• Journal of the Korean Geotechnical Society
• /
• v.23 no.2
• /
• pp.85-92
• /
• 2007

As the use of drilled shafts for foundation of a large size structure increases, the evaluation of the reliable bearing capacity of the pile has become important. The purpose of this study is to verify the reliability of bearing capacity equations for drilled shafts socketed in weathered rock by comparing the bearing capacity values from static load tests with values from bearing capacity equations. In this study, twelve data from static load test were selected from four field sites, and the data of load test and the properties of weathered rock were analyzed. Three methods widely used in practice were selected for analysis, namely the AASHTO method (1996), Carter & Kulhawy method (1988), and FHWA method (1999). The comparison of the bearing capacity values from the bearing capacity equations to those obtained from load tests showed that the Carter & Kulhawy method (1988) was the most reliable in giving conservative design values and smaller COV (Coefficient Of Variation).

• Journal of the Korean Geotechnical Society
• /
• v.23 no.8
• /
• pp.77-85
• /
• 2007

In order to estimate undrained shear strength and evaluate cone factors, various in-situ and laboratory test results at new harbor construction area near Pusan were analyzed. To evaluate Nk values and equation applicable in Korea, measured and theoretical cone factors were compared based on the test results. For comparison, various analytical solutions were adopted and used. Adopted methods include cavity expansion solutions of Baligh (1975) and Yu (1993) and steady state solutions of Teh and Houlsby (1991) and Yu et al. (2000). According to the result of comparison, cavity expansion solutions were found to be reasonable for the CPTu-based undrained shear strength evaluation.

• Journal of the Korean GEO-environmental Society
• /
• v.8 no.6
• /
• pp.53-60
• /
• 2007

L/EPS, manufactured in the shape of block and used for civil engineering, is a lightweight material with an excellent resistance to compression, and provides a superb self-sufficient stability. EPS is a suitable material capable of resolving the problem of settlement and lateral flow if it is applied as the soil on soft ground. The Korean Standards (KS) has not yet proposed any testing method for use of EPS as an engineering banking material. Only its testing and quality ordinance as a heat insulation material has been standardized. The design criteria for EPS has been established and applied through the trial construction of KHC (Korea Highway Corporation) and quality test of manufacturer, but most studies on them have been confined to factory products. This study is focused on comparing and analyzing long-term durability by conducting cyclic load test, freezing and thawing test, absorption rate test and others. EPS used in the test was chosen from construction sites and factory products, focusing on the long-term durability of EPS depending on the passage of time. Unconfined compression test results indicated that the strength of collected samples was lower than factory products. While the triaxial compression test results indicated that the shear strength increased in proportion to the increase of confining pressure, and factory products had declining shear strength as the confining pressure rose.

• Proceedings of the KIEE Conference
• /
• 2002.07b
• /
• pp.1289-1291
• /
• 2002

본연구는 한국형 고속전철용 신호시스템 시제품들의 시험평가 중 운용환경시험의 항목, 시험기준, 방법 그리고 시험결과에 대해 설명하였다. 이 한국형 고속전철용 신호시스템의 운용환경 시험을 위해 국내외 적용 가능한 규격 또는 기준을 조사분석하여 본 시험에 적합한 기준 및 방법을 도출하였으며, 이를 바탕으로 개발된 시제품들에 대한 운용환경시험을 수행하였다. 본 시험을 통해 개발된 시제품들의 운용환경 특성이 검증되었으며, 이후에는 이들 시제품들의 현장시험을 수행할 예정이며 이를 통해 최종적인 한국형 신호시스템의 시제품의 시험평가를 마무리할 예정이다.

• Journal of the Korean Geosynthetics Society
• /
• v.6 no.4
• /
• pp.39-48
• /
• 2007

This paper introduces a recently developed reinforced earth wall system with steel framed-facing. The new system incorporates a steel-framed facing that might be assembled on-site and steel strip or geogrid type reinforcements for backfill area. In order to enhance scenery view design of the wall construction, dual-structured facing is proposed in which room for planting space locates in the front of facing. A reinforced earth walls using the proposed system was constructed to verify constructability of the proposed system and facing movement and tensile characteristics of reinforcement were measured to understand the mechanical behavior.

