[in Japanese]

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[in Japanese]

View full abstract

[in Japanese]

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[in Japanese]

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[in Japanese]

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In case of water power development in Japan, so far, the aerial.photogrammetry has scarecely been applied but to make the topographical maps for planning. We, authors, thought that aerial photography should be utilized not only for the purpose above said but also for many other purposes generally in water power development. Then we introduced a new technique called “Photogeology” and have carried out the investigations and studies, by the techniques, on each area in the basin of the River Kurobe, for the development plan.
It seems that photogeology has never been applied really to civil enginneering in Japan. Therefore, in performing this research we had to resolve the elementary problems at first. And we have carried on the application in a way of “try and test”.
In this paper, we show a research on the Omachi tunnel area above all as an instance.
An unexpected fault fracture zone caused a paralysis of the tunneling work through several months and enormous loss. This paper deals with how that fault fracture zone on aerial photographs appears and how the aerial photography in planning such tuneling works should be utilized in the future.

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As a means of the beam bridge design, hitherto, has been adopted two-dimensional calculation method ; hence, main beams, floor systems and floor slabs were calculated separately. With the recent progress and development of steel highway bridge constructions and the generalization of stress measurings, it is insufficient to treat in customary means the beam bridge design, and the necessity of three-dimensional consideration has been recognized. Inasmuch as main beams of box girder bridges have especially considerable width, it is evidently inadequate to treat them as an assemblage of rods. Accordingly, in this paper, the deformation and stress of a simply supported box girder bridge with steel plate floor were three dimensionally analyzed and its approximate solution was proposed, the reliability of which was confirmed by model experiment. Further the cooperation of the floor slab in the load distribution was considered.

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Succeeding to the author's previous report on the estimation method of the probable rainfall-intensity-formula based on the Logarithmic Normal distributions, another estimation method to which the Extreme Limiting Theory is applied is proposed in the first part of this paper. Moreover, an eatimation method by the “Specific Coefficient” is further proposed, which can be determined by rainfall charactristics of a short duration time in Japan, with considerations of the type of rainfall-intensity curves. For any types of the curves, and various formulas in the past can be reduced to merely one generalized form by this method, which gives the simpler estimation of the curve with higher accuracy than the former methods. It is also an advantage of this method that it can be applicable, even if the rainfall records cannot be obtained for each duration of rainfall over a long period as in the case of local cities.

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This is a report of theoretical and experimental researches on the stress relaxation of clay which play an important role in the phenomena of earth pressure. The assumption of a special model of clay is sufficient to express a stress relaxation which proceeds linearly with the logarithm of time and after a certain duration the stress relaxes to a final value. In the new type rheometer, the constant deformation is given to clay specimen and the relaxation of the internal stress is measured. Further, the thermal effect on stress relaxation of clay is discussed. Main results obtained here are as follows

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Of the different types of analysing the stability of earth slopes the most convenient is known as the Swedish method, in which the circular slide surface can be commonly used. The socalled ψ = 0-analysis, based on the result of undrained shear tests, such as in situ vane tests or unconfined compression tests in the laboratory, is not appropriate for estimating the long-term stability, though it might give a correct result under fortunate conditions, when the stability of slopes just after a construction operation is treated.
This paper concerns with some important problems involved in another analysing method, called as c, ψ-analysis, in which the shear strength of soils is expressed in terms of effective stress. The stability analysis is applied to a slide occurred along a small river in the Norwegian quick clay. Combining the results of borings, samplings, in situ tests and pore pressure measurements in the field, together with those of laboratory tests, it is concluded that the composed slide surface should be used, in stead of simple circular surface. As the cause of the slide it is assumed that considerably large amount of excess pore pressure in the clay layer might contribute to the occurrence of the slide.

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