• Title/Summary/Keyword: On-site investigation

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Investigation Study on Underground Cavity Scale Estimation Based on GPR Exploration (지하공동 규모 평가를 위한 GPR 탐사 기반의 조사 연구)

  • Byoung-Jo Yoon;Han-Joo Lim;Yeon-Gyu Kim
    • Journal of the Society of Disaster Information
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    • v.19 no.3
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    • pp.737-746
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    • 2023
  • Purpose: Ground subsidence due to cavity can bring about various problems, such as casualties, decrease of the safety of the structures, and indirect social costs. Therefore, ground subsidence should be prevented through the exploration and recovery of the cavity under the pavements. Method: In this study, GPR exploration method was carried out on both actual roadway and mock-up site to compensate for the problems caused by excavation and restoration process. Result: This study compared the cavity scales obtained from GPR exploration results and the direct excavation of the identified cavity. It was confirmed that the predicted soil depth by GPR exploration was similar to the identified soil depth, but the predicted cavity scale by GPR exploration overestimated the longitudinal and cross-sectional widths compared to the identified cavity scale. Conclusion: Based on the correlation between the predicted cavity scales by GPR exploration, it is possible to qualitatively estimate the cavity scales using the empirical formula proposed in this study.

Analysis on the Rainfall Driven Slope Failure Adjacent to a Railway : Flume Tests (강우로 인한 철도 연변사면의 활동분석 : 실내모형실험)

  • SaGong Myung;Kim Min-Seok;Kim Soo-Sam;Lee In-Yong
    • Journal of the Korean Geotechnical Society
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    • v.22 no.5
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    • pp.83-91
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    • 2006
  • Recently, the intensive rainstorm possibly induced by global warming plays a key role on the instability of railway adjacent slopes. The instability of slopes results as covering and loss of railway lines induced by slided soil mass. According to the site investigation on the failed slopes triggered by rainfall, low types of slope failure were observed: shallow, intermediate, gully erosion, and soil-rock interface failures. The observation reveals the different characteristics of slope failure depending on the thickness of soil layer, morphological features of slope, etc. Based upon the observations, flume tests were conducted to analyze the sliding mechanism of each failure. The variables of flume test are soil layer thickness, rainfall intensity, and morphology of slope under the constant condition of the percentage of fine, initial soil moisture content, slope angle and compaction energy. Test results show that shallow failure was mostly observed from the surface of the slope and caused by the soil erosion; in addition, compared to the other types of failure, the occurrence of initial erosion is late, however, the development of erosion is fast. In gully erosion failure, the collected water from the water catchment area helps erosion of the upper soil layer and transfer of residual corestone, which impedes the erosion process once the upper soil layers are eroded and corestone are exposed. The soil-rock interface failure shows the most fast initial erosion process among the failure types. Interestingly, the common feature observed from the different types of failure was the occurrence of the initial deformation near the toe of slopes which implies the existence of surbsurface flow along the downslope direction.

Overcoming Ethical Conflicts and Dilemmas in Farm Animal Welfare: Investigation of Correlation between Ethical Awareness Level and Compliance with Animal Welfare-Related Regulations in Korean Layer Farms (축산농장 동물복지의 윤리적 갈등과 딜레마 극복: 국내 산란계 농장에서의 윤리의식 수준에 따른 동물복지 관련법규 준수여부 상관관계 조사)

  • Bonn Lee;Taesik Kim;Soo-Won Choi
    • Korean Journal of Poultry Science
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    • v.50 no.2
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    • pp.81-90
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    • 2023
  • Animal welfare was introduced relatively late to Korea in comparison with Western countries. Nonetheless, the Korean government has continuously improved animal welfare-friendly regulations as policy instruments. Given the current situation, it is predicted that spontaneous settlement of the animal welfare policies will be difficult and may cause conflict in the farm animal industry. To identify and categorize conflicts caused by animal-welfare-related policies in the last five years, we investigated the awareness of animal welfare among Korean hen farms and the level of compliance with the animal welfare regulations. We collected a sample of 53 egg-laying chicken farm operators (e.g., owners or head managers) was collected through the on-site survey (90% confidence level (Z-score: 1.65) and 10.18% tolerance, based on a number of 797 egg-laying farms in 2020). Ethical conflicts on the farms were categorized into three different types according to the hen farm's ethical awareness level: passive, moderate, and active. Additionally, we investigated the correlation between compliance with regulations and ethical consideration. This study confirmed that compliance with animal welfare-related regulations significantly correlated to the level of ethical consideration of farm operators. Interestingly, we also observed that farm operators did not comply with the regulation despite their high level of awareness of animal welfare. This conflict implies contradiction and unresolved ethical dilemmas. Therefore, this study argues that the policies cause conflict in the field despite the certain level of effectiveness on animal welfare regulations.

