• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.546-550
• /
• 2007

수중보는 하천, 하수관 또는 인공수로에 건기시 유지수량을 확보할 목적으로 설치되며 보통 10년 주기 내외의 평균 강우량에 맞추어 그 용량을 결정한다. 수처리를 위한 장치의 규모는 적정한 재현기간에 맞추어 설계하고, 재현기간을 초과하여 강우가 발생할 경우 강우 유입을 우회시켜 경제성을 확보할 수 있어야 한다. 따라서 완충회전수문은 초과하는 수량을 우회 또는 통과시킬 목적으로 개발되었으며 기존 연구에서 실내 및 현장 실험 모형을 제작하여 여러 차례 실험을 토대로 한계수심 및 충격량을 이론적으로 산정하고 현장 적용성을 검증한 바 있다. 본 연구에서는 수문의 개 폐시 원형실린더에 부착되어 있는 날개의 길이 및 개수 변이에 따른 항력의 영향으로 충격량을 측정하여 현장에 보다 적합한 완충회전수문의 최적설계방안을 제시하고자 한다.

• Journal of the Korean Geosynthetics Society
• /
• v.15 no.3
• /
• pp.49-55
• /
• 2016

Field measurement units and a system were constructed and installed in a waste-dump slope at the Imgi mine to investigate and analyze the variations in the unsaturated characteristics of the soil. The field instrumentation system was composed of a data acquisition system (DAS), a solar system, and measuring sensors. The rainfall, matric suction, and volumetric water contents were continuously measured from the units in the instrumented site. The variations in matric suction and volumetric water content were primarily affected by the rainfall intensity. At the surface of the slope, the largest increase and decrease in the changes in matric suction and volumetric water content were observed during the wetting and drying processes, respectively. Also, the matric suction and volumetric water content were 5-35 kPa and 0.12-0.24, respectively. However, the ground water level was not suddenly increased just after rainfall but gradually increased after 2 or 3 days later.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.5C
• /
• pp.229-237
• /
• 2009

A conventional way of backfilling has used sand or in-situ soil. It not only requires substantial amount of time and cost but also makes it particularly difficult to fill the bottom part and small cracks of a pipe. To address the problem with the conventional method of compaction, liquefied stabilized soil was proposed as an alternative because it reuses in-situ soil which can ensure sand supply while adjusting flowability and strength of the soil with design of mix proportion. With an aim to identify the mixing properties of liquefied stabilized soil depending on the organic content of in-situ soil, this study conducted indoor tests of material segregation, flowability, strength, and permeability by changing humic acid content of the soil. The results revealed that material segregation and flowability increased proportionally while strength decreased with the increased amount of humic acid. In the mean time, permeability of liquefied stabilized soil wasn't affected by organic content.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.5
• /
• pp.1935-1946
• /
• 2013

In this study, the behavior characteristics of bent pile structures with varying cross-section was examined through the measured results of field load test. A framework for determining the bending stress is calculated based on the stresses in the circumference of the pile using 3D finite element analysis. It is found that the bending stress near the pile-column joint changes rapidly and fracture zones occurs easily at variable cross-sections in bent pile structures. Also, the optimized column-pile diameter ratio was analyzed through the relationship between the column-pile diameter ratio and lateral crack load ratio. Based on this study, the optimized column-pile diameter ratio can be obtained near the inflection point of the curve between the column-pile diameter ratio and lateral crack load ratio. Therefore, a present study by considering the optimized variable cross-section condition would be improved bent pile structures design.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.10a
• /
• pp.721-724
• /
• 2011

A prototype needs to show the requirements of the users and help them understand better. These prototypes are useful in a variety of industries. But most existing prototypes depend on the visual representation. This method of visual expression has a limitation, which can't express the detailed contents. This paper suggests an expression method of linguistic formation as an alternative. The prototype of linguistic expression can demonstrate the detailed contents of the requirements, keep a good communication among those who are related to the project, and allow them to deal with a large number of possible problems which may happen from the developing process. As it's also easy to make the developing process documented, the prototype will be helpful to improve the software development.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.105-105
• /
• 2012

최근 우리나라는 집중호우로 인한 토석류의 발생이 현저하게 증가하고 있으며, 2002년 태풍 루사와 2003년 매미 그리고 2006년 7월 집중호우 등으로 인한 피해의 규모는 여러 조사와 문헌에서도 확인할 수 있다. 2011년 7월, 서울 우면산 일대에서는 집중호우로 인한 토석류가 발생하였으며, 16명의 인명손실을 포함한 큰 피해가 있었다. 우면산 토석류는 십여 개 지역에서 동시다발적으로 발생하였으며, 토석류 발생 유역 특성과 토석류의 유동특성을 분석하기 위한 현장 조사가 진행되었다. 조사한 자료에 따르면 우면산 일대의 일일 강우량은 서초 기상측정소를 기준으로 최대 24시간 누적 324mm 그리고 시간당 최대 68.5mm/hr를 기록하였다. 상업용 소프트웨어인 FLO-2D는 유사농도의 함수로서 점성(viscous)응력, 항복(yield)응력, 난류 및 분산(dispersive) 응력항을 포함하는 2차 유변학(quadratic rheology) 모델을 기본으로 사용하여 이류(mudflow)와 토석류(debris flow)를 모의할 수 있다. FLO-2D는 흐름의 운동량 및 에너지 보존을 고려하여 격자와 시간에 관계없이 유동심도, 속도, 압력을 예측할 수 있으며, 격자 기반의 모델로서 GIS 및 기타 응용 프로그램들과 연동이 쉽다는 장점이 있다. 그러나 하상침식에 의해 유발된 토석류의 체적 증가는 고려 할 수 없으므로 토석류의 전파 및 퇴적영역에서의 토석류 모의에만 사용할 수 있는 단점이 있다. 이 연구의 목적은 FLO-2D 소프트웨어를 이용하여 우면산에서의 토석류 현상을 재현하는 것이다. 우면산 일대에서 발생한 토석류 중 서초구 방배동의 래미안 아파트 부근에서 발생한 토석류에 대하여 수치지도(DEM)와 현장조사를 통해 얻은 지형자료, 해당 지역의 강우량 및 지질 특성 자료 등을 토대로 FLO-2D 모델을 적용하여 토석류의 흐름특성을 검토한다. 토석류 유동 및 퇴적에 대한 가용한 현장관측 자료와의 비교 분석을 통하여 토석류 특성 값을 산정하고, 모델의 적용성을 검증한다.

