• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.775-782
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• 2004

Recently, the cases which are constructed close by neighboring structure or underground structure are on the increase to get the utmost out of the land exploitation of underground space in the downtown area. As the building becomes larger, the excavation depth is getting deep, and the excavation area is getting, wide too. These are frequent occasions that the application of Strut or Anchor method is difficult, because of site boundary, civil application and the ground condition. Therefore, to solve these problem, we analyze and compare design with measuring data, change the design factor and show the improvement of course through the application of self-supported diaphragm wall using counterfort technique which is a new method. It is expected to be a contribution to the suitable exploitation method of construction.

• Journal of architectural history
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• v.17 no.4
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• pp.113-127
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• 2008

Bogildo is Byel-Seo architecture from the Joseon dynasty period. There were ruins in Nakseojae, Goksudang, Seyeonjeong and Docheonseoksil. Docheonseoksil had been protected as Scenic Site No.34. A pond, a stone embankment, a stone stairway was discovered during repair and restoration of the site. Also, a site with ondol was discovered in 2007. The literatures to know Docheonseoksil is Gosanyugo, Buyongdongpalgyeong, Bogildoji. These are important sources of data to know the original of Docheonseoksil at the moment. Accordingly we will search the original of Docheonseoksil to systematicly study the excavation report and literature now. Then the restoration of Huihwangkyo and the building site with ondol will be studied through th literatures and excavation report for an architectural point of view. Also, the location of the stone gate remaining in Docheonseoksil and the approach way to it will be studied. The translation of the literatures are referred translated books, found with help from professor. This thesis is a step to knowing the original. If Docheonseoksil is studied, we can know more of its origin.

• Tunnel and Underground Space
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• v.27 no.4
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• pp.185-194
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• 2017

This technical paper is a study on the unique displacements of Shotcrete Lining at the mined tunnel during excavation period through deep consideration with real time data from monitoring instrumentations correlation with the numerical analysis to identify the rock stresses and the rock spring points at the working face of the Conventional tunnelling by the Drill and Blast, based on the geological face mapping results of the project NS2, Transmission cable tunnel project in Singapore. The created geometry of numerical model was prepared to the real mined tunnel construction site including, vertical shaft, construction adit, tunnel junction area, and 2 enlargement caverns. The convergence measurements by the monitoring instrumentation were performed during the tunnel excavation and shaft sinking construction stages to guarantee the safety of complicated underground structures.

• Tunnel and Underground Space
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• v.11 no.1
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• pp.20-29
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• 2001

Final convergence of tunnel crown due to excavation have been well predicted by regression analysis which is expressed as a function of convergence curve on a time and distance dependent. In this study, the validity of the equations for shallow, wide tunnel was investigated by measurement and numerical analysis. Studied tunnel(Sansoo Tunnel) is located at the boundary of downtown and mountain park. Exponential predictions equation was better coincided with measured data than fractional equation for studied tunnel, although the ground was expected to be elasto-plastic. This is because weathered rock ground is changed elasto-plastic ground into elastic ground by multi-steel grouting and forepoling.

• International Journal of Railway
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• v.9 no.1
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• pp.21-26
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• 2016

When excavation under existing structure is planned for a new construction project, the underpinning method is one of the most applicable construction methods. This study introduces a new modified underpinning method which is applied to construct a new subway line in Seoul Metropolitan. The new subway line was designed to pass underneath the existing subway line. Existing subway line carries about 2 million passengers daily, which is 33% of total passengers using subway in Seoul, and is the only circulation line in Seoul. Subway trains are passing 540 times through this section in a day. By applying a new underpinning method, the subway box structure of line is exposed 54m in the air supported by bearing piles. The proposed method was carefully monitored using heavy instrumentation system during construction. This study proposed and verified the application of the modified underpinning method, which can reduce construction period by 1.5 times and the construction cost by 1.2 times comparing with conventional method. The importance of considering construction sequence is investigated and verified by analyzed data non-considering construction sequence. The unexpected heaving which can bring up a dangerous situation for train running stability were measured, so this study shows that the upward movement has to be analyzed in designing process. As the use of underground space increases, the proposed method can be a good example of underground development.

• Geomechanics and Engineering
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• v.11 no.6
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• pp.879-896
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• 2016

A new earth pressure equation considering the arching effect in $c-{\phi}$ soils was proposed for the accurate calculation of earth pressure on circular vertical shafts. The arching effect and the subsequent load recovery phenomenon occurring due to multi-step excavation were quantitatively investigated through laboratory tests. The new earth pressure equation was verified by comparing the test results with the earth pressures predicted by new equation in various soil conditions. Resulting from testing by using multi-step excavation, the arching effect and load recovery were clearly observed. The test results in $c-{\phi}$ soil showed that even a small amount of cohesion can cause the earth pressure to decrease significantly. Therefore, predicting earth pressure without considering such cohesion can lead to overestimation of earth pressure. The test results in various ground conditions demonstrated that the newly proposed equation, which enables consideration of cohesion as appropriate, is the most reliable equation for predicting earth pressure in both ${\phi}$ soil and $c-{\phi}$ soil. The comparison of the theoretical equations with the field data measured on a real construction site also highlighted the best-fitness of the theoretical equation in predicting earth pressure.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.523-533
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• 2022

Several prediction model of penetration rate (PR) of tunnel boring machines (TBMs) have been focused on applying to design stage. In construction stage, however, the expected PR and its trends are changed during tunneling owing to TBM excavation skills and the gap between the investigated and actual geological conditions. Monitoring the PR during tunneling is crucial to rescheduling the excavation plan in real-time. This study proposes a sequential prediction method applicable in the construction stage. Geological and TBM operating data are collected from Gunpo cable tunnel in Korea, and preprocessed through normalization and augmentation. The results show that the sequential prediction for 1 ring unit prediction distance (UPD) is R²≥0.79; whereas, a one-step prediction is R²≤0.30. In modeling algorithm, a gradient boosted regression tree (GBRT) outperformed a least square-based linear regression in sequential prediction method. For practical use, a simple equation between the R² and UPD is proposed. When UPD increases R² decreases exponentially; In particular, UPD at R²=0.60 is calculated as 28 rings using the equation. Such a time interval will provide enough time for decision-making. Evidently, the UPD can be adjusted depending on other project and the R² value targeted by an operator. Therefore, a calculation process for the equation between the R² and UPD is addressed.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.03a
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• pp.329-346
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• 1998

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.225-232
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• 2003

The behaviour of ground induced by tunneling of 2arch tunnels may differ from the one caused by usual type tunnels. This paper describe the behaviour created by the size of pilot tunnel and the condition on the construction method of center piller Also, loads acting on the supports of the first tunnel and the center pillar during the excavation of second tunnel is investigated by numerical analyses. The results of numerical analyses are compared to the data records of measurement results, i.e. force on the support system and ground displacement.

• Explosives and Blasting
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• v.15 no.2
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• pp.53-72
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• 1997

It is impossible to precat the behavior of ground soil and structure accurately during underground construction in urban area or excavation in soft ground area because of difference between the assumed design condition and the actual site condition. Therefore, it must be managed by measuring system and correct the difference by real data. Large scale under ground construction in urban area like a seoul subway project has needed for Intelligent Construction technique, a field of the Engineering Contractor. The automated measuring system is developed for the technique. It is described that the procedure and the method of measuring work with application of the automated measuring system.