• 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.

• The Journal of Engineering Geology
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• v.19 no.4
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• pp.475-482
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• 2009

The behavior of earth retention wall installed in cut slope is different from the behavior of retention wall applied in urban excavation. In order to establish the design method of anchored retention walls in cut slope, the behavior of anchored retention wall can be investigated and checked in detail. In this study, the behavior of anchored retention wall was investigated by instrumentation installed in cut slope for an apartment construction stabilized by a row of piles. 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. Jacking force of anchor was mainly influenced in the horizontal displacement of anchored retention wall. The displacements of anchored retention wall and slope soil were affected mainly by an rainfall infiltrated from the ground surface. Meanwhile, the horizontal displacement of anchored retention wall with slope backside was about 2-6 times larger than the displacement of anchored retention wall with horizontal backside of excavation.

• 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.

• Bulletin of the Korean Chemical Society
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• v.30 no.2
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• pp.355-362
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• 2009

The chemical modification of multi-wall carbon nanotubes (MWNTs) is an emerging area in material science. In the present study, hydroxyl functionalized oxovanadium(IV) Schiff-base; N,N'-bis(4-hydroxysalicylidene)-ethylene-1, 2-diamineoxovanadium(IV), [VO($(OH)_2$-salen)]; has been covalently anchored on modified MWNTs. The new modified MWNTs ([VO($(OH)_2$-salen)]-MWNTs]) have been characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron (XPS), UV-Vis, Diffuse reflectance (DRS), FT-IR spectroscopy and elemental analysis. The analytical data indicated a composition corresponding to the mononuclear complex of tetradentate Schiff-base ligand. The characterization of the data showed the absence of extraneous complex, retention of MWNTs and covalently anchored on modified MWNTs. Liquid-phase oxidation of cyclohexane with $H_2O_2$ to a mixture of cyclohexanone, cyclohexanol and cyclohexane-1,2-diol in $CH_3$CN have been reported using oxovanadium(IV) Schiff-base complex covalently anchored on modified MWNTs as catalysts. This catalyst is more selective toward cyclohexanol formation.

• Journal of the Korean Geotechnical Society
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• v.23 no.5
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• pp.77-88
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• 2007

Lateral earth pressure and horizontal displacement of the diaphragm walls constructed in multi-soil layers were analyzed by the field instrumentation from six building construction sites in urban area. The distribution of the developed earth pressure of the anchored diaphragm walls during excavation shows approximately a trapezoid diagram. The maximum earth pressure of anchored diaphragm walls corresponds to $0.45{\gamma}H$ and the earth pressure acts at the upper part of the walls. The maximum earth pressure is two times larger than the empirical earth pressure of flexible walls in sands suggested by Terzaghi and Peck(1967), Tschebotarioff(1973), and Hong and Yun(1995a). The horizontal displacement of diaphragm walls is closely related with supporting systems such as struts, anchors, and so on. The horizontal displacement of anchored walls shows less than 0.1 percent of the excavated depth, and the horizontal displacement of strutted walls shows less than 0.25 percent of the excavated depth. Therefore, the restraining effect of horizontal displacement to the anchored diaphragm walls is larger than the strutted diaphragm walls. In addition, since the horizontal displacement of the diaphragm walls is lower than the criterion, $\delta=0.25%H$, used for control the anchored retention wall using soilder piles, the safety of excavation sites applied with the diaphragm walls is pretty excellent.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.276-285
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• 2006

Application of anchored or strutted wall system for the earth retention of excavation works in a populated urban area or a poor soil deposit can be limited due to various restrictions. Since the strut becomes longer in a wide excavation site, the stability of an earth retaining wall is decreased, the wall deformation is increased, and the ground settlement is also increased due to an increased buckling or bending deformation of struts. Especially, in a populated urban area, the installation of anchors can be problematic due to the property line of adjacent structures or facilities. Thus, a new concept of earth retaining system like Self-Supported diaphragm Wall can solve several problems expected to occur during excavation in the urban area. In this study, Numerical analyses of counterfort diaphragm wall was introduced and the monitored data from the site was compared with the original results of numerical analyses. Also, in the case of the deep excavation applied the counterfort diaphragm wall, numerical analyses was performed to predict the wall deformation and the reinforcement to reduce the wall deformation was suggested.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.605-613
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• 2008

Application of anchored or strutted wall system for the earth retention of excavation works in a populated urban area or a poor soil deposit can be limited due to various restrictions. Since the strut becomes longer in a wide excavation site, the stability of an earth retaining wall is decreased, the wall deformation is increased, and the ground settlement is also increased due to an increased buckling or bending deformation of struts. Especially, in a populated urban area, the installation of anchors can be problematic due to the property line of adjacent structures or facilities. Thus, a new concept of earth retaining system like Self-Supported diaphragm Wall can solve several problems expected to occur during excavation in the urban area. Application of self-supported counterfort diaphragm wall was verified in this paper though comparing the design of self-supported counterfort diaphragm wall with the data monitored during excavation in Singapore.

• Geotechnical Engineering
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• v.8 no.4
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• pp.81-98
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• 1992

Deep excavation increases utility of underground spaces for high buildings. subways etc. To excavate vertically the underground, safe earth retaining walls and supporting systems should be prepared. Recently anchors have been used to support the excavation wall. The anchored excavation has some advantages toprovide working space for underground construction. In this paper the prestressed anchor loads were measured by load cells which attacted to the anchors to support the excavation walls at eight construction fields. where under-ground deep excavation was performed on cohesionless soils. The lateral pressures on the retaining walls, which are estimated from the measured anchor forces, shows a trapezoidal distribution that the pressure increases linearly with depth from the ground surface to 30% of the excavation depth and then keeps constant value regardless of the stiffness of the walls. The maximum lateral pressure was same to 63% of the Ranking active earth pressure or 17% of the vertical overburden pressure at the final depth The investigation of the measured lateral pressure on the anchored excavation walls shows that empirical earth pressure diagram presented by Terzaghi-Peck and Tschebotarioff could be applied with some modifications to determine anchor loads for the anchored excavation in cohesionless soils.

• Journal of the Korean Geotechnical Society
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• v.23 no.3
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• pp.5-13
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• 2007

The performance of innovative prestressed support (IPS) earth retention system applied in soft clay was investigated and presented. The IPS wale system provides a high flexural stiffness to resist the bending by lateral earth pressure, and transfers lateral earth pressure to strut supports. The IPS wale system provides a larger spacing of support than conventional braced and anchored systems. The IPS earth retention system was selected for temporary earth support in a building construction in North Busan area. The excavation was made 28.8 m wide, 52.0 m long, and 16.1 m deep through loose fill to soft clay. The IPS system consists of 650 mm thick slurry walls, and five levels of IPS wales and struts. Field monitoring data were collected including wall deflections at six locations, ground water levels at four locations, IPS wale deflections at thirty locations, and axial loads on struts at twenty locations, during construction. The IPS earth retention system applied in soft clay performed successfully within a designed criterion. Field measurements were compared with design assumptions of the IPS earth retention system. The applicability and stability of the IPS earth retention system in soft clay were investigated and evaluated.