https://scholarworks.bwise.kr/gachon/handle/2020.sw.gachon/464 Sat, 28 Feb 2026 16:44:47 GMT 2026-02-28T16:44:47Z https://scholarworks.bwise.kr/gachon/handle/2020.sw.gachon/89373 Title: Influences of Momentum Ratio on Transverse Dispersion for Intermediate-Field Mixing Downstream of Channel Confluence Authors: Shin, Jaehyun; Lee, Sunmi; Park, Inhwan Abstract: This study aims to analyze the influences of momentum ratio (Mr) and confluence angle (α) on the transverse dispersion in an urban scale confluence channel from the numerical simulation results using the Environmental Fluid Dynamics Code model. By changing the momentum flux and confluence angle from the simulation results, the analysis focused on the relations between the vertical variations of transverse velocity and transverse dispersion. The high momentum tributary aligned the mixing interface toward the outer bank and created a strong helical motion, which transported the contaminated water along the channel bed and inflows into the recirculation zone. The high momentum ratio induced the large vertical shear in transverse velocity with a strong helical motion and increased the transverse dispersion. However, the helical motion persistence rapidly decreased as the flow reached downstream and led to a decrease in the transverse dispersion for the large confluence angle. Thus, the transverse dispersion coefficient increased with a high momentum ratio and low confluence angle, and the dimensionless transverse dispersion coefficient was in the range of 0.39–0.67, which is observed in meandering channels, for Mr > 1 and α = 45°. Wed, 01 Feb 2023 00:00:00 GMT https://scholarworks.bwise.kr/gachon/handle/2020.sw.gachon/89373 2023-02-01T00:00:00Z https://scholarworks.bwise.kr/gachon/handle/2020.sw.gachon/89298 Title: Research on Development and Application of Earthquake Risk Assessment Model for Railway Structures Authors: 김지현; 김현기; 유민택; 하익수 Abstract: 본 연구에서는 철도 시설물에 대한 지진 피해 확산 예측 모형을 제안하고, 국내 철도종합시험선로에 적용하여 지진 시나리오가 발생하였을 때 실제로 철도 시설에 발생할 수 있는 피해를 추정하였다. 지진 피해 확산 예측 모형 개발을 위해 교량, 성토, 터널에 대한 지진 취약도 함수 선행연구를 분석하고, 이를 바탕으로 철도 시설에 적합한 손상 상태 별 지진 취약도 함수를 제시하였다. 또한, 대체 비용 및 복구시간 개념을 활용하여 예상 피해율 및 예상 복구시간 도출 프로세스를 정리하였다. 개발된 지진 피해 확산 모형을 철도종합시험선로에 적용한 결과, 성토구간에서 10% 이상의 높은 피해율이 발생하고 9일 수준의 예상 복구시간이 요구되는 것으로 평가되었으며 일련의 결과를 바탕으로 철도 시스템에 대한 효과적인 내진 보강 및 지진 대응 대책을 마련할 수 있을 것으로 기대된다. Fri, 01 Sep 2023 00:00:00 GMT https://scholarworks.bwise.kr/gachon/handle/2020.sw.gachon/89298 2023-09-01T00:00:00Z https://scholarworks.bwise.kr/gachon/handle/2020.sw.gachon/89238 Title: Strength and stiffness characterizations of geo-materials composing unpaved roads using LFWD, DCP, and CDP tests Authors: Kim, Namsun; Lee, Jong-Sub; Park, Geunwoo; Kang, Seonghun; Han, Woojin; Hong, Won-Taek Abstract: To assess the condition of the geomaterials composing unpaved roads subjected to cyclic wheel loads by moving vehicles, it is necessary to evaluate the variations in mechanical properties with depth. In this study, a crossholetype dynamic cone penetrometer (CDP) was applied to characterize the stiffness of unpaved soil along its depth. In addition, light falling weight deflectometer (LFWD) and dynamic cone penetrometer (DCP) tests were conducted for a comparative analysis. The LFWD, DCP, and CDP tests were conducted on a newly constructed unpaved road after the application of 0, 200, and 400 cycles of wheel loads by a moving vehicle. From the experimental results, the strength and stiffness properties such as Evd, NDCP, and Vs, were obtained, and their incremental ratios were investigated according to the number of cyclic wheel loads. In addition, the improved relationships between Evd, NDCP, and Vs were constructed considering the strain influence factors with depth. This study demonstrates that CDP can be an efficient testing method to profile the stiffness of unpaved roads, and the relationships considering the strain influence factors may be used effectively for reasonably estimating the engineering properties. Sun, 01 Oct 2023 00:00:00 GMT https://scholarworks.bwise.kr/gachon/handle/2020.sw.gachon/89238 2023-10-01T00:00:00Z https://scholarworks.bwise.kr/gachon/handle/2020.sw.gachon/89235 Title: Influences of binder composition and carbonation curing condition on the compressive strength of alkali-activated cementitious materials: A review Authors: Bang, Jinho; Choi, Jaesuk; Hong, Won-Taek; Jung, Jongwon; Kim, G. M.; Yang, Beomjoo Abstract: As international endeavors to diminish carbon emissions persistently escalate, the principles of net-zero emissions or carbon neutrality have gained prominence, prompting the implementation of diverse strategies globally to alleviate carbon emissions. Cement manufacturing represents a significant emission source globally, and has established formidable objectives to curtail emissions by over 60% by 2050. This review article scrutinizes the ramifications of the amalgamated composition of cement and alkali-activated construction substances, in addition to carbonation curing conditions, on compressive resilience. Initially, the resistance attributes of multicomponent materials premised on alkali-activated binding agents were examined. Subsequently, the primary variables influencing the performance of cementitious materials, encompassing Portland cement, were determined. Lastly, the compressive resilience traits of these substances were assessed under an array of carbonation curing circumstances. Tue, 01 Aug 2023 00:00:00 GMT https://scholarworks.bwise.kr/gachon/handle/2020.sw.gachon/89235 2023-08-01T00:00:00Z