Numerical strategy of EFGM is presented for the analysis of saturated soil as an elasto-plastic material. First, a formulation is described for soil-water mixture using original Cam-clay model. Interpolating functions are used for the descrption of displacement instead of shape function of usual finite elements within a weak form. Numerical performance of the analyses of soil specimen under drained and undrained condition is then examined by comparing with finite element solutions. Stress path assures the solution with high accuracy in the case where the same arrangement of nodal points is adopted. Less accuracy is found in a different pattern of the nodal points scattering near/at the critical state. Further applicability to practical problems is also pointed out.

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In a large sized paddy field, many farmers adopt the direct sowing method of rice because of low cost. This method demands the highly leveled farmland in precision. However, as a size of field lot increases, load of leveling works strongly increases. Therefore, improved land leveling techniques with high precision are needed in the consolidation of large size paddy field. The authors examined the relation between the shapes of field lot and the load of leveling works. As a result, the following conclusions have been introduced.
In condition with the same paddy field area, load of land leveling works increases strongly as the difference between the long and short side of rectangular lot becomes larger. In order to decrease the load of land leveling, in preliminary works of consolidation, we need to adjust and construct the land level to be the designed value as far as possible, and the tolerance of preliminary works becomes narrow as the lot size increases, and/or the difference of long and short sides of rectangular plot increases. Therefore, the role of management in leveling works is very important in case of the land leveling of longer shape rectangular paddy field with large size.

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Compression characteristics of sludge cake used as a construction material are investigated by one-dimensional compression tests. The sludge cake is dewatering product of dredged sludge from a lake. The specimen was prepared by cutting into granular fragments after remolding and recompression from sludge cake sampled at site in order to investigate compressibility with transformation from granular fragments to a mass. The test results show following different compression characteristics from that of ordinary undisturbed clay.(1) The e-logp curves have two large curvature points and two kinds of compression index.(2) The compression pressure which indicates the large curvature point of e-logp curve for unsubmerged test has linear relation with preconsolidation pressure, and that for submerged test is nearly constant.(3) The compression pressure at the large curvature point for submerged test is smaller than that for unsubmerged test.(4) The first compression index after the first large curvature point has linear relation with initial void ratio, while the second one after the second large curvature point is almost constant.

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It is important to know the behavior of Cd adsorption on clay minerals for the understanding of pollution mechanism in soils. The specific purpose of this study is to understand the pH dependence of Cd adsorption on clay minerals from a microscopic point of view. We investigated Cd adsorption on four different substrates: Montmorillonite (Kunipia-F), Kaolinite, Alumina, and Silica. Although Cd adsorption increased with pH, the degree of increase depended on the substrate species and background solution (NaNO₃) concentrations. We classified Cd adsorption on Montmorillonite into three pH ranges;(i) below pH 4, (ii) pH 4-7, and (iii) over pH 7 and discussed the behavior of Cd adsorption on clay minerals using the concept of ‘surface complex models’.

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This paper describes an attempt of estimating the mass budget of irrigation ponds within a watershed and the possibilities to control the effluent load of nutrients from the watershed located at Kyotanabe area.
In the study watershed, there were two ponds located at the upper and lower sides of a paddy area. The paddy field lots were irrigated by the ponds and several mountain streams. Water could be pumped up to the upper pond from the lower one, when necessary.
At the lower pond, the total amounts of inflow loads including the amounts of sediment release were larger than the total amounts of outflow loads about nitrogen and phosphorus. The rates of the sediment release to the total inflow loads were high. The amount of inflow loads except the sediment release was smaller than the amount of outflow loads for phosphorus. The study result indicates that it is possible to remove the nutrients in the ponds when larger amount of water is pumped up than in only irrigation use. Moreover, the removal capacities of the nutrients could probably increase in the both ponds by controlling the amounts of the sediment releases.

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In the previous paper, an analytical condition to do the prediction of a realistic early age crack in the RC box culvert was examined. However, the examined analytical condition is not verified with two or more structures. In this paper, the analytical condition which had been obtained by the previous paper is reexamined by three RC box culverts where a structural scale, a mixing of concrete, and the placing time were different. As a result, the analytical result of early age crack in three RC box culverts was different from the generative situation of measured crack, though the result of obtaining by previous paper had been applied. This cause is relative humidity used to presume drying shrinkage strain, relative humidity should input not actual relative humidity but an opposite value on the equation to presume drying shrinkage strain in JSCE. In this paper, a new equation to presume drying shrinkage strain using for the early age crack analysis in the concrete structure with long one direction was proposed.

