• Journal of the Korean Geosynthetics Society
• /
• v.17 no.1
• /
• pp.139-152
• /
• 2018

This study is an analysis of slope failure examples of cut sedimentary hills during construction road in Kyoungsang Basin, especially Yangsan Fault system (Ilkwang-Dongrae fault). This area involved a lot of hillslope failures compared to other areas during road construction. The exposed failure slopes were first face-mapped, and then back analyzed based on the limit equilibrium method to assess the shear strength parameters of discontinuity (bedding). The results of this analysis indicate that the shear strength parameters of discontinuity (bedding) are significantly smaller than those used in the design stage and presented in the existing works. The filling in the bedding and emerging groundwater may be decreasing strength parameters. Especially, the clay in the bedding plays a key role in the effect of the shear strength. The study also suggests that the bedding angle and the internal friction angle are proportional to each other. Using this relationship and knowing the bedding angle, the friction can easily be estimated.

• The Journal of Engineering Geology
• /
• v.17 no.2 s.52
• /
• pp.263-270
• /
• 2007

Tunnel behavior measured by monitoring during construction is a main item for safety evaluation and it depends widely upon local geological characteristics. To assess in this study how much the geological factors influence on tunnel behavior for each RMR factor, a quantification analysis was carried out using tunnel face maps and measurements as explanatory variables and dependent variables, respectively. The results showed that average significance of the influence of RMR factors - R1, R2, R3, R4 and R5, on tunnel displacements are 17.0%, 20.4%, 20.4%, 11.6% and 30.6%, respectively, and this probably indicates that the groundwater condition played a significant role for the tunnel displacement.

• Structural Engineering and Mechanics
• /
• v.69 no.2
• /
• pp.221-230
• /
• 2019

In this paper, shear behavior of non-persistent joint surrounded in concrete and gypsum layers has been investigated using experimental test and numerical simulation. Two types of mixture were prepared for this study. The first type consists of water and gypsum that were mixed with a ratio of water/gypsum of 0.6. The second type of mixture, water, sand and cement were mixed with a ratio of 27%, 33% and 40% by weight. Shear behavior of a non-persistent joint embedded in these specimens is studied. Physical models consisting of two edge concrete layers with dimensions of 160 mm by 130 mm by 60 mm and one internal gypsum layer with the dimension of 16 mm by 13 mm by 6 mm were made. Two horizontal edge joints were embedded in concrete beams and one angled joint was created in gypsum layer. Several analyses with joints with angles of $0^{\circ}$, $30^{\circ}$, and $60^{\circ}$ degree were conducted. The central fault places in 3 different positions. Along the edge joints, 1.5 cm vertically far from the edge joint face and 3 cm vertically far from the edge joint face. All samples were tested in compression using a universal loading machine and the shear load was induced because of the specimen geometry. Concurrent with the experiments, the extended finite element method (XFEM) was employed to analyze the fracture processes occurring in a non-persistent joint embedded in concrete and gypsum layers using Abaqus, a finite element software platform. The failure pattern of non-persistent cracks (faults) was found to be affected mostly by the central crack and its configuration and the shear strength was found to be related to the failure pattern. Comparison between experimental and corresponding numerical results showed a great agreement. XFEM was found as a capable tool for investigating the fracturing mechanism of rock specimens with non-persistent joint.

• Economic and Environmental Geology
• /
• v.40 no.2 s.183
• /
• pp.209-221
• /
• 2007

Numerical analysis was performed to investigate the effect of heavy metal contamination on neighboring environment in case a dam is constructed by using rockfill materials contaminated by heavy metals. The numerical simulation carried out in this research includes both subsurface flow and contaminant transport in the inside of the CFRD(Concrete Faced Rockfill Dam), using two commercial programs, SEEP2D and FEMWATER. The three representative cases of scenarios were chosen to consider a variety of cases occurring in a dam site; (1) Scenario 1 : no crack in the concrete face slab, (2) Scenario 2 : a crack In the upper part of face slab, and (3) Scenario 3 : a crack between plinth and face slab in the lower part of face slab. As a result of seepage analysis, the amount of seepage in scenario 2 was calculated as $14.31\sim14.924m^3/day$ per unit width, corresponding to the 1,000 times higher value than that in other scenarios. Also, in the simulation of contaminant transport by using FEMWATER, specified contaminant concentration of 13 ppb in main rockfill zone was set to consider continuous leakage from the rock materials. Through the analysis of contaminant transport, we found that elapsed times to take for the contaminant concentration of about 2 ppb to arrive at the end of a dam are as follows. Scenario 1 has the elapsed time of 55,000 years. In Scenario 2. it is 50 years. Finally, scenario 3 has 27,000 years. The rapid transport of the contaminant in scenario 2 was attributed to greater seepage flow by 500 times than other scenarios. Although, in case of upper crack in the face slab, it was identified that the contaminant might transport to the end of a dam within 100 years with about 2 ppb concentration, however, it happened that the contaminant was hardly transported out of the dam in other scenarios, which correspond to either no crack or a crack between plinth and face slab. In conclusion, the numerical analysis showed that the alternative usage of the contaminated sand and gravel as the dam embankment material can be one of the feasible methods with the assumption that the cracks in a face slab could be controlled adequately.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.32 no.1
• /
• pp.10-21
• /
• 2014

