• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.347-354
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• 2001

In this study, 3-D FEM analysis are carried out to investigate the effect of the corners and re-entrant corners which can't be analysed by 2-D analysis. The excavation shape is re-entrant type conditions. The wall displacement, earth pressure and effectiveness of the corner struts are investigated in the re-entrant case, The 3D analysis are peformed to evaluate the effect of various factors, such as re-entrant corner size, excavation depth, and presence of struts. The wall displacement and earth pressures are influenced the size of re-entrant corner. Therefore, the effect of re-entrant corner should be considered in the evaluation of the earth pressure and displacement of the corners. Finally, strut-support systems are not effective at the re-entrant corner.

• Geotechnical Engineering
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• v.3 no.2
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• pp.55-70
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• 1987

An analytical solution procedure is described to estimate the developed passive lateral earth Pressures behind a vertical rigid retaintng wall rotating about its toe into a mass of cohesionless soil. Various stases of wall rotation, starting from an at-rest state to an initial Passive state to a full Passive state, are considered in the analysis. Condition of failure defined by a modified Mohr-coulomb criterion, together with equilibrium conditions, is used to obtain the necessary equations for the solution. Using methods of stress characteristics and numerical finite difference, a complete solution within and on the boundaries of the entire solution domain is made possible. The variations of the soil shear strength and the wall friction at various depths and stages of wall rotation are also taken into account in the analysis. The results predicted by the developed method of analysis are compared with those obtained from the experimental model tests on loose and dense sand. The comparisons show good agreements at various stages of retaining wall rotation Fin- ally, results of analytical parametric study are presented to demonstrate the effects of wall fric- tion on the resultant thrust and distribution of developed lateral earth pressures.

• The Journal of Engineering Geology
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• v.22 no.1
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• pp.39-48
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• 2012

The behaviors of a diaphragm wall and a contiguous pile wall such as CIP(Case-in-place pile) and SCW(Soil-cement wall), applied to the top-down construction method, were analyzed using the SUNEX program, which is widely used to design earth retaining walls. Four types of earth pressures, as described by Rankine (1857), Terzaghi and Peck (1967), Tchbotarioff (1973), and Hong and Yun (1995a), were applied to the analysis program to predict the lateral displacement of walls. The results show that the displacements of an earth retaining walls vary with the applied earth pressure. The predicted lateral displacement based on Hong & Yun's (1995a) earth pressure is similar to the measured displacement. Therefore, the actual lateral displacement of an earth retaining wall, as applied to top-down construction method, can be accurately predicted by using an analysis program considering Hong and Yun's (1995a) earth pressure.

• Journal of the Korean Geotechnical Society
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• v.21 no.8
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• pp.55-61
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• 2005

Mononobe-Okabe method is generally used to evaluate dynamic earth pressure for the seismic design of retaining walls. However, Mononobe-Okabe method does not consider the effects of dynamic interactions between backfill soil and walls. In this research, shaking table tests on retaining walls were performed to analyze the phase and magnitude of dynamic earth pressure. The unit weight of walls, the amplitude of input acceleration and the base friction coefficient of walls were varied to analyze the influence of these factors on the dynamic earth pressure. Test results showed that the dynamic earth pressure was 180 degrees out of phase with the wall inertia force for the low sliding velocity of the wall, whereas small peaks of the dynamic earth pressure, which are in phase with the wall inertia force, were developed for the high sliding velocity of the wall. The amplitude of dynamic earth pressure was proportional to that of wall acceleration and the unit weight of the wall. In addition, the dynamic earth forces calculated by the Mononobe-Okabe method were the upper limit of the dynamic earth pressures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.505-513
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• 2014

This paper investigated the effect of joint on the earth pressure against an excavation wall in rockmass with the consideration of various rock and joint conditions. For this purpose, this study briefly reviewed of the previous earth pressure studies, and then numerical parametric studies were conducted based on the Discrete Element Method (DEM) to overcome the limitations of the previous studies. The numerical tests were carried out with the controlled parameters including rock types and joint conditions (joint shear strength, joint inclination angle, and joint set), and the magnitude and distribution characteristics of the induced earth pressure were investigated considering the interactions between the ground and the excavation wall. In addition, the earth pressures induced in rock stratum were compared with Peck's earth pressure for soil ground. The results showed that the earth pressure against an excavation wall in jointed rockmass were highly affected by different rock and joint conditions and thus different from Peck's empirical earth pressure for soil ground.