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Odor release from sources of odors was investigated using observed data on rural sewerage facilities with submerged biological filter. It was found that probability distribution of odor concentration from unit devices obeyed logarithmic normal distribution. Hydrogen sulfide occupied majority of odor source material, so that it was one of influence factors of odor concentration. Where one to contact sludge with humic substance was sent back to inflow part, it has been observed that concentrationof odor substance was remarkably decreased and odor index was also decreased greatly. It was guessed that these were the influence factors of odors because the condition such as ORP and temperature were related to generation of hydrogen sulfide gas. The relationship between odor index and hydrogen sulfide was assumed to represent with hyperbola equation. ORP and temperature had a considerable influence on odor index. Consequently, odor index can be estimated condition such as ORP and temperature. In addition, it was suggested that sensor response had agreed with observed odor index by appropriately setting the object of the measurement and range of odor release sources.

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BOD removal performance in aerobic filter tank was investigated using observed data on rural sewerage facilities with submerged biological filters. It was found that BOD removal in aerobic filter tank was influenced by capability to catch suspended solids and deatchment-and-elution of accumulated matter in filters of aerobic filter tank. It was assumed that an aerobic filter tank was represented as completely mixed reactor and BOD reduction was employed with a linear function. The specific surface area of contact filter and dissolved oxygen in aerobic filter tank have influence on BUD removal in aerobic filter tank. BOD removal rate was assumed to depend on influent BOD concentration, hydraulic loading, specific surface area of packing media, and dissolved oxygen in aerobic filter tank The multiple regression equation between BOD removal rate and these four factors can be derived from observed data. The control of sludge accumulation and substrate removal rate in aerated filter tank is effective in maintaining stable BOD removal efficiency.

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Effect of the physical and chemical conditions of the seepage flow on the bacterial nitrification were discussed in order to determine the nitrification within the hyporheric zone in a natural river. Several kinds of liquid medium were supplied into the cylindrical columns filled with the river sand gravel at different velocities, and the characteristics of the nitrifying capacity varying with both the flow velocity and the inorganic nitrogen concentration were clarified in detail.
In batch incubation experiments, more bacterial growth and nitrification were observed in the unidirectional, less turbulent seepage flow condition such as usually seen in the hyporheic zone than in the well-mixed condition generated by the bubble aeration. The nitrified nitrogen within the sand gravel column in unit time was strongly affected by the flow velocity. In the rich nitrogen conditions, the high nitrification was observed which was several times as large as the maximum values estimated by the logarithmic growth model using the corresponding bacterial density. Furthermore, in low concentration conditions, wherelittle bacterial growth was expected by the model, nearly the maximum oxidation, approximately 70% of that, was achieved under the seepage flow speed 3 meters/hour.

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Equations of stresses in a circular and a rectangular elastic bodies subjected to a pair of opposite symmetrical loads were derived by the stress function methods for polar coordinates and Cartesian coordinates. An equation of stress in an overhanging beam subjected to a central concentrated load was also shown. Using these equations, numerical computations were carried out, and the distributions of stresses and strains in those bodies were investigated. Concentrated loads and parabolically distributed loads in a short distance were applied to a circular body and a rectangular body, and effects of difference of loads on the distribution of stresses and strains in the vicinity of the loading parts were examined in detail. The results obtained indicated that tensile stress and tensile strain never arose in the vicinity of distributed load. Strain in the body of plane stress was distinguished from that of plane strain. In addition, equations to estimate the value of Poisson's ratio and Young's modulus from the load-strain relation of the plane stress body and the plane strain body were also presented separately.

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In order to investigate the elastic properties of brittle material, various splitting tests and flexural test of mortal were performed. During the tests, strain was measured by the strain gauge. Flexural tests by central loading were carried out for prism and rectangular plate. Splitting tests were performed for cylinder, disc and beam specimens of prism and rectangular plate. Following results were obtained by tests and considerations based on the theory of elasticity. Straight stress-strain relations in test pieces were obtained at the center of splitting test and the center of lower face of flexural test. In order to evaluate Poisson's ratio and Young's modulus of test piece, it was required to distinguish the plane stress from the plane strain. Tensile strength observed by splitting test was greatly affected by contact width between test piece and loading platen. Reason of such phenomenon was resulted from the difference of the distribution of tensile strain in the vicinity of the loading part. Reason of difference between tensile strength by splitting test and modulus of rupture was interpreted from the maximum strain theory. Tensile strength by splitting test and compressive strength of rectangular block were almost same as those of cylinder.

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The objective of this study was to investigate the erosion mechanism of bottom sediments from a viewpoint of consistency changes in armoring process. Additionally, the outflow of eutrophic components from armored bottom sediments was compared with that from non-armored.
Suspended solids in eroding water of bottom sediments higher than 75 % of sand remarkably increased with the increase in shearing stress. After erosion experiments, water content of bottom sediments higher than 75 % of sand was higher than liquid limit. It became clear that high erodibility appeared when water content of bottom sediments was beyond liquid limit. The eutrophic components outflow of armored bottom sediments was similar to that of nonarmored. It follows that the eutrophic components outflow was not affected by increasing sand percentage of bottom sediments, but affected by the concentration of suspended solids.

