• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 춘계학술대회 논문집
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• pp.190-195
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• 2001

In the present paper computational simulation of a concrete dam is performed to determine the effect of vertical ground motions on earthquake response of concrete dams. Cyclic and dynamic versions of the plastic-damage model proposed by Lee and Fenves are used to represent micro-crack development and crack opening/closing, which is important mechanism in nonlinear damage analysis of concrete structures subject to strong earthquake loading. The result shows that the vertical component of ground motion effects on final crack patterns and consequently, on displacement response.

• 대한기계학회논문집B
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• 제28권7호
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• pp.755-762
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• 2004

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2007년 가을학술발표회
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• pp.305-316
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• 2007

Free field ground motion during earthquake is significantly affected by the local soil conditions and it is essential for the seismic design to perform the site specific ground response analysis. So, Round Robin Test (RRT) on ground response analysis was performed for three sites in Korea. A total of 12 teams presented the results of ground response analysis with used input soil properties based on own judgement. In this paper, the results of one dimensional equivalent linear analysis presented by 11 teams were compared to evaluate the effect of input soil properties on ground response analysis. Additionally, 4 influence factors on ground response analysis, that is shear wave velocity of soil layer, nonlinear dynamic deformational characteristics, bedrock depth and bedrock velocity were studied for assumed simple soil conditions.

• 한국안전학회지
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• 제23권6호
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• pp.131-137
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• 2008

SCP(Sand Compaction Pile) method that forms a composite ground by driving compacted sand piles into the soft ground. This method is one of the soil improvement techniques for reinforcing and strengthening soft ground deposits. This thesis describes the investigation on the behavior of soft ground reinforced with SCP by low improvement ratio. Direct shear test and consolidation test carried out to verified behavior of composite ground reinforced with SCP. Test results were discussed with reference to the amount of consolidation settlement, variation of shear resistance with area replacement ratio and effect of the stress concentration. And, laboratory model loading test carried out to verified the effect of the location and failure mode of reinforced embankment. Residual shear strength varies with the area replacement and constrict load in the low replacement ratio. Calculated stress concentration ratio overestimate than proposed valve by experimental, theoretical and analytical method. As regards the location, improving right below of the top of the slope was more effective than below of the toe of the slope. This thesis carried out to obtain fundamental information of behavior of the composit ground. Hereafter, centrifuge test that reproduce stress state of the in-situ must be necessary through the further study about pile penetration, reinforce position and construct time.

• 한국운동역학회지
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• 제25권3호
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• pp.257-263
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• 2015

Objective : The purpose of this study was to investigate the effect of genu valgum on the body mass index, movement of lower limb joints, and ground reaction force. Methods : Gait patterns of 30 college students with genu valgum were analyzed and the static Q angle of the femur was measured for selecting genu valgum of the subjects. To analyze the kinetic changes during walking, the six-camera Vicon MX motion analysis system was used. The subjects were asked to walk 12 meters using the more comfortable walking method for walking. After they walked 12 meters more than 10 times, their most natural walking patterns were chosen three times and analyzed. Results : As a result of measuring a relationship between genu valgum and Q-angle, as the Q-angle increases, it showed a genu valgum also increased. Body Mass Index showed a significant difference between the groups was higher in the genu valgum group.(p<.001). The analysis result showed that genu valgum had a significant effect on the internal rotation moment in the hip joint(p<.05). Also, genu valgum had a significant effect on the internal rotation moment of the knee joint(p<.05). The comparative analysis of the Medial-Lateral ground reaction force in the genu valgum group showed a tendency to increase the medial ground reaction force(p<.05). The vertical ground reaction forces of the middle of the stance phase(Fz0) showed a significant increase in genu valgum group(p<.05), in particular the results showed a decrease in the early stance phase(p<.001). Conclusion : In conclusion, the change in body mass is considered to be made by proactive regular exercise for improvement of the genu valgum. In addition, the prevention of the deformation caused by secondary of the genu valgum in this study may be used as an indicator of the position alignment rehabilitation for structural and functional improvements. Applying a therapeutic exercise program for the next lap will require changes in posture alignment.

• 한국축산식품학회지
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• 제38권5호
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• pp.936-949
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• 2018

Changes in microbial community and physicochemical traits of chicken summer sausage made from spent layer thigh added with different level (0%, 0.1%, 0.3%, and 0.5% w/w) of ground chopi (Zanthoxylum piperitum) during manufacture were analyzed. The microbial community was profiled and analyzed by sequencing 16S rRNA gene using Illumina MiSeq. Samples were taken from raw sausage batter, after 15 h of fermentation, 8 h of cooking including cooling down, and 7 d of drying. The final pH of the sausage was reduced by the addition of ground chopi. However, no clear effect on water activity was observed. Ground chopi inhibited the development of red curing color after fermentation as it exhibited antimicrobial effect. However, the effect on species richness and microbial composition after cooking was unclear. Ground chopi delayed lipid oxidation during manufacture and the effect was dependent on the addition level. Fermentation reduced the species richness with a dominancy of lactic acid bacteria. The profile of microbiota in the raw batter was different from other stages, while the closest relationship was observed after cooking and drying. Proteobacteria was predominant, followed by Firmicutes and Bacteroidetes in raw samples. Firmicutes became dominating after fermentation and so forth, whereas other predominant phylum decreased. At genus level, unclassified Lactobacillales was the most abundant group found after fermentation and so forth. Therefore, the overall microbial composition aspects were mainly controlled during fermentation by the abundance of lactic acid bacteria, while bacterial counts and lipid oxidation were controlled by cooking and the addition of ground chopi.

