The slope failure prediction model using sattelite multi-spectral data and digital geographical information has been proposed. It can be used for the prediction of dangerous zone by Quantification method and mini-max method. In this paper, effectiveness for the prediction of “slope failure” and “landslide” is discussed. The summary of the results is as shown below.
1) This model is able to predict two types of slope failure phenomena, i. e. “slope failure” and “landslide”.
2) From the results of analysis by Quantification method type II and type III, there is evidently difference of degree of effect for endgeous factors between “slope failure” and “landslide”.

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The gravel drain system aims to avert liquefaction by quickly dissipating excess pore pressure. Since construction of gravel drains produces no serious vibration and noise, it is suitable to sites in urban areas and adjacent to existing structures. We have developed a compaction-rod type machine. One of the important characteristics of this machine is the compaction effect of the surrounding ground. To take advantage of the compaction effect, we undertook full scale model tests and verification field tests in which the increase in the strength of the surrounding ground was tested. In this paper, the compaction effect of the surrounding soil imparted by a specially designed compaction rod is shown by the test results.

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Various laboratory tests have been performed to investigate the strength, bearing capacity and deformation characteristics of fly ash and the application of the improvement of roadbed using fly ash for railway track causing mud-pumping. In addition, numerical calculations used the results of tests were performed to compare the effect of the improvement of roadbed using fly ash with that of the sand blanketing measures. It was found that fly ash has enough durability against repeated load and seepage water and that the calculated coefficients of subgrade reaction increase as the elapsed day. The improvement of roadbed using fly ash is useful for taking preventive measures against mud-pumping.

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In this study, ground characteristic curves describing the relation between support pressure and ground displacement were obtained from borehole unload model experiment, and optimum design of a tunnel where requirements of both safety and economy in tunnel construction are compatible was examined on the basis of these curves. Following conclusions were obtained.
(1) Back analysis is useful to the estimation of physical properties of specimens.
(2) Minimum excavation limit is more useful as an aim of optimum design of a tunnel rathar than minimum support pressure. (Excavation limit is defined by the sum of designed inner section, linning thickness and ground displacement.)
(3) In some cases, limit strain defined by ratio of unconfined compressive strength and elastic modulus is smaller than elastic limit. It may be applied to design and construction control in consideration of ground strength ratio and geology.

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In urban and suburban areas, engineers are often faced with noise and vibration complaints, caused by rock blasting. In these cases the loose blasting technique is often used. In loose blasting, a small-scale charge is used to blast the rock mass into the fractured mass, which can be excavated by ripping and bulldozing equipment. In this study, it is shown through experiments that the overall economy of the excavation method using loose blasting is determined by the number of boulders produced in the process. Large boulders result in the loss of output of ripping, bulldozing and loading equipment. The rock fragmentation mechanism in loose blasting and the technique to reduce the number of boulders and discussed.

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The natural periods of vibration of the electric poles ranges from about 1.0 to 2.0 seconds, which is controlled by types of poles, electric devices mounted on the pole, and the supporting ground conditions. Earthquake motions cotaining the same range of frequency components are likely to occur at the Tokyo alluvial plain.
The authors have deviced the aseismic criteria of such structures based on the experimental simulation of typical damages, folding of pole, collapse or slant, and drop of mounted transformer.
It was confirmed analytically that electric poles would sustain without damages the earthquake input motion of 200 gals in peak accelerations..

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In recent years, maintenance and management of civil engineerings tructures and their systematization have been of importance because of rutted asphalt pavement roads and early inferiority of concrete structures. This study sets up a Maintenance Management theory, and proposes a Maintenance Management System. The Maintenance Management System constitutes; (1) Inspection System, (2) Maintenance System, (3) Data Base System for management of road data, (4) Geographical Information System, and these three subsystems expect Inspection System are constructed. The efficiency of the proposed systems is demonstrated by verifications of systems.

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Construction works should be automated and rationalized in order to decrease the pain of workers and to increase the safety of works. In this paper, fuzzy control was applied to the action of bulldozer blade. This paper is a basic research for making up automated bulldozing system. The effects of some kinds of control conditions including diffuzification methods and the number of labels etc. were investigated with use of simulation anlysis and model tests. As the results, it was made clear that the correct choice of the control condition, especially in considering ground condition, improved bulldozing efficiency.

