The main objectives of the road technology are to achieve the following three subjects: i) to secure the road, ii) to serve the user of the road, and iii) to preserve the natural environment. This paper presents the past results of how those are accomplished based on the earthwork-technology for the expressway, as well as the expectation on the way that the road technology should be in the future.

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The New-Kitakyushu Airport is constructed on the man-made island reclaimed by dredged clay. In this paper, several problems on the reclamation by dredged clay and on the construction of the airport on such a reclaimed land are extracted. The prediction method for the volume change of reclaimed layer, the design of vertical drain satisfying requirements of runway, the countermeasure for differential settlement and the control system of settlement during the construction are investigated. A major conclusion is that the initial condition for the design of vertical drain in the rapid reclamation can be estimated by the proposed analysis of reclamation process with the consolidation parameters modified by the monitoring results.

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Generally, fiber reinforced shotcrete has much rebound of fiber, and has problem in cost performance. The object of this paper is to obtain the economical mix design of fiber-reinforced shotcrete. On the process of search for optimal mixture, it was found that fiber-reinforced shotcrete based on high performance plain shotcrete has much rebound of fiber. We surveyed the several new mixtures type of shotcrete, carried out mechanical property test, and evaluated cost performance including rebound. From the test results, it was effective that applying plasticity and viscosity.

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The objective of the present paper is to investigate the dynamic property on the high bank. The physical and tremor property were investigated with the data of the various soil tests of the bank material, of PS logging etc., and the dynamic analysis with the observational seismic wave of Tottoriken Seibu Earthquake. As the result, the initial shear modulus calculated from secondary wave velocities roughly agreed with them got by the laboratory test, and the wave calculated by the dynamic analysis making use of these modulus roughly agreed with the observational wave very well. The amplification degree of the earthquake wave tended to agree with it of the micro-tremor.

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Conventionally, a critical line forecasting for predicting slope failures has been established with rainfall factors ignoring vital differences in degrees of slope failure risk for each slope. Besides, it is composed by linear function so that it despite the complex nature of slope failure. Thus, it does not achieve high level of precision. In this paper, in order to consider slope characteristics, we classify slopes into several groups and for each group we set non-linear critical line by using RBF network and obtain RBF parameters from their results. From these results and degree of slope failure risk, we give RBF parameters by considering statistical analysis to set non-linear critical line with considering degrees of slope failure risk. We demonstrate the effectiveness of the proposed method through comparison of the results with our previous studies.

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This paper discusses the application of neural network prediction method of the annual riverbed evolution by using the long tern observation data in the Shigenobu river and its area. The proposed neural network method takes into account of the check dam structure construction effect and time-lug effects of the check dam structure, precipitation and river water flow on the river bed evolution. The multiple regression analysis and its prediction method are also discussed to compare with the proposed method. The proposed prediction method shows good agreement with the observed data including several sequential years prediction attempts, and are better than the prediction by the multiple regression method.

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Water swelling sealant developed in the early 1980s, has been used in actual construction projects for about 20 years as an effective material to ensure water-tightness of shield tunnels. Its long-term durability, however, has not yet been evaluated. Standardized durability test methods and quality evaluation standards for materials of this kind are not available at present. In this study, the authors focused on the functions required for sealant materials and established items for evaluating their durability. In addition, a durability test method, that takes into consideration such evaluation items, was devised and the long-term durability of hydrophilic sealing materials currently used was evaluated.

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We have introduced the tomographic method to the seismic exploration in tunnel investigations, and have presented a way to evaluate the performances of the tomographic method based on geological observations. Geological observation records at the face have been utilized to measure the performances of the tomographic method and the reciprocal method. And these seismic methods have been examined in 35 tunnel sites. The performances of the tomographic method varied with tunnel sites. However, the tomographic method showed same or good performances compared with the reciprocal method in many tunnel sites. This leads to the conclusion that the tomographic method as well as the reciprocal method can be applied in tunnel investigations.

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The temporary retaining wall for a deep cylindrical shaft is generally designed using earth and water pressures and eccentric lateral pressures. Although eccentric lateral pressures greatly affect the design results, there is no theoretical basis to properly determine their values at present.
This study predicted the lateral pressures acting on the retaining wall for this deep cylindrical shaft which was constructed by the diaphragm wall method, revealed from both measurement and analysis that eccentric lateral pressures could be caused by water pressure fluctuation under some circumstances, and investigated problems related to the current design methods.

