• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.4
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• pp.567-578
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• 2018

In this study, to investigate the effect of the stress reduction of group piles by dynamic loading, a dynamic p-y curve was established and the dynamic p-multiplier was calculated. Dynamic numerical analysis was performed by input sinusoidal waves to the bottom of the pile - ground system for $2{\times}2$ group pile, single pile and $5{\times}5$ group pile, single pile in dry sandy soil, and the pile spacing was changed to 2.5 and 5.0 times of the pile diameter. By establishing and comparing the dynamic p-y curves of the single pile and group piles, the dynamic group pile effect of the piles according to the pile center spacing and row position of the group pile piles is analyzed. $5{\times}5$ showed symmetry of the dynamic P-multiplier value around the pile origin coordinate. The dynamic p-multiplier value at the single pile, $5{\times}5$ pile (pile spacing: 2.5D) is 0.26 ~ 0.30 at the pile number 3, pile number 23, 0.14 pile number 13, and 0.14 ~ 0.38 at the pile number 5, pile number 18. These values differed from the static p-multiplier, especially due to the different loading conditions. The dynamic p-multiplier ($P_{dm}$) estimation through various types of input dynamic loads is expected to be used for dynamic design and analysis of group pile-ground systems of civil foundation structures.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.27-33
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• 2008

One of the central problems in astudy of the coastal surface wave environment is predicting the transformation of waves as they propagate toward the shore. The transformation is mainly due to the existence of obstacles, such as breakwaters and vertical cylinders. In general, the types of wave transformation can be classified as follows: wave diffraction, reflection, transmission, scattering, radiation, et al. This research dealtwith wave transmission and dissipation problems for two dimensional irregular waves and vertical circular cylinders. Using the unsteady mild slope equation, a numerical model was developed to calculate the reflection and transmission of regular waves from a multiple-row circular breakwater and vertical cylinders. In addition, hydraulic model experiments were conducted with different values for the properties between tire piles and the opening ratio (distances) between the rows of the breakwater. It was found that the transmission coefficients decreased with a decrease in the opening ratio and an increase in the rows of vertical cylinders. A comparison between the results of hydraulic and numerical experiments showed reasonable agreement.

• Structural Engineering and Mechanics
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• v.59 no.2
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• pp.209-226
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• 2016

Integral bridges are typically designed with flexible foundations that include one row of piles. The construction of integral bridges solves difficulties due to the maintenance of expansion joints and bearings during serviceability. It causes integral bridges to become more economic comparing with conventional bridges. Research has been focused not only to enhance the seismic performance of newly designed bridges, but also to develop retrofit strategies for existing ones. The local performance of the pile to abutment connection will have a major effect on the performance of the structure and the embedment length of pile inside the abutment has a key role to provide shear and flexural resistance of pile-abutment connections. In this paper, a simple method was developed to estimate the initial value of embedment length of the pile for retrofitting of specimens. Four specimens of pile-abutment connections were constructed with different embedment lengths of pile inside the abutment to evaluate their performances. The results of the experimentation in conjunction with numerical and analytical studies showed that retrofitting pile-abutment connections with CFRP wraps increased the strength of the connection up to 86%. Also, designed connections with the proposed method had sufficient resistance against lateral load.

• Korean Journal of Ichthyology
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• v.27 no.4
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• pp.257-262
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• 2015

The visual cells in the retina of Iksookimia longicorpa (Pisces, Cobitidae) were investigated by light and scanning electron microscopes. The retina ($216.42{\pm}13.36{\mu}m$) has several layers, and the visual cell layer consists of unequal double cones and large rods. In a double cone, two members are unequal such that one cone is longer than the other (long element $26.42{\pm}1.7{\mu}m$, short element $16.82{\pm}1.1{\mu}m$). The cones form a row mosaic pattern in which the partners of double cones are linearly oriented with a large rod. The visual cells observed have an outer segment (hematophilic), inner segment (eosinophilic). In scanning electron microscopy, the outer segment links to inner segment by so-called calyceal piles (calyceal processes) of membrane discs surrounded by double membranes.

• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.57-64
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• 2004

In order to establish the design method of anchored retention walls in cut slope, the behavior of anchored retention walls and backside ground needs to be investigated and checked in detail. In this study, the behavior of anchored retention walls was investigated by instrumentation installed in cut slope for an apartment construction site stabilized by a row of piles and anchored retention walls. When the anchor was installed at each excavating stages, the horizontal deflection of retention wall decreased, while the horizontal deformation of backside ground increased. The deflection of anchored retention wall decreased as the anchor was prestressed. The prestressed anchor farce has a great effect on the deflection of retention walls, while it has little effect on the deformation of its backside ground. The maximum horizontal deflection of anchored retention walls was developed between $1\%\;and\;4\%$ of excavation depth, which are $2\~8$ times larger than max. horizontal deflection of anchored retention walls including rock layers with backside horizontal ground. Meanwhile, SLOPILE (ver. 3.0) program analyzes the slope stability effects for anchored retention walls. As a result of analysis on slope stability analysis, the lateral earth pressure applied at anchored retention piles could be used as the mean values of empirical lateral pressures using anchored retention wall with horizontal ground at its backside.

