To investigate a most suitable grouser shape to obtain a maximum optimum effective driving and braking force, the tractive and braking performances of a 40kN rubber tracked tractor carrying up and down the asphalt pavement road of various slope angles have been analysed. As a result, it is clarified that the most suitable shape of rubber grouser is equilateral trapezoid type of contact length 5cm and the effective tractive effort and the effective braking force decrease with the increment of slope angle, and the normal contact pressure tends to increase toward the rear part of track belt for larger slope angle at driving state and vice versa at braking state.

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Control point surveys by the conventional method entail an enormous amount of work and time, since it is necessary to cut down trees from a national control station which may be dozens of kilometers away. This study discusses an easy, highly precise method of control-point surveying based on the GPS (Global Positioning System). Through series of experiments, many of the problems which were hampering this new method have been solved, including major concerns such as the position of the artificial satellite, the survey time, and the baseline analysis method.
This unique new surveying system is now fully established and has proved effective in actual surveys. Succesful results have been obtained at three tunnel construction sites, where a precision of more than 1/1000000 was achieved.

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In this study, a new system for earthwork progress measurements by using the Global Positioning System (GPS) has been developed. The GPS is an innovative satellite surveying system under development by the US Department of Defense. This paper describes the developments of a device able to control the antenna automatically and a computer program developed for the transformation of coordinates obtained by GPS surveying to the ordinary plane coordinates.
In order to verify the practical applicability of the system developed in this study, a case study was conducted, and it can be concluded that the system is useful and effective for practical earthwork progress measurements.

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Ground characteristic curve for the relationship between load on tunnel support (supporting load) and ground displacement has been ofen used to evaluate the appropriatenesss and rationality of tunnel support. Though the curve is regarded as usuful, however, few studies have been made so far as how to obtain it.
In this study, attension has been given to the fact that loading and unloading occur simultaneously during borehole loading tests, showing stress paths similar to those during tunnel excavation. Model experiments, which simulate tunnel excavation and borehole loading test, were conducted, and the usefulness of borehole loading test in determining ground characteristic curve was considered. As a result, it has been confirmed that unloadingcurve obtainable from borehole loading test can be regarded as ground characteristic curve if it is modified so that displacement becomes zero when inner pressure is equal to initial ground pressure.

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Experimental design techniques have been used at the design of supports under tunnel construction with NATM in hard rock mountains. Unfortunately, the selection of standard support pattern mainly depends on engineers' subjective judgments and the evaluation of its propriety seems to be insufficient. In this study, a new equation for the support pattern selection is proposed. The propriety of conventional support design is discussed based on the equivalent moduli which are statistically derived from BEM solutions using measured displacements in 19 tunnels. The equivalent moduli are classified into each support pattern, and coefficients of regression curves were estimated to predict moduli and final displacements for the other tunnels. Furthermore, a successive experimental design technique based on ordinary experimental technique is proposed using the above mentioned equations.

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This paper shows the actual conditions of long-term settlement of highway embankment which has been observed for 25 to 28 years and also gives considerations to these.
The terminal stage of primary consolidation of thick marine clay and the secondary consolidation of that were investigated. The reason why the settlement converges a little late in terminal stage of primary consolidation was considered that the coefficient of consolidation changes (decreases) in consolidation process. The secondary consolidation was considered as a little as it practically can be ignored.
The fact finding for long-term observation indicates the management method through settlement velocity is effective. The estimating method of residual settlement is proposed and the practical use of that is referred to.

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For the underwater bedrock excavation of large bridge piers, divers or the rotary shaping machine mounted on the SEP has been carried out to achieve the high accuracy. In case of excavation for the 3P pier of the Akashi Kaikyo Bridge, high accuracy and rapid work, was required under the severe marine conditions of great depth of water and fast tidal current, using only a large scale grab dredger.
This study intends to realization of the high accuracy and rapid work of the underwater bedrock excavation and the result of this study was proved at the 3P pier of the Akashi Kaikyo Bridge.

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These days, there are increasing needs for the underground docking technologies of the shield tunnels because of the difficulty in securing the land for the shafts.
The technical problems for the underground docking are how to dock without affecting natural ground around the shield machines and how to obtain the high water cut-off performance at the joint section.
Conventional underground docking has been commonly performed with the methods in hardening ground.
This paper discusses about the new method called Mechanical Shield Docking (MSD) method in which two shield machines facing each other directly and mechanically dock without any auxiliary work methods.

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To cope with the sulfide problems such as corrosion of concrete and malodor in the force main, ferric chloride was added to the well in the relay pump station. Although sludge is formed and settles when ferric chloride is dosed to the sewage, it is re-suspended as long as the sewage flows.
Therefore, it is judged that the fluidity of sludge does not change with the elapse of time. The decrease in pH of the sewage is not so large as to make any effect on the sewage treatment.

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This paper describes about the elastic buckling loads dependent on equivalent section properties and its application in practical structures. Those properties are obtained by applying trigonometric series to displacement of beams with changed cross sections simply supported at both ends and subjected to uniformly distributed loads, and by integrating divsionally three differential equations. By introducing equivalent slenderness ratio in relation to centrally compression columns, we suggest that the selection of construction methods should be determined by ultimate lateral buckling loads on the basis of ultimate strength curves including initial imperfections. Then, the above method is adopted to the selection of construction method for the slab concrete, of a simply supported composite I beam bridge with two steel main girders, whose ratio of the span to the distance between girders is about 20.

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