Record concentrated heavy rain hit the Nagasaki Prefecture in July, 1982. It caused a large number of debris flows. It is considered that rainfall makes a prediction of debris flow. Rainfall measures in various regions. However, there are cases where it does not cause debris flows. Therefore, we have to study the natural feature of the region to predict debris flow, since it is not clear to distinguish which torrent is dangerous. This study is clear that essential factor which extracts from natural feature data causes debris flow. We have tried to expand area of rule based on rough set theory. Finally, we have defined new rule and examined validit.

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To deal with the large deformation due to squeezing ground at the Iiyama Tunnel of the Hokuriku Shinkansen, the placement of the tunnel supports were taken into two phases. The idea of the different stages is based on two phenomena according to NATM theory. The first is the tendency of the earth pressure which allowing the lining to displace. The other is the effect of the closed shotcrete lining on the large earth pressure. From the trial excavation, we confirm that the displacement of the lining could be controlled by performing the thin secondary shotcrete layer, even after the first lining was yielded. The numerical analysis results show that the support system could be kept stable by placing the secondary lining at the distance of 3.5 times of the tunnel diameter from the tunnel face.

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The mechanized repair coating for existing bridges has long been anticipated for the reasons such as cost reduction, mitigation of painful work. The complicated bridge structure, fragile platforms, dust and paint scattering, etc., can be listed as impeding factors. HSBA has newly developed a box-girder repair coating system. This system consists of a roll brush surface preparation unit. a roll coating unit, and their manipulator which is placed on and transversed by an existing maintenance trolley car. An experimental work by this system, carried out at Ohshima Bridge, showed a successful performance as the equal qualities and ten times of productivity as manual work.

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The permeability of dam foundations is generally evaluated by Lugeon water test. Lu values obtained by the test can be converted to coefficient of permeability, which would be needed in evaluating amount of leakage from reservoir, only in the case of laminar flow condition. For the jointed rock with open fissures, Lu values are liable to be underestimated, compared to those obtained on laminar-flow condition, due to turbulent flow in testing. In this paper, examining the various kind of field testing methods to evaluate permeability on laminar-flow condition, we have shown that these methods are useful comparing the results with the analytical solutions calculated based on the actual leakage flow.

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The New PLS (New Pre-lining Support) Method is one of pre-lining methods in which the perimeter of a tunnel face is excavated with a chain cutter and immediately reinforced with a concrete shell. Firstly, this method was applied to widening Hodogaya Tunnel of New Yokohama Highway. Secondly, it was applied to Yoshii Tunnel of the Yokohama-Yokosuka Highway.
In this paper, test method and test results to select the slit concrete mix using quick hardening additive, accelerator, and setting modifier are described. This method was experimentally adopted in Yoshii Tunnel and the good results were obtained.

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In order to perform a rational tunnel design at second tunnel of parallel tunnels, it is strongly required to improve a tunnel design methodology. The case study of the parallel tunnels shows that this methodology has not yet been established. This paper deals with the rational tunnel design methodology of the second tunnel based on the first tunnel construction data by comparison each tunnel of the parallel tunnel construction data. An application of the methodology shows that the lighter support scale may be used for the second tunnel by carrying out the informational procedure to perform the realization of the rational tunnel construction.

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In this study, the author concerns with the method for reducing the cost by reducing the stiffeners. In the fabrication, for installing stiffeners to a web panel is generally carried out by robotic welding. However, reducing stiffeners are not possible on the quantitative evaluation in respect of the effect of the rationalization, as long as the process of robotic welding is not clarified. In this paper, for the purpose of quantitative evaluation on the effect of the rationalization by reducing the stiffeners, the process of robotic welding was observed for 9 days. The time necessary for each stage of work was investigated. From this result obtained in this study, we suggest the evaluation method by reducing the stiffeners.

