• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.89-96
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• 2016

Compressive axial behavior of the variable cross-section soft ground reinforced foundation is investigated from the field load test results at ${\bigcirc}{\bigcirc}$ construction site in Incheon city. Variable cross-section soft ground reinforced foundation is a type of partial-displacement pile formed by mixing bidding material with in situ soils to obtain a rigid and strong variable cross-section column in a relatively soft ground. The foundations are usually constructed as a group; however in this study, only single foundation was installed and tested under compressive axial load on foundation head. For the comparison of the variable cross-section soft ground reinforced foundation axial behavior, behavior of typical Pretensioned spun high strength concrete (PHC) pile constructed on a relatively soft ground near the surface was analyzed. It was concluded that variable cross-section soft ground reinforced foundation efficiently resists against axial load with sufficient stiffness and strength within a considerable range of axial load magnitude.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.210-221
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• 2009

A new foundation type which is called Top-Base method has been used frequently in engineering practices in Korea. In this study, the settlement behavior of concrete Top-Base foundation on soft ground is investigated since the consolidation settlement of the embedding depth and the effect of footing dimensions are not included in current Korean criterion (2007). To obtain detailed information, the model tests of the Top-Base foundation are performed using the PLAXIS 3D finite element analysis. It is shown that in-situ measurements and finite element analysis of the behavior of foundations indicate that consolidation settlement is reduced up and bearing capacity of the foundation increases up to 50%~100%, compared to the primary non-treated ground. Based on this study, it is found that the Top-Base foundation prevents the lateral deformation of soft ground and reduces its negative dilatancy to the surface settlement, and that the foundation creates rather uniform stress distribution under it to increase its bearing capacity. It is also found that the total settlement of Top-Base foundation was highly dependent on the consolidation settlement and footing configurations.

• Journal of the Korean Professional Engineers Association
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• v.37 no.3
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• pp.50-53
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• 2004

JSP(Jumbo Super Pile) method is a foundation treatment of mixing in depth, one of the soft ground improvement methods through which settlement and deformation of ground foundation is prevented. An example of this method which is applied for the foundation design of a new drainage pumping station is Introduced, and another applied example for an existing pumping station which is built on soft foundation is also introduced.

• Journal of Korean Port Research
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• v.10 no.2
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• pp.69-90
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• 1996

This study is related to save the bearing capacity from using Meyerhof formula namely, static mechanics formula with the S.P.T(N value) of the soft ground and is to choose the soft ground improvement method by the using of total load for the proper method of the pile foundation and then to design the most suitable pile foundation to fit the actual circumstance. The purpose of this study is calculating the diameter of the pile foundation by static mechanics formula and introducing the optimum design condition from the result of the bearing capacity for using N value of the S.P.T obtained from the deep soft ground about the piles such as P.H.C pile, pipe and cast-in-place pile of big diameter, etc. As above-mentioned, it is considered that the use of P.H.C pile or pipe pile is advisable on the synthetical investigation and that the selection of cast-in-place pile method is desirable in terms of the constructive safety and durability.

• Geomechanics and Engineering
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• v.24 no.6
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• pp.559-572
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• 2021

This research presents the monitoring results and their interpretation on load sharing of the pile foundation during the construction of a high-rise (124 m in height) building in Bangkok, in soft clayey ground. Axial forces in several piles, pore water pressure and earth pressures beneath the raft in a tributary area were monitored through the construction period of the building. The raft of the pile foundation in soft clayey ground can share the load up to 10-20% even though the foundation was designed using the conventional approach in which the raft resistance is ignored. The benefit from the return of ground water table as the uplift pressure is recognized. A series of parametric study by 3D-FEA were carried out. The potential of utilizing the piled raft system for the high-rise building with underground basement in soft clayey ground was preliminarily confirmed.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.932-939
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• 2005

Recently, the lateral displacement of the passive piles which installed under the revetment on soft ground is very important during the land reclamation work along the coastal line. The revetment on the soft clay develops the lateral displacement of the ground when the revetment loading is exceeded a certain limit. The lateral displacement of ground causes an excessive deformation of under structure itself and develops lateral earth pressure against the pile foundation as well. Especially passive piles subjected to lateral earth pressures are likely to have excessive horizontal displacement and large bending moment, which induces structural failure of pile foundation and harmful effects on superstructure. The subject of study is to investigate the later displacement of pile foundation during the construction of container terminal at the south port of Incheon. Actual field measurement data and finite element method(FEM) by AFFIMEX Ver 3.4 were used to analyze the displacement of pile and the vertical settlement of soft ground. This analysis was carried out at each sequence of construction work.

• Tunnel and Underground Space
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• v.20 no.2
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• pp.105-111
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• 2010

This study is to consider applicability of spiral bolt strain gauge as an instrument measuring behavior of soft ground foundation and rock slope. When the instrument was installed on the ground, it can be useful to identify the state of ground behavior because it has the characteristics of flexibility, as well as to apply the ground reinforcement because it has higher pull-out resistance to the ground. From the measurement of behavior to soft ground foundation, the strain shows a stable state in the beginning, then was observed significant change in the upper and the middle of spiral bolt strain gauge after 400 days. This is analyzed that ground loosening, which is due to occurred frequent earthquake of magnitude 1~2 with increased rainfall, lead to the instability of the ground. From the measurement of behavior to rock slope, the strain shows a stable state with very little change in a period of 0~50 days and the biggest strain at 4.2 m (P6) in a period of 50~100 days, then other places except P6 was maintained at a stable state in a period of 100~160 days. The reason is analyzed because that blasting for excavated limestone surrounding was affected to the largest at P6. However, based on the size of strain change by behavior of the soft ground foundation and rock slope, it is considered that the present condition are not effected on stability of retaining structure and rock slope. In conclusion, the proposed spiral bolt strain gauge can be useful to measure behavior of soft ground foundation and rock slope, and also to be measured behavior as well as reinforcement of the target ground.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.142-143
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• 2021

The general ground conditions in Korea are distributed in order of fill, deposit soil, weathered soil, weathered rock, soft rock. The fill soil and deposit soil located at the top have relatively low strength compared to the lower layer, and they are sometimes classified as soft ground according to the standard penetration test results. In this study, the PF method, a ground improvement method, was applied to the soft layer, a large plate load test was conducted on the improved ground, and the results were reviewed.

• The Journal of Engineering Geology
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• v.30 no.2
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• pp.131-145
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• 2020

The construction on these flimsy ground, activation of unsymmetrical surcharges, can often cause of the embankment road lateral flow or the destruction of the activities. In this study, the stability of the abutment pile foundation installed on soft ground and its behavior has been evaluated. The behavior of the abutment pile foundation under lateral flow was studied by verifying the behavior and reinforcement effects of the abutment pile foundation of previous studies about horizontal loads acting on the pile due to the lateral flow of the ground by performing finite element analysis. As a result of the consolidation analyses, the undrained cohesion or the strength of the soft ground, was increased by about 1.1 to 1.8 times by the increase in the strength of the soft ground according to the degree of consolidation. It is deemed reasonable to use 3.8 cm of the allowable displacement both economically and constructively, but considering the importance of the structure and the uncertainty of the ground, measurement shall be carried out during construction and thorough safety management of the lateral flow should be done.

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