• Explosives and Blasting
• /
• v.20 no.2
• /
• pp.33-41
• /
• 2002

화약류를 사용하여 암반을 절취하는 작업현장에서의 발파공해는 항상 발생하고 있다. 특히 폭약의 폭발로 인해 발생하는 지반진동은 크고 작은 문제를 야기하고 있다. 일반적으로 발파현장에서 사용하고 있는 일반발파와 진동제어(미진동)발파에 대한 의미와 구분 및 시공에 대해 인식시키고자 그동안의 경험과 이론을 토대로 하여 연구하게 되었다. 본 연구에서는 일반발파와 진동제어발파를 구분하는 요소로 암분류 및 진동속도를 지발당장약량과 관계, 암분류에 따른 비장약량 및 발파공당 암절취량 그리고 천공경을 선정하여 고찰하였다. 이들 요소를 기준으로 일반발파와 진동제어발파의 경계가 되는 보안물건으로부터 거리 산출방법에 대해서 연구하였다. 일반발파나 진동제어발파 모두 보안물건에는 한계 진동속도 이내의 진동이 전달되어야 하며, 그 경계가 되는 발파공당 절취암량은 연암의 경우 약$16.67m^3$, 보통암의 경우 약$12.5m^3$, 경암의 경우 약 $10m^3$을 기준으로 하는 것이 바람직하고, 그 경계가 되는 보안물건으로부터 거리는 일정하게 정해진 것이 아니므로 현장에서 대상암반에 대해 시험발파를 실시하여 암분류, 비장약량, 지발당장약량, 한계 진동속도를 기준으로 결정하는 것이 바람직하다. 진동제어(미진동)발파구간내에서 발파설계단가는 일률적이 아닌 약2~3구간으로 분할하여 산출해야한다.

• Journal of the Korean GEO-environmental Society
• /
• v.23 no.9
• /
• pp.17-23
• /
• 2022

Using cement as a road subbase is economical, easily modified and supplemented and has excellent road pavement quality control. In addition, cement adheres well to sandy soils without adhesion, and it plays a role of permanently preserving adhesion in viscous soils with adhesion, so it can be widely applied as stable treatment with the advantages of increased strength, reduced compressibility. and improved durability. However, while cement is excellent in terms of strength for a road subbase, the material properties mean that it is difficult to maintain and reinforce when cracks or fractures occur due to dry shrinkage, and the pH increases in the ground due to hexavalent chromium eluting from cement. which can cause environmental problems such as groundwater contamination. Therefore, this study evaluates the usability of alternatives in the road base layer such as environmentally cementitious stabilizer and on-site soil generated from the site. We intend to reduce the environmental damage and evaluate the durability. To evaluate the applicability of the site, Environmental stability test and freeze-thaw test and wetting-drying test was conducted to evaluate the strength characteristics of alternative materials on the road through the limited performance evaluation of environmentally cementitious stabilizer. The test ranges were set at mixing ratios of 10%, 20%, and 30% and ages of three days, and 28 days old to evaluate the early strength and reference strength according to the mixing ratio of the environmentally cementitious stabilizer.

• Korean Journal of Construction Engineering and Management
• /
• v.22 no.1
• /
• pp.47-54
• /
• 2021

According to the Korea Occupational Safety and Health Agency's (KOSHA) report on industrial accident statistics over the past four years, the number of casualties at construction sites from 2017 to June 2020 was about 93,158 and the number of deaths was about 1,977, showing a high trend of safety accidents among the eight major occupational groups, with the construction industry ranking third in total and the death rate being the highest in total. Among them, the number of deaths caused by falls in the entire occupational category is about 1,267, the highest rate of deaths due to contact is about 522, which is a frequent safety accident among the top three accident types. This paper aims to help reduce the overall proportion of construction safety accidents by developing smart safety sensing devices using ultrasonic sensors to prevent two types of safety accidents, which have the highest rate of occurrence among various types of safety accidents occurring at construction sites.

• Journal of the Korean Geotechnical Society
• /
• v.21 no.4
• /
• pp.83-98
• /
• 2005

In this paper, a conceptual approach of the stress path method was newly proposed for a rational estimation of settlements of saturated clay deposits. In the proposed approach, settlement-related characteristic deformation behaviors of a specific clay deposit, which can cover all probable stress changes expected in the field, are experimentally evaluated in advance. Then settlements of various structures constructed on the deposit are easily estimated with only the characteristic deformation behaviors and without any additional experimental effort. In Part I of this paper, in order to provide practicality to the new conceptual approach, we developed a detailed procedure which is capable of evaluating characteristic deformation behaviors of a saturated clay deposit with only a limited number of tests and easily predicting deformations under a given stress change using the characteristic deformation behaviors. The applicability of the developed procedure was clearly shown by presenting an actual application example.