This study focuses on the landscape of Daegodae(大孤臺), a prominent rock placed at the side of Namgae Stream in Hamyang, and the person who enjoy the landscape. Through the analysis of the letters such as names carved on the rocks based on ancient poetry and stone walls, the study examines the characteristics of the landscape and the space of Daegodae and the phase of hegemony to enjoy the landscape and space. The result of this study is as follow.2) There are 5 Seowon(書院: lecture halls) nearby Daegodae identified in the ancient map has 5 auditoriums nearby, and three-dimensional volume and eccentricity of the Daegodae is impressive. Daegodae, named by Noh Jin(1518~1578) in 16th century, was used in a variety of ways, including viewing, game, recreation, and meeting, by the staff of the lecture halls including Namgae Seowon(南溪書院), as a result of analyzing the ancient document Go-dae-il-Loc(孤臺日錄) written by Jung Kyung-Woon(鄭慶雲: 1556~?). The structure of Daegodae is that there is Chunggeunchung(淸近亭) on the rock face of the top and Sanangjae(山仰齋) to the west around the memorial stone for Yang Hee(梁喜: 1515~1581). The upper part of the foundation of Daegodae with 11m high and $10m^2$ wide to the east and west was widely used for lecturing and poetry reading. To the north and west of the foundation were the writing of Kim Jeong-Hee(金正喜: 1786~1856) with the words 'Seoksong Chusa(石松 秋史)' carved on the rock and the remains of a dead tree that is presumed to have been called as 'Seoksong'. They are the landscapes that further enhance the history and authenticity of this place. The two kinds of letters carved on the rock 'Daegodae Gaeeunseo(大高臺 介隱書)' and 'Mukheon JungGeunSang(鄭近相: 1893~1934)' were recorded each by Jung Jae-Gi(1811~1879) and his grandson Jung Geun-Sang, which are, as the outcome of exclusive space possession and space hegemony, the signatures indicating that they were the persons who enjoyed this place during the late Joseon and Japanese colonial era. In other words, Daegodae had some implied meaning of preoccupancy of the place as Gujolyangseonsengjangguso since the middle of Joseon, and the place was passed down as a buddhism lecturing and memorial venue called "Dungbukganghoiso Cheonryungjaeseonhyunjangguso" after going through the space hegemony of Jung Jae-Gi and Jung Geun-Sang during the late Joseon and Japanese colonial era each, Nevertheless, a number of letters carved on the rock identified also imply that 'Hadong Jung(河東鄭氏)' and 'Pungcheon Noh(豊川盧氏)' were those who enjoyed the landscape of Daegodae and the center of the space hegemony. The "letters carved on the rock of Daegudae" is another case of cultural landscape and traditional gardening space that serves as the representation of the will of enjoying the landscape in this place and the history of space hegemony.

• Proceedings of the Korean Society for Rock Mechanics Conference
• /
• 2000.09a
• /
• pp.183-193
• /
• 2000

A series of studies such as geological logging data analysis, detailed geological survey, rock mass evaluation, in-situ and laboratory tests, rock strength and mechanical properties of the rock were concerned. The stability of the slope were carried out inorder to design the pit slope and individual benches using the stereographic projection analysis and numerical methods in Roto Pit of Pasir coal fetid. The bedding plane was one of the major discontinuities in the Roto Pit and the dip of which is about $60^{\circ}$in the northern part and $83^{\circ}$in the southern part. The dip of bedding becomes steeper from north to south. The plane and toppling failures are presented in many slopes. In laboratory test the average uniaxial compressive strength of mudstone was 9 MPa and that of weak sandstone was 10 MPa. In-situ test showed that the rocks of Roto north mining area are mostly weak enough to be classified in grade from R2(weak) to R3(medium strong weak) and the coal is classified in grades from R1(Very weak) to R2(Weak). The detailed stability analysis were carried out on 4 areas of Roto north(east, west, south and north), and 2 areas of Roto south(east and west). In this paper, the minimum factor of safety was set to 1.2 which is a general criterion for open pit mines. Using the stereographic projection analysis and the limit equilibrium method, slope angles were calculated as 30~$36^{\circ}$for a factor of safety greater than 1.2. Then these results were re-evaluated by numerical analysis using FLAC. The final slope angles were determined by rational described abode. A final slope of 34 degrees can guarantee the stability for the eastern part of the Roto north area, 33 degrees for the western part, 35 degrees for the northern part and 35 degrees for the southern part. For the Roto south area, 36 degrees was suggested for both sides of the pit. Once the pit slope is designed based on the stability analysis and the safety measures. the stability of 니ope should be checked periodically during the mining operations. Because the slope face will be exposed long time to the rain fall, a study such aspreventive measures against weathering and erosion is highly recommended to be implemented.

