• Title/Summary/Keyword: Excavation shape

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Evaluation on the Applicability of a Lattice Girder for a Support System in Tunnelling (격자지보의 터널지보재로서의 현장 적용성 평가)

    • Tunnel and Underground Space
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    • v.9 no.3
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    • pp.204-213
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    • 1999
  • NATM(New Austrian Tunnelling Method) uses a support system of shotcrete, rockbolt and steel support, which are installed after tunnel excavation. Recently, a lattice girder among these support system is used in tunnelling. A lattice girder is a new steel support developed in Europe for the replacement of an existing H-shaped steel set, which is reported to have some problems in installation. This is a triangular shape welded with steel rods and is a light-weight support system which enables fast and easy installation of porepolling. The major advantage of a lattice girder is the good bonding with shotcrete. In this study, to evaluate the applicability of a lattice girder in tunnelling in Korea, field tests were performed at a high speed railway tunnel with a large section. Also, features of lattice girder in field tests were compared with those of a H-shaped steel set respectively. Field tests proved that a lattice girder fully supported the initial earth pressure developed right after excavation and limited ground deformation effectively.

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A Study on the Estimation of Stress Relaxed Zone around a Tunnel Periphery for the Design of 2-Arch Tunnel Lining (2-ARCH 터널의 라이닝 설계를 위한 터널굴착주변 응력이완 영역산정에 관한 연구)

  • You, Kwang-Ho
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.7 no.4
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    • pp.343-352
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    • 2005
  • In this study, the existing methods proposed to estimate the relaxed load due to a tunnel excavation are compared and analyzed. Also a new approach, by which the stress relaxed zone around an excavated tunnel periphery can be systematically estimated, was suggested for the design of 2-arch tunnel lining. To this end, local factors of safety are calculated from the redistributed stresses after the excavation of a tunnel. The height of the relaxed load is inferred based on the assumption that the stress relaxed zone might coincide with the region corresponding to the local safety factor of 2.0 or 3.0. The new approach proposed in this study has the advantage of estimating the height of the relaxed load independent of the shape of a tunnel and the ground conditions, Since the height of the relaxed load is estimated according to the local factor of safety, which is a relatively clear criterion, the designer's subjectivity involved in the design of concrete tunnel lining might be reduced.

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Numerical simulation study on applicability of electrical resistivity survey at tunnel face (터널 굴착면에서의 전기비저항 탐사 적용성에 관한 수치해석 연구)

  • Yi, Myeong-Jong;Kim, Nag-Young;Lee, Sangrae;Hwang, Bumsik;Ha, Myung Jin;Kim, Ki-Seog;Cho, In-Ky;Lee, Kang-Hyun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.3
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    • pp.279-292
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    • 2022
  • Unexpected anomalies in the geotechnical investigation at design stage may cause problems during tunnel excavation. Therefore, it is important to predict the ground condition ahead of a tunnel face during tunnel excavation in order to prevent tunnel collapse. Despite the fulfillment of an electrical resistivity survey at the tunnel face, the existing electrical resistivity survey program can produce distorted results by the limitation of tunnel modelling. In this background, this study develops a modelling program for an electrical resistivity survey considering the tunnel shape. Numerical simulation and inverse calculation were performed for the electrical resistivity survey in the tunnel using the developed program. As a result, it was proved that the developed program could predict accurately the anomalous object's location and condition ahead of the tunnel face.

Achievement of Excavation of Gwiam(Turtle Rock) and Nakseojae Restoration in Bogil-do Yun,Seondo Wonlim (보길도 윤선도원림(명승 제34호) 낙서재지역 원형복원과 귀암(龜巖) 발굴의 성과)