A Study on the Architecture of the Original Nine-Story Wooden Pagoda at Hwangnyongsa Temple (황룡사 창건 구층목탑 단상)

  • Lee, Ju-heun
    • Korean Journal of Heritage: History & Science
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    • v.52 no.2
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    • pp.196-219
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    • 2019
  • According to the Samguk Yusa, the nine-story wooden pagoda at Hwangnyongsa Temple was built by a Baekje artisan named Abiji in 645. Until the temple was burnt down completely during the Mongol invasion of Korea in 1238, it was the greatest symbol of the spiritual culture of the Korean people at that time and played an important role in the development of Buddhist thought in the country for about 700 years. At present, the only remaining features of Hwangnyongsa Temple, which is now in ruins, are the pagoda's stylobate and several foundation stones. In the past, many researchers made diverse inferences concerning the restoration of the original structure and the overall architecture of the wooden pagoda at Hwangnyongsa Temple, based on written records and excavation data. However, this information, together with the remaining external structure of the pagoda site and the assumption that it was a simple wooden structure, actually suggest that it was a rectangular-shaped nine-story pagoda. It is assumed that such ideas were suggested at a time when there was a lack of relevant data and limited knowledge on the subject, as well as insufficient information about the technical lineage of the wooden pagoda at Hwangnyongsa Temple; therefore, these ideas should be revised in respect of the discovery of new data and an improved level of awareness about the structural features of large ancient Buddhist pagodas. This study focused on the necessity of raising awareness of the lineage and structure of the wooden pagoda at Hwangnyongsa Temple and gaining a broader understanding of the structural system of ancient Buddhist pagodas in East Asia. The study is based on a reanalysis of data about the site of the wooden pagoda obtained through research on the restoration of Hwangnyongsa Temple, which has been ongoing since 2005. It is estimated that the wooden pagoda underwent at least two large-scale repairs between the Unified Silla and Goryeo periods, during which the size of the stylobate and the floor plan were changed and, accordingly, the upper structure was modified to a significant degree. Judging by the features discovered during excavation and investigation, traces relating to the nine-story wooden pagoda built during the Three Kingdoms Period include the earth on which the stylobate was built and the central pillar's supporting stone, which had been reinstalled using the rammed earth technique, as well as other foundation stones and stylobate stone materials that most probably date back to the ninth century or earlier. It seems that the foundation stones and stylobate stone materials were new when the reliquaries were enshrined again in the pagoda after the Unified Silla period, so the first story and upper structure would have been of a markedly different size to those of the original wooden pagoda. In addition, during the Goryeo period, these foundation stones were rearranged, and the cover stone was newly installed; therefore, the pagoda would seem to have undergone significant changes in size and structure compared to previous periods. Consequently, the actual structure of the original wooden pagoda at Hwangnyongsa Temple should be understood in terms of the changes in large Buddhist pagodas built in East Asia at that time, and the technical lineage should start with the large Buddhist pagodas of the Baekje dynasty, which were influenced by the Northern dynasty of China. Furthermore, based on the archeological data obtained from the analysis of the images of the nine-story rock-carved pagoda depicted on the Rock-carved Buddhas in Tapgok Valley at Namsan Mountain in Gyeongju, and the gilt-bronze rail fragments excavated from the lecture hall at the site of Hwangnyongsa Temple, the wooden pagoda would appear to have originally been an octagonal nine-story pagoda with a dual structure, rather than a simple rectangular wooden structure.

Assessing the repeatability of reflection seismic data in the presence of complex near-surface conditions CO2CRC Otway Project, Victoria, Australia (복잡한 천부구조하에서 반사법 탄성파자료의 반복성에 대한 평가, 호주, 빅토리아, CO2CRC Otway 프로젝트)

