saline groundwater interface in the study well. It was found that freshwater groundwater, saline groundwater, and freshwater groundwater are distributed from the surface to approximately 16 m, 16~50 m, and 50~60 m, below the ground, respectively. In order obtain saline groundwater and minimize the inflow of freshwater into this well, the drilling depth should be limited in the range of 16~50 m from the surface. Thus, saline groundwater well development should be carried out with reference to the measurement results, which depend on the drilling depth and EC (electrical conductivity) obtained with drilling apparatus for geology and ground handling.

• 지질공학
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• 제31권2호
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• pp.199-209
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• 2021

본 논문은 SOC시설물 건설에 따른 지반 안정성을 평가한 논문으로, 기존 지반 및 숨골 조사결과에 따른 지반 물성치를 이용하여 SOC시설물 하부지반의 안정성을 평가한 것이다. 연구내용은 다음과 같다. 1) 기존 지반조사 자료를 기반으로 지반현황을 분석하여 숨골 및 지반 물성치를 산정하였다. 2) 수치해석을 통한 지반의 안정성 및 변형 범위를 파악하였다. 3) 지반안정성 해석단면(대형장비 주행로) 결정한 후 단면에 대한 모델링을 하여, 지반 안정성을 평가하였다. 본 연구는 SOC시설물 전체 부지를 크게 3개의 단면으로 나누어 해석하였으며, SOC시설물 하부지반의 각 단면별 지반, 하중조건 및 포장조건을 파악하여 컴퓨터 수치해석 모델링을 통해 응력, 침하량, 변형률을 산정하였다. 현 지반 조건에 따른 각 단면별 해석결과, 침하량은 0.11~0.18 m, 전응력은 92.75~445 kPa로 해석되었다. 이 결과들은 하부지반의 숨골을 고려하여 지반의 강도 정수를 감소시켰을 뿐 아니라, 하부지반의 보강이 없는 조건으로 해석한 결과이므로, 적절한 하부지반의 조건을 고려하여 약액주입 등의 간단한 지반 보강만으로 충분한 SOC시설물 지반 안정성을 확보할 수 있다.

• 한국지반신소재학회논문집
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• 제22권2호
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• pp.55-61
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• 2023

본 연구에서는 제주 지역의 대표적인 지반 특성(클링커층)을 고려한 흙막이벽의 측방토압 적용을 고찰하기 위해 2개의 현장 사례를 이용하여 수평변위에 대한 계측값과 예측값을 비교하였다. 흙막이벽의 수평변위 발생에 기인하는 측방토압 예측은 Rankine 토압, Terzaghi & Peck 수정측방토압, Tschebotarioff 측방토압을 이용하여 탄소성해석을 실시하였다. 그 결과, A현장에서 예측된 최대 수평변위는 계측값에 비하여 약 5배가 큰 것으로 확인되었으며, 예측에 의한 최대 수평변위 발생 지반은 클링커층으로 나타났다. 그리고 B현장의 경우에는 예측값이 계측값에 비하여 4배에서 최대 7배까지 크게 나타났으며, 최대 수평변위가 발생한 지반과 수평변위 발생 경향은 예측 방법에 따라 매우 다른 경향을 보였다. 이는 암반층과 클링커층이 교호되어 분포되는 제주 지역의 다층지반 특성에 기인한 것이라 판단되기 때문에, 지역 특성을 고려할 수 있는 측방토압에 관한 연구가 지속될 필요가 있음을 의미한다.

• 수산해양기술연구
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• 제54권2호
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• pp.157-163
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• 2018

In the area around Jeju Island, the squid jigging fishery and the hair-tail angling are popular. Therefore, the study on the characteristics of the formation and shift of fishing grounds is very important. We have received and analyzed AIS data of all vessels around Jeju Island from October 16, 2016 to October 16, 2017, and extracted the positions of the fishing vessels with the same operational characteristics as the fishing vessels of their fisheries. The distribution chart of the frequency of fishing vessels appearing in each predefined fishing grid ($1NM{\times}1NM$) was analyzed. So we took a analogy with the monthly shift of fishing grounds. Many fishing vessels appeared in the seas around Jeju Island from November 2016 to January 2017, and the frequency of their appearance was maintained. In November, however, fishing vessels were mostly concentrated in coastal waters. Yet, the density gradually weakened as they moved into January. From February, the frequency itself began to decline, making it the worst in April. The high concentration of fishing vessels in the waters leading from Jeju Island's northwest coast to south coast in November is believed to be related to the yellowtail fishery that are formed annually in the coastal waters off the island of Marado. In May 2017, the appearance frequency of fishing vessels increased and began to show a concentration in coastal waters around Jeju Island. Fishing vessels began to flock in waters northwest of Jeju Island beginning in July and peaked in August, and by September, fishing vessels were moving south along the coast of Jeju Island, weakening the density and spreading out. Between July and August, fishing vessels were concentrated in waters surrounding Jeju Island, which is believed to be related to the operations of fishing vessels for the squid jigging fishery and the hair-tail angling.

