Firstly, as a representative realization of water-related disasters due to the global warming, emphasis is placed on the importance of river maintenance works as well as river improvement works for reducing flood disaster damages in Shikoku Island that was struck by 6 severe typhoons in 2004. Secondly,a dynamic equation (Fukuoka equation) describing a relationship between dimensionless river width, dimensionless depth and dimensionless discharge was derived on the basis of data of natural rivers in Japan and Canada and the first class rivers in Japan. Fukuoka equation derived thus suggests that a desirable river cross section for flood control and river environment shoud be a cross-section shaped like a ship bottom and dimensionless sediment transport rate be shown to be regulated by the same mechanism as the determination of dimensionless width and depth of the stable river.
  Finally, the framing of comprehensive plan of close-to-nature rivers for the harmonization of flood control and river environment is discussed as well as methods of river engineering adaptation in the global warming age.

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  Asphalt facing method is one of the sealing work methods which are used for fill dam and reservoir. The multiple layer structure having intermediate drainage layer as impervious surface membrane is common for the dam with a height of over 30m in Japan. The multiple layer method which is composed of 2 to 3 layers of 5 to 6 cm each has been used for the upper impervious layers. However, in recent years, reservoirs are constructed in a severe cold weather presenting technical improvements such as shortening of construction period have become in a great demand as such the asphalt facing of the conventional work method of multiple layer structure and method which can not satisfy the above demands. In order to solve these technical improvements, the paving tests were carried out to examine the thick lift method, when was compared with the conventional work method, which will reduce the number of the impervious layers by increasing the thickness of each layer to 8-10cm, and the workability and quality level of the asphalt facing of the thick lift method and the conventional work method have been compared based on the various paving test results.

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  In the Tokyo International Airport (Haneda Airport), the new offshore expansion project with the fourth runway (D-runway) is being conducted. A design build by the performance ordering was employed, and the construction of the D runway adopted the integrated supply method including the maintenance.
  By planning method for preventive maintenance, we report the way of thinking of a rational maintenance plan of airport.

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  In case of the underground flood way constructing by Shield driven Tunnelling Method with RC segment, the watertightness of the RC segment against inner water pressure had not been studied well, regarding the validity of the conventional crack width calculation formula and the relationship between the crack width and the leak water. In this paper, new formula is proposed and the relationship is exhibited by means of full-size RC-segment loading tests and leak water tests. As a result, the maximum interval of the cracks should be used the interval of the assembly steel bars, and the crack width of about 0.1mm is not leakable in long term, are shown.

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  This paper proposes a new type of steel-concrete hybrid slab structure. It consists of a steel deck, longitudinal flat ribs welded to the upper surface of the deck, reinforcing bars arranged on top of the ribs in two directions and concrete. Compsite action between the steel part and concrete is ensured using horizontally arranged round rods inserted in the steel ribs. The proposed sytem is lighter than conventional composite slab and PC slabs. In addition, it has a simple system, in which the fabrication procedure is easier than conventional steel deck plate. From experimental study, it is clarified that the newly employed round rod for connectors has higher strength compared to that stipulated in Japan Highway Bridge Specifications (JHBS). Through moving vechicle test, high durability of this new system is also confirmed.

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  In many cases, the existence of consolidation dam has been obstructing the passing of fishes, and it has been losing the environment of shoals and pools. To improve this problem, the authors constructed the group of low distributed drop works to the Iwatake River, Fukuoka Prefecture, for trial purposes, which united big and small boulders as the model of natural difference steps in the mountain river. Their basic form was the masonry arch, and was applied the stability theory of body in the flow. In the execution, Japanese traditional masonry technique was used. After the completion, we investigated the situation of river channel before and after floods and observed their structural changes after the floods. As a result, even if the stones or gravels between the keystones were moved, the steps are replenished and reproduced with stones from upstream because the keystones were stabilized. From the trial construction by the design method of riverbed structure learnt from nature, it was able to be confirmed that distributed drop works maintained shoals, pools, and bed height in mountain rivers.

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  Under flood conditions, a river flow can have a scouring action on a bridge pier foundation, reducing its stability and even toppling it, and as a result causing a severe train accident. In addition to installing protection works and rebuilding deteriorated piers, imposing operational restrictions according to water level is a practical method to secure safe train operations. This paper presents a study on a practical method for evaluating the natural frequency of a bridge pier based on microtremor, in order to support a decision when to lift such res restrictions imposed. In this paper we have proposed an algorithm for estimating the natural frequency accurately and swiftly on the basis of microtremor measurement obtained from a hydraulic model test and existing bridge piers test during high water level. Moreover, the effectiveness of the algorithm has been verified through its application to several different bridge piers.

