• Tunnel and Underground Space
• /
• v.28 no.1
• /
• pp.1-24
• /
• 2018

The use of TBM (tunnel boring machine) gradually increases in worldwide tunneling projects. TBM machine are often applied to more difficult and complex geological conditions in urban area, and many problems and difficulties have been reported due to these geological conditions. However, in Korea, there is a lack of research on difficult grounds so far. This paper discussed general aspects of investigation method, and problems of TBM tunneling in difficult grounds. Construction cases that passed through the difficult grounds in worldwide were analyzed and the typical difficult grounds were classified into 11 cases. For each case, the definition and general problems were summarized. Particularly, for mixed ground and boulder ground, and fault zone, which are frequent geological conditions in urban area with shallow depth, classification system, investigation methods and major considerations were discussed, and proposed the direction of future research. This paper is a basic study for the development of TBM construction technology in difficult ground, and it is expected that it will be useful for related research and construction of TBM in difficult ground in the future.

• Tunnel and Underground Space
• /
• v.28 no.6
• /
• pp.528-546
• /
• 2018

Cases of TBM tunnelling have been consistently increasing worldwide. In many recent subsea and urban tunnelling projects, TBM excavation has been preferably considered due to its advantages over drill and blast tunnelling. Difficult ground conditions are highly probable to appear in subsea and urban tunnels because of the shallow working depth and alluvial characteristics. Under the difficult ground conditions, ground reinforcement measures should be considered including grouting, while it is of great importance to select the optimal grout material and injection method to cope with the ground condition. The benefits from TBM excavation, such as fast excavation, increased safety, and reduced environmental impact, can be achieved by applying appropriate ground reinforcement with the minimum overrun of cost and time. In this report, various grouting methods were reviewed so that they can be applied in difficult ground conditions. In addition, domestic and international cases of successful ground reinforcement for difficult grounds were introduced for future reference.

• Journal of Korea Trade
• /
• v.26 no.5
• /
• pp.88-105
• /
• 2022

Purpose - This paper studies whether economic sanctions can be used as grounds for a party to an international sales contract to get an exemption if he fails to meet his contractual obligation. Because the answer can differ depending on the governing law of the contract, this study focuses on CISG, the most widely recognized international uniform legal instrument as the governing law of the international sale of goods. Design/methodology - This paper focuses on analyzing the conditions to meet before getting an exemption under CISG. For such analysis, this paper examined various scholarly writings, cases, and hypothetical examples reflecting a wide variety of economic sanction measures. Findings - The findings of this paper are as follows. The main provision for exemption under CISG is Article 79(1), which provides for an exemption for a party that failed to perform if such failure was caused by an impediment that was uncontrollable, unforeseeable, and unavoidable; either a seller or a buyer may rely on the Article for his non-performance, delay, or defective performance. The Article is applicable not only where the economic sanction caused impossibility of performance but also where it caused hardship. The economic sanction will likely be found to be an uncontrollable impediment; however, it will be relatively more difficult to prove it to be unforeseeable or unavoidable. Originality/value - The subject of this paper is whether a party can be exempted from liability under CISG when he fails to perform his contractual obligations due to economic sanctions. Given that this issue is now actually faced by many involved in international trade, it is expected to provide practical help to practitioners and companies alike.

• Tunnel and Underground Space
• /
• v.29 no.6
• /
• pp.394-406
• /
• 2019

Difficult ground conditions (e.g., fault zone and mixed grounds) are highly probable to appear in subsea and urban tunnels because of the shallow working depth and alluvial characteristics. TBM usually experienced decrease of penetration rate and increase of downtime when it meets these difficult ground conditions. The problems are usually caused by the adverse geological conditions, and it is preferable to determine the optimal operational parameters of TBM based on the previous operational data obtained while excavating a preceding tunnel. This study carried out for efficient TBM excavation in fault zone and mixed grounds. TBM excavation data from the tunnel site in Singapore and the characteristics of the TBM excavation data was analyzed. The key operational parameters (i.e., thrust, torque, and RPM), penetration rate, and downtime were highly influenced by the presence of fault zones and mixed grounds, and the features was discussed. It is expected that the results and main discussions will be useful information for future tunneling projects in similar geological conditions.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.09a
• /
• pp.829-834
• /
• 2009

Alluvial soil is one of the most difficult grounds for tunneling works due to the insufficient ground strength and excessive ground water inflow. Dduk island in Seoul has a wide alluvium developed by two rivers, Han and Jung-Ryang. Subway tunnel of $\bigcirc\bigcirc$ line planed across Dduk island has highly poor ground conditions due to small cover and deeply developed alluvium. Moreover, much part of this tunnel is located parallel to the bridge foundations of another railway with a small horizontal distance. Original design was done in 2002 and construction has been in progress. During the construction, tunnel design has been partly changed and adjusted for the complex ground condition and the demand from related organizations. This paper intend to introduce the urban tunnel design and construction in alluvial soils. This line could be divided three sections(A, B, C) according to ground and adjacent conditions. Section A is featured by mixed tunnel faces consisted with alluvial soils and weathered or weak rocks. The feature of section B is that tunnel underpasses near the bridge foundations of another subway. Lastly, section C with a very short length is the most difficult construction conditions due to the small cover, poor ground, obstacles on and underneath ground surface.

