Efficiency of improved barrier called “Noise Reducer” was investigated by Boundary Element Method. The noise calculation was made to the condition that this device was mounted at the top of highway noise barriers. The results showed good agreement with the data measured at a real highway with the improved barrier of 3.5m height.

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A series of full-scale and in-situ freezing tests were performed to establish a reasonable frost heave prevention method for the national expressways in Japan. These test results showed that the quantity of frost heave is influenced not strongly only by the ground water table, but also by the initial water content of freezing soils. In this study, a simple expression which may predict the frost heave rate at the expressway embankments was derived. The observations in the cold district for three years since 1990 indicated that the expression proposed can explain well the performance of the in-situ frost heaving.

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We construct a judgment system on the collapsible and noncollapsible sediment in a disaster, due to rainfall and natural torrential factors. The system examines the influential factors on the collapse of sediment in a disaster and some problematic points are brought under scrutiny in forecasting it. We present a prevention control of disaster for each torrent by applying a method in the judgment system for determining the critical rainfall of sediment collapse.

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Sand Compaction Pile method has been widely used to improve soft clay ground. Recently limited amount of the sand suitable for the method requires investigations to find new materials for the method. Authors started a series of laboratory, model and field tests on applicability of copper slag sand, the by-product obtained from refining process of copper, as a SCP material. In this paper, outline of field construction test is described, in which construction process and profile of compacted copper slag piles are investigated. The tests show the copper slag sand has a similar material properties and is applicable as SCP material.

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The collapses of cut-off slope during heavy rain had been caused by slope evaluation factors that are topograpical, geological and earth-work related factors as well as rain-fall factors over a certain limit of value. Until now, there are many studies related to an evaluation of slope-collapse possibility based on only rain-fall factors. But, there are few studies based on the combinatoin of slope evaluation and rain-fall factors. In this research, we have constructed a system that can forecast the collapse or non-collapse of metamorphic rock-slope in real time during heavy rain using neural network based on slope evaluation together with rain-fall factors. Then, we present a rule for selecting efficient study data and the best combination of rain-fall factors to improve the reliability of the system.

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The road surfaces on steel deck bridges have more amount of frost and snow cover than those on any other ones, because the former heat capacity is smaller. Therefore, traffic accidents occur frequently. Some field investigations were carried out to solve this problem in Fukui, a snowy and rather mild city. It was found that the insulator beneath the steel deck was ineffective. Phase change material which has the 3-5°C solidifying and melting point was set in the pavement on the steel deck to increase the heat capacity at just above the freezing point of water. This experiment showed that the phase change material saved solar energy in daytime for preventing the road surface from freezing on the following morning.

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Concrete structures generally suffer in material characteristics or workmanship, and cracks, construction joints, or separator portions often prove unsatisfactory. The authors have devised an easy way to repair or seal areas that are not watertight. Cracks and other defects that affect watertightness can be repaired by grouting with a super-fine cement suspension.
This paper discuss the concept of this method and the result of a basic experiment, and report on the results of the experiment using the midair cylinder concrete structure of an engineering scale.

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The stability control of discharging is an important factor in order to control the stability of cutting face by an earth pressure balanced shield. Due to the lack of theoretical background, this study is carried out to clarify the discharging mechanism of a ribbon screw type earth pressure balanced shield. First the theoretical background is developed, and then the theory is verified by using the both experimental study on a model and the data obtained from the practical operations. Good agreement between the analytical results and the both test and practical operation data are obtained.

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