• Journal of the Korean Geotechnical Society
• /
• v.15 no.5
• /
• pp.141-155
• /
• 1999

Korea Ocean Research & Development Institute(KORDI) conducted an offshore geotechnical investigation for the Eardo Ocean Research Station with the help of the Fugro International Limited at a site location approximately 152 km away from Mara Island, Korea. The primary purpose of the geotechnical investigation was to obtain information on soil and foundation conditions, and to develop foundation design data for a fixed offshore observation platform. This paper discussed the details of the geotechnical investigation and the foundation design recommendations for the Ocean Research Station. Clear recommendations were proposed for the foundation type of driven pile considering the existing soil conditions.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.09a
• /
• pp.157-171
• /
• 2009

A 151 storey super high-rise building located in an area of reclaimed land constructed over soft marine clay in Songdo, Korea is currently under design. This paper describes the design process of the foundation system of the supertall tower, which is required to support the large building vertical and lateral loads and to restrain the horizontal displacement due to wind and seismic forces. The behaviour of the foundation system due to these loads and foundation stiffness influence the design of the building super structure, displacement of the tower, as well as the raft foundation design. Therefore, the design takes in account the interactions between soil, foundation and super structure, so as to achieve a safe and efficient building performance. The site lies entirely within an area of reclamation underlain by up to 20m of soft to firm marine silty clay, which overlies residual soil and a profile of weathered rock. The nature of the foundation rock materials are highly complex and are interpreted as possible roof pendant metamorphic rocks, which within about 50m from the surface have been affected by weathering which has reduced their strength. The presence of closely spaced joints, sheared and crushed zones within the rock has resulted in deeper areas of weathering of over 80m present within the building footprint. The foundation design process described includes the initial stages of geotechnical site characterization using the results of investigation boreholes and geotechnical parameter selection, and a series of detailed two- and three-dimensional numerical analysis for the Tower foundation comprising over 172 bored piles of varying length. The effect of the overall foundation stiffness and rotation under wind and seismic load is also discussed since the foundation rotation has a direct impact on the overall displacement of the tower.

• Geomechanics and Engineering
• /
• v.22 no.4
• /
• pp.305-318
• /
• 2020

Stone columns are widely used to treat soft clay ground. Optimizing the design of stone columns based on cost-effectiveness is always an attractive subject in the practice of ground treatment. In this paper, the design of stone columns is optimized using the concept of robust geotechnical design. Standard deviation of failure probability, which is a system response of concern of the stone column-reinforced foundation, is used as a measure of the design robustness due to the uncertainty in the coefficient of variation (COV) of the noise factors in practice. The failure probability of a stone column-reinforced foundation can be readily determined using Monte Carlo simulation (MCS) based on the settlements of the stone column-reinforced foundation, which are evaluated by a deterministic method. A framework based on the concept of robust geotechnical design is proposed for determining the most preferred design of stone columns considering multiple objectives including safety, cost and design robustness. This framework is illustrated with an example, a stone column-reinforced foundation under embankment loading. Based on the outcome of this study, the most preferred design of stone columns is obtained.

• Geotechnical Engineering
• /
• v.12 no.3
• /
• pp.73-82
• /
• 1996

Limit state design(LSD) principles employing load and resistance factor design(LRFD) are coming into use in geotechnical engineering community around the world. Current working (allowable) stress design principles are expected to be replaced by LRFH method in the near future. North America has recently adopted LRFD principles, and European community has also developed its own code called "Eurocode" based on partial safety factor design which is essentially the same as LRFD. Relevant review and analysis of new global design codes are prerequisites to adopting these codes in the Korean construction industry and in the Korean foundation design prac titre. This paper reviews geotechnical aspects of LRFD and Eurocode, and analyzes the geomaterial resistance factors in LRFD for the design of axially-loaded driven piles.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.07a
• /
• pp.35-52
• /
• 1999

This paper addresses on new codes of practice, limit state design; load resistance factored design and Eurocode 7, which have recently been adopted by foundation engineers in North America and European Communities. A brief description of the limit state design concepts and some introductions to Australia and Sweden national code for pile foundation are made on behalf of pile capacity determination. Also, simple closed form solution for rational resistance factor when resistance is log-normally distributed, has been derived for pile foundation.

