[in Japanese]

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Fiber reinforced cable bolt is one of the capable and powerful supporting measure. However there are many difficulties to product the suitable characteristic fiber cable bolts, because it is hard to form a fiber bundle into the cable shape. Kumihimo Method is old fashioned Japanese fiber twisting method, but it is also suitable in modern days.
In this paper we introduced the new branded fiber cable bolts adopting the Kumihimo Method and a lot of experiments has been carried out to reveal a fundamental properties of this fiber cable bolts comparing with the steel one. As a result, it became clear that fiber cable bolts has the reliable strength as tension, shearing and frictional properties. Especially frictional strength is higher than steel one. We suppose it is closely related to the adopting the Kumihimo Method.

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The earth pressure shield method can be applied to various kinds of soil, but a certain countermeasure is needed to prevent the gush of water at the gate of soil removal with excavating some types of soils such as granular soil.
The “Silica shield method” uses silica jelly as an additive to solve the above mentioned problem.
This report describes the various effects of silica jelly such as improvement of fluidity of excavated granular soil, the optimum mixing ratio of silica jelly and the safety features.

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The deformations were observed over wide range when the soil excavation works were conducted in the soft clay. To make clear a mechanism of this deformation and to investigate a countermeasure work, the creep tests and deformation analysis by the FEM were carried out. From these tests and analysis following results could be drawn. A creep deformation of the clay takes large part and creep strength is 60 or 70% of the peak strength from the triaxial test. The CCP method was adopted as the countermeasure work. It is clear from the FEM analysis considering the creep characteristics that a bigger rigidity of the CCP is necessary to stop the deformation.

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In order to adopt spread founcdations on slightly weak gravel bed ground, Authors have conducted a series of plate bearing tests using for the purpose of establishing reasonable design method on spread foundations.
This paper describes not only the bearing capacity and the modulus of subgrade rcaction but also useful information obtained from comparing plate bearing test results with actual elastic settlement.

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A 5m hard rock TBM was used to bore pilot tunnels for a three lane road tunnel with a shallow overburden (15m) in a residential area. The vibrations and noise from the TBM were measured on the ground surface and apartment building and the spectra analysis were carried out.
On the ground surface near an apartment building, the vibration level was about 60dB and the noise level was around 50dB when the resultant distance was 25m between the TBM and measuring unit. A few complaints from the apartment residents against nuisance and disturbance their sleep during TBM construction were registered. The spectra analysis revealed that the predominant frequencies were 5Hz, 30-60Hz and 90-100Hz in the apartment building and 20-60Hz on the ground surface.

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In excavating the large underground cavern, it is necessary that techniques of survey-test, analysis-design and construction-measurement, which are related each other, work as a total technique. But in fact these techniques do not always work as a system because of an unbalance of these techniques so far, so whenever we were faced with some problems, we actually tried to solve the technical problems individually.
This report describes the application of “computerized construction management system technique” that was systematized as a total technique using each technique that had been improved during the range from survey to cavern excavation completion of recent underground power plant at Kazunogawa.

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We studied frequency distributions of horizontal convergences (the variation of length between two points on the sides) measured during construction of expressway tunnels The large part of these are small, less than 20mm and few supports are deformed. These facts suggest issues that vertical and horizontal convergences depend on the support effect or the properties of rock mass, and raise a question about what index we should use for support selection at site. Then we tried to reduce tunnel support in the moderate rock mess at 28 sites. We examined the difference in convergences and support stress in order to study the probability of reducing tunnel. support and the effect of it. Judging from this study, it is observed that convergences depend on the ground conditions and the role of support is not to control these displacements, but to prevent falling of rock blocks and loosening of rock mass.

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It is indispensable to use corrosion prevention countermeasures for marine steel structures. In order to evaluate the long term performance of corrosion prevention methods, it is most reliable at this moment to continue the periodical monitoring of corrosion prevention performance of full scale marine steel structures. The authors have been monitoring time-dependent change of corrosion prevention effects of several kind of corrosion prevention methods. From the ten years monitoring, the following results were obtained. (1) Most methods show good performance (2) Protection cover should be enough against wave force (3) Zinc-rich undercoating is necessary for painting system (4) Electro-chemical monitoring methods need to be improved.

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Generally speaking, the secondary lining of NATM has been considered the foundation of the cutting surface. Currently, it is presumed only to operate under low Pressure. However, under special conditions such as a squeezing ground, the primary support cannot control rock deformation. Thus, it becomes necessary to have a method to estimate the durability of the secondary lining as a permanent structure.
By measuring the squeezing ground and conducting a series of experiments related to rock deformation, we were able to establish a method to estimate the load for the secondary lining. This effective method will play a vital role in the design of secondary lining in the future.

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Cut blasting tests were performed in an open pit of a limestone mine. The goals were to confirm earlier experience in blasting parallel hole cuts with emulsion explosives, to obtain the relation between charge concentration and burden, and to obtain basic data for ANFO in rounds with 4m advance.
The goals of the project have been reached; basic data for ANFO in 4m long rounds have been obtained and a design formula for parallel hole cuts which is useful both for ANFO and decoupled emulsion explosives has been found.
Our experience of the requirements for obtaining good breakage in a four-section cut have been listed. In order to obtain a better design basis for parallel hole cuts, the effect of the following factor should be investigated: primarily the corperation of multiple relief holes and decoupling, and to some extent initiation delay and bad drilling.

