• Water for future
• /
• v.15 no.4
• /
• pp.13-29
• /
• 1982

본 논문은 제15권 제3호(1982년 9월)의 제(I)보에 이어 기재되는 제(II)보이다. 제(I)보에서는 1. 서론 2. 분석기법과 수질모형의 이론, 3. 분석자료의 목차 순으로서 연구의 내용과 이론적 근거와 분석에 필요한 자료를 정리하여 제시하였다. 본 연구의 목적은 노량진 및 뚝도 지점의 DO, 탁도, 수온등의 특정수질에 대하여 (1) 수질의 주기성 발견, (2) 수질변동의 특성파악, (3) 시별 DO에 대한 자기 회귀모형의 추론, (4) 일별 DO에 대한 ARIMA 모형의 적용평가에 대한 것이다.

• The Hankook-Saengyark Bo
• /
• no.225
• /
• pp.1-1
• /
• 1998

• The monthly packaging world
• /
• s.224
• /
• pp.50-51
• /
• 2011

• Journal of the Korean Geotechnical Society
• /
• v.16 no.4
• /
• pp.31-42
• /
• 2000

In this study, the stability of group piles installed in deep sea to the seaquake was studied by performing the calibration chamber model tests for open-ended pipe piles, grouted piles under soil plug and close-ended piles installed in the simulated deep sea. For each case (a single pile, 2-pile and 4-pile groups), series of seaquake tests were performed. While, during the simulated seaquake, the compressive capacity of the single open-ended pile depended on pile penetration depth(=7m), were found to be stable. But, a single grouted pile with penetration depth of 13m kept "mobility" state, the one with penetration depth of 20m was stable and grouted pile groups with penetration depth of 7m were stable regardless of pile penetration depth. By grouting soil plug of open-ended piles and soil under the pile toe of open-ended pipe piles installed in the deep sea, failure of soil plugging was prevented. Thus, close-ended piles were more stable than open-ended pile against the seaquake motionake motion.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.42 no.4
• /
• pp.509-517
• /
• 2022

The demand for underground infrastructures such as tunnels is expanding due to rapid urbanization. Tunnels in urban areas are usually constructed adjacent to structures supported by piles. Therefore, a proper understanding of pile-tunnel interaction due to tunnel excavation activities is vital. Thus, in this study, a numerical analysis is conducted to analyze pile settlements, ground surface settlements and shear deformations above an existing tunnel subject to the presence of an adjacent tunnelling, with vertical offsets, the number of piles and the pile spacing considered as variables in the analysis. The results show that the vertical offsets between the tunnel crown and the pile tip generatelarger settlement than the pile spacing. In addition, the vertical offset shows an inversely proportional relationship to the shear deformation due to new tunnelling.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.8
• /
• pp.25-31
• /
• 2006

Over the years the investigation of behaviour of piles in groups connected to a cap in consolidating soil has attracted far less attention than the study of isolated piles in groups. In this paper, a series of three-dimensional numerical simulations have been performed to study the behaviour of pile groups connected to a cap in consolidating ground. Both elastic no-slip and elasto-plastic slip analyses were considered. Based on the analysis results, when piles were connected to a cap, tensile forces were developed near the pile head at the outer piles. Elastic solution and no-slip analysis over-predicted the tensile force near the pile head for outer piles. Relatively speaking, the number of piles in a group is more important than the pile spacing in terms of the influence of negative skin friction on the pile behaviour. The issue on the development of tensile forces on the pile head at the outer piles is perhaps needed to be carefully considered in the pile design to prevent the damages of the pile-cap connection.

• Journal of the Korean Geotechnical Society
• /
• v.21 no.5
• /
• pp.15-24
• /
• 2005

Modeling techniques of piled pier were reviewed and the influences of pile cap's boundary conditions were analyzed in this study. The method using flexible springs seems to be useful fur the practical design since its simplified model can represent the complex behaviors of pile groups efficiently. Parameter studies were performed far various pile group arrangements, pile spacings, end bearing conditions, and loading stages to analyze their effects on the lateral displacements, maximum pile bending stresses, and lateral stiffness of pile groups. Through the parameter studies, it was found that when lateral stiffness of pile groups was estimated by using three-dimensional analysis method (YSGroup), its complex behavior could be predicted better than other methods based on single pile analysis.

• Journal of the Korean Geotechnical Society
• /
• v.23 no.9
• /
• pp.39-49
• /
• 2007

The load deformation behavior of the cap-pile-soil system is investigated, based on numerical analysis. Special attention is given to consideration of pile cap flexibility. Rigid pile cap analysis and flexible cap analysis were conducted for comparison. A numerical method that takes into account the coupling between the rigidities of the piles, the cap, and the column has been introduced to analyze the response of pile group supported columns. The prediction of the lateral loads and bending moments in the pile cap is much more conservative for a flexible cap than for a rigid cap.

• Journal of the Korean GEO-environmental Society
• /
• v.17 no.7
• /
• pp.15-25
• /
• 2016

In the present work, a number of advanced three-dimensional (3D) parametric finite element numerical analyses have been conducted to study the behaviour of single piles and pile groups in consolidating ground from coupled consolidation analyses. Single piles, $4{\times}4$ and $6{\times}6$ piles inside groups with a spacing of 2.5D were considered, where D is the pile diameter. It has been found that dragload and downdrag on the piles developed rather quickly at the early stage of consolidation. However, when the degree of consolidation was more than 50~75%, only little increases of dragload and downdrag were induced on the pile. Negative Skin Friction (NSF) on the pile in the fill layer was mobilised quickly and remained constant throughout further consolidation. The development of NSF is influenced both by the relative shear displacements at the pile-soil interface and the vertical effective soil stresses during consolidation. The former governed the early stage of consolidation and the latter affected the later stage of consolidation. The vertical effective soil stresses adjacent to the piles were reduced due to the shear stress transfer at the pile-soil interface, in particular for piles inside the pile groups. The range of NSF influence zone concerning the reductions of the effective vertical soil stresses was about 20D measured from the piles in the horizontal direction. On the contrary, the effective horizontal soil stresses acting on the piles were similar to those at the far field.

• Journal of the Korean Geotechnical Society
• /
• v.38 no.4
• /
• pp.47-58
• /
• 2022

Many 1g shaking table tests with an SDOF structure supported by a single pile were performed to evaluate the soil-structure interaction (SSI) effect. Since most structures supported by group piles are MDOF structures with columns, the SSI effect is simulated using a large 1g shaking table test and numerical analysis. According to the results, the movement in the piles tends to increase with input acceleration and when the input frequency is similar to the natural frequency. Furthermore, the slope of the dynamic p-y curve remains constant regardless of the variation of acceleration and input frequency. According to the results of the dynamic p-y backbone curve and the moment of group piles, a center pile with a leading pile has more soil resistance than side piles with a trailing pile, and the effect of group piles is observed above the 7D center to center pile distance.