  • Lee, Won-Ho
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.30 no.3
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    • pp.111-120
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    • 2012
  • This study regards a series of achievement on Wonlim(Garden) Cultural Properties Excavation Project, led by field of landscape architecture. It will mainly describe excavation results of Gwiam(龜巖: Turtle rock) and historical value of it in terms of Nakseojae(樂書齋) restoration in Bogil-do Yun,Seondo Wonlim(Scenic Sites, No.34). Gwiam(Turtle rock) was found 14.6m apart from the north of Nakseojae, and it covered with 10~15m topsoil tilted toward Nakseojae, The size of Gwiam, which was Granite, was 360cm length, 270cm width, 95cm high. The Edge of Gwiam's North west part was of triangular shape forming Turtle head. The back of the Turtle head was form of Tortoise-shell because of wide backboard with both side groove. The southeast part of Gwiam projected was Turtle's tail. This Granite was obvious Turtle shape artificially made, and there are less likely to relocate from place to place. This Turtle-shaped Gwiam is important landmark for Nakseojae, which is one of the four spiritual creatures written in Bogildoji(甫吉島識) and Gosanyugo(孤山遺稿) by Yunwi. According to Bogildoji, it is estimated that Gwiam were on the axis with Soeunbyung(小隱屛), Nakseojae and was buried when Yiguan(Gosan's grandson) reconstructed a building. Also, it was place for enjoying the moon. But, Even after three times excavation in Nakseojae, there was no way to identify further information regarding Gwiam, so it was a matter of mystification. As a result of this study, Gwiam is laid bare to light in at least 260 years, so it is good example for boosting importance of landscape architecture field and restoring Nakseojae. Furthermore, firm base-soil was discovered in 135m high Rock Mass below, so natural ground of Nakseojae can be estimated by this basis. To be conclusion, Preservation Process for Gwiam and Estimation Space through interpretation of four spiritual creatures(四靈) in Gosan's Poetry should be continue.

A stability study of deep and double-deck tunnels considering shape and reinforcing method of an enlarged section by using numerical analyses (수치해석을 이용한 대심도 복층터널의 확폭단면 형상 및 보강방법에 대한 안정성 연구)

  • You, Kwang-Ho;Jin, Su-Hyun;Kim, Young-Jin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.1
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    • pp.41-56
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    • 2017
  • Recently, the necessity of deep and double-deck tunnels has been grown day by day due to the increase of traffic volume at metropolitans and thus the study on the divergence of those tunnels becomes required. Therefore sensitivity analyses were conducted with FLAC 2D program by selecting ground condition, coefficient of lateral pressure, support pattern, and depth of rock cover as parameters. Ultimately, this study is to find the optimal shape and support method of a diverged section. As the results of this study, it turned out that the box type gave higher stability of the section than arch type unlike the general thought. It can be explained that the arch type has about 30% bigger excavation area than the box type. When the ground conditions are poor, steel pipe grouting reinforcement gives higher stability than rockbolt reinforcement, but its thickness and range do not give a great influence on the stability of the enlarged section.

Development of Design and Field Quality Control Techniques of Shallow Foundation Resting on Intermediate Geomaterials (중간토에 지지된 직접기초의 설계 및 현장품질관리기법 개발)

  • Byun, Young-Gi;Park, Young-Ho;Jeong, Hoon-Jun;Lee, Woo-Jin
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.1148-1155
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    • 2010
  • To suggest a modified shallow foundation design method which can be considered the scale effect of foundation on IGM(intermediate geomaterial) soil layer, the weathered soil layer that is uniformly formed up to 8m(2B) with over 50 N-value is selected and 3 times field loading tests are performed on several sized square-shaped shallow foundations with 30, 75, 150, 240 and 400cm in width respectively. Because the soil modulus of elasticity(Es) calculated by soil investigation and 1st field test(PBT) results showed an underestimated tendency, a modified correlation is required for the reasonable estimation of Es on the weathered soil. Also, the N-value was increased with an increasing in depth. However, the N-values around the test foundations showed the different values even though the foundations on the same level because the test site was arranged by excavation. Therefore, the more detail soil investigations are required for the each test foundations respectively. Since Es based on elasticity theory is determined by the stress distribution shape of the foundation and elasticity modulus of the soil, the scale effect considered pressure-settlement curve can be clearly derived from the correlation on stress distribution shape and the variation of soil elasticity modulus with depth. Therefore, the modified correlation will be suggested to estimate a reasonable Es on the weathered soil, and the scale effect considered shallow foundation design method is also developed based on the elastic theory and field tests in this research.

