• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.25-32
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• 2005

Modeling techniques of piled pier were reviewed and the influences of pile cap's boundary conditions were analyzed in this study. Among various modeling techniques, equivalent cantilever method seems relatively simple for modeling pile groups and it has some problems to determine the virtual fixed points. Through the analyses, it was found that the method of nonlinear p-y model with soil springs was more appropriate than equivalent cantilever method. The method modeling a pile group using stiffness matrix seems useful for practical design, which can represent the nonlinear three-dimensional behavior of a piled pier. In this study, the stiffness matrix of a pile group could be estimated efficiently and precisely using three-dimensional nonlinear analysis programs of pile groups (FBPier 3.0, YSGroup).

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.417-422
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• 2005

The appropriate ventilation system in vehicular tunnel should be the most economical solution with regard to both construction and maintenance. The damages on tunnel lining was affected by formula of ventilation system in long vehicular tunnel. In this study, carbonation, one of main experimental items in precision safety diagnosis, was analyzed by contouring damage area with ventilation system. Considerations of carbonation were also given to the design and maintenance which manage the long-term safety in tunnel.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.235-242
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• 2004

For this study, a Peliyagoda area located on a route was selected among many sections of a CKE(Colombo to Katunayake Expressway) route in Sri-Lanka. Its subground consists of a very weak and thick peat soil named amorphous or fibrous peat. All of data, obtained in the design process of soft ground treatment were analyzed to evaluate the settlement characteristics resulted from an embankment load and to present reasonable methods for estimation of secondary compression settlement. For these purposes, soil parameters were used obtainedby field and laboratory tests the settlement analyses were conducted base on the field monitoring results within 20 months. In addition, Reasonable methods were studied to estimate primary consolidation and secondary compression settlement.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.44-49
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• 2004

The settlements of footings in send are often estimated based on the results of in-situ tests, particularly the standard penetration test (SPT) and the cone penetration test (CPT). In this paper, we analyze the load-settlement response of vertically loaded footings placed in sands using both the finite element method with a non-linear stress-strain model and the conventional elastic approach. Calculations are made for both normally consolidated and heavily overconsolidated sands with various relative densities. For each case, the cone penetration resistance qc is calculated using CONPOINT, a widely tested program that allows computation of qc based on cavity expansion analysis. Based on these analyses, we propose a procedure for the estimation of footing settlement in sands based on CPT results.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.765-774
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• 2004

This paper presents a damage assesment method for buried pipelines subjected to Deep Excavation-induced ground movements. Ground deformation characteristics resulting from 3D finite element analysis was represented mathematically by a hyperbolic tangential function. A parametric study was performed on excavation depth and burial position of pipeline. The result of the parametric study indicate that length of hyperbolic tangential function affects the results of damage assessment. Using numerical studies for buried pipeline response to ground movements by relative flexibility of the pipe-soil system. The result of numerical studies are presented in forms of design charts which can be readily used for various condition encountered in practices.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.958-967
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• 2004

This paper deal with cause and analysis about case of collapsed reinforced-soil retaining wall. The analysis of the cause was carried through experimentation, slop stability analysis and literature study. The experimentation treated the large direct shear test, the hydraulic conductivity test and the other basic test through backfill extracted from collapsed reinforced-soil retaining wall. The ultimate tensile strength was established by rib tensile strength test of geogrid. The analysis of internal and external stability of reinforced-soil retaining wall was performed on the basis of parameters. The result of analysis, reinforced-soil retaining wall and the slope at the dry season are stable. However, the factors that fine-grained soil at hydrometer test exceed the standard of the design, rainfall duration is too long at the time of collapse and monthly pricipitation is heavy are cause of the collapse.

• Coupled systems mechanics
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• v.9 no.5
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• pp.473-498
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• 2020

This paper presents a careful theoretical investigation into interfacial stresses in reinforced concrete foundation beam repairing with composite plate. The essential issue in the analysis of reinforced structures with composite materials is to understand the individual behaviour of each material and its interaction with the remaining ones. The present model is based on equilibrium and deformations compatibility requirements in and all parts of the repaired RC foundation beam, i.e., the reinforced concrete foundation beam, the composite plate and the adhesive layer. The theoretical predictions are compared with other existing solutions, By comparisons between the existing solutions and the present new solution enable a clear appreciation of the effects of various parameters such as the geometric characteristics and mechanical properties of the components of the repaired beam, as well as the geotechnical stresses of the soil are considered. This research is helpful for the understanding on mechanical behaviour of the interface and design of the composite-concrete hybrid structures.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.307-314
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• 2001

The bearing capacity of drilled shafts that take excavation by Percussion Rrotary Drilling(PRD) into consideration was evaluated using static and dynamic pile load tests. The emphasis was on quantifying the allowable bearing capacity and point load-transfer at the pile tip on seven instrumented steel piles. Of the seven instrumented piles, five piles are placed to the bottom of the excavation by rotary and pushing into the final depth of the excavation, as opposed to the two driven piles. Based on the results obtained, it is shown that the skin friction mobilized by PRD is much greater than point resistance, whereas in driven piles, the point resistance is greater than skin friction. It is also found that much greater pile capacity was proved in the case of drilled shafts, compared to the driven piles and thus, the excavation by rotary drilling gives reliable pile capacity required to design axially loaded piles.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.577-584
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• 2001

For construction and design of tunnels, groundwater flow models are used to find the influence of groundwater to the stability of tunnels considering the geological condition around the tunnels and the materials used in tunnel linings. For the analysis of tunnel flow, some commercial programs, e.g. MODFLOW, SEEP/W etc., are used. These programs have limitations that MODFLOW could not define curved surface smoothly in three dimensional flow media and SEEP/W is the 2-dimensional flow model. In this paper, the ability of a finite element program developed for analyzing 3-dimensional groundwater flow is examined. Confined steady state groundwater flow solution in non-homogeneous media is obtained using isoparametric element with eight trilinear hexahedron nodes and is compared with the result of MODFLOW. It was found that the solution yielded a good result with the three dimensional flow studied.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.323-330
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• 2001

The existing bonding methods of steel pipe piles into pile caps have many problems during construction or design. To overcome these, the composite bonding method of the bolting type and the welding type are proposed in this stud\ulcorner. The full scale test and the numerical analysis using finite element method were performed to verify the function of them. As results, the method of the filled with concrete in steel pipe piles head was good effective to increse strength. And the composite bonding methods are effective to protect the damage caused by earthquake than the bolted bonding method. Also, the composite bonding methods are cheaper than the existing bonding methods and a good construction as well.