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  Serious deteriorations on sewer pipe networks which is an essential lifeline supporting our life by an active consortium of bacteria are becoming a major social concern in many advanced countries in recently. Because the sewer pipe networks were generally arranged into the ground, it is expected to develop a rational method for preventive maintenance. This paper describes an integrated maintenance system for the sewer pipe networks combined with the latest information processing technologies and intelligent health monitoring techniques. It will be able to estimate the deteriorating conditions inside the pipe based on more accurate knowledge about the environmental conditions such as hydrogen sulfide gas density, temperature & humidity history inside the pipes, etc. from a monitoring system via information technology. This paper also describes a prototype maintenance system that was developed for a sewer pipe networks in Ube City area as a specific example.

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  A new 4000m runway was opened on August 2, 2007 at Kansai International Airport. The pavement and aeronautical ground lights installation work for the second runway was conducted as a large-scale and high-speed construction that was essentially completed in the short period of one year. And the construction of the runway featured several innovative methods and advanced technology. The new installation method for the aeronautical ground lights integrated with the runway pavement work was one of the high-light features of the construction work.
  This paper describes the process on how to solve the technical problems for the development of new integrated construction method through the field tests. As a result, this innovative method contributed to the shortening of the construction period, construction cost reduction and environment conservation in the construction of the second runway of Kansai International Airport.

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  The underground in the city part is congested with various infrastructures now. Therefore, the shield-driven tunnel in the future comes to be often planned by large depth. In that case, it is very important for the design of segment to investigate the influence due to construction loads in detail. Shield-jack thrust is the largest influential load to segments.
  In this study, the result of measurements in the deep underground tunnels are investigated at first. Secondary, the basic experiments are operated. These results are verified by three-dimensional FEM analysis. At last, the case studies are executed.
  Results of this study, the influence on segments by shield-jack thrust are showed clearly and the rational design on segments due to the loads.

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  Air sparging was sorted as an optimum in situ remedial technique to clean up first and second benzene-contaminated aquifers at a former coal gas manufacturing plant. Double-layer sparging wells and gravel drains were installed into the second aquifer to apply air sparging. Flushing and bio-sparging is also applied as an effective post-treatment of air sparging to shorten operation period. The average benzene concentrations in first and second aquifers were 24 mg/L and 47 mg/L before remedial operation, respectively. At the end of operation for 2 years, benzene concentrations in many monitoring wells were less than 0.01 mg/L as the environmental standard quality. The final removal rate of benzene in groundwater was up to 99.9 %. The remediation design method based on field trail test demonstrate to be possible to predict remediational period and benzene concentrations with some improvements.

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  A paper-based drafting model for general civil engineering structures is able to show properly the intent of the design using design parameter. Coordinate data of paper-based drafting is not, however, able to be recreated in an actual data because expressible accuracyis limited by scale size. As such, it is necessary for coordinates of perpendicular plane coordinate system to adjust the scale size due to the curvature of the earth and to compensate projection due to difference oftheelevation.However,these adjustmentsarenotabletoimprove accuracybeyondascaleof 10,000:1. Additionally, these adjustments are not able to accurately recreate coordinates perpendicular to the earth’s axis of gravity because the origin of the plane perpendicular coordinate system is in a fixed location.
  This paper shows that a 3D-manifold design model of civil design structures that assumes a point of origin in the center of the earth is able to use 3 dimensional orthogonal coordinate system on the surface of the earth which is perpendicular to axis of gravity at anypoint. Further, this model is able to reducing errors due to differences in length between the design and actual measurements. Therefore, the 3D-manifold design model presented in this paper is able to be used as a universal design concept.

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  In order to use the light-weight foamed mortar supported by the piles as the structural beam member of the slope to the railway viaduct on the liquefiable ground, the high strength and light-weight foamed mortar that has more than 5N/mm² compressive strength was developed. The authors carried out the material experiments to investigate the material characteristics, the shear and bending experiments of the beam specimens strengthened with the reinforcing bars. As the results, the influence factors to the shear strength in the range of the shear span ratio from 0.5 to 3.0, the compressive strength from 5.1 N/mm² to 12.8 N/mm², the main reinforcement ratio from 0.23% to 1.06% were the same as that of concrete. The authors proposed the calculation formula for the shear strength based on the calculation formula of the reinforced concrete members aimed at the shear span ratio from 0.5 to 2.5. Therefore, these development results put the high strength and light-weight foamed mortar into practical use at the slope (about 77 meter in length) to the railway viaduct on the liquefiable ground.

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  We set an occurrence and non-occurrence rule of debris flow disaster in Nagasaki on July 23, 1982, based on comparison analyses among the collected data of it. The analytical method was proposed by Shinozaki et al., combining Support Vector Machine with Rough Set Theory. The rule made it possible to explain more cases of occurrence and non-occurrence debris flow disaster in torrents compared to the case of using only the Rough Set Theory. As these results, we assumed that the analytical method proposed by Shinozaki et al. achieved a high efficiency to extract rule with high versatility, maintaining sufficient accuracy in case study analyses of occurrence and non-occurrence of the disaster.

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