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A Study on the Change of Shape of "Jagui" (Adze) Used in Korean Traditional Architecture (전통건축에 사용된 자귀의 형태 변화에 대한 고찰)

  • Lim, Chae-Hyun
    • Journal of architectural history
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    • v.20 no.3
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    • pp.23-38
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    • 2011
  • The Axes and Adzes are the oldest tools since the beginning of human history which is used to cut the tree and make part of architecture such as boards, square timber etc. Nowadays, these old woodworking tools especially "Jagui(자귀)" (adze) has been almost disappeared at the working site of residential and cultural properties. It is necessary to study Korean traditional woodworking tools to keep Korean traditional skill and technology. It has been reviewed the change of shape of "Jagui(자귀)" (adze) from before Samhan (삼한) period to Joseon Dynasty through excavated relics and paintings and summarize as follows: Based on excavation relics of Dahori, both plate type blade and pocket type blade are used for "Tokki(도끼)" (axe) and "Jagui(자귀)" (adze). The excavated "Jagui(자귀)" (adze) from Jeongbaikri 356 tomb, near Pyongyang is prototype of "Jagui(자귀)" (adze) used nowdays which has almost same shape as well as the insert method of blade and handle. The auxiliary handle is inserted to blade and the main handle is inserted to the auxiliary handle which is different from the method of Chinese and Japanese "Jagui(자귀)" (adze). The length of handle of "Jagui(자귀)" (adze) until late Joseon Dynasty is short by which we assume it is used for a sitting position as hand held Jagui and from that time long handle has been introduced for a standing position which is called "Sunjagui(선자귀)". "Jagui(자귀)" (adze) has been used since the beginning of human history but it is almost disappeared at the most of woodworking site which is the crisis of Korean traditional architecture and we have to do something to keep it.

Study on the restoration of Soswaewon Garden's Goam-Jeongsa and Boohwondang buildings (소쇄원 고암정사와 부훤당의 복원적 고찰)

  • Cheon, Deuk-youm;Choi, Jung-mee;Kim, Dyeon-jin
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.34 no.4
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    • pp.103-111
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    • 2018
  • The Soswaewon Garden, which was constructed by Yang San-Bo around 1520, is a private traditional garden in Korea. Soswaewon Garden has long been and still is the focus of continuous research. However, relatively few studies have been conducted on the restoration of buildings that were lost in the past. The Goam-Jeongsa and Boohwondang buildings, which were lost in 1597 during the Japanese invasion, were restored in 1614 and depicted in a picture of Soswaewon Garden in 1755. However, they eventually disappeared and no longer exist in the present. Therefore, the restoration of these two buildings is considered an urgent task. This research aims to search for the original location of these buildings and estimate their size and shape in terms of physical space. Several years ago, an estimation of the building site was carried out, providing a stepping stone on this matter. This can be studied through "Soswaewon's 48 quatrains with five Chinese characters in each line," "Soswaewon-sasil," and "Soswaewon's drawing." Some parts of the shape of Soswaewon also appear in the "Yuseoseokrok," which is helpful. Thus, in this research, information on the Goam-Jeongsa and Boowondang buildings appearing in research results and literature to date are collectively analyzed. The location and architectural features of both buildings are identified by focusing on excavations. Also, for the purpose of restoration planning, base data on the location, size, and shape of both buildings are presented. In line with this process, a valid restoration plan is presented by analyzing the abovementioned historical research materials and comparing empirical data, such as excavation results.

A Fundamental Study of the Silla Shield through the Analysis of the Shape, Dating, and Species Identification of Wooden Shields Excavated from the Ruins of Wolseong Moat in Gyeongju (경주 월성 해자 유적 출토 목제방패의 형태, 연대 및 수종분석을 통한 신라 방패의 기초적 연구)

  • NAM, Tae-Gwang;KIM, Hun-Suk
    • Journal of the Korean Wood Science and Technology
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    • v.49 no.2
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    • pp.154-168
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    • 2021
  • Various types of wooden relics are being unearthed following the full-scale excavation in Wolseong palace site, Gyeongju in Korea. In particular, a large number of relics were found in the moat surrounding the Wolseong Fortress. This study attempted to secure basic data on the shields of the Silla era through species identification, radiocarbon dating, and shape analysis of the two wooden shields excavated from the Wolseong moat. As a result of the radiocarbon dating, it was confirmed that the shields were made of wood procured in the period between the mid-4th century and the early 5th century. The species identification confirmed that the body of the relic was made with Pinus soft pine group and the handle with Zelkova serrata. It was also confirmed that the excavated wooden shield was made by first marking a thin line on a flat grain board, then marking double concentric circles and perforating small holes. The distance between the division lines is constant at about 6cm, and spaces between them are colored in red and black. The shape analysis estimated that two artifacts were more than 50cm and 36cm in width, respectively.

