• Interaction and multiscale mechanics
• /
• v.2 no.3
• /
• pp.235-261
• /
• 2009

This study illustrates the differences between the elasto-plastic cap model and Lade's model with Cosserat rotation through the analyses of two large-scale geosynthetic-reinforced soil (GRS) retaining wall tests that were brought to failure using a monotonically increasing surcharge pressure. The finite element analyses with Lade's model were able to reasonably simulate the large-scale plane strain laboratory tests. On average, the finite element analyses gave reasonably good agreement with the experimental results in terms of global performances and shear band occurrences. In contrast, the cap model was not able to simulate the development of shear banding in the tests. In both test simulations the cap model predicted failure loads that were substantially less than the measured ones.

• Journal of the Korean Society of Safety
• /
• v.12 no.4
• /
• pp.108-113
• /
• 1997

Plate anchors are primarily used in the foundation construction of earth-supported and earth-retaining structures. In order to estimate uplift capacity as well as suction force of clay, model tests were peformed with respect to various embedment depths and two different moisture contents in the prepared saturated kaolinite. Further, suction effects on the ultimate uplift capacity, at the various embedment depths of anchor, were also taken into account. Test results show that ultimate uplift capacity including suction force increases from 4.2kg at H/D=1 upto 11.6kg at H/D=5 in K1 and from 2.3kg at H/D=1 upto 7.3kg at H/D=5 in K2 respectively. The ratio of $F_s/Q_n/$ decreases along with the increases in the embedment ratio. In general, mud suction force under the ultimate uplift capacity in kaolinite decreases or becomes constant along with the increase of the embedment ratio.

• Journal of the Korea Institute of Building Construction
• /
• v.8 no.4
• /
• pp.61-69
• /
• 2008

The size of the construction projects become huge and complex, and the depth of excavation for the underground structures become deeper. Also the working area is not enough for loading materials and temporary facilities. This is the most case of recent construction projects in downtown area. Top-down is the most useful method for this kind of construction projects. Top-down construction method consists of supporting method, retaining wall type, foundation type and construction direction such as up-down or up-up. construction managers have to select sub-elements for top-down construction method in planning phase. This study is to suggest the sub-elements selection model for the top-down construction method, and the case study is conducted for evaluating this model.

• Tunnel and Underground Space
• /
• v.4 no.1
• /
• pp.63-76
• /
• 1994

This paper discusses contents of the existing design, the behaviours prediction on the strut and retaining wall around subsurfaces, and also evaluates the measured results in comparison with the management criterion during excavation period of ventilation shaft at Pusan-Subway 220. Field measurements showed that maximum displacement 23.74 mm at boundary site of multistratification and the weathered rock to be formed at 0.2~0.6 H of total excavating depth(H), 68 ton of maximum axial force and 4.4X102 kg/cm2 of stress on strut. The measured axial force exceeds prediction levels by up to 50 percent at the weathered soil & rock, and the others come under the category of their levels. The great gap of both field measurements and prediction on behaviour makes a difference of the site situation at the design stage and the practical working. This measured value is greatly safety in comparison with that of the safety criterion, but axial force at 4~5 strut of ventilation shaft l is higher than the prediction.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2005.10a
• /
• pp.404-409
• /
• 2005

The reinforced concrete blocks for reinforced earth layer are combined with soil structures consisted of facing unit, reinforcing materials and soil. Those environmentally friendly facing units of reinforced concrete blocks are made of mine waste and tailing and that will be played a role of the effects of recycling use of wasted resources. The block are consisted of three types as curved or straight in order to control topography. The systems are also not limited to wall hight so that they are effectively used for protecting the slope of banking and cutting of earth works. The reinforced concrete blocks developed this time will be effectively applied for not only retaining wall, road, park, golf course, public office building constructions but also protecting of slope stabilization projects.

• Geomechanics and Engineering
• /
• v.20 no.2
• /
• pp.121-129
• /
• 2020

In the design of geotechnical structures, engineers choose either peak or critical state friction angles. Unfortunately, this selection is based on engineer's preference for economy or safety and lacks the assessment of the expected level of deformation. To fill this gap in the design process, this study proposes a strain based empirical method. Proposed method is founded on the experimentally supported assumption that higher dilatancy angles result in more brittle soil response. Using numerous triaxial test data on ten different soils, an empirical design chart is developed that allows the estimation of shear strain at failure based on soil's peak dilatancy angle and mean grain diameter. Developed empirical chart is verified by conducting a small scale retaining wall physical model test. Finally, a design methodology is proposed that makes the selection of design friction angle in structured way possible based on the serviceability limits of the proposed structure.

• Wind and Structures
• /
• v.7 no.2
• /
• pp.71-88
• /
• 2004

In this paper the capacity of Covariance Proper Transformation (CPT) analyses to provide information about the wind loading mechanisms of bluff bodies is investigated through the application to square cylinders. CPT is applied to the fluctuating pressure distributions on a single cylinder, as well as on a pair of cylinders in the tandem and side by side arrangements, with different separations. Both smooth and turbulent flow conditions are considered. First, through the analysis of the contributions of each CPT mode to the total fluctuating aerodynamic forces, a correspondence between modes and aerodynamic components is sought, which is then verified through examination of the mode shapes. When a correspondence between modes and aerodynamic components is found, an attempt is made to separate the different frequency contributions to the aerodynamic forces, provided by each mode. From the analyses it emerges that (a) in most cases each mode is associated to one single force component, that (b) retaining a limited number of modes allows reproducing the aerodynamic forces with a rather good accuracy, and that (c) each mode is mainly associated with one frequency of excitation.

• Journal of the Korean Society for Railway
• /
• v.5 no.2
• /
• pp.93-103
• /
• 2002

Reinforced earth structure has been regarded as general structure in order to achieve efficient land utilization as well as securing safety in railway service lines in other countries, but there are no construction actual results in Korea. In this study, the soil-geogrid interaction mechanism was investigated experimentally and numerical analysis was performed to predict Pull-out behaviour of geogrid embedded in reinforced earth body. This experimental data and analysis result can not contribute to understand the soil-geogrid interaction mechanism at soil-geogrid interface but also be used in design practice of the railway reinforced earth structures.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.11a
• /
• pp.723-726
• /
• 2004

Porous polymer concrete can be applied to roads, sidewalks, river embankment, drain pipes, conduits, retaining walls, yards, parking lots, plazas, interlocking blocks, etc. This study is to examine a content ratio of polypropylene fiber to improve bending strength, impact resistance and freezing and thawing rssistance of porous polymer concrete. Also, this study is performed to develop the porous polymer concrete using recycled coarse aggregate and blast furnace slag for application of structures needed permeability. At 7 days of curing, compressive strength, flexural strength, water permeability and flexural load are in the ragge of $17\~21MPa,\;5\~7MPa,\;4.1\times10^{-2}\~7.7\times10^{-2}cm/s$, respectively. It is concluded that the recycled aggregate can be used in the porous polymer concretes.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2009.05b
• /
• pp.41-44
• /
• 2009

Top-Down construction is becoming a popular construction method in China as there is a growing need for building high-rise structures in crowded urban areas. This paper deals with the explanation and analysis of characteristics of Top-Down construction in China. In China, usually construction site is relatively large or sometimes huge compared to that in Korea. Thus, as the high-rise portion of the building needs to be constructed first and fast, island method is used at the center p망t of the building. In the meanwhile, the remaining area of the building is constructed using Top-Down method to provide working area for equipments and workers. Also, the case studies of construction examples are provided in this paper. The purpose of this paper is to promote international understanding and interaction between neighborhood countries for the utilization of Top-Down construction.