• Journal of the Korean housing association
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• v.22 no.3
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• pp.59-71
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• 2011

The purpose of this study is to investigate the basic historical characteristics and its modern trend of Torajan traditional housing architecture in Sulawesi Province, Indonesia. The Toraja culture belongs to the cosmological culture with Cosmos centric characteristics. A traditional house, being called 'tongkonan' in Toraja region, is more than just a structure, representing the symbol of family identity and tradition. The Torajan architecture is a combination of the myth and cosmos, also regional conditions. With a short description of the general conditions and spiritual values of the Toraja, this paper explains the space-composition, the stylistic characteristics, the ornamental elements, construction, and its modern trend, etc. In general, it is raised on stilts several metres high, with a dramatically boat-shaped roof. Village layout varies according to size. The houses are arranged in a row, side by side, with their front gables facing north. Each house stands opposite its own rice-barn. The houses with their oblong ground-plans, built on piles set on stones. The interior is divided into three or four rooms, having few window. The houses are embellished with carving and paintings, and the facades display engraved and painted geometric and figural designs. The most frequent motif is the buffalo head, ranging from the realistic to the highly stylized. The Torajan traditional housing have experienced radical changes during the Modern period. In spite of the popularity of new modern house-styles, the traditional architectural style is often now constructed as an icon of Toraja identity. This paper will be helpful for understanding regional diversity of the traditional housing in Southeast Asia.

• Journal of Digital Convergence
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• v.17 no.3
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• pp.205-213
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• 2019

In a construction site, excavation work has a close relation with temporary earth retaining structure. In order to build the underground structure most effectively in a narrow space, prevent soil relaxation of the external behind ground in excavation work, and maintain a ground water level, it is required to install a temporary earth retaining structure that secures safety. To prevent soil washoff in underground excavation work, the conventional method of temporary earth retaining structure is to make a temporary wall and build the internal support with the use of earth anchor, raker, and struct for excavation work. RSB method that improves the problem of the conventional method is to remove the internal support, make use of two-row soldier piles and bracing, and thereby to resist earth pressure independently for underground excavation. This study revealed that through the field application cases of RSB method and the measurement result, the applicability of the method for installing a temporary earth retaining structure, the assessment result, and displacement all met allowable values of measurement, and that the RSB method, compared to the conventional method, improved constructability and economy.

• Journal of the Korean Geosynthetics Society
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• v.20 no.1
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• pp.1-8
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• 2021

In urban areas, structures are installed deep underground in the lower part of the structure to utilize space. Therefore, a retaining wall is used to prevent earth pressure from the ground when constructing a structure. Due to the development of construction technology, retaining wall applied to excavation work are used to prevent danger such as falling rocks and landslides in temporary facilities when construction or retaining walls are installed. In general, the application of a retaining wall to a temporary facility during the embankment construction is the case of expanding an existing roads or railways. Therefore, it is necessary to study the retaining wall applied to the embankment construction such as the double-track site of the high-speed railway. In this study, two types of common one row H-pile retaining wall and two types of IER retaining wall were analyzed, and the stability of the retaining wall applied to the construction of double-track of the high-speed railway was analyzed. The earth retaining wall is a construction method that combines forced pile applied to the stabilization of the slope with the wall of the earth retaining wall. As a result of the analysis, the IER retaining wall had maximum lateral displacement of 19.0% compared to the type with H-plie installed only in the front while dynamic load was applied. In addition, the slower the speed of high-speed railway, the more displacement occurred, and the results show that more caution is needed when designing the ground in low-speed sections.

• Journal of the Korean Geotechnical Society
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• v.33 no.10
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• pp.15-24
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• 2017

A self-supported temporary excavation method called Inclined Earth Retaining structure (IER) has been developed by improving an existing excavation method. The stability of the IER was proved with both model tests and field tests. Especially, the results of the model tests proved that the lateral displacement of a model retaining wall was significantly reduced in clay. In this study, the applicability of the IER installed in the soft clay ground is estimated by analyzing survey data collected in the construction field. The results of FE analysis show that the lateral displacement of the IER decreased by 70.9% of that of a single row, self-supported retaining wall using the same number of H-piles. Thus, using the IER method in the soft clay ground will increase the stability of the excavated ground with the effect restraining its lateral displacement. Furthermore, using Deep Cement Mixing (DCM) to the upper half embedded depth of front support is recommended as a subsidiary method of reducing the lateral displacement of IER in the soft clay ground based on FE analysis results.

• The Journal of Engineering Geology
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• v.15 no.2 s.42
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• pp.155-168
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• 2005

The behavior of earth retention wall installed in a cut slope is different from the behavior of retention wall applied in an urban excavation. In order to establish the design method of anchored retention wall in the cut slope, the behavior of anchored retention wall needs to be investigated and checked in detail. In this study, the behavior of anchored retention wall was investigated by the instrumentation installed in the cut slope, where was stabilized by a row of piles in an apartment construction site. The horizontal displacement of anchored retention wall was larger than the displacement of slope soil behind the wall at the early stage of excavation. As the excavation depth became deeper, the horizontal displacement of slope soil was larger than the displacement of anchored retention wall. It means that the horizontal displacement of anchored retention wall due to excavation is restrained by soldier pile stiffness and jacking force of anchor at the early stage of excavation. lacking force of anchor was mainly influenced on the horizontal displacement of anchored retention wall. The displacements of anchored retention wall and slope soil were affected mainly by rainfall infiltrated from the ground surface. Meanwhile, the horizontal displacement of anchored retention wall with a sloped backside was about $2\~6$ times larger than the displacement of anchored retention wall with a horizontal backside of excavation.