• Geomechanics and Engineering
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• v.23 no.6
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• pp.523-533
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• 2020

The current study focuses on the effect of the end shape of steel pipe piles on installation effort and bearing resistance using the pressing method of installation under dense ground conditions. The effect of pile rotation on the installation effort and bearing resistance is also investigated. The model steel piles with a flat end, cone end and cutting-edge end were used in this study. The test results indicated that cone end pile with the pressing method of installation required the least installation effort (load) and showed higher ultimate resistance than flat and cutting-edge end piles. However, pressing and rotation during cutting-edge end pile installation considerably reduces the installation effort (load and torque) if pile penetration in one rotation equal to the cutting-edge depth. Inclusion of rotation during pile installation reduces the ultimate bearing resistance. However, if penetration of the cutting-edge end pile equal to the cutting-edge depth in one rotation, the reduction in ultimate resistance can be minimized. In comparing the cone and cutting-edge end piles installed with pressing and rotation, the least installation effort is observed in the cutting-edge end pile installed with penetration rate equal to the cutting-edge depth per rotation.

• Geomechanics and Engineering
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• v.20 no.2
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• pp.147-154
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• 2020

A novel approach for predicting lateral displacement caused by pile installation in anisotropic clay is presented, on the basis of the cylindrical and spherical cavities expansion theory. The K₀-based modified Cam-clay (K₀-MCC) model is adopted for the K₀-consolidated clay and the process of pile installation is taken as the cavity expansion problem in undrained condition. The radial displacement of plastic region is obtained by combining the cavity wall boundary and the elastic-plastic (EP) boundary conditions. The predicted equations of lateral displacement during single pile and multi-pile installation are proposed, and the hydraulic fracture problem in the vicinity of the pile tip is investigated. The comparison between the lateral displacement obtained from the presented approach and the measured data from Chai et al. (2005) is carried out and shows a good agreement. It is suggested that the presented approach is a useful tool for the design of soft subsoil improvement resulting from the pile installation.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1303-1311
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• 2006

Most of the piles are designed as group piles. In certain geotechnical environments, the installation of group piles causes heaving of the already installed piles. The unfavorable effects of pile heaving on pile bearing capacity have been well known to field engineers. However not many engineers pay enough attention to this subject. According to our recent researches, not only the bearing capacity but also the pile material could be seriously damaged due to the installation of nearby piles, especially with the cases of precast concrete piles. When the pull-out force due to installation of neighboring piles acting on the already installed precast concrete pile exceeds the shaft friction, pile heaving occurs. At the same time, if the pull-out force exceeds the allowable tensile strength of the precast concrete pile, tensile failure is inevitable, which is critical for the pile integrity. In other cases the pile material was not damaged but serious relaxation occurred as the results of pile heaving. In this paper, the pull-out mechanism due to the installation of group piles is explained.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.28-35
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• 2004

Driven pile has the excellent bearing characteristics and good economics, so it is known as the comparative piling method. To use the advantages of driven pile fully, it is necessary to perform the proper construction management. Engineers must drive pile to the proper bearing layer with proper blow energy and measure the blow count and penetration per certain depth to analyze the bearing capacity and driveability. In conventional method, these parameters have been measured manually so it was difficult to get good accuracy. After PIR-D(Pile Installation Recorder-Driven Pile) was attached to the driving equipment, the hammer efficiency, blow count and penetration in blow/10cm were measured automatically. In this paper, to givethe rational judgement criteria of bearing layer, driveability, blow/10cm according to pile depth during pile driving, the some relationship between the driving resistance and ground layer distribution was analyzed. The ground investigation during piles (PHC ${\Phi}450,\;{\Phi}400\;&\;Steel\;Pile\;{\Phi}609{\ast}16t$) installation in the marine clay layer in Incheon, the sandy soil layer in Yongin and the tuff layer in Pusan was done. And measuring hammer efficiency not doing recently, we could compare hammer efficiency(Eh) by PIR-D and energy transfer ratio(ETR) by Pile Dynamic Analyzer(PDA).

