• Geomechanics and Engineering
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• v.11 no.2
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• pp.235-252
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• 2016

This paper presents a new numerical solution of the ultimate lateral capacity of rectangular piles in clay. The two-dimensional plane strain finite element was employed to determine the limit load of this problem. A rectangular pile is subjected to purely lateral loading along either its major or minor axes. Complete parametric studies were performed for two dimensionless variables including: (1) the aspect ratios of rectangular piles were studied in the full range from plates to square piles loaded along either their major or minor axes; and (2) the adhesion factors between the soil-pile interface were studied in the complete range from smooth surfaces to rough surfaces. It was found that the dimensionless load factor of rectangular piles showed a highly non-linear function with the aspect ratio of piles and a slightly non-linear function with the adhesion factor at the soil-pile interface. In addition, the dimensionless load factor of rectangular piles loaded along the major axis was significantly higher than that loaded along the minor axis until it converged to the same value at square piles. The solutions of finite element analyses were verified with the finite element limit analysis for selected cases. The empirical equation of the dimensionless load factor of rectangular piles was also proposed based on the data of finite element analysis. Because of the plane strain condition of the top view section, results can be only applied to the full-flow failure mechanism around the pile for the prediction of limiting pressure at the deeper length of a very long pile with full tension interface that does not allow any separation at soil-pile interfaces.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.334-408
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• 2006

In Hong Kong, large-diameter (${\ge}600mm$) bored piles and large-section excavated rectangular barrettes are commonly used to support tall buildings to resist both vertical and horizontal loads. These piles and barrettes penetrate through and may found in saprolitic soils and decomposed rocks. Generally, the design of these large bored piles and barrettes involves considerable amount of uncertainty and design parameters must usually be verified by field tests. In this paper, over 50 full-scale load tests on large-diameter bored piles and over 15 large-section of rectangular barrettes in Hong Kong are reviewed and interpreted critically, in particular the degree of mobilisation of side shear resistance using a mobilization rating (MR) factor and a displacement index (DI) for floating bored piles and barrettes and rock-socketed piles, respectively. The author was heavily involved with many of these load tests. The diameter of the bored piles tested ranges from 0.6m to 1.8m and the depth varies from 12m to 75m. Sizes of barrettes critically reviewed include $2.2m{\times}0.6m,\;2.2m{\times}0.8m,\;2.8m{\times}0.8m\;and\;2.8m{\times}1.0m$ (on plan) and the depth varies from 36m and 63m. Based on these field tests, a new failure load criterion for large-diameter bored piles and barrettes is developed and proposed. The side shear resistance of the bored piles and barrettes is quantitatively analyzed with respect to local displacements, standard penetration tests, unconfined compressive strength (UCS) for rock sockets and using the effective stress principle. In addition, the effects of construction including post-grouting, construction time, side scraping and excavation tools on side shear resistance are investigated and reported.

• Journal of the Korean Geotechnical Society
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• v.24 no.4
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• pp.23-36
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• 2008

This study describes model tests on instrumented rectangular-shaped passive row piles embedded in horizontal sand-ground undergoing lateral soil movement. We tried to find the property of row piles dependent on the shape of pile, including the position of the pile in row, pile spacing, and soil movement. The results of test are as follows. The lateral earth pressure diagram variously appeared to be triangle, trapezoid and rectangular by shape and position of pile. The outer pile has a larger bending moment than the inner pile in the case of B-type, the inner piles has larger one than outer pile in case of H-type. $R_f$ (the ratio of resistance to lateral soil movement) was found to increase with increasing pile spacing irrespective of pile-shape. Y/L (location of action of lateral resistance force) for $d_s$ (displacement of soil) and $S_h$ (spacing of pile) appeared to be nearly regular position, and H-type is higher than B-type.

• Journal of the Korean Geotechnical Society
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• v.25 no.11
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• pp.39-51
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• 2009

This is a study on rectangular-shaped passive row piles in inclined sand-ground by model tests. The experiment controlled the angle of inclination of ground and induced the ground destruction. We also measured the behavior of row piles, by adjusting the shape, position and spacing of piles. As a result, we confirmed the earth pressure, the lateral resistance, and the effect of depressing on the ground variation working on passive pile. The effect of B-type pile of which the front width is wide is bigger than that of H-type pile of which the side width is wide. We can find out the failure angle of slope, the shared force of pile and soil by using the lateral resistance graph based on slope angle.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.6
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• pp.615-626
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• 2019

In this study, the applicability of PHC pile jointing method using rectangular steel tubular was studied. PHC pile joints are welded and bolt assembly. The bolt assembly method is a method that improves the various problems of welded joints. Numerical analysis and tests were conducted to analyze the applicability of the PHC pile jointing method using a rectangular steel tubular. The tests were carried out to test the material properties of the rectangular steel tubular material and the bending test of the pile joints. The numerical analysis was interpreted in the same conditons as the tests conditions. As a result, the material strength of each rectangular steel tubular could be used as a joint material. In the bending test, it was evaluated as a sTable material above the allowable stress of piles. In the numerical analysis results under the same conditions as the tests, it was possible to apply the pile joint material without exceeding the allowable stress of the material.

