• Geomechanics and Engineering
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• 제34권4호
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• pp.397-408
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• 2023

Pipe pile walls are commonly used as retaining structures for excavation projects, particularly in densely populated coastal cities such as Hong Kong. Pipe pile walls are preferred in reclaimed land due to their cost-effectiveness and convenience for installation. However, the pre-bored piling techniques used to install pipe piles can cause significant ground disturbance, posing risks to nearby sensitive structures. This study reports a well-documented case history in a reclamation site, and it was found that pipe piling could induce ground settlement of up to 100 mm. Statutory design submissions in Hong Kong typically specify a ground settlement alarm level of 10 mm, which is significantly lower than the actual settlement observed in this study. In addition, lateral soil movement of approximately 70 mm was detected in the marine deposit. The lateral soil displacement in the marine deposit was found to be up to 3.4 and 3.1 times that of sand fill and CDG, respectively, mainly due to the relatively low stiffness of the marine deposit. Based on the monitoring data and site-investigation data, a 3D numerical analysis was established to back-analyze soil movements due to the installation of the pipe pile wall. The comparison between measured and computed results indicates that the equivalent ground loss ratio is 20%, 40%, and 20% for the fill, marine deposit and CDG, respectively. The maximum ground settlement increases with an increase in the ground loss ratio of the marine deposit, whereas the associated influence radius remains stationary at 1.2 times the pipe pile wall depth (H). The maximum ground settlement increases rapidly when the thickness of marine deposit is less than 0.32H, particularly for the ground loss ratio of larger than 40%. This study provides new insights into the pipe piling construction in reclamation sites.

• Coupled systems mechanics
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• 제5권3호
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• pp.203-221
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• 2016

The present study deals with the numerical modelling for the one dimensional contaminant transport through saturated homogeneous and stratified porous media using meshfree method. A numerical algorithm based on element free Galerkin method is developed. A one dimensional form of the advectivediffusive transport equation for homogeneous and stratified soil is considered for the analysis using irregular nodes. A Fortran program is developed to obtain numerical solution and the results are validated with the available results in the literature. A detailed parametric study is conducted to examine the effect of certain key parameters. Effect of change of dispersion, velocity, porosity, distribution coefficient and thickness of layer is studied on the concentration of the contaminant.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1994년도 봄 학술발표회 논문집
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• pp.137-144
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• 1994

In this study, a new procedure for solving 2-D dynamic problems of semi-infinite medium in time domain by boundary element method (BEM) is presented. Efficient modelling of the far field region, infinite boundary elements are introduced. The shape function of the infinite boundary element is a combination of decay functions and Laguerre functions. Though the present shape functions have been developed for the time domain analysis, they may be also applicable to the frequency domain analysis. Through the response analysis in a 2-D half space under a uniformly distributed dynamic load, it has been found that an excellent accuracy can be achieved compared with the analytical solution

• 환경영향평가
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• 제2권2호
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• pp.49-53
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• 1993

Before the EIA was established in the Federal Republic of Germany, the impact mitigation principle - a planning instrument, which has its legal foundation in the German nature conservation legislation already had {and still has} the function to valuate environmental impacts. The valuation principles and methods which have been developed in correlation to this instrument are now also used in the EIA. Particularly for the valuation of alternating effects on the different ecological landscape functions and for the valuation of ecological mitigation and compensation measures this valuation methods are used. These methods base on a special kind of modelling nature and environment Following the aim of the nature conservation act, which is to save the capacity of the landscape to perform its essential functions, not the ecological factors (soil, water, air etc.) itselfs are evaluated but the ecological functions of the landscape, which are based on the ecological factors.

• 한국농공학회논문집
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• 제47권5호
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• pp.43-49
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• 2005

In this study. it was suggested that the elastic model to analyze the behavior of pore water pressure in saturated sand specimen on the condition of non-drainage. The model based on the experiments which were performed for the relationships between the pore water pressure and the grain size of specimen, and effective stress, respectively. The suggested model embodied the pore water and soil grain as separate elastic springs of different stiffness. The springs were joined parallel and the axial strains were restricted to the same deformation. The suggested model was well consistent with the experiments.

