• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.4 s.19
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• pp.49-57
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• 2005

The purpose of this study is to closely examine the influence of the surcharge load applied to the retaining wall through some model tests, in which wall stiffness in each stage of excavation, horizontal displacement of the retaining wall and surface displacement of the backfill according to wall stiffness and ground conditions, and change and distribution of the earth pressure applied to it were measured and their values were produced, then these values were mutually compared with their theoretical values and their values after analysis of the data obtained at the field, and they were analytically studied, in order to closely examine the influence of the surcharge load applied to the retaining wall. Findings from this study are as follows: The shape of ground surface settlement curve on the model ground under surcharge load, different from the distribution curve of regular probabilities which is of a shape of ground surface settlement under no surcharge load, appears in that settlement in an arching shape shows where the center part of surcharge load shows the maximum settlement. In examining the maximum horizontal displacement with the surcharge load applied to each stage of excavation, it occured at the point of 0.8H(excavation depth) when finally excavated. Regarding the range in which the displacement of the retaining wall increases according to application of surcharge load, the increment of displacement showed till the point of depth which is of two times of the distance of load from the upper part of the wall. Also since each displacement of the foundation plate caused by the ground surface settlement according to each stage of excavation occured most significantly at the final stage. Also since regarding wall stiffness, the wall of its thickness of 4mm(flexible coefficient $p:480m^3/t$), produced maximum 3 times of wall stiffness than its thickness of 9mm(flexible coefficient $p: 40m^3/t$), it was found out that influence of wall stiffness is so significant.

• Journal of the Korean Geotechnical Society
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• v.25 no.5
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• pp.39-46
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• 2009

In this study, behavior of a rigid continuous wall, earth pressure distribution with construction stage, and axial force of earth anchors were evaluated based on field monitoring data and numerical analysis results. For this purpose, a construction site excavated using the diaphragm wall was selected and full instrumentation system was introduced. From monitoring results, it was found that the values of horizontal displacement of the wall measured from the inclinometers, which were installed within the diaphragm wall were similar to analytical value. The earth pressure increased with excavation progress due to jacking force of the ground anchors installed in previous excavation stages. When the excavation depth reached 60% of the final depth, observed earth pressure distribution was similar to that estimated from Peck's apparent earth pressure distribution. When the excavation depth was around 90% of the final depth, values of observed earth pressure showed middle values between those of Peck's and Tschebotarioffs apparent earth pressures. It was also observed that, when excavation depth is deep, values of the earth pressures from the rigid wall were similar to those estimated from conventional earth pressure distribution shape proposed for flexible walls.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.347-352
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• 2007

Recently, automated construction machines have been developed for technically solving construction industry problems such as labor, productivity, quality and the profit decrease. In domestic construction industry, a research for developing an intelligent excavation robot has been performed. The primary objective of this research is to analysis state-of-the art technologies in order to recognize local ground shape in real-time and compute soil volume of earth moving. This research analyzed five elemental technologies for 3D modeling of local ground shape and selected an optimal technology among the five technologies through using AHP method. It is anticipated that the optimal technology selected for 3D modeling of local ground shape can be effectively used to develop the intelligent excavation robot.

• 보존과학연구
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• s.31
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• pp.17-30
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• 2010

There were excavated many relics about 200 pieces including gilt-bronze cap, gilt-bronze shoes, bronze mirror and armor, etc. in Ahndong tumulus, Gildu-ri, Goheung. The National Research Institute of Cultural Heritage was undertaking excavation of major damaged relics that were corroded by several environment and were destroyed by a lump of earth. Shoes are consolidated with soils in order to stop destroy during excavation. And these are relocated in order to treat for conservation. Before treatment, X-ray radiography and CT(Computed Tomography) are used in order to examine the original surface and the shape of shoes. As a result, we confirm the condition of shoes. If soils are removed, gilt-bronze shoes are crumbling into little pieces because gilt-bronze shoes are damaged by corrosion and deformation. So, shoes are consolidating with inner soils and are removing outer soils. Throughout conservation treatment, shoes recovered original form and inner soils are consolidated in order to keep the shape of shoes.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.3
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• pp.167-181
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• 2021