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Construction of underground wall with 2.2m thickness and 75.5m depth for 1A Anchorage of Akashi-Kaikyo Bridge was finished in September 1990. The wall was placed with the slurry trench method, in which powerful slurry trench excavating machines named Super Hydrofraise 10000' and Electro Mill 320 had been used since March 1990. The foundation of 1A anchorage is cylindrical, shape with 85m outerdiameter and 64.5m depth. The wall having a circumference length 267 meter consists of in 46 panels which are divided into two types: 8.9m long panels and 3.2m ones. The former (preceeding panels) are bowed-shape, and the latter (following panels) are straight shape excavated between adjacent two preceeding panels, whose excavation was associated with cutting the concrete of the preceeding panels in order to assure continuity and watertightness of the wall. This paper describes various simulations and final design based on the construction process, and also it deals with construction process of the underground wall.

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Recently a considerable number of cable-based brides such as suspension bridges and cable-stayed bridges have been constructed, and several cases of bridge damage and repair or replacement of cables have been reported. Cables are the most important members in cable-based bridges; their further investigation, therefore, is deemed to be necessary for the future development of the bridges. Presented in this paper are the subjects and the future prospects of the cables of cable-based bridges. Firstly the changes and the trends on the main cables of suspension bridges are stated, secondly those on the stay cables of cable-stayed bridges. Thirdly on both types of bridges, the instances of cable damage, the strength of corroded wires, the inspection methods of cables, and the point of cable maintenance are mentioned. Furthermore the significance and the possibility of new cables are discussed as future prospects: rust-free cables, stronger cables and lighter cables.

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Underground electric power and heat supply pipelines have been constructed in the central urban area of Utsunomiya in connection with the project of a new substation and local heat supply service by Tokyo Electric Power Company. NATM was partially adopted for the excavation method accounting for the influence on environments and economical factors.
The length of 91.19m was excavated through the soft rock by a partial face machine. The cavern could be completed including the section with the small curvature and various cross sectional shapes. The open shafts excavated for the vertical manholes were jointed with the tunnnel previously excavated.
Additional monitoring was carried out grasping the influence on the surrounding ground and observing the tunnel behavior.

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The determination of the type of bridge-foundations which is most suitable to the condition of soil has important effect not only for the total cost of construction, but the term of the construction works, and also for insuring the safety at field excurtion.
In HOKKAIDO, the lowlands belong to the big rivers are characterized with the silty, peaty and water contented clay. These grounds are spread over this island everywhere. In this paper we deseribed the typical bridge-foundations that we developed or improved on these grounds. (1) Radically obliquely combined steel piles-foundation: Analysis and field experimentation. (2) Open caison: Sinking execurtion works with-out any weights. (3) Open caison enclosed with joined steel pipe piles: Analysis and laboratory model test. (4) Open caison enclosed with field executes, extremely deep concrete wall: Analysis and excurtion.

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Malti-spectral data has been mainly processed by a general purpose computer. But it takes higher cost to process multi-spectral data and in general users can't easely operate. For that reason, we developed the system processing and analyzing multi-spectral data with a personal computer. there are many processing and analyzing functions in this system. And by introducing a menu system to the composition of this system, very complicated operation of image processing and analyzing has become very simple. Furthermore, we succeeded in a big reduction of processing time which has been the biggest problem of image processing and analyzing system with a personal computer. As a result, everyone has been able to process multi-spectral data simply at a high speed with a cheap system configulation.

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A new steel pipe pile foundation is developed, to which soil-cement mixture method is applied. The characteristics are as follows.
1) The foundations have high bearing capacity, i. e., the end bearing capacity is greater than that of cast-in-place concrete piles and the frictional resistance is greater than that of bored piles.
2) Smaller amount of waste soil arises, compared with cast-in-place concrete piles and bored precast piles.
3) As to economy of pile material, the strength of steel pipe is nearly equal to the bearing capacity of ground in the foundations, whereas the strength is higher than the bearing capacity in usual pile foundations.

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The method of marking based upon quantification analysis, which is of practical use, is developed and employed to estimate the possibility of rockfalls in rock slopes. The applicability is examined by comparing with field observations. As a result, it is shown that the method produces satisfactory judgement so far as the slopes, which should be discriminated between safe and dangerous, have the same geological features as have been used for the preparation of a criterion.

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