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Possibility of Long Distance and High Speed Construction in Shield Tunneling Method –Case Study on Undersea Tunnel Project in Osaka Bay–
Published in T. Adachi, K. Tateyama, M. Kimura, Modern Tunneling Science and Technology, 2020
T. Adachi, T. Hashimoto, K. Tateyama, N. Fukazawa
Figure 1 shows the route of the tunnel supposed in this case study. This tunnel is a double tracks railway tunnel and it will connect the Kobe city and the Kansai Airport by an undersea tunnel excavated in the seabed under the Osaka Bay. Main part of the tunnel route has been set to be a straight one to reduce a tunnel distance except near the Kansai airport. The Kansai airport has the expanding planning of its land area by reclamation and thus the tunnel route has been set to make a detour to avoid the new land area of the airport. The vertical shafts will be excavated in both sides of Kansai Airport and Kobe. The length of the tunnel is supposed to be 23.3 km and the rapid trains, which run in the tunnel, are expected to connect Kobe city and Kansai airport in less than 30 minutes. When we suppose that a couple of shield machines will start to excavate the tunnel from both vertical shafts and they meet each other around the middle part of the tunnel, the tunnel length which one shield machine excavates is supposed to be more than 10km.
Outdoor and Indoor Cellular/Personal Handy Phone System Base Station Antenna in Japan
Published in Lal Chand Godara, Handbook of Antennas in Wireless Communications, 2018
Cellular phone service has begun to cover terrestrial areas, and the coverage area is expanding to include tunnels, subway stations, and large buildings such as shopping malls and hotels. A system covering these areas is referred to as an in-building system. This system uses a booster for the relay station between the outside base station and the new coverage area, or a microcellular system using an exclusive base station. The booster system receives a downlink signal from the outdoor base station, re-radiates its downlink signal after amplification, and vice versa for the uplink. A leaky coaxial waveguide has been widely used for a 900-MHz cellular system to expand its coverage area to the underground tunnels in the metropolitan highways in Tokyo [16]. An in-building system was installed in the newly built undersea tunnel in 1994. This novel system uses an optical fiber as a transmission line and a flat antenna as a radiating element to provide 1.5-GHz band and 900-MHz band service [17]. In this system, an optical laser diode is directly modulated by the downlink radio frequency (RF) signal from the outdoor base station, and its modulated optical signal is transmitted to inside the tunnel by an optical fiber. A very small transmission loss and a wide bandwidth enables the optical fiber to carry two frequency bands at 900 MHz and 1.5 GHz. After the transmission by the optical fiber, the downlink signal is re-radiated by low-gain flat antennas installed on the sidewall at a few hundred meters apart. The reverse is done for uplink.
Taiwan Strait Transportation (TST) Corridor
Published in Ronald C. Chaney, Marine Geology and Geotechnology of the South China Sea and Taiwan Strait, 2020
The TSC will probably involve a combination of bridges and undersea tunnel. A number of issues will be involved in the design process. These issues are in part: design concept, construction technology, availability of materials, skilled laborers, equipment availability, transportation networks (Wu and Shen, 2003). In the following the issue of design concepts for both a tunnel and bridge will only be explored. The remaining issues have been discussed in considerable detail in a special issue of the Journal of Marine Georesources and Geotechnology (Volume 21, Number 3–4, 2003). The special issue was entitled Preliminary Study of the Taiwan Straiat Tunnel Project. The editors for this special issue were Professors Hsai-Yang Fang, Funan Peng, and Zhiming Wu.
Water inrush risk assessment for an undersea tunnel crossing a fault: An analytical model
Published in Marine Georesources & Geotechnology, 2019
Yiguo Xue, Zhiqiang Li, Shucai Li, Daohong Qiu, Maoxin Su, Zhenhao Xu, Binghua Zhou, Yufan Tao
An undersea tunnel is a tunnel that is partly or wholly constructed under a body of water. Due to the extremely complex geological condition of a subsea tunnel, which is as difficult to conduct an engineering survey for as with a mountain tunnel, water inrush and mud disasters are prone to occur when the submarine tunnel passes through the fault and the stratum of water (Palmstrom 1994; Tsuji, Sawada, and Takizawa 1996; Shi et al. 2017a; Li et al. 2018a). Once a water inrush disaster occurs in a subsea tunnel, it will result in great disastrous consequences for the adequate water from the above sea. Therefore, many research studies have been performed to reduce the occurrence probability of water inrush disasters (Shi et al. 2017a; Li et al. 2018a). The previous research mainly concentrates on three aspects: the water inrush mechanism, disaster management, and water inrush prevention (Tang et al. 2011; Li and Li 2014; Wu et al. 2016; Jiang et al. 2017; Li and Wu 2017; Zhang et al. 2017). It is widely recognized that the disaster-induced geological structure is the intrinsic condition and controlling factor of water inrush; through case studies and geological surveys, many different types of geological structures that have induced heavy water inrush are identified in mountain tunnels, and these results are meaningful to the similar study in subsea tunnels (Li et al. 2017a; Wang et al. 2017a; Li et al. 2018b; Shi et al. 2017b, 2018). Advanced geological technology is a useful way to forecast geological structures before a certain distance of tunnel face (Wang et al. 2007; Xue et al. 2009). Grouting technology is a key method to control the water disaster (Kitamura 1986; Ganerød, Braathen, and Willemoes-Wissing 2008); nevertheless, when and where to apply grouting is an important problem, which needs effective methods or theories as guidelines. In addition, escape routes should be emphasized when constructing a tunnel, especially in a subsea tunnel (Li et al. 2018a; Wu, Li, and Xu 2018).