The purpose of this study is to examine the effect of low-heat portland cement and joint for inducing crack which control thermal cracking in thick concrete wall of cut and cover tunnels, through the measurement for massive concrete structures and the numerical analysis by the finite element method. As a result of the examination, it is found out that not only use of low-heat portland cement and joint for inducing crack are effective to control thermal cracking of massive concrete structures, but it is necessary to establish the character of concrete dynamics, specially the compensative coefficient of Young's modulus which is used for the analysis so as to evaluate that effect suitably. Then, the compensative coefficient of Young's modulus corresponding to a kind of the cement is estimated through the measurement and the numerical analysis.

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　2008年2月シークエンスデザインの路面表示オプティカルドットが首都高本線埼玉大宮線美女木JCT付近下り本線の上下勾配区間にて運用開始された．現在までの3カ年の通行車輌の実勢速度について, 現地に設置された車輌感知器によるデータを元に分布の推移を分析したところ, 運用直後の当該区間で速度超過交通に対して速度抑制効果が確認された［韓, ITS Symp. 2008］ことを裏付け, さらに制御効果の経年による減退傾向はほぼ認められず, 制御の持続的安定を示す結果が出た．

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We propose a method for presenting visual stimuli to change a driver's sensation of speed on a freeway: utilizing vection, one of the perceptual properties needed for self-motion and show that this method can be used on a freeway with CG simulation movies. Furthermore we investigated the relationship between the velocity of vection-inducing stimuli and the sensation of speed. Our study consists of three experiments. In all experiments, the simulated freeway 3D movies were presented on a wide hemisphere screen and the magnitude of the observer's sensation of speed was measured. Vection-inducing stimuli were produced by flickering in the boards on both sides of the freeway. This flickering yielded apparent motion. We set the speed of the vection-inducing stimuli and that of the driver's car as experimental variables. The observer compared two movies consecutively presented with different conditions and selected the one that gave a sensation of faster speed. The observer's sensation of speed increased linearly with the speed of vection-inducing stimuli. Our study suggests that controlling the speed of vection-inducing stimuli could enable the driver's sensation of speed to be manipulated in real freeways.

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