New type of rock excavation method using a waterjet system is being developed to secure economic feasibility and to reduce vibrations during excavation. In waterjet rock excavation, overlapping of cutting width is essential for high efficiency. In this study, cutting experiments for granite specimens were performed using abrasive waterjet system according to the overlapping ratio and standoff distance. Based on the experimental results, the granite cutting performance was analyzed according to the overlapping ratio. In addition, removal shapes of the cross-section were analyzed in terms of the cutting depth, width, and volume after waterjet cutting. When the overlapping ratio is less than 58%, rock specimens are partially removed due to the insufficient overlapping ratio. However, when the overlapping ratio exceeds 67%, overcutting phenomenon is observed. For the partial overlapping ratio (i.e., 25~75%), cutting efficiency is increased in the removal volume. This study is expected to be used as the important basic data for determining the optimum overlapping ratio when the waterjet system is applied for rock excavation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.2
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• pp.133-141
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• 2007

The excavation damaged zone (EDZ) is an area around an excavation where in situ rock mass properties, stress condition, displacement, groundwater flow conditions have been altered due to the processes induced by the excavation. Various studies have been carried out on EDZ, but most studies have focused on the mechanical bahavior of EDZ by in situ experiment. Even though the EDZ could potentially form a high permeable pathway of groundwater flow, only a few studies were performed on the analysis of groundwater flow in EDZ. In this study, the 'hydraulic EDZ' was defined as the rock zone adjacent to the excavation where the hydraulic aperture has been changed due to the excavation by using H-M coupling analysis. Fundamental principles of distinct element method (DEM) were used in the analysis. In the same groundwater level, the behavior of hydraulic aperture near the cavern was analyzed for different stress ratios, initial apertures, fracture angles and fracture spacings by using a two-dimensional DEM program. We evaluate the excavation induced hydraulic aperture change. Using the results of the study, hydraulic EDZ was defined as an elliptical shape model perpendicular to the joint.

• Korean Institute of Interior Design Journal
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• v.20 no.6
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• pp.228-235
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• 2011

The 卍 shape which is used as an aesthetical feature for traditional architecture can be seen in the stair railings of the house shaped ceramic potteries in the Eastern Han dynasty(A.D. 25-220) but with the introduction of Buddhism, it has been widely used for the decoration of the sarira(small crystals of the cremated monks) case. After the shape was seen in the Yungang and Dunhwang grottoes mural paintings, the use of it has been expanded. In Korea during the excavation of the Gyeongju Anapji which was the Eastern palace of the Shilla dynasty, a 卍 shaped wood which had been used as a handrail was found and this shape was also used in the railings of the Shilsangsa Baekjangarn temple stone pagoda and lantern and in the sarira case excavated in the Songrimsa temple stone pagoda. In Japan, the Nara period(A.D. 710-794) when there were many cultural exchanges with the Korean peninsula, the handrails of the 2ndfloor of the main hall of Hoyu-ji temple has a 卍 shape. This can be confirmed that this shape has been widely used as a design in Asian Buddhist architecture. Gilsangoonhae(吉祥雲海) which is the symbolic meaning of this shape means for long life and luck which had been used generally for the window designs of temples, palaces, and houses. In this study, it is giving the definition the beginning and the symbolic meaning of the 卍 shape which is being used from the ancient times until nowadays and the change of this shape used for window designs.

• 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.

• Korean Journal of Construction Engineering and Management
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• v.12 no.6
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• pp.130-141
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• 2011

The intelligent excavating system(IES), the development in South Korea of which has been underway since 2006, aims for the full-scale automation of the excavation process that includes a series of tasks such as movement, excavation and loading. The core elements to ensure the quality and safety of the automated excavation equipment include 3D modeling of terrain that surrounds the excavating robot and the technology for detecting objects accurately(i.e., for detecting the location of nearby loading trucks and humans as well as of obstacles positioned on the movement paths). Therefore the purpose of this research is to ensure the quality and safety of automated excavation detecting the objects surrounding the excavating robot via a 3D laser scanning system. In this paper, an algorithm for estimating the location, height, width, and shape of objects in the 3D-realized terrain that surrounds the location of the excavator was proposed. The performance of the algorithm was verified via tests in an actual earthwork field.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.10
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• pp.1069-1077
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• 2015

In tunnel excavation using blast, the wire saw rock cutting method generates a discontinuity perimeter around the center cut, and thus prevents blast vibration propagation to reduce vibration and noise. Therefore, the method is expected to be easy to use and economical compared with other methods. In this paper, the cutting mechanism of wire saw in tunnel excavation is investigated. A model describing the changes in cutting depth and wire saw shape inside a rock during cutting is established and validated for this purpose. Through a simulation using the model, the important characteristics of wire saw cut are investigated, and the influences of cutting conditions, such as wire saw tension, wire saw speed, feed speed, depth, and diameter of boring, on cutting performance are also examined. A method to improve the cutting performance is proposed based on the results.