This study highlights the reasons of disagreement between the preliminary tunnel design and design at construction stage through the geological investigations at both stages. For this purpose, the geological details for three existing tunnels at both stages were investigated. Data from elastic wave velocity, geological survey details and interviews and answers to questionnaires from several design and construction engineers were considered for the evaluation and assessment. The reasons for disagreement were determind comparing the items differed at preliminary design stage and design at construction stage for each tunnel site and interpretation from geological engineers.

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Reinforced concrete (RC) slabs which are now widely prevailed as the slabs of steel bridges, are historically investigated how and why they have developed. Namely, the various types of slabs applied for the steel bridges before RC slabs are surveyed to show that they had influences on the design of RC slabs such as the thickness and the span of the slab. And the bridge-flooring structures to support the slabs are also studied how they affected the design of the RC slab. At the same time, the traffic development and the material supplying conditions are also studied to make clear the the background of development of the RC slabs.

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Manufactures of the conventional reinforced concrete segment involved the application of heavy vibrating compaction to concrete with an extremely stiff consistency. Focusing on one of distinctive features of high flowing concrete, that is self-compacting into the steel form, the authors put into practice a new segment manufacturing system aimed at cost reduction through rationalization of manufacturing process by such means as omission of vibrating compaction and of surface finishing work on the back of the segment. This paper shows that the segments made of high flowing concrete proved to have an engineering performance equal to or better than the conventional one in various tests. It also describes the quality of this new type of segment under the condition of mass production.

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This article reports a positioning with GPS from Tsukuba to Kamioka over a distance of 250km. In the present work, we proposed a GPS positioning for a very long baseline positioning among a several of existing techniques. In fact, the precision of the positioning has been demonstrated in the neutrino experiment (particle-physics experiment) carried out between Tsukuba and Kamioka. The very long-baseline GPS positioning is one of techniques expected to be utilized in civil engineering when GPS continuous observation stations are completed by GSI (Geographical Survey Institute). The present work gives useful technical suggestions and prospects for future applications of long baseline GPS positioning in civil engineering.

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It is important to control the injection rate less than the critical injection rate q_cr in order to obtain sufficient effects on chemical grouting, q_cr is the maximum permissible injection rate to make good solidified shapes, q_cr is determined with the relation between injection pressure p and injection rate q (p-q curve) of the standard water injection test. But for several causes on measurement, q_cr based on p-q curves of injection sites must be often modified. This paper investigates the improvement of method of determining correct q_cr. And the authors suggest that the ratio of p₁₀ (at q=10l/min) and p₂ (at q=2l/min) calculated with p-q curve is useful for deter-mining correct q_cr easily.The relation between q_cr and p₁₀/p₂ value is follows: q_cr=10(p₁₀/p₂) -10

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It is one of the methods in which the stress which arises in the earthquake is reduced to install the layer with low-rigidity and high shearing deformation performance around the underground structure.
The property of the developed asphalt-based seismic isolation was shown. And, It was proven that not only rigidity ratio of seismic isolation layer and ground but also that of structure and ground caused large effect by the numerical simulation.
The field test for actual operation was carried out, and a constructive knowledge was obtained.

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A prestressed concrete multi-span stress ribbon bridge with roadway slab decks consists of decks, columns which support the decks, and stress ribbons. The overall stiffness of the structure is increased using elastic connections with horizontal neoprene bearings and prestressing tendons which are installed between the ends of the roadway slabs and the abutments.
This paper presents structural characteristics of a multi-span stress ribbon bridge with roadway slab decks and a simplified procedure for the determination of the spring constant of a elastic connection.

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The aim of this study is to propose a support system as part of Bridge Management System (BMS) developed by authors, which is able to present a more effective maintenance strategy. This support system has a estimation function of deterioration cause and a selection function of maintenance measures. The former function enables some deterioration cause to be estimated by inspection data and non-destructive testing. The latter function allows a maintenance strategy to be determined using the output of the estimation function. Furthermore, the new system is applied to exisitng concrete bridges so as to demonstrate the validity of the proposed system.

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Recently, there is a sharp increase in the number of construction cases adopting a lightweight banking method using foamed mixture lightweight soil. Because there is a great variety of material soil used at present, the establishment of a streamlined quality control method is urgently needed.
This paper attempts to clarify the factors that affect the major performance requirements of the foamed mixture lightweight soil-flow value, wet density, and unconfined compression strength, for which recurrence analysis of numerous test results were performed. Also, a quality control method of foamed mixture lightweight soil is proposed, its practicability verified using control data obtained in actual works.

