• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.17 no.2
• /
• pp.98-105
• /
• 2005

A new type breakwater is developed for small scale harbors and fishing ports with low design wave and soft ground. The structure of the developed breakwater is similar to the soldier pile used in soil excavation. Structural performance of the new type breakwater can not be accurately evaluated by numerical analysis due to nonlinearity of joints between piles and honelasticity of soil support. Therefore, this paper investigates the structural performance of the breakwater with experimental method and compares the results with numerical analysis.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.1302-1313
• /
• 2010

The west express way is notorious for extremely heavy traffic area in the west of Seoul, South Korea. Hence, the city government recently initiated a new underground BTO (Build-Transfer-Operate) road project to solve traffic congestion and a high construction cost. The proposed underground express road being designed is the first double-level tunnel ever designed in South Korea and using Conventional tunnelling method (NATM). A total length of tunnel for light vehicles is 10.91km long including both open cut structures and concrete lining with middle-deck in bored tunnel. There are also 4 ventilation shafts for ventilation and evacuation on emergency. Many design issues had been aroused during the preliminary design phase and detail design phase is currently going on. This paper discusses design focuses including excavation methods, ground water issues, a deck slab installation, and a construction cost etc. for the double level road tunnel design of urban area.

• Explosives and Blasting
• /
• v.15 no.1
• /
• pp.44-60
• /
• 1997

The design of underground cavern is basically governed by the mechanical properties of ground mass distributed around excavation. It is seldom possible to consider all the factors of ground mass properties in the evaluation of ground mass behavior as well as to classify those factors to a simple category. Until computer sciences have developed to calculate complex and laborious mechanical simulation of underground openings, ground behavior was quantitatively and qualitatively evaluated using empirical classification system. In this paper, analysis methods of ground behavior for underground cavern using the prediction of loosening zone, empirical method derived from rock mass classification and element stress analysis are described with chronological sequence.

• Journal of Korean Medical classics
• /
• v.21 no.3
• /
• pp.69-81
• /
• 2008

Gwae(卦氣) theory was one of the main theoretical foundation of yiology in the Han(漢)-dynasty. It was based on the concept that the trigram or hexagram of the book of change corresponds to the seasonal point such as 24 solar terms in one year, so there was so much influence from astronomy and divination system of that time in the development of theoretical principle of Gwae(卦氣) theory. Since Han(漢) Dynasty, the theoretical method such as Gwae(卦氣) theory that correlates the astronomy and divination system with the book of change, had become one of the main academic thoughts throughout the entire history in China, and it was also like that in medicine. Nevertheless there still exists the skeptical sights that Gwae(卦氣) theory was not a part of orthodox yiology, that had been developed by Confucian scholar and had also been recognized as the right path to the study of the book of change. Nowadays because of the new opportunity such as the excavation of the ancient silk script, this kind of controversy has moved on its another step. With regard to this problem, this article will treat the current thoughts about the Gwae(卦氣) theory and think about the substantial basis of each point of view.

• Economic and Environmental Geology
• /
• v.17 no.1
• /
• pp.57-78
• /
• 1984

The object of this study is to offer the standarized data for the design and calculating engineering cost of the rock excavation an the construction of the 3rd and 4th Seoul Subway lines From Jnauary to March in 1983, this study was carried out by the both methods of the field and laboratary studies. In the field, the geological survey in the entire area of Seoul City and sites on the subway lines were carried out and also a site measure of uniaxial compressional strength of rock masses by using Schmidt hammer was done. The labartory studies were carsied out by a study of preuions surveyes, microscopic studies of the mineral composition and degree of weathering of rocks, and measure of uniaxial compressional strengths Finally an engineering classification of each rock masses of South Africa council for Scientific and Industrial Research, CSIR, after Bieniawski, 1974. was done. In this method of classification 6 parameters such as strength of intact rock material, rock quality designation, spacing of fractures, condition of fractures, groundwater conditions, and the effect of fracture strike and dip orientation in tunnelling were used to evaluate rating of each rock mass.

