In the earth work for agricultural land reformation in paddy fields in Japan, cutting volume per area is small in comparison with usual works of soil engineering. The earth work for the preparation of farm land comprises leveling and border making besides cutting and banking of soil. In land adjustment, land cutting is shallow and wide, therfore the efficiency of the earth work with bulldozers is not same as that when soil is carried from a point to another point. The mean distance of carrying the soil is not so simple that a single value is not expected. In this study the efficiency of bulldozers in the earth work in paddy fields was measured, and the results are as follows.
A feature of the earth work with bulldozers in such work is that the time for leveling amounts to more than 40-50% of total time. It is expected that the combination work of two bulldozers improves the efficiency as compared with that done by the single. In case of usual leveling accuracy (±5 cm), small bulldozers are suitable for land cutting, because many times of side edge cutting must be done in terrace work, on the other hand large bulldozers engage in carrying soil and leveling land. The combination work of bulldozers for aiming at the improvement of efficiency is much useful for the earth work of grading paddy fields.

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In the present paper, we shall propose a technique for simulating the wind-driven current which may be the most dominant flow in a freshening reservoir. The governing partial differential equations representing the two dimensional reservoir circulation are transformed into the corresponding normarized equations by using L, D and f which denote the typical horizontal dimension, the maximum depth and the Coriolis factor respectively. Then we may obtain the dimensionless parameter R₀=gD/(fL) ² which indicates the magnitude of non-linearity of the flow field.
In order to simplify the computer program and to improve the accuracy of time-integration, the dimensionless partial differential equations with three independent variables are reduced to the ordinary differential equations. The resulting equations are solved without tedious procedures through the calling of the ready-made program which may be stored in a computer for solving the ordinary differential equations numerically.
The investigations of both the computational accuracy and stability are made through a sample run of the program.
Eventually, we find that this computer algorithm can positively be put to the practical use.

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Since final closure of land reclamation works is an opening to be constructed at final stage of banking works, the flow caused by tide becomes to have high velocity at final closure with advance in banking works of other portion than itself. It is of important for making plan of safe and easy execution of final closure banking works to know hydraulics, especially velocity and direction of flow caused by tide and affected by progress of the works of other portion, at neighbourhood of final closure being planned to be constructed. Numerical studies were done with finite difference scheme of Navier-Stokes equations for viscous incompressible fluid flow to estimate flows caused by tide at Kasaoka bay where land reclamation works having been carried out. Results of the studies are illustrated by two dimensional velocity vector plots in order to indicate flow patterns at the basin with respect to progress of banking works other than final closure.

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How large must be the capacity of a set of concrete mixing plants is the fundamental problem in designing an optimal construction planning for a concrete dam, because the change of the set is almost impossible after the concrete placing work begins. This paper deals with the method for finding the optimal set of concrete mixing plants composed of mixing and conveyance equipments by the case study on the Uchinokura Dam.
The method adopted here consists of the following steps.
1) The hypothetical sets of concrete mixing plants are selected.
2) The construction period for every set is examined by applying the author's method for finding the optimal concrete placing process, under a given working condition.
3) The effect of unworkable rainy days and holidays on the construction period is investigated
4) The cost analysis is performed for finding an economical plant capacity.
5) The optimal set of the plants is decided after examining of time to spare for miscellaneous conveyance.
As the result of applying this method to the Uchinokura Dam, it was pointed out that the actual plant capacity was near to but slightly larger than the optimal one, and that the actual concrete placing process was too hasty in the early stages of the construction work.

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Although the two-dimensional distribution of sand has been investigated in detail by geologists and the optical method for clay has recently been proposed, the correlation between the above two methods is an important problem when we consider the soil structure.
Introducing the normal distribution function for the optical method, the relation between the ratio of min. and max. intensities of transmitted ligt (β) and the variable k of the function which is the measure of concentration of the model distribution is 1≤β≤0 for 0≤k≤∞ and by taking the vector strength (a), another relation is obtained by 0≤a≤1 for 0≤k≤∞. Within the limit of a few measurements, both models on the equiareal polar paper agree well if each grain size under the microscope is taken as a unity. This relation is based on the assumption that the arrangement of grains is that along the long axis, the direction of the long axis coincides with the vibration direction of light in the grain, and the measurement must be done with identical number of grains.

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The creep of compacted soils is influenced greatly by the change in its moisture content at compaction.
The creep velocity dε_c/d log t increases with creep stress when the moisture content is on the dry side of optimum moisture content wopt; but dε_c/d log t of cohesive soils shows constant value independent of creep stress on the wet side of wopt. Thus, the relation between dε_c/d log t and moisture content is influenced by soil properties. In the case of sandy soils, dε_c/d log t is increased with moisture content, but dε_c/d log t of cohesive soils does not always increase with moisture content.
The creep strain is increased with moisture content and the change in creep strain with moisture content is greatest at the optimum moisture content.
Further, the relation among creep strain ε_c, creep stress σ_dc and time t has been obtained experimentally.

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The author investigated the mechanical properties of bituminous mixtures for use in irrigation structures using an Instron-type testing apparatus.
The followings were concluded, as far as these experiments were concerned.
(1) The stress-strain curves depend principally on the temperature and on the strain rate. At low temperatures or at high strain rates, these stress-strain curves are expressed approximately by straight lines. At high temperatures or at low strain rates, the influence of the viscosity becomes predominant and the stress-strain relationship deviates from a linear manner to a considerable degree.
(2) Characteristics of bending, compressive and tensile strength differ from one another. Especially the bending strength shows a peak at a certain temperature. The temperature which corresponds to this peak is shifted with the change in the deformation rate.
(3) The stiffness varies in a straight line on a logarithmic scale chart and this straight line moves parallel, with the change in strain rate.
(4) The temperature and the strain rate are closely related as far as the strength and the stiffness are concerned. For example, the increase in strain rate gives as an effect similar to that the decrease in temperature gives; in other words, this material shows a thermo-rheologic simplicity.
(5) The deflection or strain produced by rupture varies considerably with the temperature. At low temperatures with high strength, the deflectrion or the strain decreases, while increases at high temperatures with low strength. Thus, there is a somewhat complemental relationship between the strength and the deflection.
(6) With increasing quantity of the filler, the strength of the mixture is increased and the mechanical properties become less sensitive to temperature.

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