• The Journal of Engineering Geology
• /
• v.19 no.1
• /
• pp.43-50
• /
• 2009

A 3-D numerical analysis was carried out to observe potential effects of orientation of inherent weak zones to tunnel behaviors and stress distributions during tunnel excavation. Weak zones used for the analysis were placed at the upper 1D part from crown, on the crown and on the center of face, using orientations derived from the 6th RMR parameter for assessment of joint orientation effect on tunnel. Mechanical properties of rock mass were derived through a in-situ displacement measurement-based back analysis. Finally, a classification chart for crown settlement with five ranks based on orientation and location of weak zones is suggested.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.21 no.5
• /
• pp.865-879
• /
• 1997

Journal of the Korean Society of Clothing and Textiles Vol. 21, Nt. 5 (1997) p. 865∼879 The purpose of the study is to identify a historical change about the women's underwear and trousers this nation of ours until an ancient times to modern ages. Because the record of the women's trousers exist scarcely anything, the study refers to several documents, for example, the literatures of the Chinese and the Chosun Dynasty, the Koryu's fresco, the Tou of Shinra, the painting of the rock face, the archaeological dresses and genre pictures, and The folkways methods through the residents is used to collect and to arrange of an enlightened age and modern times. Originally, the women's trousers appeared for the nomadism and the hunting in the northern distric and the northeastern provinces. Male and female, old and young wear the trousers which are the clothes native to Korea. The trousers which are originally narrow trousers are influnced by Chinese wide trousers. The trousers at the time of Samsuk hand down until Korea. The Skirt on the trousers is nothing but a courtesy. But gradually, it is distinguished only the trousers, and then, there are exchanged an underwear which not only the protection angainst the cold but also the beautiful. Therefore, the form of skirt is diminished, and the underwear is simplified as the increasing status and the activity of woman in the age of civilization. In a way, the reform trousers and Three-kingdom era trousers appeared and the Dansogok and Sogok disappeared at present. There are confirmed in my investigation of folk customs.

• Explosives and Blasting
• /
• v.13 no.4
• /
• pp.5-27
• /
• 1995

Korea-America tungsten treaty is not only Earnning Us Dollar but also it was turnning point of tunnelling technology development such as a burn cut. Because 10th of specialist worked at Sangdong mine under treaty. The first of all, Experimental blasting pattern for single free face carried out. As a result it has brought the burden and $charge/m^3$ and also space distance. After the center holes are blasted. Remain of the works was the implementation of bench cut against the openning to make the full sectional are required. $Ca=\frac{A}{SW}$ where as A =ndi=m activated area S = Peripheral length of Charged room Ca = Rock Coefficient di=Holes diameter Later in 1980, The Oynaite Explosive is Replaced into Emulsion & Milli-Second Delay Electric Cap. Seqential Blasting machine were Applied in the Site. The Subway Tunnelling have been worked so Carefully for Vibration and Noise to near Shopping and housing area. We carried out Empirical formula to solve city Envoirement pollution as follow For Granite: $V=KW^{0.57}D^{-1.75}$ For Granite : $V=KW^{0.5}D^{-1.5}$ V=PPV(cm/sec) K=Coefficency D=Distance(m) W=Amount of power/delay(kg)

• Proceedings of the Korean Geotechical Society Conference
• /
• 2001.03a
• /
• pp.25-32
• /
• 2001

Doosan Construction & Engineering Co., Ltd is building a railway tunnel beneath the Soo-Young River connecting MinLak Station and Centum City Station, a section 230, subway line 2, Pusan City, Korea. When completed the tunnel will have a finished inner diameter of 6.5m(21.311) throughout its total length of 840m(420m = 0.52 miles, Two Single Track Tunnel : 420m＋420m). The ground profile of the face toward shield machine is composed of multi layers, silty clay, clayey gravel, soft rock etc. This research paper is to predict ground deformation and variation of stresses around tunnel using Hyperbolic model, and to reflect the works on the next shield tunneling project. And this research paper is analyzed data of measuring instrument (such as settlement gauge, inclinometer, Multiple extensometer, etc.) which is installed along tunnel line for safety of tunnel. For calculations, the finite difference Method is applied. Backfill grouting material is supposed to have instantly strength of 10kg/$\textrm{cm}^2$ above, although its strength is available after 24 hours passed.