• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.147-152
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• 2003

The purpose of this paper is to develope an understanding of fundamental mechanism of shear behaviour between granite and concrete interfaces. The interface of pile socketed in rock can be modeled in laboratory tests by resolving the axisymmetric pile situation into the two dimensional situation under CNS(constant normal stiffness) direct shear condition. In this paper, the granite core samples were used to simulate the interface condition of piles socketed In granite. The samples were prepared in the laboratory to simulate field condition, roughness(angle, height), stress boundary condition, and then tested by CNS direct shear tests. This paper gives some points about shearing behaviour of socket piles into domestic granite through the analysis of CNS tests results.

• Geotechnical Engineering
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• v.8 no.3
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• pp.13-22
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• 1992

Model pile tests using calibration chamber are performed in !his paper in order to clarify the effect of the fundamental differences between the newly developed SPLT(Simple Pile Loading Test)and the conventional pile loading test on the pile bearing capacity. They are : (1) the direction of the applied load to mobilize the skin friction ; and (2) the use of reduced sifted sliding core. The conclusions obtained from the model pile tests are as follows : (1) The skin friction in tension loading is found to be somewhat smaller than that in compression loading. The average ration is 0.73 with the coefficient of variation (COV) of 0.18. (2) The ratio of the tip resistance rosin연 the reduced sized sliding core to that using the whole shoe shows wide scattering ; its average is 0.99 and the COV is 0.28. The aver - age of 0.99 means that there is no considerable difference in the tip resistance whether the reduced sized sliding core or the whole shoe is used, on condition that penetration depth ratio is larger than 4 : if the boundary effect of the chamber test is considered, the resistance of the whole shoe might be even larger.

• Journal of the Korean Geotechnical Society
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• v.34 no.8
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• pp.15-26
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• 2018

Recently, as the seismic performance based design methods have been introduced, dynamic numerical analyses need to be performed to evaluate the actual performance of structures under earthquakes. The verification of the numerical modeling is the most important for the performance based design. Therefore, 2-dimensional numerical analyses were performed to simulate the seismic behavior of a pile-supported structure, to provide the proper numerical modeling and to determine of input parameters. A dynamic centrifuge test of a pile group in dry loose sand was simulated to verify the applicability of the numerical model. The numerical modeling was carefully made to reflect the actual condition of the centrifuge test including dynamic soil properties, soil-pile interaction, boundary condition, the modeling of the group pile and structure and so on. The predicted behavior of the numerical analyses successfully simulated the acceleration variation in ground, the moment and displacement of the pile, and the displacement and acceleration of the structure. Therefore, the adopted numerical modeling and the input parameters can be used to evaluate the seismic performance of pile groups.

• Journal of the Korean GEO-environmental Society
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• v.10 no.5
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• pp.69-73
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• 2009

In this study, three dimensional numerical analyses were performed with variation of pile spacing (S=3D, 4D, 5D) to compare the behaviour of single pile and pile group with cap in granite soil. In order to compare and analyze the lateral resistance of single pile and pile group by changing pile spacing, the pile group with array of $1{\times}3$ was employed. To reduce the computation time the symmetric boundary condition was used. And Druker-Prager model and elasticity model were used for granite soil and for concrete pile and cap, respectively. Using the analyses results of pile group in granite soil under lateral loading, p-y curve for pile group and single pile with changing pile spacing was drawn. With p-y curve p-multiplier was evaluated. As a result of analysis, the value of p-multiplier was increased with increasing pile spacing under 1.0 due to pile shadow effects.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.173-183
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• 2010

Numerical analysis using a three dimensional finite element program(ABAQUS) is a powerful method which can evaluate the soil-pile-structure interaction under the dynamic loading and reduce the computation time significantly, but has not be widely used because modeling a soil-pile system and setting the parameter for the entire model are difficult and a three dimensional finite element program is not user friendly. However, a three dimensional finite element program is expected to be widely used because of advance in research of modeling technique and development of the modeling and visualization. In this study, ABAQUS is used to simulate the 1g shaking table model pile test, and the numerical results are compared with the 1g shaking table test results. The application about the soil stiffness and boundary condition change is estimated and then parametric study for various input acceleration amplitudes, various input frequencies, and various surcharge is carried out.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.187-193
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• 2023