• 한국운동역학회지
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• 제24권1호
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• pp.43-50
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• 2014

The purpose of this study was to analyze of the GRF (ground reaction force) parameters according to the change of positions and weights of bag during downward stairs between dominant and non-dominant in upper & lower limbs. To perform this study, participants were selected 9 healthy women (age: $21.40{\pm}0.94yrs$, height: $166.50{\pm}2.68cm$, body mass: $57.00{\pm}3.61kg$, BMI: $20.53{\pm}1.03kg/m^2$), divided into 2 carrying bag positions (dominant arm/R, non-dominant arm/L) and walked with 3 type of bag weights (0, 3, 5 kg) respectively. One force-plate was used to collect GRF (AMTI OR6-7) data at a sample rate of 1000 Hz. The variables analyzed were consisted of the medial-lateral GRF (Fx), anterior-posterior GRF (Fy), vertical GRF (Fz), impact loading rate and center of pressure (COPx, COPy, COP area, COPy posterior peak time) during downward stairs. 1) The Fx, Fy, Fz, COPx, and COP area of GRF were not statistically significant between dominant leg and non-dominant leg, but non-dominant leg, that is, showed the higher COPy, and showed higher impact loading rate than that dominant leg during downward stairs. 2) In bag wearing to non-dominant arm, Fx, Fz, COPx, COPy, impact loading rate and COP area showed increase tendency according to increase of bag weights. Also, against bag wearing to dominant arm, non-dominant showed different mechanism according to increase of bag weights. The Ground Reaction Force parameters showed different characteristics according to the positions and weights of bag during downward stairs between dominant and non-dominant arm.

• 수산해양기술연구
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• 제55권2호
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• pp.138-144
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• 2019

The purpose of this paper is to explore the fishing grounds of trawl fishery, which are operating in the waters around Jeju Island, and to investigate the monthly shifting changes of the explored fishing grounds. Information on AIS of fishing vessels operating near Jeju Island was collected and analyzed from October 16, 2016 to October 16, 2017. Thus, the location of fishing vessels with the same operational characteristics as those in this industry was extracted and displayed on Google Maps' location drawings to analyze the dense distribution of fishing vessels according to the frequency of their appearance. In the distribution of fishing vessels that appeared in October, a wide range of fishing grounds connecting the upper and lower waters of the 221 and 222 sea of fishing area was found to have gradually expanded and increased density, showing the widest range and highest density in December, and then gradually decreasing from January 2017 to near extinction in May. The distribution of fishing vessels that appeared in the left and lower waters of the 243 sea estuary increased not only in November and December, but also in the appearing sea areas gradually moved to the 242 sea and the range of their appearance was extended to the 241 sea. In other words, the highly dense fishing area in December indirectly shows that it is winter fishing grounds for these industries. The distribution of these dense fishing vessels gradually moved north and west with each passing day, reducing their density and reaching a near extinction in August. However, in September, the density was gradually restored again. Fishing vessels that appeared in high density in the northern waters of the 224 sea east of the Yeoseo island in December were thought to be fishing vessels, whose density decreased over time, almost disappeared in May, and reappeared in July and August, showing a certain degree of density, and then decreased again.

• 한국지반공학회논문집
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• 제23권6호
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• pp.103-114
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• 2007

제주도 해안지역에 분포하고 있는 모래는 화산암류가 풍화되어 형성된 모래와 조개 등의 어패류가 풍화되어 탄산염 $(CaCO_3)$ 함유량이 많은 모래, 그리고 이들 두 가지 특징이 혼재한 모래로 분류할 수 있었다. 분류된 모래들 중 삼양, 김녕, 제주외항 지역의 모래에 압축 특성을 알고자 압축시험을 수행한 결과, 삼양인 경우 초기압축이 다른 모래에 비해 큰 것으로 나타났으며 김녕, 제주외항 모래인 경우 초기압축외의 추가적인 압축도 상당히 발생하였으며, 이는 압축시험 전·후의 모래의 입도분포 분석 결과 입자의 파쇄와 재배열에 의한 것으로 나타났다. 또한 현재 제주외항 항만시설 축조공사에 따른 지반의 침하특성을 분석한 결과 초기 압축 외에도 모래의 파쇄성과 재배열에 의해 상당시간동안 압축이 일어난 것을 알 수 있으며, 파쇄성과 재배열이 고려되지 않은 기존 탄성침하량 산정법을 이용한 침하량과 기존의 침하시간 산정 시 과소평가 될 우려가 있는 것으로 나타났다.

• 한국수산과학회지
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• 제47권1호
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• pp.59-61
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• 2014

We conducted eight surveys in the northern East China Sea (ECS) in winter (February - April), summer (July), and autumn (October) 2004-2009, to investigate the seasonal distribution of T. pacificus. A total of 482 paralarvae, ranging in mantle length (ML) from 1.0 - 17.0 mm, were collected at 73 out of 181 stations. There were higher numbers of paralarvae during the winter and summer months than in the autumn. There was significant seasonal variation in the paralarval mantle lengths; mantle lengths were longer in winter (April) than in summer (July). The position of oceanic fronts in the study area played an important role in restricting paralarval distribution along the inshore edge of the Tsushima Warm Current (TWC). When the TWC expanded to western Jeju Island in winter and autumn, the paralarval distribution range extended to include western Jeju Island. However, when the TWC was located southeast of Jeju Island in the summer, paralarvae were distributed along the frontal zone off southeast Jeju Island. Sites at which paralarval mantle length was <2.0 mm ML indicated that the spawning ground were likely to be within the northern ECS in winter and summer, but north of the study area in autumn.