  • Al-Jabri, Yousuf;Urosevic, Milovan
    • Geophysics and Geophysical Exploration
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    • v.13 no.1
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    • pp.24-30
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    • 2010
  • This study utilises repeated numerical tests to understand the effects of variable near-surface conditions on time-lapse seismic surveys. The numerical tests were aimed at reproducing the significant scattering observed in field experiments conducted at the Naylor site in the Otway Basin for the purpose of $CO_2$ sequestration. In particular, the variation of elastic properties of both the top soil and the deeper rugose clay/limestone interface as a function of varying water saturation were investigated. Such tests simulate the measurements conducted in dry and wet seasons and to evaluate the contribution of these seasonal variations to seismic measurements in terms of non-repeatability. Full elastic pre-stack modelling experiments were carried out to quantify these effects and evaluate their individual contributions. The results show that the relatively simple scattering effects of the corrugated near-surface clay/limestone interface can have a profound effect on time-lapse surveys. The experiments also show that the changes in top soil saturation could potentially affect seismic signature even more than the corrugated deeper surface. Overall agreement between numerically predicted and in situ measured normalised root-mean-square (NRMS) differences between repeated (time-lapse) 2D seismic surveys warrant further investigation. Future field studies will include in situ measurements of the elastic properties of the weathered zone through the use of 'micro Vertical Seismic Profiling (VSP)' arrays and very dense refraction surveys. The results of this work may impact on other areas not associated with $CO_2$ sequestration, such as imaging oil production over areas where producing fields suffer from a karstic topography, such as in the Middle East and Australia.

A Study on Relevant Range of Vertical vertical grade at Urban Intersections (도시부 평면교차로의 종단경사 적정범위 도출 연구)

  • Yoon, Byoung-Jo;Jung, Jae-Hoon;Kim, Jin-Han
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.1
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    • pp.187-192
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    • 2015
  • In general, design of urban intersections are fundamentally different from rural intersections, but current urban intersection design has been appled to rural standards. This study has suggested the design standard for urban intersection grades based on the existing literature, field investigating and comparative analysis. Moreover, this study analyzes and compares the differences between urban and rural intersections, and intersections have been derived by appropriate design standards after reviewing the domestic and international grades design criteria. Site survey was performed to validate the derived design criteria by analyzing statistically to establish the design standards. Results were produced for the intersection portion grade standards by comparing the number of instructions which produced appropriate slope degree from 2.5% to 3% in normal condition and slope can be extended to 5% in some critical cases. In-situ investigation was performed to validate the produced data where slope was found from 0.0~8.6%. Additional data of accident analysis were also collected for the validation of the suggested data and correlation analysis was performed using the SPSS tool. Data were analyzed statistically using 95% significance level for vehicle-to-vehicle collided, head-on collision accident rates, where accident rates significantly correlated with the grade. Therefore, appropriate grade at the intersection should be designed and applied in order to reduce the number of accidents at the intersection. Finally, appropriate grades for urban intersections are suggested from 1-3% for normal cases and grades could extend up to 5% for unavoidable cases where extra care must be taken when designing.

Short-term Change in Channel Morphology of the Naeseong Stream before the Operation of Yeongju Dam, Korea (영주댐 운영 전 내성천에서 하도 형태의 단기 변화)

  • Lee, Chanjoo;Kim, Donggu
    • Ecology and Resilient Infrastructure
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    • v.4 no.1
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    • pp.12-23
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    • 2017
  • The Naeseong Stream is a meandering sand-bed stream flowing through mountains and has so long maintained its geomorphological uniqueness characterized by extensive braided bare bars. Recently, its long-lasting landscape has been changed due to encroachment of vegetation. In this study being a part of long-term monitoring research morphological changes of the 56.8 km long study reach of the Naeseong Stream, which occurred during the period of 2012 - 2016 were analyzed. Airborne LiDAR and terrestrial cross-section surveys were carried out. Hydrological and on-site investigation data were also collected. Among the main four sites, two bend reaches showed point bars enlarged, while along the other two straight reaches mid-channel bars were either newly formed or increased in area and height. At the highest deposition point of each bar, vertical changes which were caused by one or two times of sediment deposition amounted to 0.6 - 1.4 m. On the contrary channel bed degradation was not obvious. Overall morphological changes in the study reach were attributed to deposition of sediment which occurred during the flood in July 2016 on the bar surfaces vegetated during the precedent dry seasons. These kind of geomorphological processes are thought to be the same as those related to the existing mid-channel islands along the mid- and downstream reach of the Naeseong Stream.

