To get a rational executive method of ridge construction, that is, the most important problem in land consolidation of sloped paddy field, we made various experiments and investigations comparing A-method (the usual method) with B-method (the elaborate method) and examined the results obtained.In consequence, the following points were clarified.
1) To learn the most suitable banking layer thickness for ridge construction, we made a compaction test by the operation of bulldozer in various banking layer thicknesses (20, 30, 40, 60cm).As a result, we found that the compaction of 3-5 times by the bulldozer in about 30cm banking layer thickness is most rational, and in this case the control of moisture ratio is important.
2) According to the mean value, the standard deviation and the coefficient of change between moisture ratio and density after the ridge construction obtained by the A and B-methods, the B-method gives smaller change than A-method.Therefore, it may be thought that the more uniform ridge is constructed by the B-method.
3) Cone index was larger in the B-method than in the A-method, and showed a uniform value in depth.In consequence, we found a very uniform consolidation in the B-method.
4) As a result of investigation of the section after the ridge construction, it was found that large spaces are scattered in the case of A-method as shown in Photograph-1, that these spaces are the cause of ridge destruction and that the section is uniformly consolidated in the case of B-method as shown in Photograph-2.
5) As to the quantity of percolation water after the ridge construction obtained by the A and B-methods, it was found that the coefficient of percolation water is larger by the order of about 2.0 in the A-method, than in the B-met hod and that, from the result of the distribution of pressure obtained by a tensiometer, the B-method is superior to the A-method.

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Because the relationship between sand which is a basic material of a river bed and water which causes a tractive force involves a number of factors that are intricately interwoven, it is highly difficult to assess with reasonable accurracy the mechanism and actual mode of a movement of a river bed, or to determine a tractive sediment load which constitutes a basic element of such movement.
In view of this, an attempt was made by the author to analyze the aforesaid mechanism and mode by processing stochastically and statistically the intensive data which were obtained by means of an experiment using a simulation models. The experiment was intended to enable the basic nature of the foregoing phenomenon to be analized by finding out the latent properties which so far remain undiscovered.
The experiment was made by detecting sand movement with a strain gauge buried in sand which forms the bed of a water channel and by analysing auto-covariance funtion and power spectrum. Through such an analysis, the relationship between the variation of frequency characteristic and the hydraulic quantity which causes such variation were studied.
It, however, should be noted that the power spectrum thus observed indicates a relative quantity within a given range of experimental analysis and, therefore, should not be expected to serve satisfactorily the purpose of comparing the quanties in different ranges of analysis.
The auto-covariance function at lag time 0 is equal to the value obtained by integrating the power spectrum density function throughout a full range of the analysis. In other words, the aforesaid function is equal to the squared average of the fluctuation value in the same range of analysis. It follows from this that the characteristics in one range of analyse can be compared with those in another range if the power of each fuquency is divided by a squared average of the fluctuation value for the corresponding range of analysis.
The power spectrum density observed during the movement of water channel bed was characterized by a fact that extraordinarily predominant power having a linear spectrum form was generated almost always at a certain specific frequency. From the fact that such a predominant power took place at a certain specific frequency irrespective of the complicated fluctuation of hydraulic conditions in a high frequency range, it was assumed that the foregoing phenomenon was attributable to some cause which was irrelevant to the movement of fundamental nature. In a medium frequency range, the power was observed to change corresponding to the hydraulic quantity which also changed in a complicated manner. Investigation of the relationship between the power of the predominant frequency and the hydraulic quantity in this frequency range indicated that the Froude number was related to the non-dimensional quantity of the tractive force by an exponential function. In future study, the author intends to take up and analyse in detail prablems relating to response functions.

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This paper describes the application of finite element method to the steady state confined and uncofined flow problems in porous media.
In the unconfined flow analysis, in particular, the detailed method of estimating the free surface and its exit point was shown.
Furthermore, the effective stress distribution due to seepage flow in an earth dam was calculated by means of the finite element method.
From this calculation, we found that the compressive principal stress due to seepage flow reaches about fifty percent of the stress due to the earth dam's own weight near the downstream face of the dam.

