• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1215-1224
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• 2013

Great efforts have been made worldwide to reduce the Green House Gas (GHG) emission following the "Kyoto Protocol" declared during the United Nations Framework Convention on Climate Change in 1997. Many industries have restructured to meet the standard set by the Protocol. However, no clear guidance has been established for the purpose of reducing the GHG emission in construction industry. In addition, no significant effort has been made to conserve the energy during construction activities. For more effective energy saving in construction industry, it is essential to collect data about energy consumption, quantity of environmental emissions and costs. However, most studies on sustainable construction have been concentrated on the use of equipment, maintenance and repair works during construction due to the difficulties of collecting such data. This study suggests a method to select the most environmentally friendly equipment combination for earthwork with comparing environmental loads and costs using the database of Life Cycle Inventory in the Ministry of Knowledge Economy and Ministry of Environment of Korea.

• Journal of the Korean Geotechnical Society
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• v.25 no.9
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• pp.57-66
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• 2009

In the preliminary investigation (Park et al., 2009), the use of compressional wave velocity and its measurement techniques were proposed as a new quality control measure for trackbed fills. The methodology follows exactly the same procedure as the density control, except the density being replaced by the compressional wave velocity involving consistently with resilient modulus of design stage. The specifications for the control also include field compaction water content of optimum moisture content ${\pm}2%$ as well as the compressional wave velocity. In this sequel paper, crosshole and resonant column tests were performed as well direct-arrival method and laboratory compressional wave measurements to verify the practical applicability of a methodology far the new quality control procedure based upon compressional wave velocity. The stress-modified crosshole results reasonably well agree with the direct-arrival values, and the resonant column test results also agree well with the field crosshole results. The compressional wave velocity turned out to be an excellent control measure for trackbed fills both in the theoretical and practical point of view.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.501-509
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• 2020

Earthwork in the construction field is a core process of construction, and it is used in almost all processes and is connected to the safety of the structure directly. Therefore, it is essential to analyze and confirm the road tamping through a plate bearing test and a field density test. The current analog measurement methods for road tamping measurement is difficult to check in real-time, accurate location information, time information, and the history management of workers in the field. Therefore, IoT (Internet of Things)-based DCPT (Dynamic Cone Penetration Test) was developed for a smart construction environment with a solution to the problem. The Smart DCPT system operated in a smartphone environment is IoT-based. The Smart DCPT system can apply various applications and has advantages of flexibility, low cost, and high efficiency. The IoT-based DCPT records the digital road tamping information, location information, time information, and worker information per measurement count. In addition, the various information is transmitted in real-time to the management center through a smartphone. This system is expected to contribute to the management of the construction process.

• Geotechnical Engineering
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• v.14 no.4
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• pp.61-76
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• 1998

Various kinds of reinforced soil methods have been developed by many researchers or companies for their economic merits mainly. These methods have generally used sandy soils which have high permeability as embanking or backfill material. That is because, if poor embanking materials, especially like a clayey soil which has very low permeability, are used in a reinforced soil embanking, and if excessive pore water pressure is produced by external factors, the friction resistance between reinforcing members and Boils decrease, as a result possible damage or collapse of the body of a reinforced embankment. In fact, clayey Boils can also be used as a embanking materials with reinforcement which has high permeable capacity, and are expected to be able to dissipate the excess pore water pressure effectively. In this study reinforcing effects have been examined through a serries of direct shear tests in which clayey soils are reinforced with nonwoven geotextiles of which permeability is very high and tensile strength is relatively weaker than geogrids which are usually used in reinforced soil wall. Even though such nonwoven geotextile are used as reinforcement of high saturated clayey soils. the test results show the possibility that nonwoven geoteztiles could be used as a reinforcement for reinforced soil walls effectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.153-166
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• 2017

Recently, the construction industry has been pursuing economical construction by introducing improved construction equipment and methods. However, in many cases, the equipment operation according to the intuition of the field manager and in the manner of traditional methods impedes the increase in effectiveness in terms of productivity and economy. The performance of new construction equipment has rapidly improved; however, the maximum effect of mechanized construction cannot be obtained unless the effective management and operation methods are implemented. According to the expert survey, it has been discovered that the problems of conventional construction equipment operation methods can be classified into several categories: allocation of construction equipment that is not suitable for the construction work, the combination of equipment that does not take into consideration real-time field situations, the decline in the skill of the construction equipment drivers, and lack of real-time access to necessary information. This paper proposes a construction equipment management system to solve these problems. The construction equipment management system can provide a method to maximize the work rate of the construction equipment fleet by developing an equipment allocation plan based on field conditions, whenever necessary, and transferring this information to the construction equipment drivers in real time. Ultimately, it is believed that the application of the construction equipment operation system in the field will make it possible to reduce carbon emissions by improving productivity and reducing fuel consumption.

