With the modernization of agriculture, the improvement of heavy clayey soils with high water content have become an important problem to be solved. Now, however, it is considered that these heavy clayey soils which give inferior conditions to eathworks, cultivation and plant growth are hard to be improved especially in reclaimed lands.
From this point of view, the author and his co-workers have investigated the improvement of these soils by the use of a soil conditioner.
This is a summary of the investigation for improvement of the physical properties of these soils by the use of a new synthetic soil conditioner (EB).
The synthetic soil conditioner (EB) used has the following two characteristics;(1) a cation polyelectrolyte and (2) a water-soluble high polymer.
The materials used were (1) Kamigamo Clay (from the Forestry Experimental Station of Kyoto University) (2) Reclaimed Land Clay (from Hachiro-gata Reclaimed Land, Ak: ta Prefecture).
The experimental results are as follows;
(1) The flocculation of clay particles by a caion polyelectrolyte may probably be due to an ionic bond between the negative charge of the clay surface and the cation polymer, and it can form a water stable aggregation with the cross-link format: on (bridge action).
(2) The interaction between clay particles and EB are dependent not only on the rate of EB to the weight of dry clay, but also on the rate of dilution of EB added. Therefore the sedimentation volume of the samples is dependent on the rate of EB to clay, and also on the rate of dilution of EB added.
(3) Owing to forming a water stable aggregation, the permeability of the samples are increased more than 100 fold, and the water holding capacity is increased.
(4) The air drying treatment after adding EB promotes aggregation, which may be expected after addition of even a little amount of EB.
(5) The flocculation of clay particles causes a change in the rheological properties of soils, i. e. both the liquid limit and the plastic limit are remarkably increased.
(6) The maximum dry density by compaction test may be decreased due to the addition of EB, but the optimum water content is a higher value than the untreated soils. And the unconfined compression strength has a maximum peak at a higher water content. These results are extremely important to earthworks concerning these heavy clayey soils with high water content, especially at reclaimed land.
(7) The sample with polymer added may be strong against slaking. And these samples nre remcrkably stable againt water erosion.
(8) The optimum quant: ty of EB added is in the range of 8-10%, but this value can vary according to soil samples and initial mo: sture conditions. In the case of air drying treatment, it was found that adding EB of 3-4% of the soil by weight was very effective to improve soils.
Thus, from the results of these experimental investigations, it can be concluded that this new synthetic soil conditioner, EB, is one of the best soil conditioners for improvement of heavy clayey soils with high water content.
And we hope that used EB can contribute to an epock-making change in the improvement and the conservation of these soils.

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Recently Dr. Kerr pointed out that the Pasternak Foundation is a mechanical model for the so-called “generalized” foundation. He also showed that the problems of a finite beam or plate resting on this type of foundation which had been believed nonsolvable by Wieghardt and Pflantz are solvable for any load distribution permissible in classical plate theory.
In this paper, the authors deal with the further developement of practical application of the Pasternak Foundation. Here, the treatment is limited on the beam problems resting on this type of foundation. It is demonstrated that these problems are effectively treated by the slope deflection equation method.
The results obtained are as follows.
1) The slope deflection equation for beams on the Pasternak Foundation is deduced.
2) It is shown that in the stress analysis by the slope deflection equation method, the condition of continuity of the shear layer which is required at the end point of the beam as the characteristic of the Pasternak Foundation can be taken into account not at the item of boundary conditions but at the equilibrium epuation of the shearing force.
3) If the relation._??_is held among the coefficients of the foundation, the basic solution of the beams on the Pasternak Foundation is identical with that on the Winkler Foundation. Thus under this condition, the slope deflection equation for beams on the Winkler Foundation which had already been deduced by the authors is applicable and the effect of the existing shear layer on beam stresses is given by the concentrated force _??_working at the end point of this beam.

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The auther represented previously the forms of separation layer occurring at the angular upstream end of broad-crested weirs.
This report shows that these forms are used to design the rounded inlet (rounded upstream end) of the weirs.
First, it explains the method of designing rounded inlets corresponding with the separation layer.
Next, it examines the efficiency of the rounded inlets by the experiments such as observation of occurrunce of eddies, or measurements of discharge coefficient, water surface, pressure distribution and velocity distribution, etc.
It seems that the foundation for the practical use of the rounded inlet corresponding with the separation layer was given by this report.

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It had been believed that the valley for an arch dam should be narrow and the side walls of the canyon should be rigid enough for the efficiency of the arch dam.
However, recent investigations indicate that the construction of arch dams in a wide valley is feasible. And we have 5everal reports showing that arch dams have been built successfully on deformable rock foundations.
But we have also learned from these reports that if we require to develop the principal advantage of on arch dam fully in such cases, a peculiar design of structural and geometrical feature of the darn should be chosen by taking the shape and the geological feature of the valley into account.
The authors have studied the design of the Osako arch darn projected to be constructed in a wide valley, by laboratry model tests. It is generally known that the arch dam stability in a wide valley mainly depends on the cantilever action and that applicatian of a horizontal joint is one of the effective works to decrease this action.
In this paper the authors investigate the effect of a horizontal joint on the stress distribution and its influence on the ultimate strength of the Osako arch darn.
The abstract of results obtained is as follows.
(1) Arch action is satisfactorily developed along the lower arch element by inserting the horizontal joint at EL. 338m.
(2) The maximum compressive stress on the intrados side would be at the abutment region of the middle height of the dam. This region coincide with the discontinuous part of the elastic property of the foundation rock. But it is observed that the maximum compressive stress region is lowered in height by inserting the horizontal joint. This is preferable for the stability of the both darn and foundation.
(3) Although the value of safety factor (K) of the dam with horizontal joint is slightly decreased compared with that without horizontal joint, we can conclude through the whole tests that the ultimate strenght of the Osako arch dam which has horizontal joint is large enough.

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1) This study was carried out in order to examine the characteristics of forms and limitation of reclamation of a citrus orchard on slope land.
2) Three forms of reclamation of orchards investigated were as follows: I. horizontal terraced field. II. sloped terraced field with a wide oblique section. III. sloped field.
Items of the reclamation for these forms were an original sloping angle of 8°-30°, sloping face of a terraced field of 45°-80°and sloping face of a sloped field of 45°-55°. From these conditions, the author extracted the generalization of the data.
3) To clarify the characteristics of the forms of reclamation, the author investigated the following factors: precentage of reclamation of fields, the function of field surfaces and limiting factors of excution, excution by a bulldozer, quantity of soil originated in excution, and ecology and methods of management of a citrus orchard. The author examined the suitability for citrus management on each item.
4) From the view-point of characteristics of the forms of reclamation on slope land, the sloped field ranked as the best, which was followed by the sloped terraced field with a wide oblique section, and the horizontal terraced field showed many problems.
5) The limiting angle of reclamation of orchards on slope land was 20° at the horizontal terraced field and the sloped terraced field with a wide oblique section, and the sloped field showed from 20° to 25° in the original slope.
6) From the characteristics of forms of reclamation, the above mentioned items are the limit of reclamation. But hereinafter, for the modernized citrus orchard, rational land utilization, reasonable planning of arrangement of equipment, planning of settlements of accounts, etc, must be discussed and brought into practice.

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