• The Journal of Engineering Geology
• /
• v.7 no.1
• /
• pp.81-90
• /
• 1997

The Korean historical 1iteratures describe that great eaathquakes with destructive damages occurred mainly in Kyongju-Ulsan areas during the period of 1 to 8 century and 16 to 17 century. It seems that the Ulsan fault system shows a little curved ttend with N-S strike in the southern part and diverges into three directions from the mid-northern lart of the fault. The dominant trends of the lineaments are NNE-SSW, NE-SW and NS directions. Trench excavation in the mid-northern part of the Ulsan fault shows thrust facies cutting slope deposit containing a compacted laminar structure whose origin may due to severe cryogenic activities of the last cold period(ahout 25OOO B.P.). Detailed observation of the facies gives some evidences related to two earthquake episodes of thrust components along the Ulsan fault system. Fault outcrop and trench study suggest that Ulsan fault seems to he one of the active fault which has reworked several times even in the late Quaternary.

• Geomechanics and Engineering
• /
• v.15 no.6
• /
• pp.1227-1236
• /
• 2018

From all of the environmental problems, blast-induced vibrations often cause concern to surrounding residents. It is often claimed that damage to building superstructures is due to blasting, and sometimes the building owner files a lawsuit against the company that perform blasting operations. The blast-vibration problem has been thoroughly investigated in the past and continues to be the subject of ongoing research. In this study, a tunnel construction has been performed by a construction company, according to their contract they must have used drilling & blasting method for excavation in tunnel inlet and outlet portal. The population is very condensed with almost tunnel below in the vicinity houses of one or two floors, typically built with stone masonry and concrete. This situation forces the company to take extreme precautions when they are designing blasts so that the blast effects, which are mainly vibration and aerial waves, do not disturb their surrounding neighbors. For this purpose, the vibration measurement and analysis have been carried out and a new methodology in minimizing the blast induced ground vibrations at the target location, was also applied. Peak particle velocity and dominant frequencies were taken into consideration in analyzing the blast-induced ground vibration. The methodology aims to employ the most suitable time delays among blast-hole groupings to render destructive interference of surface waves at the target location.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.52 no.4
• /
• pp.73-81
• /
• 2010

The cemented sand and gravel (CSG) method is a construction technique that adds cement and water to rock-like materials, such as rivered gravel or excavation muck which can be obtained easily at areas adjacent to dam sites. This study was performed to evaluate the compaction and compressive strength properties of stress-strain, elastic modulus and fracture mode CSG materials reinforced polypropylene fiber. Polypropylene fiber widely used for concrete reinforcement is randomly distributed into cemented sand. The two types of polypropylene fiber (monofillament and fibrillated fiber) were used and fiber fraction ratio was 0, 0.2 %, 0.4 %, 0.6 % and 0.8 % by the weight of total dry soil. The effect of fiber fraction ratio and fiber shape on compaction and compressive strength were investigated. The optimum moisture contents (OMC) of CSG material increased as fiber fraction increased and the dry density of CSG material decreased as fiber fraction. Also, the maximum increase in compressive strength was obtained at 0.4 % content of monofillament and fibrillated fiber. CSG material behaviour was controlled not only by fiber fraction but also fiber distribution, fiber shape and fiber type.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.16 no.2
• /
• pp.125-133
• /
• 2014

In this study, TBM selection methods to meet soil and site conditions were presented. Factors and excavation equipment affecting TBM selection by soil and environmental condition were selected and classified. Weights between equipment and influencing factors selected were calculated by applying the AHP (Analytic Hierarchy Process) method. The results of the analysis influence factors, Ground condition was a major factor in objective factors and strength was a major factor in the hard condition of criteria factors and water pressure was a major factor in the soft ground condition of criteria factors. In Environment condition, existence of adjacent structures was evaluated more important than existence of feasible site. Lastly, Adequacy was verified through the deduction of results that coincide with input equipment by applying derived weights to actual site conditions.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.03a
• /
• pp.742-753
• /
• 2008

Currently an increasing number of urban tunnels with small overburden are excavated according to the principle of the New Austrian Tunneling Method (NATM). Therefore, a possibility of a tunnel collapse during excavation is getting higher in a proportionate manner. This paper will analyze causes the failure mechanism of a shallow NATM tunnel for different geological conditions, ground-water and invert solutions by investigation typical collapse site during tunnel construction. In this paper, this analysis performed two phase, firstly, the field investigation considering displacement measurement, ground-water level, geological characteristic, secondly, the numerical simulation considering the exist of invert construction and the effect of ground-water. It has been found that environmental factors such as state of underground water or construction sequences could influence failure mechanism of a shallow tunnel.