This paper presents the buckling behavior of a pile considering its self-weight. The differential equation and boundary conditions governing the buckling of partially embedded piles in nonhomogeneous soils are derived. The buckling load and mode shape of the pile are numerically computed by the Runge-Kutta method combined with the Regula-Falsi algorithm. The obtained numerical solutions for bucking loads agree well with the results available from the literature. Numerical examples are given to analyze the buckling load and mode shape of the piles as affected by the self-weight, embedment ratio, slenderness ratio and boundary condition of the pile as well as the aspect ratio and rigidity ratio of the subgrade reaction. It is found that the self-weight of the pile leads to the reduction of the buckling load, indicating that neglecting the effect of self-weight may overestimate the buckling load of partially embedded piles.

• Journal of the Korean Geotechnical Society
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• v.20 no.1
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• pp.5-12
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• 2004

The purpose of this paper is to make an understanding of fundamental mechanism of shear behaviour between rock and concrete interfaces in the pile socketed into granite. The interface of pile socketed in rock can be modeled in laboratory tests by resolving the axi-symmetric pile situation into the two dimensional situation under CNS(constant normal stiffness) direct shear condition. In this paper, the granite core samples were used to simulate the interface condition of piles socketed in granite in our country. The samples were prepared in the laboratory to simulate field condition, roughness(angle and height), stress boundary condition, and then tested by CNS direct shear tests. This paper describes shearing behaviour of socket piles into domestic granite through the analysis of CNS test results. It was found out that the peak shear strength increases with the angle of asperity and CNS value, and also the dilation increases with the angle of asperity but decreases with the CNS value.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.204-213
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• 2003

A survey for finding corrosion examples was performed on the underground steel piles buried for 19 years in the area of iron and steel making factory near Young-il bay. A failure probability model, which can be used to check the reliability of the corrosive mechanical element, based on Von-Mises failure criterion and the standard normal probability function is proposed. The effects of varying boundary conditions such as temperature change, soil-friction, internal pressure, earthquake, loading of soil, traffic loads and corrosion on failure probability of the buried steel piles are systematically investigated. To allow for the uncertainties of the design variables, a reliability analysis technique has been adopted; this also allows calculation of the relative contribution of the random variables and the sensitivity of the failure probability.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.117-124
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• 2002

The major purpose of this study is to determine the dynamic behavior of soil-pile-structure interaction system considering the underground cavity. For the analysis, a numerical method fur ground response analysis using FE-BE coupling method is developed. The total system is divided into two parts so called far field and near field. The far field is modeled by boundary element formulation using the multi-layered dynamic fundamental solution that satisfied radiational condition of wave. And this is coupled with near field modeled by finite elements. For the verification of dynamic analysis in the frequency domain, both forced vibration analysis and free-field response analysis are performed. The behavior of soil non-linearity is considered using the equivalent linear approximation method. As a result, it is shown that the developed method can be an efficient numerical method to solve the seismic response analysis considering the underground cavity in 2D problem.

• Magazine of korean Tunnelling and Underground Space Association
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• v.21 no.2
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• pp.117-129
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• 2019

Tunnelling in urban environments is very common nowadays as large cities are expanding and transportation demands require the use of the underground space for creating extra capacity. Inevitably, any such new construction may have significant effects on existing nearby infrastructure and therefore relevant assessment of structural integrity and soil-structure interaction is required. Foundation piles can be rather sensitive to nearby tunnel construction and therefore their response needs to be evaluated carefully. Although detailed three-dimensional continuum finite element analysis can provide a wealth of information about this behaviour of piles, such analyses are generally very computationally demanding and may require a number of material and other model parameters to be properly calibrated. Therefore, relevant simplified approaches are used to provide a practical way for such an assessment. This paper presents a simple method where the pile is modelled with beam finite elements, pile-soil interaction is modelled with soil springs and tunnelling-induced displacements are introduced as an input boundary condition at the end of the soil springs. The performance of this approach is assessed through some examples of applications.