Rock tunnels suffered severe damage from recent large earthquakes in Japan, despite the empirical knowledge that tunnels tolerate earthquakes better than surface structures. Seismic design for rock tunnels have therefore become a fascinating subject for many tunnel engineers. However, even basic behavior of tunnel during earthquake has not been fully understood due to lack of actual seismic data. In this study, the authors installed dynamic measurement system including accelerometer and strain meter at two actual road tunnels. The major results include: Seismic intensity at the tunnel is smaller than that on the ground surface. Seismic intensity at the tunnel is almost the same as that in the surrounding ground.

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 Cracking of tunnel lining concrete is a potential initial defect leading to falling of concrete pieces, leakage, etc., which impair tunnel safety, water tightness and durability. Therefore, preventing these cracks is very important in ensuring the quality of tunnels and maintenance.
 In order to accurately predict the initial cracks of tunnel lining concrete, it is necessary to accurately predict the temperature change due to the hydration heat of the lining concrete at first. Since the thickness of the lining concrete is thinner than that of the mass concrete, there are limits to applying the existing criteria. In this study, we consider the thermal analysis which is important in predicting the initial crack of the concrete lining.

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 We developed a new method for crack width measurement with image analysis using multiscale LoG (Laplacian of Gaussian) kernel. This method makes it possible to measure the width of cracks by detecting the precise directions and the edge positions of them due to that the kernels can reduce noise while they can detect the structure of the objects. The measured width in pixels can be precisely transformed to the width in mm by using a calibration target which can be also used to correct the perspective in a photograph. The transformation errors can be also used as criteria for judging the image quality of photographs whether we can measure the widths with sufficient precision with them. In this report, we describe the algorithm of the method and show the experimental results at real tunnels. The experimental results suggest that our method can measure the width of cracks with sufficient precision for periodic maintenance operation of tunnels.

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 During the shield tunneling under extremely high depth and water pressure, several type of temporary construction load, such as jack force, backfilling injection pressure, tail grease pressure, tail brush pressure, etc., affects serious damage to the segment. Because the recent use case of the shield tunneling method are increasing in the high depth condition, numerous defects are reported due to these construction loads in the curved part. Therefore, accounting these effects into the segment design are considered in this project.
 In this report, tail grease pressure, which is one of the temporary construction load, is considered to provide the feedback for the calculation. The data collected during the tunneling progress is used to compare with the initial condition which was set during the designing.

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