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.381-388
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• 1999

The existing methods for installation of long steel pipe pile have some uneconomical problems such as increase of installation cost and period due to the welding of two piles and removal of soil plug, and decrease of driving efficiency due to the increase of driving resistance by time effect during the welding of piles and removal of soil plug, etc. Thus, in this study, new installation method for long steel pipe pile is suggested to work out the existing problems, and calibration chamber tests are peformed to investigate both driving and economical efficiency for the suggested method. The test results showed that the new installation method has increase bearing capacity as well as reduce installation cost and period for long steel pipe piles as compared with existing methods.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.11a
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• pp.110-121
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• 2001

The interest in suction piles by the oil industry was risen in the middle of 1980's. Recently, suction piles have been applied increasingly in offshore engineering due to its low cost, simplicity, efficiency, and reliability. Suction piles have normally been used as anchors of floating structures and foundations of marine structures in deep-water locations. Suction piles have several technical advantages over conventional piles and anchors; fast and easy installation at any depth of water, extremely large resistance due to its huge size, and easy retrieval by applying a positive suction pressure inside the pile, etc. Daewoo E&C Co., Ltd. has conducted a series of field suction pile installation and loading tests inside the Okpo harbor located in Geojedo and the Onsan harbor in Ulsan, Korea, during the summer of 2001, which may provide additional validation of the analytical solutions previously developed by the US Naval Facilities Engineering Service Center. This is a brief description of the general mechanisms of suction pile installation and loading capacity based on the study conducted by the US Navy and Daewoo E&C Co., Ltd.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.922-927
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• 2004

The bending moment and settlement of the slab track can be reduced by the installation of small numbers of micro piles beneath the track. This paper presents the effect of micro pile installation on the reduction of bending moment and settlement of slab track, estimated by a numerical method. The slab track is modeled as a plate based on the Mindlin's plate theory, and soil and piles are modeled as Winkler and coupled springs, respectively. The stiffness of piles is obtained by the approximate analytical method proposed by Randolph and Wroth. and the modulus of subgrade reaction is adopted to evaluate Winkler spring constant. From the analysis results, the effect of the micro pile installation is significant to considerably reduce the settlement of slab track. However, for the proper reduction of bending moments in a slab track, the pile arrangement should be reasonably taken into account to prevent the stress concentration at pile location.

• Journal of the Korean Geotechnical Society
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• v.27 no.4
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• pp.5-20
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• 2011

A numerical analysis has been conducted to propose the effective installation methods of Micro-pile in a sandy soil or a soil with rock layer. As a result, the bearing capacity of reinforced soil by rigid Micro-pile has influence on a connection state of the tip of pile and surface of rock layer. But that by flexible Micro-pile has more influence on a penetration length of pile than the connection state of the tip of pile and surface of rock layer.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.65-70
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• 2005

In this study, the large scale model tests were executed to estimate the Load Sharing Ratio(LSR) of raft in a piled footing under various conditions. The conditions such as the subsoil type, pile length, pile spacing, array type and pile installation method etc. were varied in the pile loading tests about the free-standing group piles and a piled footing. As the results of this study, it was found that there were no differences of the load-settlement curves, along with the pile installation method and subsoil type. The piles supported most of the external load until a yielding load of the piled footing, but the raft supported a considerable load after a yielding load. And it was also found that the LSR didn't be affected by the pile installation method and the subsoil type. As the relative density of sands increased, the LSR decreased. As the pile spacing was wider and the pile length increased, there was a tendancy for the LSR to increase.

• Journal of the Korean Geotechnical Society
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• v.28 no.4
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• pp.55-65
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• 2012

This study performs model test to propose the installation method of micro-pile appropriate to various soil conditions such as sand or silt soil. As a result, the crossed installation method (${\theta}$ < $0^{\circ}$) of micro-pile is effective in resisting a compression displacement of soil in the case of silt exhibiting the punching shear failure. And the inclined installation method (${\theta}$ > $0^{\circ}$ or ${\theta}$ < $0^{\circ}$) of micro-pile is effective in resisting a lateral displacement of soil in the case of sand to exhibiting the general or local shear failure.