• KOREAN POULTRY JOURNAL
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• v.52 no.7
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• pp.148-152
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• 2020

• KOREAN POULTRY JOURNAL
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• v.53 no.4
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• pp.148-149
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• 2021

• KOREAN POULTRY JOURNAL
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• v.54 no.9
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• pp.148-150
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• 2022

• KOREAN POULTRY JOURNAL
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• v.54 no.2
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• pp.152-154
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• 2022

• KOREAN POULTRY JOURNAL
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• v.54 no.4
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• pp.134-137
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• 2022

• KOREAN POULTRY JOURNAL
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• v.56 no.6
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• pp.102-104
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• 2024

• Journal of the Korean GEO-environmental Society
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• v.16 no.1
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• pp.5-16
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• 2015

In the long span bridge construction, construction cost portion of large scale marine foundation is about 40% (KICTEP, 2007). In this study, designs for deep water depth large composite foundation of a super long span cable-stayed girder bridge of prototype were performed by three design methods (ASD, LRFD, Eurocode) and the behaviors of a large diameter drilled shaft were analyzed and the 3D numerical analysis was performed. As a result, the soft rock socket lengths in allowable stress design estimation method were the longest. The soft rock socket lengths estimated by the design approach 2 among Eurocode and the LRFD were similar. The longer the socket length socketed in the soft rock was, the smaller the axial force acting on a large-diameter drilled shaft head was and the smaller the settlement of drilled shaft was.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.30-37
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• 2013

A soft rock fracture zone is an important element for rock slope or earth retaining, however stability studies of earth retaining wall have been lack. Therefore, this study is analyzed for a behavior of earth retaining wall with condition of fracture zone or no fracture zone and then a numerical analysis (Finite Element Method) was performed considering interaction with field monitoring data between ground and structures. As a result, applied horizontal displacement on retaining wall is correspond between result of numerical analysis and field monitoring data and displacement point stress distribution with fracture zone condition analyzed to be stable side but no fracture zone condition is expressed to be unstable side. The results of this study is purpose for applying safety construction as a top priority at field when designing for future.

• Tunnel and Underground Space
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• v.17 no.1 s.66
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• pp.9-16
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• 2007

The influence of round length on the tunnel stability and construction cost is well acknowledged by many researchers and engineers but the coherent procedure is not available for its determination. In this study, the behaviour modes of the face and unsupported span was investigated for weak rock tunnel by a small scale model test, PFC3D and FDM analyses in consideration of the round length. Total five types of behaviour modes are defined and quantitative estimation of the behaviour modes was established in terms of the safety factor for the face stability and the conditional chart. Although the proposed method has some restrictions, this method can provide useful information for the optimization of the round length and excavation, especially in design stage.

• Tunnel and Underground Space
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• v.27 no.4
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• pp.230-242
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• 2017

Seismic velocities measured from in-situ tests (n=177) and through rock core samples (n=1,035) are reviewed in light of construction standards, widely used standards as a first-hand approximation of rock classification solely based on seismic velocities. In-situ down hole tests and refraction survey for soft rocks showed seismic velocities of 1,400~2,900 m/s which is faster than those specified in construction standards. For moderate~ hard rocks, in-situ down hole tests and refraction survey showed 2,300~3,800 m/s which roughly corresponds with the range specified in the construction standards. A similar trend is also observed for seismic velocities measured from rock core samples. The observed differences between construction standards and seismic velocities can be explained in two ways. If construction standards are correct the observed differences may be explained with seismic velocities affected by underlying fast velocities and also possibly with selection of intact cores for velocity measurement. Alternatively, construction standards may have intrinsic problems, namely artificial discrete boundaries between soft rocks and moderate rocks, application of foreign standards without consideration of geologic setting and lack of independent verification steps. Therefore, we suggest a carefully designed verification studies from a test site. We also suggest that care must be exercised when applying construction standards for the interpretation and accessment of rock mass properties.