• Journal of the Korean Geotechnical Society
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• v.25 no.1
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• pp.21-29
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• 2009

On plane strain condition, many researchers have investigated the earth pressure according to the shape of wall, and standardized method has been applied to the design of the retaining wall. But on cylindrical diaphragm wall, at-rest earth pressure has been generally used. Even though this method is on conservative side, it may lead to over-design. In this paper, the application of convergence confinement method to the calculation of the earth pressure acting on the cylindrical diaphragm wall of a shaft was suggested. In addition, a model test was carried out to investigate the distributions of earth pressure. Model test results show that the earth pressures of diaphragm wall are about 1.4 times larger than active earth pressure and about 0.8 times less than at-rest earth pressure.

• Journal of Astronomy and Space Sciences
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• v.27 no.2
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• pp.97-106
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• 2010

To prepare for a Korean lunar orbiter mission, a precise lunar orbit propagator; Yonsei precise lunar orbit propagator (YSPLOP) is developed. In the propagator, accelerations due to the Moon's non-spherical gravity, the point masses of the Earth, Moon, Sun, Mars, Jupiter and also, solar radiation pressures can be included. The developed propagator's performance is validated and propagation errors between YSPOLP and STK/Astrogator are found to have about maximum 4-m, in along-track direction during 30 days (Earth's time) of propagation. Also, it is found that the lifetime of a lunar polar orbiter is strongly affected by the different degrees and orders of the lunar gravity model, by a third body's gravitational attractions (especially the Earth), and by the different orbital inclinations. The reliable lifetime of circular lunar polar orbiter at about 100 km altitude is estimated to have about 160 days (Earth's time). However, to estimate the reasonable lifetime of circular lunar polar orbiter at about 100 km altitude, it is strongly recommended to consider at least $50\;{\times}\;50$ degrees and orders of the lunar gravity field. The results provided in this paper are expected to make further progress in the design fields of Korea's lunar orbiter missions.

• Journal of the Korean GEO-environmental Society
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• v.11 no.2
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• pp.53-60
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• 2010

Considering environmental issues and lack of space, it is a necessity to minimize the amount of excavation. Various types of excavation methods are being used in practice. This study proposes a reasonable method for estimating the earth pressure acting on a reinforced wall in front of a excavated slope. The measured data in the field and numerical analyses were used. Results of the study shows that the earth pressure acting on the excavated wall is less than that estimated by Rankine's equations. It was shown that when the excavated slope is used with the reinforced wall, the pressures acting on the reinforced wall can be greatly reduced.

• Journal of the Korean Geotechnical Society
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• v.15 no.4
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• pp.261-277
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• 1999

The horizontal and vertical earth pressures in backfill space which is narrowly excavated like ditch are affected by the share of ditch backfill space and the wall friction between excavated surface and backfill soil. In this paper, for the excavated surface the Handy's equation of a symmetric vertical case and the Kellogg's equation of a symmetric sloped one are modified to show the minor principal stress arch for the unsymmetrical excavated backfill space. Compared with the soil test box result, a similarity in magnitude and distribution of backfill earth pressure shows that the earth pressure has been observed. The backfill earth pressure in unsymmetrically sloped space has been shown twice as much as the one in vertically excavated space and also remarkable decline of arching for the former case. It is verified that the earth pressure equation should account the shape and size of backfill space to calculate the earth pressure for similar structure to the one handled in this study.

• Journal of the Korean Geotechnical Society
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• v.20 no.2
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• pp.107-113
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• 2004

A new innovative prestressed support (IPS) earth retention system has been developed and introduced. The IPS is a wale system prestressed by steel wires. The IPS consists of wale, wires, and H-beam support. The IPS provides a high flexural stiffness to resist the bending by earth pressures. The IPS earth retention system provides a larger spacing of support, economical benefit, construction easiness, good performance, and safety control. This paper explains basic principles and mechanism of new IPS system and presents a design method of IPS earth retention system. In order to investigate applicability and safety of new IPS system, field tests were performed in a trench excavation. The new IPS system applied in a trench excavation was performed successfully. The measured performances of IPS system were presented and discussed.