• Journal of Korea Water Resources Association
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• v.34 no.6
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• pp.641-649
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• 2001

This study analyzed the general scour characteristics around group pile foundations through laboratory experiments. The experiments were performed for the pile groups consisting of 4, 9, 15 and 35 piles to investigate the effects of pile number, mean velocity and the angle of attack on the scour hole shape, and the magnitude and the position of maximum scour depth. Results reveal that the maximum scour depth for 4 and 9 piles have almost same values with single pier case regardless of approach velocity. The scour depth for 15 and 35 piles, however, increases as the mean velocity increases and reaches up to 2.2 times of maximum scour depth for single pier case. As the number of piles increase, the single scour holes are superposed and the overall scour hole turned out to be rectangular shape. The experimental results for the case of 35 piles indicate that the scour depth has the maximum value at angle of attack of 35 degree and that the main scour hole is formed in diagonal direction.

• Journal of Ocean Engineering and Technology
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• v.11 no.1
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• pp.65-73
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• 1997

The floating body discussed in this study is a 2-D rectangular floating unit supported by four vertical piles at its corners. Structures of this type are frequently seen as floating piers for the crafts in a small harbour. The movement in some modes of motion of such a flating body is fully or partially restrincted by the piles. The authors(Kim et al. 1994) carried out a series of model tests on its wave control function, its motion and the loads on piles. The experimental results showed that a certain degree of intial constriction force which clamps the floating unit in the horizontal direction can effectively reduce the body motion and wave energy without increasing mooring forces. This may be due to the friction forces occuring between the piles and the rollers installed in the mooring equipments on the floating unit. In this paper, we develop a numerical model for the prediction of wave transformation and floating body motions, where the friction force is idealized as the Coulomb friction and linearized into a damping force using the equivalent damping cofficient. This linearization is verified by comparing the results of motions between the linear and nonlinear analysis of the ezuations of motion. We further compare the caculation results by the linear model with the experimental results and discuss the effect of the friction force or the constriction force on body motions and wave energy dissipation.

• Journal of the Korean Society for Railway
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• v.9 no.4 s.35
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• pp.493-498
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• 2006

In this study, two large pile load tests were performed in the deep sand gravel deposit of Nakdong river basin so that the characteristics of the load transfer was identified. The fully instrumented rectangular barrette pile in the size of $1.5\times3.0m$ and the circular bored pile of the diameter 1.5 m were placed into the ground below 50 m. Under the applied loads of 2,400 tonf and 4,000 tonf, the test results of the load transfer showed the portion of 83% and 93% of the applied loads on the barrette pile and the bored pile, respectively, were supported by the skin friction along the pile shaft. It was revealed that the most of these skin friction mobilized in sand layer underlying clay layer having N-value more than 30 and that the friction per unit area of the bored pile was larger than the friction of barrette pile. However, if embedded in the stiff sand graval layer, the both piles were proven to be sufficient for using as the friction piles.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.3
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• pp.183-190
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• 2019

Recent changes in the construction method of piles to minimize noise, along with the development of high-strength reinforcement, have provided an economical high performance RC pile development to compensate for the disadvantages of existing PHC piles. In this study, a methodology for the development of cross - section details of high performance RC piles of various performances is presented by freely applying high strength steel and concrete. This study suggested a technique for calculating bending moments for a given axial force corresponding to the allowable crack widths and this can be used for serviceablity check. In calculating the design shear force, the existing design equation applicable to the rectangular or the I section was modified to be applicable to the hollow circular section. In particular, in the limit state design method, the shear force is calculated in proportion to the axial force, and the procedure for calculating PV diagram is established. Last, the section details are determined through PM diagrams that they have the similar flexural and axial-flexural performances of the PHC pile A, B and C types with a diameter of 500 mm. To facilitate the application of the selected standard sections to the practical tasks, the design PM diagram and design shear forces are proposed in accordance with the strength design method and limit state design method.

• Coupled systems mechanics
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• v.1 no.2
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• pp.115-131
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• 2012

Paper presents an improved solution algorithm based on Finite Element Method to analyse piled raft foundation. Piles are modelled as beam elements with soil springs. Finite element analysis of raft is based on the classical theory of thick plates resting on Winkler foundation that accounts for the transverse shear deformation of the plate. Four node, isoparametric rectangular elements with three degrees of freedom per node are considered in the development of finite element formulation. Independent bilinear shape functions are assumed for displacement and rotational degrees of freedom. Effect of raft thickness, soil modulus and load pattern on the response is considered. Significant improvement in the settlements and moments in the raft is observed.