Relationship between The Shape of Palatal Vault and Tooth and The Thickness of Palatal Masticatory Mucosa (구개 및 치아 형태와 구개부 저작점막의 두께와의 연관성)

  • Seok, Hwa-Suk;Lee, Man-Sub;Kwon, Young-Hyunk;Park, Joon-Bong
    • Journal of Periodontal and Implant Science
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    • v.33 no.3
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    • pp.519-531
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    • 2003
  • The aim of present investigation was to clinically measure the thickness of palatal masticatory mucosa in the hard palate as potential donor site for mucogingival surgery, to determine the relation to shape of palatal vault, form of tooth, gender, and to serve the clinical criteria t o choose the proper surgical technique. 84(mean age:25yrs) systemically and periodontally healthy volunteers participated in this study and 18 standard measurement points were defined in the hard palate, located on 3 lies which ran at different distances parallel to the gingival margin. 6 positions were designated on each of these 3 lines between the level of canine and 2nd molar and a bone sounding technique using a periodontal probe with minimal local anesthesia was utilized to assess the thickness of palatal masticatory mucosa. Student t-test was used to determine the difference in mucosal thickness between 2 groups gender, shape of palatal vault (high palatal vault vs. low palatal vault), tooth form (short-wide vs. long narrow) The result of this study were as follows: 1. Soft tissue thickness progressively increased in sites further away from the gingival margin (p<0.01). 2. Depending on position, in line a and line c the masticatory mucosal thickness increased from Ca to M2(p<0.01), but in line b the thickness increased from Ca to P2, and decreased to M1 and increased again to M2. 3. Gender did not influence the thickness of masticatory mucosa. 4. Palatal vault shape was associated with the thickness of masticatory mucosa. Thickness of low palatal vault group was thicker than high palatal group between P2 and M2 position. 5. Form of tooth did not influence the thickness of masticatory mucosa. In conclusion, palatal vault shape was associated with the thickness of masticatory mucosa. So, mucogingival surgery can be considered as a treatment modality in high palatal vault group. But, Gender and tooth form did not influence the thickness of masticatory mucosa.

A case study on the bolt failure of the moving parts of a marine diesel engine (선박용 디젤기관의 운동부 볼트 손상사례에 대한 연구)

  • Kim, Jong-Ho;Lee, Jae-Hyun
    • Journal of Advanced Marine Engineering and Technology
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    • v.41 no.1
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    • pp.118-124
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    • 2017
  • To investigate and analyze the cause of the failure of the connecting rod bolt and the crank pin bearing bolt of the diesel engine of this study, the following results were obtained through site surveying, the investigation of literature referring to similar failures, testing and inspection of the fracture surface, and the experience of the researchers. The fractured crank pin bearing bolt of the diesel engine is estimated to be damaged later than the connecting rod bolt. From the shape of fracture surface, it is evident that the failed connecting rod bolt is fractured by fatigue failure due to abnormally repeated loads (e.g. loosening of the connecting bolt, etc.), and is not failed by brittle fractures due to the impact load. The surface of the U-nut on the fractured connecting rod bolt has been worsening due to the improper use of lubricant (agent for prevention of thread fixing) and no usage of separating the each connecting rod on each cylinder. Moreover, there is the possibility that those poor surface conditions of the fractured connecting rod bolt have affected the failure of the connecting rod bolt of the main engine. And it could be assumed that the mechanical characteristic and manufacturing process of the failed connecting rod bolt and crank pin bearing bolt, which were made by a domestic company, conform to the design requirements for those bolts.

Cancer Incidence in Kangwha County(1986-1992) (강화지역 암의 발생률(1986-1992))

  • Kim, Soh-Yoon;Kang, Hyung-Gon;Kim, Suk-Il;Yi, Sang-Wook;Ohrr, Hee-Choul
    • Journal of Preventive Medicine and Public Health
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    • v.32 no.4
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    • pp.482-490
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    • 1999
  • Objectives : This paper presents the information on the incidence of cancer from the population-based cancer resistry in Kangwha County. Material and methods : This investigation is based on Kangwha cancer registry. The data included cases of cancer diagnosed from 1986 through 1992. The diagnosis of cancer was confirmed by a team of physicians and nurses with the medical records kept in the clinics and hospitals based on the diagnostic criteria recommended by WHO. Home visitings were also made to cancer patients confirmed in every 6 months for the follow up and for the collection of relevant information directly from the patients. Results : A total of 992 cancer cases were registered during 1986-1992. The age-adjusted cancer incidence rate of all site is 201.7 in men and 110.7 in women. The most common cancer is the stomach cancer in both sexes. The age-adjusted incidence rate of the stomach cancer is 65.9 in men and 25.0 in women per 100,000 population. The lung cancer(33.8) and liver cancer(27.7) are next common cancers in men. The cervical cancer(21.8) and lung cancer(8.4) are next in women. Conclusion : The most common cancer is the stomach cancer in both sexes. The annual age-adjusted incidence rate of the stomach cancer is 65.9 in men and 25.0 in women per 100,000 population.

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