• 한국산학기술학회논문지
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• 제19권12호
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• pp.279-286
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• 2018

그라우팅공법은 지반강화와 차수를 위한 공법으로 약액을 주입하여 지반을 고화시키는 것이다. 시멘트계 그라우트 주입재는 수세기 전부터 보통 포틀랜드 시멘트를 사용하였으나 시멘트 입경이 커 주입효과에 한계가 있다. 이에 본 연구는 초미립자 시멘트가 사용된 암반지반에서의 그라우팅 주입효과를 분석하기 위함이다. 이를 위해 초미립자 시멘트로 3S-1호가 사용되었고, OPC와 3S-1호를 각각 적용하여 암반그라우팅 현장시험시공을 실시하였으며 수압시험 공내재하시험 주입시험을 통해 그 결과를 비교분석 하였다. 시험 결과, 암반지반에서는 OPC보다 초미립자 시멘트(3S-1호)를 사용하는 것이 차수효과(K, $10^{-6}cm/sec$)가 더 높으며 보강효과도 확인할 수 있었다. 또한 초미립자 시멘트(3S-1호)가 OPC보다 약 4~9배 주입성이 더 높은 것으로 나타났다. 따라서 본 연구는 암반그라우팅 시공시 OPC대신 초미립자 시멘트를 적용하는 것이 더 유리한 것으로 판단이 된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.224-231
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• 2005

The ground excavation causes the deformation of the ground where the neighborhood structure is located. The ground deformation result in the vertical settlement of the neighborhood structure as well as the horizontal displacement of the temporary earth retaining structures. The decreased volume of the soil due to the ground settlement is defined as 'the ground loss quantity' or 'the ground loss'. When excavation is performed nearby existing structures, retaining walls should be designed and constructed to minimize the ground loss. Among various methods for reducing the ground loss, this study introduces the pre-loading method which has been recently developed. The reduction effect of the ground loss by pre-loading has been found to be larger as using a wall with relatively smaller rigidity.

• Geomechanics and Engineering
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• 제29권2호
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• pp.133-143
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• 2022

The catastrophic earthquake-induced failure of slopes concentrically distributed at near-fault area, which indicated the special features of near-fault ground motions, i.e. horizontal pulse-like motion and large vertical component, should have great effect on these geo-disasters. We performed shaking table tests to investigate the effect of both horizontal pulse-like motion and vertical component on dynamic response of slope. Both unidirectional (i.e., horizontal or vertical motions) and bidirectional (i.e., horizontal and vertical components) motions are applied to soft rock slope model, and acceleration at different locations is reordered. The results show that the horizontal acceleration amplification factor (AAF) increases with height. Moreover, the horizontal AAF under unidirectional horizontal pulse-like excitations is larger than that subject to ordinary motion. The vertical AAF does not show an elevation amplification effect. The seismic response of slope under different bidirectional excitations is also different: (1) The horizontal AAF is roughly constant under horizontal pulse-like excitations with and without vertical waves, but (2) the horizontal AAF under ordinary bidirectional ground motions is larger than that under unidirectional ordinary motion. Above phenomena indicate that vertical component has limited effect on seismic response when the horizontal component is pulse-like ground motion, but it can greatly enhance seismic response of slope under ordinary horizontal motion. Moreover, the vertical AAF is enhanced by horizontal motion in both horizontal pulse-like and ordinary motion. Thence, we should pay enough attention to vertical ground motion, especially its horizontal component is ordinary ground motion.

• Structural Engineering and Mechanics
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• 제70권2호
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• pp.143-152
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• 2019

In this study, stochastic responses of a cable-stayed bridge subjected to the spatially varying earthquake ground motion are investigated for variable local soil cases and wave velocities. Quincy Bay-view cable-stayed bridge built on the Mississippi River in Illinois, USA selected as a numerical example. The bridge is composed of two H-shaped concrete towers, double plane fan type cables and a composite concrete-steel girder deck. The spatial variability of the ground motion is considered with the coherency function, which is represented by the components of incoherence, wave-passage and site-response effects. The incoherence effect is investigated by considering Harichandran and Vanmarcke model, the site-response effect is outlined by using hard, medium and soft soil types, and the wave-passage effect is taken into account by using 1000, 600 and 200 m/s wave velocities for the hard, medium and soft soils, respectively. Mean of maximum response values obtained from the analyses are compared with those of the specific cases of the ground motion model. It is concluded that the obtained results from the bridge model increase as the differences between local soil conditions cases of the bridge supports change from firm to soft. Moreover, the variation of the wave velocity has important effects on the responses of the deck and towers as compared with those of the travelling constant wave velocity case. In addition, the variability of the ground motions should be considered in the analysis of long span cable-stayed bridges to obtain more accurate results in calculating the bridge responses.