• Geomechanics and Engineering
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• 제3권1호
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• pp.17-28
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• 2011

This paper presents an analytical solution for steady state flow into a close-ended cylindrical permeameter. The soil medium is considered to be uniform, isotropic, and of infinite thickness. Laplace equation is solved by considering rotational symmetry and by using curvilinear coordinates obtained from conformal mapping. The deduced shape factors, which are compared to approximate relationships obtained from both numerical and physical modelling, and idealizations involving ellipsoidal cavities, are proposed for use in field measurements. It is shown that some of the shape factors obtained are significantly different from published values and show a much higher dependence of the rate of flow on the aspect ratio, than deduced from approximate solutions.

• 한국해양공학회지
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• 제18권3호
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• pp.20-25
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• 2004

For the structural foundation above the soft clay layer conditions, the design charts are first presented for the evaluation of both bearing capacity and total settlement in the basic raft foundation system. wad settlement relationship curves are used to evaluate the ultimate soil bearing capacity. The total settlement is evaluated by applying various traditional factors into the ultimate bearing capacity. Then, the parametric studies are carried out for the piled-raft foundation system. In the numerical analysis, the elasto-pastic finite element model(Mohr-Coulomb model) is used to present the foundation response and design charts, which enable the determination of the raft size and pile length and spacing.

• 한국지반환경공학회 논문집
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• 제9권3호
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• pp.5-9
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• 2008

하수관거는 지중에 매설되기 때문에 균열발생 시 오염원이 빠르게 지하로 침투되어 오염을 야기한다. 본 연구에서는 하수관거 균열발생 시의 오염원의 확산에 대한 수치모델링을 수행하였다. 모델링 수행 결과를 이용하여 오염원의 이동경로를 예측해보았으며, 다음과 같은 결론을 얻었다. 오염원의 이동방향은 지표면의 지형경사에 따른 흐름과 비슷한 경향을 보이는 것으로 나타났으며, 지하방향으로는 약 8~10m 깊이까지 침투되는 것으로 나타났다. 본 연구를 통하여 장래 하수관거 관리에 효율성을 제공할 것으로 기대된다.

• Geomechanics and Engineering
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• 제21권3호
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• pp.237-245
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• 2020

The process of evaporation from free water surface was simulated in a large scale environmental chamber under various controlled atmospheric conditions and also was modelled by a new mass transfer model. Six evaporation tests were conducted with increasing wind speed and air temperature in the environmental chamber, and hence the effect of atmosphere parameters on the evaporation process and the corresponding response of water were investigated. Furthermore, based on the experiment results, seven general types of mass transfer models were evaluated firstly, and then a new model consisted of wind speed function and air relative humidity function was proposed and validated. The results show that the free water evaporation is mainly affected by the atmospheric parameters and the evaporation rate increases with the increasing air temperature and wind speed. Both the air and soil temperatures are affected by the energy transformation during water evaporation. The new model can satisfactorily describe the evaporation process from free water surface under different atmospheric conditions.

• 대한원격탐사학회지
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• 제23권1호
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• pp.15-20
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• 2007

This study is to apply QuickBird satellite image for the simulation of storm runoff in a small rural watershed. For a $1.05km^2$ watershed located in Goesan-Gun of Chungbuk Province, the land use from the QuickBird image was produced by on-screening digitising after ortho-rectifying using 2 m DEM. For 3 cases of land use, soil and elevation scale (1:5,000, 1:25,000 and 1:50,000), SCS-CN and the watershed physical parameters were prepared for the storm runoff model, HEC-HMS (Hydrologic Modelling System). The model was evaluated for each case and compared the simulated results with couple of selected storm events.