• Journal of the Korean Geotechnical Society
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• v.39 no.11
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• pp.85-95
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• 2023

This study implemented intelligent compaction technology at the construction site of the AY Highway in Gyeonggi Province, with a focus on obtaining the representative intelligent compaction value, CMV. The target CMV for quality control was established through trial construction, and the validation of the compaction quality control process based on intelligent compaction was conducted. The optimal approach for determining the target CMV was confirmed to be through linear regression of the average CMV measured within a 5-m radius from the plate load testing location. Upon assessing compaction quality against the target CMV, it was observed that the quality criteria outlined in the domestic intelligent compaction standard were met. However, the criteria outlined in Austria and the United States were not satisfied. Notably, indicators related to the variability of compaction quality did not meet the specified criteria, suggesting a stringent standard compared to the observed variability of CMV, ranging from 17% to 55%. Consequently, it is recommended to conduct additional field tests to further validate the compaction quality control process based on intelligent compaction. This will aid in confirming and enhancing the appropriateness of the regulations stipulated in each standard.

• Tunnel and Underground Space
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• v.9 no.2
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• pp.158-167
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• 1999

There are substantial difficulties in assessing the volume of soill/rock to be excavated and the cost thereof, which is attributable to the subjective and qualitative methods of rock mass classification prevailing at the moment. This paper intends to introduce more objective and quantitative rock mass classification method easily applicable to the excavation of granites in Muakjae, Seoul. As a result of such study it is proven that Schmidt hammer and point load strength tests are fairly reliable and easily applicable to estimate and quantify uniaxial compressive strength of granitic material in Seoul. In an efforts to confirm the granitic rock mass conditions in 12 meters underground, seismic refraction surveys were made on the top of vertical exposures from where underlying rock mass conditions could be directly inspected. Rock mass boundaries determined by seismic refraction methods were found to agree within a 1m variance with visible differences in rock mass conditions in the vertical exposure beneath the test site. Thus it can be concluded that detailed geotechnical mapping on cutting slopes is a most efficient, dependable and cost-effective technique in assessing likely excavation conditions of shallow granitic mass in Seoul.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5C
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• pp.193-198
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• 2012

Field and laboratory tests were performed to investigate the swelling(L value) and shrinkage modulus (C value) of soil and rock mixtures using 2 sites. According to test results, when disturbed soil and rock were mixed with same amount (5:5), the maximum density was achieved and showed 19% and 18% increased at each site comparing with the unit weight of rock only. Since measured L values of mixtures were overestimated about 4 to 11% compare to estimated values based on the conventional method. While C values were underestimated about 13~20% compare to conventional values due to the development of compacting equipments and effective construction management. When rock and soil were mixed in the ratio of 5 to 5, the unit weight of the mixture was higher than that of other mixtures and rock or soil only.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.99-106
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• 2020

Man-made slope is inevitable to make a new road, which may result in environmental problems as well as collapse of slope. To prevent these problems, various methods such as geogrid reinforced retaining wall, precast concrete-panel retaining wall, and so on, have been introduced and developed. Among these methods, this paper presents the evaluation of field application of precast concrete-panel retaining wall attached to in-situ ground (so called top-down) compared to the conventional construction method of precast concrete-panel retaining wall (so called bottom-up) through the field test and numerical analysis. As a result, the safety factor of both methods in final stage is similar, however, top-down method guarantees the slope stability during the construction compared to bottom-up method.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.4
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• pp.584-590
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• 2015

Objectives: The purpose of this study was to evaluate quartz concentrations in airborne total and respirable dusts. Materials: Respirable dust samples were collected using a 10 mm aluminum cyclone equipped with a 37 mm$5{\mu}m$ pore size PVC filter. Total dust samples were collected with a three stage cassette from three work sections at earthwork sites located in the South Chungcheong-do Province area. Results: The geometric means of quartz concentrations were $0.008mg/m^3$ and $0.004mg/m^3$ in total dust and respirable dust, respectively. The geometric means of quartz contents analyzed by FTIR were 3.74% in total dust and 3.16% in respirable dust. The geometric mean of quartz concentrations and contents in secondary blasting operations were higher than those in other operations. Conclusions: Given that secondary blasting operations had higher quartz concentrations, there is a need to reduce respirable dust, such as through wet operations.