• Journal of the Korean GEO-environmental Society
• /
• v.12 no.3
• /
• pp.37-46
• /
• 2011

To investigate the applicability of Precious Slag Ball as the alternative material such as vertical drains, it is necessary to check the drainage effect of it in the field construction. In order to attain an successful design it is important to predict problems encountered in field construction. Accordingly, in this study the laboratory tests were executed under different conditions before applying of the field. 4 cases including Precious Slag Ball, sand+Precious Slag Ball, pack Precious Slag Ball and sand as vertical drains were conducted, and under the base of the laboratory tests the field test was executed and analyzed. By the upper results it is apposite to use Precious Slag Ball as vertical drains.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.973-976
• /
• 2008

Recently, it is increasingly reported that the deterioration of concrete structure under marine environments is due to diffusion and penetration of chloride ions. It is very important to estimate the diffusion coefficient of chloride ion in concrete. Estimation methods of chloride diffusivity by concentration difference is time-consuming. Therefore, chloride diffusivity of concrete is mainly conducted by electrically accelerated method, which is accelerating the movement of chloride ion by potential difference. However, there has not been any proper method for field quality control to closely determine the diffusion coefficient of chloride ion through accelerated tests using potential difference. In this paper, the various test methods for determination of chloride diffusion coefficient in concrete were investigated through comparison accelerated tests. From the results of estimated diffusion coefficient of chloride ion, relationship between the ponding test and acceleration test was examined.

• Journal of the Korean Geotechnical Society
• /
• v.17 no.6
• /
• pp.225-233
• /
• 2001

Field model tests were performed to develop the grid-net landfill leachate leakage detection system using electrical resistance. Electric circuit tests were also carried out to investigate the expected electrical effects of grid-net electric circuit. The resistance of leaking point showed lower value than that of non leaking point. Grid-net leakage detection system was thought to be effective to locate the leachate leaking point. The measured electrical resistance along the wire including the leaking point was slightly reduced following the reduction of electrical resistance at the leaking point, which was explained by electric circuit test results.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.2015_2016
• /
• 2009

전기방식이 실시되고 있는 상수도 관로는 관의 노후화, 코팅의 열화, 부적절한 방식시스템의 적용 및 타 시설물과의 간섭 등으로 부분적으로 방식전위 미달구간이 존재한다. 이러한 방식전위 미달구간에 대하여 토양환경 측정 및 방식소요전류량 산정, 간섭 시험 등을 통하여 토양환경은 부식이 '발생하는 구간' 및 '미약하게 발생'하는 구간으로 나타났다. 임시 가통전 시험을 통하여 방식소요전류량을 구할 수 있었다. 간섭영향 시험으로 간섭 여부 및 전식 발생지점을 추정할 수 있다. 현장 측정 결과와 설계기준을 바탕으로 적절한 전기방식 보강 계획을 수립하여 현장에 부분적으로 설치하였으며 방식상태를 분석하였다. 단순히 설계된 소요전류량만을 증가시키는 방안보다 부분적인 방식보강 및 주변 배관 상태를 고려하여 적절한 통합 방식방안을 적용하는 것이 더 효율적인 것으로 나타났다.

• Journal of the Korean Geotechnical Society
• /
• v.19 no.1
• /
• pp.163-172
• /
• 2003

The engineering properties of composite silicate grout materials that were developed recently were analyzed. In this laboratory tests, OPC (Ordinary Portland Cement) was mainly used as grout materials. Moreover, the properties of composite silica, silica sol and sodium silicate (No.3) acting as coagulating agent were analyzed and compared with each other. For the purpose of finding the engineering properties of composite silicate grout materials, various physical and chemical tests were performed : naked eye measurement, photographing by using SEM, uniaxial compression test and in-situ application test. A series of test results showed that the strength of composite silicate grout materials was about 3～6 times that of ordinary sodium silicate grout materials in 6～24hr. Especially, based on the evaluation of the application of JS-CGM grout to the construction fields, composite silicate grout would be very effective in reducing the coefficient of permeability.