• Proceedings of the Korean Geotechical Society Conference
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• 1998.03a
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• pp.173-178
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• 1998

• Journal of the Korean Geotechnical Society
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• v.22 no.10
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• pp.47-54
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• 2006

H-pile can be more easily driven than pipe pile by pile driver and shows high skin friction and plugging effect. This experimental study was devoted to investigate skin friction of H group piles in granite soil under laboratory test. Pile arrangements $(1{\times}2,\;1{\times}3,\;2{\times}2,\;2{\times}3,\;3{\times}3)$, pile space (2D,4D,6D), and soil density $(D_r=40%,\;80%)$ were tested. The main results obtained from the model tests can be summarized as follows. Distribution ratio of skin friction for total load decreased by $48{\sim}39%$ (dense soil), $32{sim}27%$ (loose soil) as piles space ratio increases in case of $3{\times}3$ group piles. And the distribution ratio of skin friction by pile settlements under loose soil decreased by about $58{\sim}33.2%$ in $2{\times}2$ group piles and about $65{\sim}38%$ in $3{\times}3$ group piles respectively.

• Structural Engineering and Mechanics
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• v.54 no.5
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• pp.829-853
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• 2015

This is an experimental study to investigate the behaviour of piled raft system in different types of sandy soil. A small scale "prototype" model was tested in a sand box with load applied to the foundation through a compression jack and measured by means of load cell. The settlement was measured at the raft by means of dial gauges, three strain gauges were attached on piles to measure the strains and calculate the load carried by each pile in the group. Nine configurations of group ($1{\times}2$, $1{\times}3$, $1{\times}4$, $2{\times}2$, $2{\times}3$, $2{\times}4$, $3{\times}3$, $3{\times}4$ and $4{\times}4$) were tested in the laboratory as a free standing pile group (the raft not in contact with the soil) and as a piled raft (the raft in contact with the soil), in addition to tests for raft (unpiled) with different sizes. It is found that when the number of piles within the group is small (less than 4), there is no evident contribution of the raft to the load carrying capacity. The failure load for a piled raft consisting of 9 piles is approximately 100% greater than free standing pile group containing the same number of piles. This difference increases to about 4 times for 16 pile group. The piles work as settlement reducers effectively when the number of piles is greater than 6 than when the number of piles is less than 6. The settlement can be increased by about 8 times in ($1{\times}2$) free standing pile group compared to the piled raft of the same size. The effect of piled raft in reducing the settlement vanishes when the number of piles exceeds 6.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.107-114
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• 2001

When group pile supporting structures are to be subjected to large lateral loads, generally, hatter piles are used in group pile with vertical piles. It is well known that batter piles resist lateral static loads which are acted upon the piles as axial farces quite well but, they show a poor performance under seismic loads. However, it is not yet known how the batter piles behave under dynamic loading and how to strengthen the batter piles to improve the seismic performance. Shaking table tests were performed to investigate the seismic behavior of the batter pile and to bring up the countermeasures to improve the seismic performance. As the result of the shaking table tests, batter piles failed due to not only the excessive increase of compressive force near the pile head but also that of tensile force. In case that the pile head was connected with pile cap by rubber joint, the max. acceleration at the pile cap was reduced due to the high damping ratio of rubber and the max. moment and max. axial farce at the pile head was decreased remarkably. When the inclinations(V:H) of the batter pile were 8:3 and 8:4, max. moment, max. shear force, and max. axial farce were reduced notably and max. acceleration and max. displacement at the pile cap was diminished, too.

• Journal of Korea Water Resources Association
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• v.47 no.10
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• pp.907-919
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• 2014

This study presents scour processes and its characteristics around the pile groups using the large eddy simulation (LES) coupled with sediment transport and morphodynamic models. The scour and deposition around pile groups were significantly influenced by the pile interval. In case the non-dimensional pile interval was less than 3.75, the local scours as well as the contraction scour were observed around the pile group. On the other hand, in case the non-dimensional pile interval was more than 3.75, the contraction scour disappeared and only local scours were developed at individual piles. Change in the scour depth at piles located in the upstream was similar with the case of single pile, but the scour depth around piles located in the downstream was lower and showed a significantly different tendency due to the presence of piles in the upstream. The non-dimensional maximum scour depth around the pile group decreased as the pile interval increased.

