A study was made to investigate the effects of cation species and salt concentrations on the liquid limit and the sediment volume of marine sediment and paddy soil samples. For the paddy soil sample containing smectite as the main mineral, the liquid limit of the sample equibrated with 0.01N NaCl was higher than that of the sample equibrated with 0. 01 N CaCl₂ and decreased with an increasing NaCl concentration. These tendencies were almost the same as those of montmorillonite and were interpreted by intracrystalline swelling. The liquid limit of the marine sediment sample, in spite of the fact that it contained smectite as the main mineral, exhibited a tendency which is inverse to that of montmorillonite and similar to that of illite. These trends for the marine sediment samples were interpreted by particle arrangement like illite. The sediment volume of the marine sediment samples which contained smectite as the main mineral decreased with a decreasing NaCl concentration under the flocculated condition, and this trend was more remarkable when the pH value was higher.

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The purpose of this paper is to analyze theoretically and experimentally the initial motion of negative surge caused by the opening or closing of a gate.
Assuming that the downstream side of the gate is free of water, four types of generating? conditions of negative surges are studied in case of a horizontal channel with a nonviscous flow:
Type A, a sudden full opening of a gate;
Type B, a sudden partial opening of a gate;
Type C, slow opening of a gate and
Type D, a sudden full opening of a gate at the top of a weir.
In the case of Type A, where the so-called Dam Break Wave is produced, Rittter has already obtained the theoretical solution.
But a further analysis is made here for the purpose of comparing it with other types of negative surges.
For Type B, formula (16) is obtained.
ΔH=0.84D…(16)
where ΔH is the height of the surge and D is the degree of opening of a gate.
For Type C, the shape of the water surface and the velocity distribution of the surge can be expressed by formulas (29) and (31), which are considered to involve Ritter's solution.
For Type D, z/H is found to play a most significant role in forming the flow state after the negative surge passes the weir, where z is the height of the weir and H is the initial depth of the water.

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This study proposes an evaluation method for readjustment of the farm road network system to promote better field management. The fundamental idea for this method is to introduce the total amount of field working hours indispensable for farm management into theevaluation of the roads and traffic planning.
In this paper, a model system of farm roads connecting several hamlets and apple orchards is created to simulate a real one.
The evaluation of road usability for farming is ranked in order of the total amount of working time.
The method could also be applied to the field for multi-cultural farming. The total usability (ΔS) of a road (j) during ten days (k) by a farmer (i) is calculated using the following equation:
ΔS_ijk=Σ_ikA_ij·T_ijk
where, Aii is the acreage of a farmer (i) leading to the road (j), and Tiik is the working hours per unit area carried out in a field during a period (k) of 10 days by a farmer (i) through road (j).
The results are shown in Table 2 indicate where the busiest road is located and when the road network will be used efficiently for farm management throughout a period of a year.
And these are summarized as follows.
(1) The evaluation of road usability for farm productivity could be better carried out by the total amount of working hours than traffic numbers.
(2) A feasible solution for the multi-cultural management combined with paddy fields could be calculated by this method.
(3) The planning amount of traffic for agricultural management could be predicted by a convertible coefficient of working hours to traffic number.
(4) The method of evaluation could be extended to the estimation of the investment effect to the improvement of the farming road network system.

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Recent developments in the numerical analysis methods have been better applied to the estimation of the dynamic behavior of large-scale soil structures. There is much difficulty, however, in these analyses where inelastic behavior and the structural failure develop in the soil structure. With respect to these problems, the importance of model experiments has recently been recognized for the purpose of examining numerical methods and for recognizing the physical phase of structural failure.It thus appeared to be more important that the knowledge obtained from the model experiments should be introduced into the numerical analysis procedure.
First, in this paper, the results of the model experiment of a fill-type dam shown in the previous paper are compared with those obtained from the numerical analysis, and then, the different feature in the response amplification of the acceleration is found especially near the slope of the embankment between the numerical method and the model experiment.
First, to consider the important effect of the dynamic moduli, that is, the shear modulus and damping ratio, on the amplification behavior second, those moduli in the model embankment are identified from the response acceleration records, assuming the model to be a single degree of freedom hysteretic system. And it is shown that the dynamic moduli and those dependence characteristics on the shear strain occurring in the model are so different between the parts of the center and the slope of the embankment.

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The author denoted the formula of elasto-plastic consolidation analysis and the method for analysis using a finite element, and expressed the equations which could explain both the elastic consolidation settlement and plastic failure. And by the development of a concrete computer program and its execution, the author clarified the characteristics of two-dimensional consolidation problems in the plane strain condition. Especially, it became clear that depending on the difference of the load's increasing rate, the failure load of the ground, the dissipation of the pore water pressure and the increase in stress tended to vary remarkably, and this fact was thought to be important in the practical execution of works.