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Structural properties of concrete pile reinforced by strands which have high strength and flexibility, and its construction method are proposed for efficient construction in the site with limited space in height. In the present paper, the results of design and construction of concrete pile reinforced by strands in a project which improve AKIHABARA station, which is the first case to apply it to the real structure, are discussed. Using strands for reinforcement of piles, the diameter of pile and construction term of assembling reinforcement bars are reduced.

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It has been already suggested that the Beam-Spring Model, in which ground springs set all around the tunnel lining, is the most rational design method of shield tunnel lining constructed in hard and strong ground. Using the design model, some sensitivity analysis with several kinds of factors are carried out. Applicability of the model to actual design of tunnel lining is investigated by comparing the result of the analyses and the in-situ measurements. Consequently, it reveals that this design model is able to simulate the behavior of shield tunnel lining and also execute both safeness and economizing for shield tunnel lining.

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Plate girder bridges have been recently planned and constructed in our country because of economical reason. Plate girder bridges are prone to oscillation due to wind such as a vortex excitation. Therefore, it will be necessary to examine the dynamic response characteristics of a moving vehicle on the oscillating plate girder bridge. In this paper, measurements were carried out to grasp the natural frequency of standard-sized cars. The dynamic response characteristics of moving vehicles on a wind-induced oscillating bridge are investigated through the numerical simulation analysis to check the driveablity of vehicle on such a bridge. A simplified method for evaluating the dynamic responses of the vehicle is also proposed with the required accuracy in engineering.

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Research of the project management (the following PM) technology which achieves whole optimization of the project is energetically advanced in western countries and Japan.
This study has aimed to develop a new project management model applied for civil engineering field in Japan. Here, it is called “PM for civil engineering field”, and under principle of the requirements satisfaction from customers and oneself, the backgrounds and the necessity of study, setting of ideas and the definition of PM for civil engineering field, concept formation of body of knowledge and management elements, and the execution procedure are proposed.

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To employ performance base design criteria is going to prevail in many fields. For underground structure design, the importance to assess load of groundwater during the life cycle of the structure is going prevail. In this paper, correlation between ground water level and precipitation in the catchment area is analyzed by using a public weather observation data around Tokyo and a method is proposed to determine load of groundwater for performance base design on the basis of probable rainfall intensity.

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Recently the requirement of the improvement for the productivity, safety and the cost in the shield tunnel construction are increasing. The ways of the improvement are automated and rapid erection of segment or long distance construction with one machine and omission of secondary lining. We have also developed and practical researched the ductile segment without bolt joint. The purpose of this R&D is to realize automated and rapid erection of the ductile segment. We developed the new joints for ductile segment and we have several test constructed by the ductile segment with the new joints. This paper is described about the process and the result for these R&D.

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This paper focuses on the basic concept how to rationally allocate geotechnical risk in construction projects. Firstly, risk allocation policies specified in each typical construction contract represented by FIDIC are investigated. Finally, conclusions make it obvious that both project owner and contractor principally share geotechnical risk in construction projects, and that both parties should cooperate to establish methodologies associated with the reduction of potential loss due to the geotechnical risk.

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Portland cement based materials are widely used for enhancing strength of soil mass as in cement deep mixing (CDM) method or other similar methods. However, the strength of improved soil may fluctuate by the workability during CDM method even under a same mixing proportion. The authors studied a correlation between the physico-chemical property of soil and results of the vane shear test after aware of the fact that clay fraction content may cause insufficient mixing of soil. As a result, knowledge on the material development such as a relation among clay minerals and electric charge was obtained.

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The authors have been working for some time on the development of a maintenance support system for concrete structures based on a combination of both the fuzzy hierarchy structural model and the fuzzy set theory which deal with the subjective information related to the serviceability assessment. In this study, in order to improve the flexibility and practicality of the maintenance support system, a modeling system by fuzzy flexible interpretive structural modeling (FISM/fuzzy) for hierarchy modeling was newly developed and also compared FISM/fuzzy with fuzzy structural modeling (FSM) to apply the system to alkali-silica reaction.

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