• Geotechnical Engineering
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• v.13 no.2
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• pp.137-154
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• 1997

Piling engineers in limit state design should consider both capacity of a pile and settlements of pile for stability of a structure. This paper analyzes the prediction of the settlements of single piles and nine-group piles installed at an overconsolidated clay site by common prediction methods and cone penetrometer test data obtained closely at pile locations. The effects of Young's modulus, which varies spatially in soil profile, on estimating the set tlements of piles have been investigated briefly. The predicted settlements for single piles and nine-pile group by using simple linear elan tic methods, Vesic's method and Poulos's method, overestimated overalls the measured valroes, and the assumption of Youngs modulus, which are to be varied linearly through the soil layers. did not significantly affect the settlement predictions.

• Geomechanics and Engineering
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• v.19 no.6
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• pp.473-484
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• 2019

In this paper, the geotechnical report of the Northern Fereshteh area in Tabriz is used and the characteristics of shallow foundation of a single pile and compared pile group and geogrid in terms of the settlement of a building foundation on clayey soil. Additionally, impacts of existing variables such as the number of geogrid layers, the length of the pile, and the depth of groundwater level affected by the dynamic load caused by the Taiwan Jiji earthquake via numerical analysis using PLAXIS software are examined. The results of fifty-four models indicated that the construction of a pile group with a diameter of 1 meter and a length of 14 meters significantly diminished the consolidation settlement of the soil in the Northern Fereshteh area, where the settlement value has been triggered by the load inflicted by earthquake. Moreover, the construction of four layers of geogrid at intervals of one meter led to a significant decrease in the settlement. Finally, after reaching a maximum depth, it had no reducing effects on the foundation settlement.

• Journal of Industrial Technology
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• v.15
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• pp.147-152
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• 1995

The purpose of this paper is to analyze the bearing capacity, settlement and pile action of pile groups in cohesionless soil, based on a wide range of model test in laboratory. Model test were conducted with changing the variables affecting the behavior of group pile; Number of pile, Diameters, Spacings between piles and Arrangement of piles. Effects of these variables on group efficiency were investigated by analyzing test results. Test results were also compared with the existing analytical method and data obtained in-situ tests.

• Geomechanics and Engineering
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• v.16 no.2
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• pp.187-194
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• 2018

Application the pile group foundation to reduce overall settlement of the foundation and also avoid a very fruitful settlement of foundations, inconsistent was carried out. In such a case, in event that the Foundation, not as a mere pile group, which as a system consisting of a broad foundation with pile Group, economic design criteria will be provided in spite of high safety. A new approach in the design of the Foundation can be introduced as the piles are just a tool to improve the parameters of soil hardness; that it can work with detachable piles from raft. Centralized arrangement of piles as the most optimal layout of piles in reducing inconsistent settlement, which is the lowest value of resulting layout in this differential settlement. Using the combination of piles connected and disconnected to form the raft, bending moment created in the raft is reduced. It also concentrated arrangements have greatest effect in reducing amount of moment applied to the raft.

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.19-30
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• 2005

A coupled three-dimensional pile group analysis method was developed by considering complex behavior of sub-structures (pile-soil-cap) which included soil nonlinearity and the behavior of super-structure (pier). As an intermediate analysis method between FBPier 3.0 and Group 0.0, it took advantages of each method. Among the components of a pile group, individual piles were modeled with stiffness matrices of pile heads and soils with nonlinear load-transfer curves (t-z, q-z and p-y curves). A pile cap was modeled with modified four-node flat shell elements and a pier with three-dimensional beam element, so that a unified analysis could be possible. A nonlinear analysis method was proposed in this study with a mixed incremental and iteration techniques. The proposed method for a pile group subjected to axial and lateral loads was compared with othe. analytical methods (i.e., Group 6.0 and FBPier 3.0). It was found that the proposed method could predict the complex behavior of a pile group well, even though piles were modelled simply in this study by using pile head stiffness matrices which were different from the method introduced in FBPier 3.0.