Generally, assisting methods in mountain or urban tunnels constructed by NATM were adopted in order to stabilize behaviour of tunnel face or reinforce support system under tunnel construction, but there is no definite criterion of assisting methods for adoption. In this paper, we investigate evaluation of rock condition at tunnel face and adoption of assisting methods in twin tunnels constructed in Schist mountains. As a result, we understand the actual conditions of the evaluation of rock condition and adoption characteristics of assisting methods in twin tunnel.

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A new water purification technique in closed water area polluted by muddy and waste water was developed by use of the aerators which can generate a large quantity of micro bubble, which diameter is less than 100μm, and form large-scale circulating flow in the whole water area.
The efficiency of the new technique was experimentally proved for the several kinds of waste water quality in laboratory and fields. The results indicate that the both of turbidity and concentration of suspended solid in the waste water of a pond were decreased by about 90% in 668 hours.

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Taking advantage of an opportunity that the inner part of slurry wall at Kawasaki man-made island for Trans Tokyo Bay Highway was being excavated, we could estimate the effct of soil improvement work done by the offshore sand compaction piles for the said excavation area was as deep as from TP-28.0m to TP-55.0m. We investigated on the quality of sand piles and characteristics of clay in-between the sand piles at each depth after a lapse of four years. It resulted in our confirmation that sand piles installed into the undersea ground has kept good condition in its quality and appearance, and the strength of clay in-between piles increased.

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The Multi-Circular Face shield method, which is possible to excavate in overlapped-circular shape safely, is expected to be applied to underground construction projects in the future. We had three subjects to expand the Double-Circular Face method to the Multi (Triple)-Circular as follows: 1) managing the slurry flows at three chambers independing each other, 2) structuring the triple segment including two large columns; 3) backfill grouting for a volume of the tail-void.
In the OBP station construction project, we had accomplished the tunnel work in the Multi-Circular Face shield method in April 1995 successfully, which was to locate under the upper structures and in crumbly sand with high pressure underground water.

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Despite taking many precautions, there are still many accidents at construction sites. Unfortunately, this is also true for the erection sites of steel bridges. As a result, the authors have developed a new Safety Control System, which safeguards the work being carried out by using CCD Cameras and Lasers. The system is also linked to an alarm device, consisting of a siren and a warning light, which can be set off if dangerous behavior is observed. The system was successfully applied to the Transferral Erection of a steel arch bridge, resulting in the safe control of the operation. This paper describes the concepts of the Safety Control System and the results of applying the system to the Transferral Operation.

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This paper presents a development of surface measurement method of impact force using a sheet piezoelectricity under the debris flow. This system is used for setting directly to check dam and measured at area. Impact tests were executed for the three types of condition at measuring impact force using sheet piezoelectricity, load-cell and measure of acceleration. It was found from the load-time curves at three equipments that sheet piezoelectricity is made good use of surface measuring of impact force.

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Laboratory tests on three types of model grounds were made to grasp the solidified shape of the urethane grout forepoling and the following have been recognized. 1. When the groutingwas made to the ground of pit soil or decomposed granite, the solidified grouted materialformed a block-shape when the soil was of low water content, and the grouted material formed a leaf-blade-shape when the soil was wet. 2. Even when the solidified shape of the grouted material was spherical or cylindrical in grouting the type of “fracture/permeation grouting” was observed in the internal structure.

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In recent years, the studies at the view point of landscape design are done in the process of constructive planning of a new highway. This study examines the psychological evaluation for the shape of tunnel gates and noise barriers by semantic differential method. For the comparison of evaluation by civil engineer, architect, graphic design and user the questionnaire survey is carried out and the evaluative method in the design process is discussed.

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Recent increases of the traffic volume and load provide a severe condition to the bridge slab, which results in replacement of the deteriorated bridge slab to a stronger slab.
The present study aims to obtain the behavioral information of the precast slab system subjected to bending, and focuses to the statical strength and crack width of the joint part of precast slabs. Test results indicated that some of the reinforcing joint systems, especially a vertical loop system, have both sufficient strength and less crack width, and that prestressing joint systems have also more strength than the strength evaluated from the JSCE Concrete Standard Specification.

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A seismic-isolation bridge must be effective for both medium sized earthquakes, which may be applied to the serviceability limit state design method, and extremely large earthquakes, which may be applied to the ultimate limit state design.
In this paper, the authors propose a practical design method that optimizes the characteristics of seismic-isolation device (Lead Rubber Bearing) for both types of earthquake. A design chart which can be applied to every bridge is offered. The domain of seismic-isolation characteristics that create a reasonable reduction of inertia force is then obtained.

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This paper deals with a study of special spacer with damping device developed for suppressing wake galloping in tandem cables of cable-stayed bridges. Numerical calculations demonstrating the damping characteristics due to the installation of the proposed damper are presented for the tandem cable model with the length of 100m and 200m. It was ascertained that the structural damping characteristics with this type of damper for the out of phase cables would be very dependent on the torsional rigidity of the cable. Cable vibration tests on a full-scale bridge were also performed to verify the effectiveness of the proposed damping device.

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Fully grouted rock bolts are usually used as a support measure for stabilizing tunnels and caverns excavated in jointed rock masses, though the design methods for rock bolts have not been thoroughly developed yet.
In this paper, therefore, a constitutive equation for jointed rock masses reinforced by fully grouted rock bolts is derived on the basis of continuum mechanics, and a design method is proposed by using the derived equation. Case studies for a large cavern are performed to evaluate this design method, and the efficiency of the method is clarified.

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Recently, geotextile filter materials are often used to from drainage layers within earthfill embankments and at earthfill-foundation. This is because scarcity of traditional river- bed materials and concern over the environmental impact of using remaining resouces.
The geotextile filter material will become clogged soil particle over time, thus reducing its permeability. However, this drawback has not been considered in design up to this time.
We proposed an alternative method which carefully considers this reduction in permeability so its indispensable items, and incorporated the results of thorough field testing.

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In urban and suburban areas, rock blasting is often used in tunnelling and formation of housing site, at this time, the considerable effect on people is often a problem, and engineers need to evaluate the effects of blasting vibration on people. In this paper, we carried out a simulation of velocity wave induced by blasting, including factors related to blasting vibration, and cleared characteristic of PPV (the peak particle velocity) and VL (vibration level) as an evaluation uint of blasting vibration. And we investigated evaluation unit of blasting vibration based on the effects on people.

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Recently, there is a worldwide interest in environmental problems, especially in developing countries where rapid economic growth is expected. In this research, an available system for bridge type selection is further developed for considering problems specific to developing countries such as assessment of the environmental impact of the bridge and technology transfer requirements. The environmental impact of each candidate bridge type is evaluated by the volume of energy consumed and CO₂ emission from the material and construction equipment. In addition, the effect of recycling construction materials is also considered.

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In this study consists of the following two topics, one is a basic consideration on the extended Kalman filter in parameter identification problems of road tunnel, and the other is estimated for a thermal behavior in tunnel-ground from identified parameters. In the former study, the extended Kalman filter which was incorporated with the one-dimensional finite element thermal analysis in order to identify unknown thermal parameters in ground.
In the latter one, the estimated tunnel-ground temperatures from identified parameters, compared with the observed temperatures of actual tunnel. Finally, numerical examples are worked out to demonstrate the usefulness of this method in identification of the thermal characteristics and estimation of thermal behavior in ground.

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