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In placing massive bottom slab concrete of LNG underground tank, authors had misgivings about the generation of the cold joint that could cause the lower performance in consolidation joint of fresh concrete, because of placing under the summer environment and the delay of consolidation time. Therefore, prevention measures and quality management methods were examined. In the selection of measures, a penetration resistance was adopted as an estimation index based on the shear test and the setting test, and measures to obtain performance in consolidation joint more than the equal that in construction joint were chosen. Good quality concrete was able to be constructed by the vibrator examination and the human sensitivity examination as quality management methods.

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There are many studies on setting a critical line for prediction of slope failure caused by rainfall. However, because of the complexity of nature, it is difficult to distinguish the rainfall causing slope failure by a linear critical line. In this study, we set up a critical rainfall for the warning and evacuation for prediction of slope failure by using Data Envelopment Analysis. We compare the result with that in case using conventional Critical Line and showed effectiveness of the proposed method. We examine prediction of slope failure by proposed method. Warning Line and Evacuation Line are also determined based on Data Envelopment Analysis, and that effectiveness is studied.

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This paper discusses the applicability of satellite infrared (IR) data and normalized vegetation index (NVI) for evaluating the hazardous-slope composed of the shirasu-deposit, based on the SSE model (Slope Stability Evaluation model). In this model the geographical information (GIs) and the satellite data are integrated to produce the slope-stability evaluation map. The following case studies are executed: Case-1) using GIs, IR and NVI; Case-2) using GIs and IR; and Case-3) using GIs and NVI. In the case of using IR data, the high agreement with respect to the training samples of the slope failures are confirmed. As a final product, “Risky-side” and “Safe-side” assessment sub-areas are also delineated on the difference map (termed “DIF-map”) of “Case1 vs. Case3” as supporting information for the slope-failure prevention plans.

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The purpose of this study is to investigate the realizability of ultra long-span cable-stayed suspension bridges, which seem to have more excellent structural characteristics than ordinary suspension bridges by combining the advantage of cable-stayed bridges. In this paper, using trial-design cable-stayed suspension bridges with center span of 2, 500m in which ratios of suspended parts were used as variable, static structural chatacteristics, buckling stability and aerodynamic stability were compared with suspension bridge. Moreover, from all results, the authors discussed about the economical efficiency of ultra long-span cable-stayed suspension bridges.

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The cross sectional design method for buried water supply pipeline of thermal power stations is studied. Limit state design is introduced to establish rational design method, and the design requirements as well as related limit states for the pipeline are investigated. Moreover several partial safety factors are proposed under the consideration of the loads combination and the uncertainties for load action, material property, and construction. In addition, non-linear FEM, in which soil property and interaction of steel pipe and surrounding ground are adequately calculated, is also introduced as rational analysis procedure. Finally the proposed design method is verified based on the data of experiments and field measurements.

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In this study, the methodology associated with the risk assessment and the risk management of the oversea construction projects was investigated. In details, this paper revealed that the basic concept of project management, which has been developed in Europe countries, heavily focuses on the contract administration to allocate the risks to players participating in construction projects, and that furthermore, the management methodology is independent from the essential risk reduction method. Finally, the proposal of the methodology related to risk management of construction was presented.

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The object of this research is to construct the pipe-heating pavement system at mountain tunnel exits. When the amount of spring water is short for thawing of snow, additional water must be supplied from the outside of tunnel. The amount and temperature of river water were surveyed when the water run through pipe under the tunnel, i.e. center drain. It was proven that an enough volume of water and the water temperature were secured from the experiment results for heating of the river water possible by the tunnel pit. Finally, initial cost and running cost of this system was calculated on trial based on experimental results, its economical effectiveness was confirmed.

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After IMF economic crisis, the great efforts have been made to break down the high-cost and low efficiency structure in Korean construction industry. Korean government introduced Design VE Program to cope with that situation, connected with Technique Improvement Incentive Program and Budget Saving Incentive Program.
This paper is to review the present condition and drawbacks of those programs and design VE with several examples and to present recommendations to go on with Design VE program.

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