Immersed tunnel elements at Kobe Minatojima tunnel are made with steel-concrete composite structure for the purpose of decreasing total construction cost. Super workable concrete is used to be cast into steel elements. A series of laboratory and model tests on applicability of super workable concrete are examined. In this paper, outline of construction management system with super workable concrete is described. This system is effective for construction with steel-concrete composite structure.

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As a parts of long-stator LSM and for good riding quality, it is important to construct MAGLEV guideway to a high accuracy. In case of beam type guidway, we have succeeded in three steps of highly acccurate connstruction which are production of beam in the field factory, production of shoe in-place and erection of beam. In all construction steps, allowable error values are almost satisfied. and the riding quality of MAGLEV vehicle on this seciton will be equal to Tokaido SHINKANSEN even if the maximum velocity of MAGLEV is as twice as SHINKANSEN.

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The RC T type pier discussed in this paper was severely damaged by the Great Hanshin Earthquake. And the jack-up method was employed to correct this RC pier which had inclined approximately 2.2 degrees in the transverse direction by rotating around the plastic hinge near the lower end of the pier.
Before the restoration work, we carried out the experimental studies and the numerical studies by non-linear analysis in order to make the restoration work effective. And the inclination was corrected successfully by the jack-up method.

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A new type improved barrier called “Planting Type Noise Reducer”, which integrates the results of full scale model field tests and two-years nomentenance planting tests, was actually mounted on highway barriers. This paper describes the results of countermeasure and analysis by Boundary Element Method (BEM) for the efficientcy of the improved barrier. The results show that the insertion loss of this device is the same as that of the previous device.

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In this paper, the effect of pre-loading to structural mechanism of RC composite beam is discussed. We carried out flectural tests on RC composite beam which was built by adding reinforcement and concrete to the pre-loaded beam. The results show that the crack width of RC composite beam can be estimated adequetely using the amount of stress of reinforcing bar subjected to pre-loading. It is also found that the effect of the direction and the amount of pre-loading to the ultimate moment of RC composite beam is negligible.

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Block Theory, which can find falling or sliding blocks by intersecting structural discontinuity, was applied for the excavation of large scale underground rock cavern. This paper proposed the procedure how to observe the excavation surface, to search key blocks and then to design support system. This method was executed during the excavation of Okutataragi underground power station, and detected key blocks were supported by shotcrete, rock bolting or rock anchor. It is shown that the proposed method based on block theory can help to reduce an amount of supporting system and to design the structures of rock cavern properly in discontinuous rock mass.

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While the project is executing, it is necessary to get a sort of function to watch and monitor all the contractual matters from the over all project management points of view. For the fixing contractual problems, there are two different types of analysis shall be required. One is the qualitative analysis witch figure out contractual entitlements, and the other one is quantitative analysis witch is fixing the magnitude and volume of the contractual entitlement. The contract administration based on qualitative analysis, it shall be required the participation of site engineers who are in front, and know facts and actual history of the matters, is now recognized as the much practical way than the contract administration based on quantitative analysis that may be handled by people who have contractual and/or legal back ground.

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Availability of new snow-melting system where the geothermal energy collected by building piles with circulating water was used for melting the snow on the ground was evaluated from the practical applications in parking lot & c. and its numerical simulation. For example, in the snow-melting area having present system, the depth of laying snow was kept less than 6cm through 5 seasons nevertheless the snow laid 66cm depth in maximum at the surrounding areas. Measured heat quantity collected by building piles agrees well with the result obtained from the numerical simulation. The results of numerical simulation based on the data of famous 56-heavy snow fall season obtained from Meteorological Observatory suggest that the present system is enough to melt the snow in such season. Moreover, the maximum thermal stress and displacement in the piles caused by the cooling due to circulating water used for snow-melting were evaluated by numerical calculation.

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Investigation method of underground methane gas is under development and only qualitative analysis is available so far. This paper presents the results of our study for the quantitative evaluation of underground methane gas, applying BAT Sampling System which was developed by B. A. Torstensson, Sweden. In our study, we 1) collected underground gas in an artesian, inactivated condition as is the condition in the ground, 2) quantitatively evaluated the concentrations of the gas both in water and air and 3) applied this sampling system to the underground work.

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This paper proposed the evaluation algorithm of the SSE model (Slope Stability Evaluation model) incorporating the ground characteristics of the steep slope composed of the shirasu deposit affected by the erosive collapse. In the SSE model, the causal factors, such as geographical information (GI) and satellite remote sensing (RS) data, are used to produce the slope stability evaluation map. In thus study, as the other causal factor, the “Natural Shirasu Stabilization Coefficient(NSSC)” was newly defined with respect to the ground condition. To evaluate the effectiveness of the NSSC, the following two cases were executed; Case-1) Using the NSSC, GI and RS data, Case-2) Using GI and RS data. As the results, through the quantification method type-II and type-III, it was indicated that the NSSC is useful causal factor for presuming the hazardous area. Furthermore, the difference map (termed DIF map) between two evaluation maps, based on Case-1 and Case-2, was provided. This DIF map and its interpretation are effective as the supporting information in making the prevention plans on the slope failure.

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Using a model embankment, finite element analyses based on initial stress method and using comparatively simple input parameters have been performed to investigate the effectiveness of steel anchor plates installed within embankments built over soft ground. This paper presents the results of the analyses made considering steel anchors placed in three layers within a test embankment. The effects with or without such steel anchors as well as the number of layers installed on the magnitude of stresses on steel anchors, the lateral movement and the stability of the embankment were analyzed using finite element method. The results showed that steel anchors not only restrained the lateral movement of the embankment but also increased its stability. Moreover, it was also observed that placing the steel anchors either in two layers or in three layers have the same effects on the embankment.

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