An Study on Cognition and Investigation of Silla Tumuli in the Japanese Imperialistic Rule (일제강점기의 신라고분조사연구에 대한 검토)

  • Cha, Soon Chul
    • Korean Journal of Heritage: History & Science
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    • v.39
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    • pp.95-130
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    • 2006
  • Japanese government college researchers, including Sekino Tadashi(關野貞), have conducted research studies and collected data, on overall Korean cultural relics as well as Silla tumuli(新羅古墳) in the early modern times under the Japanese imperialistic rule. They were supported by the Meichi government in the early stage of research, by the Chosun government-general, and by their related organizations after Korea was coIonialized to carry out investigations on Korean antiquities, fine arts, architecture, anthropology, folklore, and so on. The objective for which they prosecuted inquiries into Korean cultural relics, including Silla tumuli, may be attributed to the purport to find out such data as needed for the theoretical foundation to justify their colonialization of Korea. Such a reason often showed locally biased or distorted views. Investigations and surveys had been incessantly carried out by those Japanese scholars who took a keen interest in Korean tumuli and excavated relics since 1886. 'Korea Architecture Survey Reports' conducted in 1904 by Sekino in Korea gives a brief introduction of the contents of Korean tumuli, including the Five Royal Mausoleums(五陵). And in 1906 Imanishi Ryu(今西龍) launched for the first time an excavation survey on Buksan Tumulus(北山古墳) in Sogeumgangsan(小金剛山) and on 'Namchong(南塚)' in Hwangnam-dong, which greatly contributed to the foundation of a basic understanding of Wooden chamber tombs with stone mound(積石木槨墳) and stone chambers with tunnel entrance(橫穴式石室墳). The ground plan and cross section of stone chambers made in 1909 at his excavation survey of seokchimchong(石枕塚) by Yazui Seiyichi(谷井第一) who majored in architecture made a drawing in excavation surveys for the first time in Korea, in which numerical expressions are sharply distinguished from the previous sketched ones. And even in the following excavation surveys this kind of drawing continued. Imanishi and Yazui elucidated that wooden chambers with stone mound chronologically differs from the stone chambers with tunnel entrance on the basis of the results of surveys of the locational characteristics of Silla tumuli, the forms and size of tomb entrance, excavated relics, and so forth. The government-general put in force 'the Historic Spots and Relics Preservation Rules' and 'the Historic Spots Survey Council Regulations' in 1916, establishing 'Historic Spots Survey Council and Museum Conference. When museums initiated their activities, they exhibited those relics excavated from tumuli and conducted surveys of relics with the permission of the Chosun government-general. A gold crown tomb(金冠塚) was excavated and surveyed in 1921 and a seobong tomb(瑞鳳塚) in 1927. Concomitantly with this large size wooden chamber tombs with stone mound attracted strong public attention. Furthermore, a variety of surveys of spots throughout the country were carried out but publication of tumuli had not yet been realized. Recently some researchers's endeavors led to publish unpublished reports. However, the reason why reports of such significant tumuli as seobong tomb had not yet been published may be ascribed to the critical point in those days. The Gyeongju Tumuli Distribution Chart made by Nomori Ken(野守健) on the basis of the land register in the late 1920s seems of much significance in that it specifies the size and locations of 155 tumuli and shows the overall shape of tumuli groups within the city, as used in today's distribution chart. In the 1930s Arimitsu Kyoichi(有光敎一) and Saito Tadashi(齋藤忠) identified through excavation surveys of many wooden chamber tombs with stone mound and stone chambers with tunnel entrance, that there were several forms of tombs in a tomb system. In particular, his excavation survey experience of those wooden chamber tombs with stone mound which were exposed in complicated and overlapped forms show features more developed than that of preceding excavation surveys and reports publication, and so on. The result of having reviewed the contents of many historic spots surveyed at that time. Therefore this reexamination is considered to be a significant project in arranging the history of archaeology in Korea.