• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.1
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• pp.51-57
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• 2011

Irregular distributions of limestone cavity in Gang-Won province area may cause unexpected accidents from reduced serviceability or failure of structure. It is requested that an appropriate ground reinforcement method should be used to improve bearing capacity of structure, and the method should also be satisfied with environmental requirements. Among several methods used for foundation constructions in cavity area, Rod Jet Pile(RJP) method has been widely used. While the RJP method was used to improve bearing capacity for the railway bridge foundations, water pollutions of drinking water as well as fishery located adjacent to this project area were occurred. The main reason of the water pollution was cement runoff used in cement mortar during injecting material in RJP method. Laboratory tests were performed to prevent water pollution. The compaction mortar method using low movable material was selected for this project. The quality of water at a fishery adjacent to the site and the compressive strength of cores taken from the construction site were measured. Test results show that the water pollutions was minimized, and the average compressive strength of foundation material was over 5 MPa. As a result of this study, compaction mortar method can be used to ensure the bearing capacity of foundation and to prevent environment pollutions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.142-143
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• 2021

The general ground conditions in Korea are distributed in order of fill, deposit soil, weathered soil, weathered rock, soft rock. The fill soil and deposit soil located at the top have relatively low strength compared to the lower layer, and they are sometimes classified as soft ground according to the standard penetration test results. In this study, the PF method, a ground improvement method, was applied to the soft layer, a large plate load test was conducted on the improved ground, and the results were reviewed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.5
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• pp.88-95
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• 2015

The thickness of adsorbed molecular layers is the most critical factor in studying thin-film lubrication, and it is the most essential parameter that distinguishes thin-film from thick-film lubrication analysis. The thin film between the shaft and bearing surface within a very narrow gap was considered. The general Reynolds equation has been derived for calculating thin-film lubrication parameters affecting the performance of the circular journal bearing. Investigation of the load-carrying capacity and pressure distribution for the journal bearing considering the adsorbed layer thickness has been carried out. A Reynolds equation appropriate for the journal bearing is used in this paper for the analysis, and it is discussed using the finite difference method of the central difference scheme. The parameters, such as eccentricity and attitude angle, are used for discussing the load-carrying capacity of the journal bearing. The results reported in this paper should be applied to analysis of the journal bearing with different lubrication factors. The steady-state analysis of the journal bearing is conducted using the Reynolds model under thin-film lubrication conditions. For a journal bearing, several parameters, such as a pressure, load capacity, and pressure components of the bearing can be obtained, and these results can be stored in a sequential data file for later analysis. Finally, their distribution can be displayed and analyzed easily by using the MATLAB GUI technique. The load-carrying capability of the journal bearing is observed for the specified operating conditions. This work could be helpful for the understanding and research of the mechanism of thin-film lubrication.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1031-1034
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• 2007

Electric transmission lines pass through a variety of area. Foundation supporting the conductors and tower are selected properly in accordance with external load, for example dead load, wind load, snow load, construction load etc, and topography and geology condition. Typical types of foundation are as follows: pad foundation for small load and hard soil or rock in mountainous area, pile foundation for medium or large load and soft soil in plain field area. This paper introduced cylindrical foundation design & construction for large load and mountainous area. This foundation failure mode against pulling-out show splitting failure by tensile force toward circumferential direction.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.355-362
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• 2001

Since micropiles were conceived in Italy in the early 1950s, which have been widely used for In-situ reinforcement, bearing pile or the concept of combination in the world-wide. The meaning of micropiles usually differs from that of a general deep foundation. Because the load capacity of it was mainly affected by skin friction. Also, it could be obtained the improvement effects of load capacity or ground's rigidity by the unitary behavior of ground and micropiles. In this study, The model tests were peformed on the dense sand where micropiles are set to the vertical direction. Strip footing was used in it. Steel bars of dia. 2 and 4㎜ were used in model tests of which the sand was attached on the surface, and the length of it was changed as 2B to 6B(where, B is width of strip footing) Through this process, the load capacity were analyzed from the test results in the relationship between load and displacement.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.83-89
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• 2018

In this study, the settlement of concrete rectangular pyramid foundation on soft ground is investigated based on a finite element analysis. considering the grounding load and the grounding area of square pyramid foundation, we compensate the insufficient design bearing capacity and investigated the effect of settlement by load. Based on this study, it is found that the rectangular pyramid foundation shows the smallest settlement of three different type of foundations. As a result of this study, it was resulted that the square pyramid foundations were more effective than the crushed stone foundations by 18%. These results show that the ground pressures of the square pyramid bases are divided into horizontal and vertical stresses, so it is analyzed that the horizontal stress builds up the rigid ground on the foundation of the structure and distributes the load widely to increase the resistance to the overhead load.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.137-144
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• 2010

Up to now, common studies of top base have concentrated upon bearing capacity and settlement by in-situ loading test in Japan and Korea. But most of all preceding study for top base must analyze how to deliver overburden loading on bottom of foundation. Therefore, in this study, the stress delivery mechanism of Top-Base Foundation developed in Japan and Floating Top Base developed in Korea is investigated through numerical analysis and laboratory model test. Analyzing the load delivery mechanism of top base, it was found that the division rate of load reduction of top base for overburden load was largest in peripheral skin friction between the top base and the crushed stone. Further, total stress dispersion angle of Top-Base Foundation including internal stress dispersion effect of top base was $41.8^{\circ}$ and total stress dispersion angle of Floating Top Base was $44.5^{\circ}$.

• Journal of the Korean GEO-environmental Society
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• v.10 no.6
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• pp.5-18
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• 2009

In construction of buildings in Korea, the buildings are frequently founded on the weathered ground (weathered soil/rock, fractured rock). In this case, to make a full use of a bearing capacity of a weathered ground for economic design, the shallow mat foundation system could be used. In this study, we have researched three cases of mat foundations on the weathered ground in Korea, and analyzed and considered the design procedures and the reinforcing methods. That is, we have considered the detail design, analysis proceedings, the ground settlement evaluation proceedings, the rock face mapping evaluations after excavation and reinforcing methods of the mat foundation on the weathered ground. And large scale plate load tests on the weathered ground supporting the mat foundation were performed and also load bearing capacity and settlement of actual mat foundation, considering the scale effect, were evaluated.

• Journal of the Korean Geotechnical Society
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• v.29 no.1
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• pp.61-70
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• 2013

This paper presents the results of a two-dimensional finite element analysis of end bearing capacity of single pile installed in fractured rock mass. A number of cases were analyzed using Hoek-Brown criterion that can consider the condition of rock joints. Considering a wide range of joint conditions in which the pile is embedded into the rock, GSI was set as a main parameter. And the effects of pile diameter, unconfined compressive strength of rock and Hoek-Brown constant $m_0$ were considered. Based on parameter study, end bearing load factor graphs were suggested.

• Journal of the Korean Geotechnical Society
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• v.25 no.7
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• pp.23-33
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• 2009

In this study the characteristics of piled raft was investigated by using both centrifuge and numerical modeling. The ultimate bearing capacities of single pile, unpiled raft, freestanding pile group and piled raft were compared in order to investigate load sharing of each element : pile and raft. The comparison determined parameters to simply evaluate the ultimate bearing capacity of piled raft. Centrifuge test results were simulated by numerical simulation to verify the parameters.