In this paper the elastic and plastic state of stress in the ground around a circular shaft is studied by the means of Mises' condition of yielding.
At the first an approximate solution is found as a problem of plane strain under the assumption of the incompressibility of the ground material for the cases that a shaft has a lining or not. Next another solution is found under the condition of yielding that the vertical stress distributed uniformly at the same depth from a horizontal surface is taken into. Then the results of the both solutions are compared.

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This paper reports the result of the vibration tests on Tsukabaru Gravity Dam (height 78m, crest length 215m, ungrouted key joints) and its consideration.
The vibration was given by an exciter having about 12 tons max. capacity whith was installed at one point in the gallery. And the vibration propagated into the whole structure through the ungrouted key joints, but a large phase lag in horizontal direction and some slip between neighbouring two blocks were obserbed.
From the result of this test, it will be reasonable to consider the gravity dam joint ungrouted as a three dimensional structure from the dynamical or statical point of view.
Accordingly we proposed an engineering method of eartquake-proof design for a gravitydam, considering cantilever and twist elements in it.
But for the simplicity, the phase lag and slip were not considered, and it will be necessary to observe the motion of the several points in the dam during natural earthquakes to know the rationality of this simplification.

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The skew network difference equations for the differential equation of the deflection surface of the orthotropic parallelogram plate (κ=H/(B_x⋅B_y)^1/2<1) supported simply at the opposite two skew sides and supported by flexible girders at the other two sides were induced for the general interior point, interior point near simple support, interior point near top edge, general edge point, interior point and edge point near sharp and blunt corner. As an example of the use of the above difference equations, the influence coefficients of the deflection and bending moment of the orthotropic parallelogram plate (B_x/B_y=36, a/b=1, κ=1 and 0) with various angle of skew were calculated and the influence of the angle of skew on the deflection and bending moment was researched.

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The diffusion and dilution of liquid wastes, continuously disposed into a stream from an outfall at one side, as shown in Fig. 1, were analized theoretically and investigated experimentally. Concerning the dilution effect, the relationship between hydraulic elements of the amounts and rates of the stream flow and waste flow was clarified and a method, estimating the change of dilution ratio or distribution of concentration of the wastes along the flow direction in the down-stream, was proposed.

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In this paper, the author makes some considerations for water erosion of land surface mainly, based on the data observed for applications of the contour trench method on the hillside in our country. He supposes the phenomenon of water erosion is developed by the tractive force of rain water flow including the effect of rain drops. Some experiments for the law of resistance to thin sheet flow on the land surfaces are attempted to present the rate of water erosion in dimensionless form. By the above treatment, an experimental formula for the rate of water erosion is proposed, and, moreover, some considerations on the soil detachment and the transportation by rain water flow are made on the basis of the results.

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In Isikari-gawa basin, many trees were blown down by the strong typhoon which passed by Hokkaido in 1954. Computing the unit-hydrographs (Fig. 3) by means of the method of least square (associated linear equations (5)), the author concluded that the runoff in 1956 (after the disaster) is uniformly larger than in 1952. Data of rainfall and water-level were obtained at So-unkyo and Simo-Aibetu respectively in July, August and September (Fig. 1). Fig. 2 (correlograms of rainfall) and Table 1 (r: average daily rainfall, σ: standard deviation of rainfall, f: percentage of the number of days in which it rained more than 10mm, r_m : maximum daily rainfall, and h: average water-level) show that hydrological conditions in these three years were not different each other.

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In this paper, a method by which the rainfall characteristics were analysed by considering the topographic effects upon the precipitation was applied to the upper basin of the Yura River, and using its results, the average depth of precipitation over the basin was estimated rationally. Furthermore, a rational method to compute the average hourly depth of precipitation over the basin was proposed and compared with the one which has been applied in the past. The author is hoping that these results would contribute much to the analysis of runoff phenomena.

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This is a report of theoretical and experimental researches on the settlement and bearing capacity of the friction pile driven into a soft clay. In this paper, the authors indicate that the behaviour of friction pile can be solved with the theory deduced from the Theological stand-point, from which a new formula concerning the settlement of friction pile is derived. This formula well agrees with the results of laboratory and full-scale tests. Furthermore, a new measuring method of allowable bearing capacity of the friction pile is proposed and the increase in bearing capacity with time is investigated.

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Experiments on water-hammer phenomena have been carried out. Comparisons between theoretical and observed water-hammer waves are shown. The effect of restricted orifice surge tank for the case of rapid closure of gate has especially been studied, and also comparisons between theory and experiments are shown, which demonstrate a considerably fair agreement. Adiagram for estimating the effect of the restricted orifice surge tank is presented.

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As one of the research projects of clear formulation in hydraulic characteristics of transitional behaviours from subcritical to supercritical or vice versa, this paper deals with the hydraulic behaviours of boundary characteristics in shape, roughness and bed slope to channel transitions and controls in divergent or convergent channel.
The open channel flow in divergent or convergent channel is changed in its flow regimes by the existence of singular points of water surface profile equation based on the one-dimensional procedure in gradually varied flows, and therefore the theoretical approach in analysis of transitional flows will be established by the application of the theory of singualr point in ordinary differential equation and the topological method in non-linear mechanics.
The classification of singular points and hydraulic significance of transitional characteristics of flows passing through the singular point, and especially from a standpoint of practical application, those for the Chézy and Manning flows are presented.
The present procedure of analysis is applied not only to the flow in divergent or convergent channel but also to the flow with side in- or outflow and similar problems in hydraulics of open channel flows.
Finally, the application of the analysis described here to the discharge measurement of open channel flows is briefly discussed.

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In consideration of the recent development of road traffic and the existing state of roads in our country, there are many problems yet to be solved on the concrete pavement. Especially, it is required to rationalize the technique of concrete road construction, above all the design and construction of pavement slabs, the structure and construction of subgrades, the use of mechanical methods of construction, the management of construction, quality control of materials, and others.
For this purpose, about the concrete pavement the author has surveied the state of cracks, the causes of defects, the conditions of drilled cores, the state and construction of subgrades, and the practices of its construction, also, the author has introduced many interesting conclusions and guides to the technique of design and construction of concrete roads, as a result of this survey.

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The paper states some elastic behaviours of spiral rope specially manufactured for suspension bridges.
Furthermore, the authors have developed the theoretical formulae concerning elastic deformation of spiral rope, compared the computed values with the experimental results, and given a reasonable hint for pretension works.

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