• Coupled systems mechanics
• /
• v.8 no.6
• /
• pp.523-535
• /
• 2019

Artificial Intelligence (AI) is anticipated to be the future of technology. Hence, AI has been applied in various fields over the years and its applications are expected to grow in number with the passage of time. There has been a growing need for accurate, direct, and quick prediction of geotechnical and foundation engineering models especially since the success of each project relies on numerous amounts of data. In this study, two applications of AI in the field of geotechnical and foundation engineering are presented - spatial interpolation of standard penetration test (SPT) data and prediction of consolidation of clay. SPT and soil profile data may be predicted and estimated at any location and depth at a site that has no available borehole test data using artificial intelligence techniques such as artificial neural networks (ANN) based on available geospatial information from nearby boreholes. ANN can also be used to accelerate the calculation of various theoretical methods such as the one-dimensional consolidation theory of clay with high efficiency by using lesser computation resources. The results of the study showed that ANN can be a valuable, powerful, and practical tool in providing various information that is needed in geotechnical and foundation design.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.486-493
• /
• 2010

Recently, it has been a worldwide issue to develop offshore wind farm based on the past technical experiences of onshore wind turbine installation. In Korea, the government has the wind-energy to be a new-sustainable field of development to bring green-growth in near future and put political and fiscal efforts to support the academic and industrial technical development. Especially, there are much advancement for the fields of turbine, blade, bearing, grid connection, ETC. Correspondingly, technical needs do exist for the offshore foundation installation techniques in geotechnical point of view. Within few years, 2~5MW offshore wind turbines will be constructed at about 30m water depth and it is known that monopiles of D=4~6m are suitable types of foundation. In order to construct offshore wind-turbine foundation, technical developments for drilling machine, design manual, monitoring&maintenance technique are required. This paper presents technical issues with related to offshore wind farm and large diameter monopile in the point of renewable energy development.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.549-558
• /
• 2008

Well known and widely used in urban area and limited installation condition, a low noise and vibration piling method which has being called Bored Prefabricated Piling Method was reviewed in terms of design guide, and introduced a few case as well. Among the areas being applied of that method, a structural guide of architectural foundation was reviewed and compared to civil engineering foundation area to provide wider information for the foundation engineers. With introducing a few case application including pile load testing review especially dynamic testing in normal building foundation work, engineers may have a useful information on the design and construction of the piling method even different engineering area. It may also make enhancement a view of foundation engineering knowledge to various pile foundation area.

• Geomechanics and Engineering
• /
• v.21 no.1
• /
• pp.73-84
• /
• 2020

In the seismic design of bridges, formation of plastic hinges plays an important role in the dissipation of seismic energy. In the case of conventional fixed-base bridges, the plastic hinges are allowed to form in the superstructure alone. During seismic event, such bridges may be safe from collapse but the superstructure undergoes significant plastic deformations. As an alternative design approach, the plastic hinges are guided to form in the soil thereby utilizing the inevitable yielding of the soil. Rocking foundations work on this concept. The formation of plastic hinges in the soil reduces the load and displacement demands on the superstructure. This study aims at evaluating the seismic response of bridge pier supported on rocking shallow foundation. For this purpose, a BNWF model is implemented in OpenSees platform. The capability of the BNWF model to capture the SSI effects, nonlinear behavior and dynamic loading response are validated using the centrifuge and shake table test results. A comparative study is performed between the seismic response of the bridge pier supported on the rocking shallow foundation and conventional fixed-base foundation. Results of the study have established the beneficial effects of using the rocking shallow foundation for the seismic response analysis of the bridge piers.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.571-578
• /
• 2009

Recently, micropiling techniques are increasingly applied in foundation rehabilitation/underpinning and seismic retrofitting projects where working space provides the limited access for conventional piling methods. Micropiling techniques provide environmental-friendly methods for minimizing disturbance to adjacent structures, ground, and the environment. Its installation is possible in restrictive area and general ground conditions. The cardinal features that the installation procedures cause minimal vibration and noise and require very low ceiling height make the micropiling methods to be commonly used for underpin existing structures. In the design point of view, the current practice obligates the bearing capacity of micropile to be obtained from skin friction of only rock-socketing area, in which it implies the frictional resistance of upper soil layer is ignored in the design process. In this paper, a new micropiling method and its verification studies via field installation are presented. The new method provides a specific way to grout bore-hole to increase frictional resistance between surrounding soil and pile-structure and it allows to consider the skin friction of micropiles for upper soil layer during design process.