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In this paper the response behavior of an earth dam under seismic action is considered, using the results which have been obtained in a previous paper, Part. 1. Two types of the dam, one of which is the dam on the rigid base, and the other is on the soft foundation, are analyzed and compared from many points of view.
It becomes clear that under various types of vibration, these two types of earth dam behave differently in the response displacement and stress. The relation between the statistical parameters of applied accelerograms and the response quantities is shown.
The effects on the stress distribution caused by the dynamic force from view point of limitting equilibrium are investigated, and the dynamic seismic coefficients are given.

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The placing order of concrete blocks composing the body of a concrete dam is a fundamental matter to obtain an optimal construction planning of a dam. It is believed to be useful to apply the techniques of PERT to find the optimal construction planning for comlex works in general, but the order of construction is beyond the techniques.
In this first report a study was made, therefore, on the effectiveness of applying the techniques of PERT/MANPOWER for scheduling and of the DP process for ordering the dam concrete placing on the assumption that the plant capacity for concrete placing was given.
The order of concrete placement adopted here is as follows;
1) a block of which the date of placing is assigned,
2) a block promising the priority if its constraint conditions are satisfied,
3) a block remaining the longest construction period up to completion of the work,
4) a block located at the lower zone.
Here, the remaining construction period of the i-th block is defined as the sum of periods required for placing the i-th block and for placing the sequential blocks following the block, and the period is computed by the technique of backward DP.
The proposed method was applied to an actual dam construction work, and the usefulness of this method was examined. Various interesting problems were also pointed out by comparing the computed schedule and the actual process.

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Expression of estimation for soil thrust of crawler type vehicle with uniform contact pressure may be used to calculate soil thrust for wheel type vehicle as an approximate expression. Soil thrust calculated by expression of soil thrust taking the trajectory of wheel into consideration shows the considerable difference comparing with soil thrust obtained by the expression of soil thrust for wheel type vehicle. This reason remains unknown. Further efforts will be made to obtain more precise soil thrust.

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Experimental investigation was done concering wind pressure on two houses of she same type adjacent to each other.
The object of this paper is to obtain the characteristics of the wind pressure distribution by the change of the interval index r (r=l/h; l is the distance between the walls facing each other and h is the height of the house) and the direction of the wind (at 0°and 45°).
The houses were of gabled roof type (with inclination of roof at 10°, 20° and 30°) and of round shaped roof type (with semicircular and semielliptical roof).
From the results of investigation the following conclusions were obtained:
(1) It is on the walls and roofs faced to each other that the distribution of wind pressure is most affected by the change of r.
(2) In case that r is smaller than 2, the mean wind pressures coefficient on the walls faced to each other show a same tendency when the wind direction is 0° and a different tendency when it is 45° for both gabled roof houses and round shaped roof houses.
(3) In cases that r is smaller and larger than 2, the relation between r and the mean wind pressure distribution is different.
(4) In case that r is more than 5, a tendency was observed that the wind pressure on the house of the upstream side is not affected by the house of the downstream side.

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We made two-dimensional experiments on the dispersion of dumped sand from a 1/20 model of a hopper-barge of 850m³ in capacity, using the sand picked up from the sea-bottom far off the coast of kannonii in Kagawa Prefecture as the material.
(1) The dumped sand sank into water as a mass accompanying a sinking flow, so that, as was reported by Ogawa and Takeuchi, it is thought to be an example of the sinking of Froude similitude. The sand was dumped down from the model hopper-barge which was in the state of floating.
(2) A non-dimensional equation represents an empirical formula that expresses the functional relation between the rate of cumulative deposition of the dumped sand (P₀) and the dispersion distance (X), and in so doing we have compared the height of deposit obtained by computation with the experimental value.
(3) When a pair of riprap works were laid at the position where the rate of cumulative deposition (P₀) ≅0.6, and when the sand was dumped down it deposited between the said riprap works such that P₀≅0.8.
The dispersion speed of sandy water was remarkably retarded at the position where the riprap works were laid.
(4) The sand which had fallen and piled up already at the bottom gave nearly the same distribution of soil particles as that remaining in the hopper-barge, for the dispersion distance up to about one and half times deeper than that of dumping. When the dispersion distance was over that depth, size of sand at the battom became smaller than the dumped sand.
(5) As for the experiment (3), it was carried out by use of fine river sand as well as sea-botton sand, but as for the rest, all the results of experiments were obtained by using as the material only the sand picked up from the sea-bottom far off the coast of Kannoji.

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