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Engineering, Japan

Tsuno K.,Tunnel Engineering Laboratory | Kojima Y.,Tunnel Engineering Laboratory | Kishida K.,Kyoto University
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2013

This paper describes a method for quantitatively evaluating the falling of concrete pieces from tunnel linings, comparing the shear stress acting on crack surfaces with the shear capacity. The shear capacity of cracks of various width, inclination angle and roughness were investigated by double shear tests simulating the fall of concrete pieces and on a simulation method, whose applicability is also described in this paper. The resisting capacity against the fall of concrete pieces was estimated using the proposed method under conditions reproducing an actual tunnel. Source


Tsuno K.,Tunnel Engineering Laboratory | Hirata R.,Tunnel Engineering Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2014

A monitoring method using a wireless sensor network was developed to lighten the data acquisition workload and reduce the costs for monitoring railway tunnels. A relay method was proposed for transmitting the data over a long distance. The performance of the monitoring system was verified by means of field tests in actual railway tunnels. This paper also describes a data processing method which eliminates the short-term change caused by daily temperature changes in order to utilize the real-time monitoring data for tunnel maintenance. It is found that a low-pass filter is an effective tool for eliminating the short-term change. Source


Yashiro K.,Tunnel Engineering Laboratory | Kojima Y.,Tunnel Engineering Laboratory | Fukazawa N.,Transport and Technology Agency | Asakura T.,Kyoto University
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2010

In this study, the authors performed case studies and model experiments to investigate the mechanism behind seismic damage to mountain tunnels and their aseismic performance, and the conditions under which such damage tended to be severe were clarified. Model experiments were performed with focus on damage to shallow tunnels or those in ground characterized by poor geological conditions, and the degree and extent of disasters caused by mountain seismicity were successfully reproduced. The experiments clarified the damage mechanism and seismic performance of tunnels in question. It was concluded that sound tunnels and those with inverts are less susceptible to seismic damage, and it was also confirmed that such damage tends to be greater when tunnels have voids above the lining and a lack of thickness, or when local displacement acts on them. Source


Yashiro K.,Tunnel Engineering Laboratory | Shimamoto K.,Tunnel Engineering Laboratory | Kojima Y.,Tunnel Engineering Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2011

In this study, the authors performed model tests and numerical analyses to clarify the quantitative effect of seismic countermeasures for existing mountain tunnels in poor geological conditions. It has become apparent that inner reinforcement can control the initiation of cracks and prevent spalling; backfill grouting can improve deformation performance of the tunnel and control compressive failure in arch crowns; and rock bolts can control heaving of the roadbed. Even though there are many restrictions associated with construction of inverts, it has become apparent that inverts are a fundamental countermeasure to control tunnel deformation and heaving of the roadbed. Source


Kojima Y.,Tunnel Engineering Laboratory | Yashiro K.,Tunnel Engineering Laboratory | Funahashi T.,Tunnel Engineering Laboratory | Miyabayashi H.,Transport and Technology Agency | And 2 more authors.
Harmonising Rock Engineering and the Environment - Proceedings of the 12th ISRM International Congress on Rock Mechanics | Year: 2012

In this study, the authors performed model experiments to investigate the mechanism behind seismic damage to mountain tunnels and their aseismic performance, and the conditions under which such damage tended to be severe were clarified. Model experiments were performed with focus on damage to shallow tunnels or those in ground characterized by poor geological conditions, and the degree and extent of disasters caused by mountain seismicity were successfully reproduced. The experiments clarified the damage mechanism and seismic performance of tunnels in question. It was concluded that sound tunnels and those with inverts are less susceptible to seismic damage, and it was also confirmed that such damage tends to be greater when tunnels have voids above the lining and a lack of thickness, or when local displacement acts on them. © 2012 Taylor & Francis Group, London. Source

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