• International Journal of Automotive Technology
• /
• v.3 no.4
• /
• pp.129-135
• /
• 2002

Durability estimation of a prototype vehicle has traditionally relied heavily on accelerated durability tests using predefined proving grounds or rig tests using a road simulator. By use of those tests, it is very difficult to predict durability failures in actual service environments. This motivated the development of an integrated CAE (Computer Aided Engineering) methodology for the durability estimation of a prototype vehicle in actual service environments. Since expensive computational costs such as computation time and hardware resources are required for a full vehicle simulation in those environments with a very long span of event time, the conventional CAE methodologies have little feasibility. An efficient computational methodology for durability estimations is applied with theoretical developments. The effectiveness of the proposed methodology is shown by the comparison of results of the typical actual service environment such as the city mode with those of the typical accelerated durability test over the Belgian road.

• Annals of Clinical Neurophysiology
• /
• v.4 no.1
• /
• pp.7-11
• /
• 2002

Among drug-induced myopathy, steroids are probably the most common cause. The risk of steroid myopathy(SM) increases with the dose and duration of use. It is typically a proximal myopathy, preferentially affecting the hip girdle muscles. Motor and sensory nerve conduction studies are normal. The needle EMG is usually within the normal range or may be minimally abnormal. Occasionally, low-amplitude, short-duration MUAPs may be seen in the proximal muscles. Of note, abnormal spontaneous activity is not seen. This point is often very useful in differentiating polymyositis(PM) from SM. It is common for patients with PM to be treated with steroids, respond well, and then have the steroids tapered. If muscle weakness then returns, it may be very difficult to differentiate recurrent PM from SM on clinical grounds. The presence of abundant abnormal spontaneous activity strongly suggests PM rather than SM.

• Journal of the Daesoon Academy of Sciences
• /
• v.25_2
• /
• pp.137-176
• /
• 2015

This study intends to focus on feasible measures to take advantage of pilgrimage to inspire adherents of The Fellowship of Daesoonjinri with the ideology of Daesoon and to overhaul existing missionary work. This study addresses preceding researches with regard to pilgrimage as theoretical grounds to review what pilgrimage has been meant to be. Also, this study conducts the survey on the motif and preference of pilgrimage that are expected to affect pilgrim behaviors, and it includes the satisfaction with the pilgrimage as a parametric effect. The survey and analysis results say that the motif and preference of the pilgrimage are the leading variables that significantly correlate to the pilgrimage satisfaction. In addition, the pilgrimage satisfaction is not only a key factor that affects pilgrim behaviors but a parametric effect that strongly relates to the motif and preference of the pilgrimage. Conducted based on empirical analysis, this study offers a diversity of approaches to tourism program development with respect to pilgrimage: customized pilgrimage programs, unique storytelling about the holy places, content development with a range of topics and difficult levels, and evaluation and feedback systems for pilgrimage programs

• Journal of the Korean Geosynthetics Society
• /
• v.6 no.4
• /
• pp.15-20
• /
• 2007

Recently, the demand for industrial and residental land are increasing with economic growth, but it is difficult to acquire areas for development with good ground condition. For efficient and balanced development of land, new development projects are being carried out not only the areas with inland but those with the soft ground as well. As soft grounds have complex engineering properties and high variations such as ground subsidence especially when their strength is low and depth is deep, we need to accurately analyze the engineering properties of soft grounds and find general measures for stable and economic design and management. Vertical drain technology is widely used to accelerate the consolidation of soft clay deposits and dredged soil under pre-loading and various types of vertical drain are used with there discharge capacity. Under field conditions, discharge capacity is changed with various reason, such as soil condition, confinement pressure, long-term clogging and folding of vertical drains and so on. Therefore, many researcher and engineer recommend the use of required discharge capacity. In this paper, the experiment study were carried out to obtain the discharge capacity of six different types of vertical drains by utilizing the large-scale model tests and discharge capacity, degree of consolidation with the time elapsed.

• Journal of the Korean Geosynthetics Society
• /
• v.7 no.1
• /
• pp.39-44
• /
• 2008

Recently, the demand for industrial and residential lands are being increased with economic growth, however, it is difficult to acquire the land for development with good ground condition. For efficient and balanced development of land, new development projects are being carried out not only the areas with inland but those with the soft ground as well. As soft grounds have complex engineering properties and high variations such as ground settlement especially when their strength is low and depth is deep, it needs to accurately analyze the engineering properties of soft grounds and find general measurement for stabilization and economic design and management. Prefabricated vertical drain technology is widely used to accelerate the consolidation of soft clay deposits and dredged soil under the preloading and various types of vertical drain are being used with the discharge capacity. Under field conditions, the discharge capacity is changed with various reason, such as soil condition, confinement pressure, long-term clogging and folding of vertical drains, and so on. Therefore, many researcher and engineer recommend the use of required discharge capacity. In this paper, the experimental study were carried out for two different types of vertical drains by utilizing the large-scale model tests and waste lime.