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In a series of studies, the seepage failure problem of a piece-wise homogeneous sand column caused by a vertically ascending seepage flow was considered. In this paper, pased on the previous papers, the relation between the residual effective stress and the stability of a sand column at a critical time is discussed.
The residual effective stress is referred to as the effective stress at a critical time. h_c is then referred to as the critical difference in total hydraulic head between the topmost position and the bottom position of a sand column. It is considered that the residual effective stress within a sand column relates to the stability of the sand, column at a critical time: The larger the residual effective stress within the sand column grows, the higher the stability of the sand column becomes. The stability of a sand column consists of the following:
(1) Resistance (stability) to the movement of sand particles;
(2) Resistance (stability) to the rising (heaving) of a sand column;
(3) Resistance (stability) to external forces (horizontal and vertical shear forces).
Thus, the seepage failure problem should be discussed from the standpoint of not only the hc value but also the residual effective stress (i. e., the internal effective stress).
A loaded filter is also considered from the standpoint of a two-layer case. Consider that the submerged unit weight of the upper layer is equal to that of the lower layer and the thickness of the upper layer is smaller than that of the lower layer. And when the coefficient of permeability of the upper layer is about twenty times larger than that of the lower layer, then assuming the upper layer to be a loaded filter doesn't have much of an error from the standpoint of the residual effective, stress and the discharge rate per unit cross section at a critical time (see Table 1).

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In this papaer, at first, the empirical equations for predicting the dry density, achieved by 8 passes with full-sized rollers, were derived from the data of the compaction tests carried out with small-sized smooth steel-wheeled rollers and small-sized pneumatic tyre-type rollers, under the condition of various diameters, weights and a given width.
We showed that the increment of dry density achieved by 8 passes could be expressed by the exponential function of the factor W/B²Dγd₀ indicating the compaction capacity of the rollers, coefficients. a₁, a₂ in those equations by the linear function of the ratio (w/wopt) of the moisture content to the optimum moisture content for compaction and other coefficients b₁, b₂ by the palabola function of the, ratio.
Secondly, the relation between experimental coefficients aγ, bγ, which were derived in the equation relating to the number of passes and the rolled-dry density, and the ratio (w/wopt) were considered as follows.
The products of coefficient aγ by initial dry density γ_d0 was expressed by the hyperbolic function of the ratio, while _bγ, γ_d0 were the result of the palabola function of the ratio.

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This paper describes a mathematical analysis of pore pressure distribution in cylindrical soil specimens under the triaxial compression test. The basic equation is derived from expressing approximately the specimen deformations shown in Fig. 1 by means of a cosine function with considering “soil” as a two-phase material consisting of a solid skeleton and pore fluid. Stresses and deformations in specimens are given by equations 22, 23, 24 and 50; pore pressure distribution is given by equation 51. Constants of mechanical properties of soil being used in the analysis ΔG, Δν and Δφ₀ involving pore pressure are given by equations 56, 57 and 58. Figs. 5, 6 and 7 present distributive characteristics of the pore pressure in the specimens. The analysis indicates that the pore pressures in the central portion of specimens are lower than those of end platens of the specimens by nearly 60% under the triaxial compression test with changing the confining pressure in four steps. The deformation modulus and Poisson's ratio do not vary remarkably in both cases of reckoning with or without the pore pressure.(Refer to Figs. 8 and 9)

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This paper describes tensile stress relaxation of concrete and its application.
First, the long-term stress relaxation properties at an early age were mainly examined in one stress level and in a mix proportion.
The results were as follows.
(i) The test results have some random nature and differ from the short-term results by Kiyama-Nishibayashi et al.
(ii) The best experimental equation is Nishibayashi-Kiyama's which has physical meanings.
(iii) The mean 1/2 relaxation times A are 4-9 hours for water curing test pieces and 3-6 hours for air curing.
(iv) The final relaxation coefficients C' are under about 70%, but scatter due to the loaded ages.
(v) The influence due to the loaded ages is not apparent in A and C'.
Secondly, a thermal stress analysis were carried out, in which the previous results ware applied. From the results, it is recognized that tensile stress relaxation is important.

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To investigate the collapse behavior of an elasto-plastic soil mass, finite deformation analyses based on the Lagrangian frame of reference are carried out using finite element methods with reduced integration techniques.
Drucker-Prager criterion with the associated and non-associated flow rule are applied for flexible strip footings and the results are compared with those obtained from infinitesimaldeformation analyses. The load-displacement relations by the finite deformation analyses show larger displacements than those of infinitesimal deformation case. Furthermore, a finite element solution approach for a ‘implicit’ rate type constitutive model for soil proposed by Davis et al. is presented. Appropriate linearized relations are used for iterative schemes to delete the residual forces due to nonlinearity. This approach is essentially a variable stiffness method together with a modified Newton-Raphson procedure.

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