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This paper proposes a new evaluation system for the condition of rock mass at a tunnel face as follows: 1) the condition of rock mass is evaluated from the strength of rock mass and the condition of ground water and stress, 2) the strength of rock mass is scored by a weighted mean of the rank which corresponds to the rock strength, degree of weathering, and frequency and openness of fractures, 3) the score is adjusted by the rank which corresponds to the ground water inflow and that calculated by the ratio of strength and vertical load of the rock mass. This new system is found to be more effective than the current appraising method for the support determinations.

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The aim of this experimental research is to clarify the effect of longitudinal pitch, lateral pitch and direction of rotation of cutting drum of point attack bit on the impact cutability for mortar, and to find the optimum longitudinal pitch, lateral pitch and direction of rotation of cutting drum that the amount of debris per unit cutting work takes a maximum value. As the result, it was observed that the amount of debris per unit cutting work increases with longitudinal pitch, the optimum lateral pitch exists at the case of shallow cutting depth, and the optimum direction of rotation of cutting drum is the reverse direction of down cut.

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The deteriorations of earth environment have been of keen concern recently. In constructing the infrastructure construction, a system which would make possible of sustainable use of energy, natural resources and environment is strongly demanded. This study seeks for a new design method which would take into account not only economy and reliability of the structures but also energy consumption and environmental loads. To realize such design method, the energy consumption and the environmental effects are measured by the amount of CO₂ emission during the construction. Thus the design become a multiobjective decision making problem which should take into account economy, reliability and CO₂ emission simultaneously. Both Analytic hierarchy process and multi-attribute utility analysis are examined as tools to accomplish this task.

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This experimental study has been projected on the method of the pressure input type permeability test for the reinforced concrete silo. The method of this permeability test at the reinforced concrete silo being cutoff defects was verified as a proper test method on condition that the test temperature and pressure was fixed. In this study, the results of average coefficient of permeability at this reinforced concrete silo being the controling and causing cracks has been confirmed of 10^-10m/s and 10^-11m/s.

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We had developed an expert system for supporting civil engineers who design the details of steel I-or box-girder bridges. This system was blushed up by adding to the function of knowledge acquisition and knowledge sharing. However, the system can deal with only Part21 format with geometric element in the exchange of desirable detail design data.
In this study, the expert system was added to the function that can easily acquire and share desirable detail design data. To standardize design data, an application protocol was proposed for desirable detail design.

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During the construction of tunnels under poor soil conditions, the long-fore-piling method is often employed as an adjunct construction technique to stabilize the tunnel face and to prevent the ground settlement. This paper proposes criteria for designing the geometry of pile section employed by the AGF (All Ground Fasten) method which is one of the long-fore-piling methods. The applicability of the design criteria proposed in this paper is discussed by examinng the measured data from four tunnels constructed by the AGF method.

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The Prestressing technique with external tendons (EPS technique) have been regarded as widely applicable technique to bridge structure systems for both of the new construction and strengthening. It is recently noticed in Japan that the EPS technique is one of efficient methods for strengthening of existing bridges, then several attempts have been done on the strengthening application to not only concrete bridges, but also composite girder bridges. So the necessity of developing a computer aided design system based on CAE concept has been lately pointed out for the design-strengthening works using the EPS technique to existing composite girder bridges. In this paper, a Design-Strengthening Support System for Composite Plate Girder Bridge using the External Prestressing Technique, DSSEPT, newly developed in order to attempt to make rational design-strengthening work processes is described.

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Although various types of segments and segment joints are employed, most segment joints are butt type joints with flat face or tongue and groove. Therefore, the forces in the lining are transferred through contact face at the joint. The force transfer at the contacted surface is very complicated phenomenon and may produce local high stress concentration. The local stress at segment joint of basic types segments such as rectangular or trapezoidal shape under various forces is investigated by photo-elastic method. The results show that smooth stress transfer can be obtained but high stress may develop in local area which should be considered in design.

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On the construction of tunneling method for poor soil conditions, nowadays the long-fore-piling method is generally employed as a auxiliary construction method to secure a stability of tunnel facing and prevent a ground settlement. But the effective mechanism of this method has not been solved yet. This paper describes some considerations on the effects of AGF (All Ground Fasten) method; one of the long-fore-piling method, by refering to construction records, indoor model experimental data and monitoring data in four construction fields.

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The objective of this study is to develop the evaluation method of the slope failure using not only satellite multi-spectral data and geographical data but also secondary generated data for planning highway route in shirasu area.
As for the feature of the erosive area, as a Shirasu plateau, mudflow occurring simultaneously with slope failure brings about disaster frequently. In this study, using the slope stability evaluation map which was made from satellite mulli-spectral data and geographical data, the evaluation procedure making a comparison between the distributions of extracted pixels in the catchment areas calculated from digital terrain model (DTM) was proposed. It was shown that the proposed procedure was very useful for pre-evaluation of highway route in shirasu area.

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This paper deals with the relationship between damages at housing lots by the Hyogoken-Nambu earthquake and various factors. we have instituted stability analysis at representive sites, and have investigated the relationship between horizontal seismic intensity and safety factor. As a result, the cause of damages by the earthquake and the level of horizontal seismic intensity were revealed roughly.

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After the Hyogo-Ken Nanbu Earthquake occurred, the steel bearings underneath the girder bridges came to be substituted with rubber bearings in order to prevent seismic damage to the bridges. However, in this change of design, the concern of vibration increased by response amplitude has been overlooked and, therefore, the new design (with rubber bearings) had to be verified safer for also normal traffic conditions. In the process of analysis, data were collected from three span girder bridges those are equipped with only rubber bearings or steel bearings. In a consequence of analysis, it was revealed that rubber bearings caused not only damping difference but also the difference of vibration mode shapes, which was accountable enough for the phenomena that response from unit sinusoidal load of rubber bearings exceeded that of steel bearings.

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