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Water quality of canals in villages was measured in order to study the relationship between water quality and multi-purpose water use. Four villages were selected for the subject of study from the Kohoku area, Shiga Prefecture.
Domestic wastewater is diluted with canal water in three villages, where domestic wastewater gets into canals. Water was purified in the other village, where wastewater treatment plant operates.
Questionnaires show that water of canals is mainly used for mad washing, fire prevention and removing snow in every village, but that there were differences in the frequency of water use among villages. Many people also pointed out that the problems of water quality and sanitation is the factor of obstructing water use.
As a result of comparing measured water quality with some standards, water quality of low frequency villages is worse than water quality standards. Therefore, it can be said that water quality has large influence on multi-purpose water use.

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Labyrinth weirs have high discharge performance and high effect as dam spillways, check gates. Though their overflow state often becomes unstable from their thin sectional shape which is inevitable for their zigzag plane shape. This unstable overflow state is generally undesirable for their application to dam spillways, check gates and so on. To avoid or restrain this unstable state on design of labyrinth weirs, we made clear about relations between their shapes and overflow regimes in this study. From the results, it became clear that H/P range of unstable overflow was narrow in shapes of W/P =1.5-2 in spite of change of A/W, L/W (P: Weir height, W: Width of 1 cycle of a labyrinth weir except its elbow, L: Crest length of 1 cycle of a labyrinth weir except its elbow, A: Apex half length of a labyrinth weir).

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This research was carried out to evaluate the effect of ordinary Portland cement (OPC) and fine aggregate replacement with fly ash and cinder ash respectively on mechanical properties of massive concrete. Chemical properties of the fly ash and cinder ash indicated that both materials had analogous chemical composition. The replacement percentages of fly ash were 10, 20 and 30% while that of cinder ash was 10%. The addition of cinder ash lowered the workability of fresh concrete as confirmed from slump test, due to high absorption of water. A high percentage of fly ash replacement decreased the volume of temperature rise during the early age of concrete, as confirmed by measured temperature. Results of pulse velocity method indicated that a higher percentage of fly ash replacement enhances strength development than the lower percentage. Moreover, fly ash could promote the relation between inner and outer parts of massive concrete through a steady improvement in strength. The increment in the development of mechanical properties had a direct relation with the dosage of fly ash. Test results of extracted surface and central cores show that a 30 % dosage of fly ash had a significant effect on the mechanical properties of massive concrete due to ultrasonic pulse velocity and compressive strength.

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Overflow division facilities are most often used in pipeline irrigation systems for paddy fields in Japan. Division structures have been designed and constructed individually because of different values for input discharge, division ratio, and output discharge. A new tower division structure using twin cylindrical pipes has been invented to reduce construction costs. Water flowing into a central pipe underground overflows from the pipe and empties into a doughnut-shaped secondary tank. Discharge is divided with several partitions and flows out through pipes.
Two division devices have been tested with hydraulic experiment to determine whether they can adequately divide discharge. One device allows water to overflow uniformly from around the edge of the central pipe and divides discharge by the length of the arc. The other device allows the water to overflow water from several weirs at the top of the central pipe and divides discharge by the weir widths. Adequate water division will be performed if a suitable combination of input and central pipes is selected and the top end of the centeral pipe is accurately adjusted in a horizontal direction.

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The transitions of soil physics caused by several kinds of chemical fertilizers and two kinds of crops in the continuous yearly use test field of the three major nutrients of chemical fertilizers were researched by a Hasegawa type soil penetration tester, paying attention to the hardness of the soil layers. The test crops are soybean and corn.
The hardness of the soil layers is shown commonly by the degree of softness in the case of a Hasegawa type soil penetration tester, but the writers indicated the necessary number of knocks (drops of a heavy plumb) to he penetrated at every ten centimeters depth of soil layer.
The number of knocks needed to penetrate soil layer from field surface to one meter depth, and at intervals of each ten centimeters of unit depth in the vertical direction of soil layer was examined by a statistical analysis.
As a result of these examinations, significant differences by several kinds of chemical fertilizers were not recognized within the same crop test fields, hut were recognized between different crop test fields. It means that the differences of soil layer hardness are induced by the two different crops.

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Frequent occurrence of subsurface pollution caused by leakage or dumping of toxic chemicals has led rapid progress in researches on mass transport in subsurface. In this paper, recent advances in the theories on multiphase flow of water, non-aqueous phase liquids, and air through porous media are comprehensively reviewed. The relation between capillary pressures and fluid saturations is first reviewed, followed by the relation between relative permeabilities and fluid saturations. Governing equations of the multi-phase flow are finally derived using these functional relations together with equations of state.

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