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As the noise emanating from the impacts of machine is very noisy, countermeasures against such noises have to be carried out by users as well as makers. However, in the case when users have taken some countermeasures against machine noise, it is difficult to evaluate the noise control effect. This paper deals with its evaluation method which is convenient for users by the analysis of noisy waves for impact machines.
Further more, “simulation of evaluation for noise control” has been developed. By using this simulation method, it becomes possible to make a listening comparison with two different noises associated with two different impact machines.

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A vertical shaft of shield tunnel plays a role of bearing pile-wall to resist earth pressure at excavation, but the part of the shaft must be cut to proceed a shield tunnel horizontally. Therefore, the requested properties for the shaft are sufficient resistance against bending moment and easiness for cutting by shear force. For this purpose the authors have developed a hybrid member consisting of a fiber reinforced foamed urethane (FFU) member and a steel pile member. The key of the hybrid member lies in how to connect both members. Two connection methods, such as a cotter connection and a bond connection are proposed and the mechanical behaviors of them are examined experimentally in terms of flexure and shear. Finally, the prototype is tested and is proved to have sufficient strength for actual use.

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In various design standards, the method in recommended for Chang on the design of piles. The assumption in the method of Chang is that the lateral resistance (k_h) is constant in spite of the direction of depth. In the existing grounds, such a ground is not general, but the k_h in the ground changes with depth.
In this paper to confirm the applicability of the methods of Chang and Reese-Matlock, the lateral loading tests of the pile in the sandy and clay/sand layered grounds were performed using a geotechnical centrifuge. Moreover, the new method to certain the stress condition of pile, which used the k_h distribution determined by triaxial compression tests and stiffness matrix of beam member, was proposed.

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It is well known that the longitudinal motion of girder plays an important role in the seismic response behavior of long span cable-stayed bridges with longitudinally free or elastic support conditions. Therefore, it is needed to know the dynamic responses to seismic loads of this type of cable-stayed bridges from the initial stage of design. In this paper, a simplified method for estimating longitudinal seismic responses of long span steel cable-stayed bridges is presented from the practical standpoint. Numerical examples are also worked out to demonstrate the efficiency of the proposed method.

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In conventional research, precision forecasting of slope failures during heavy rainfall using critical rainfall line is not so accurate, because it used only rainfall factors for forecasting. In this research, the slope failure prediction system using both rainfall factors and geomorphological factors is constructed based on multiple discriminate analysis. Then we determined the critical rainfall line and try to improve the precision forecasting. The result shows that the precision had improved more than 80% in forecasting.

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In this paper, data mining is applied to the data on slope failures in Yamaguchi prefecture, for the purpose of the detection of critical causes of slope failures. First, the methodology based on rough set theory is applied to geological data, and it is shown that relatively small number of causes can explain most of the slope failures. Next, the same methodology is applied to the data with geological and rainfall factors, and the classification of slopes for preliminary warning and evacuation is proposed. This paper shows the effectiveness of data mining using rough sets in the analysis of slope failures.

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A new measurement method with GPS was proposed to measure the suspension bridge girder displacements, and field measurements were carried out. The semi-static displacement was success-fully obtained and corresponded to the wind tunnel test and the FEM analysis. As for the fluctuating displacement component, power spectrums of GPS data agreed well with acceleration data, FEM and the bridge dynamic test, besides the GPS data corresponded to the acceleration data. The gust response estimated by the analysis was correlated with the GPS data but scattered. This method is proved to be useful for semi-static and dynamic measurements of long-span bridge girder displacements.

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This paper proposes a methodology related to risk management of slopes closed to highway. The basic concept of this method is that by adopting an event tree, the occurrence of hazard is clearly associated with the corresponding damage scenarios. And, risk due to natural hazard is evaluated as monetary value from socio-economical viewpoints considering repair cost, compensation, the financial losses due to the interruption of highway service and so on. The result shows that the proposed methodology is very effective to establish rational risk mitigation strategv considering cost-benefit effect.

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Fundamental study has been carried out to develop a new type of submarine cable layer. The new cable layer has multi-ploughs which will excavate trenches in sea bed and water-jet device which will make sandy soil fluid in front of each plough. The cutting resistance acting on the ploughs is expected to be reduced by flowing sandy soil, and the deep and high-speed excavation will be realized. In this paper, the relationship between the nozzle conditions, soil properties and flowing phenomena of sandy soil has been investigated through the experiments, and the design of the new cable-layer was discussed by predicting the cutting resistance acting on the layer.

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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, an automatic drawing system for hierarchy modeling was newly developed and also verified by applying the system to some actual problems related to the structures under multiple damages.

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