The estimate equation of the coefficient of earth pressure at rest, K₀-value, in normal consolidating process, what we call Jaky equation is very famous. Also in overconsolidating process the estimate equation for K₀-valueshave been proposed by Schmidt and Mayne. In these estimate equation parameter of α and m_r. are calculated with a internal friction angle φ', the same with Jáky equation.
In this study, authors reconsidered whether or not the estimations to be effective, and tried to derive a way to decide parameter of α and m_r without using φ'.
The result of K₀ consolidation tests show that these K₀-value equations are effective. Parameter a was derived using K₀-values in normal consolidating process and plastic index, parameter m_r was derived using K₀-values in normal consolidating and swelling process and maximum overconsolidating ratio. And authors confirmed both parameter were effective.

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This paper presented the progressive failure and scale effect in the retaining wall problem on passive mode by comparing experimental investigation and finite element analysis. The experiments were conducted with air-dried Toyoura sand in plane strain condition where the wall was moved horizontally in sand. The heights of sand mass (h) in these experiments were 5 cm, 10 cm and 15 cm. The finite element analysis employed a constitutive model in which a non-associated strain hardening-softening elasto-plastic model was employed and the shear band thickness was introduced as a characteristic length in the constitutive equation. Finite element analysis simulated the experiment well. The results indicated that the scale effect was not clearly seen up to h=15 cm, but there was clear evidence of the scale effect for h over 15 cm. In the case of evaluating the scale effect using a parameter of h/d₅₀ (d₅₀; mean grain diameter), the scale effect was evident for h/d₅₀ over 1000.

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Effects of excessive-water stress on corn root and its nitrogen content were investigated in environmentally controlled growth chambers. Two excessive water treatments (surface-submerged at 3-cm depth and water table at 15-cm beneath the soilsurface) each with four excessive-water stress levels (equivalent to 90, 180, 270 and 360 cm-days of stress as defined by SEW₃₀concept) were imposed 23 days after plant emergence in the crop establishment stage. Data on root distribution, root length, root dry matter and root nitrogen content were compared for the both water table positions. Corn roots were significantly larger when water table was maintained at the 15-cm depth than when the surface wasubmerged at all excessive-water stress levels. Excessive-water stress resulted in higher nitrogen content (%) in root dry matter but smaller root nitrogen per plant for surface-submerged treatment compared with 15-cm water tabletreatment. The overall results of the study conclude that lowering the water table position from the surface submergence to beneath the soil surface may be a useful practice to avoid significant loss of crop in poorly drained soils.

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In this paper, the results of the consolidation deformation analyses, which were carried out to clear the behavior of the foundation ground during/after the construction of the embankment in the right bank of New Shiroishi sluiceway, were described. These analyses were based on the infinitesimal and finite deformation theories. From comparing the results obtained by the analyses with the results of the field observation, it was cleared that the settlement obtained by finite deformation analysis, in which the coefficient of permeability k ten times greater than k obtained by standard consolidation tests was used, on condition that there was the inundation on the surface was well coincident with the observed one. And then, finite deformation analyses, in which the reduction of the total head in the aquifers (i.e. sand layers) was taken into consideration, were carried out. As a result, the settlement obtained by the analysis using the variation pattern of the total head, which was similar to the variation pattern of the ground water level at Saga prefecture's subsidence observational well nearest new Shiroishi sluiceway and whose maximum reduction value of the total head was 4m, was well coincident with the observed one.

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In this paper, the occurrence spheres of various pipe flows with one steep slope are shown experimentally as regards ventilation and non-ventilation, as well as being investigated by using the boundary of full pipe flows to the indexes. The results are as follows.
First, it is indicated that H_o/D=1. 5 (H_o: depth in front of the pipe inlet, D: diameter of pipe) of non-ventilation remain on the boundary between full pipe flow and the flow in case a mass of air exists, and the relationships between pressure head in air mass and H_o/D are indicated. Next, it is indicated that full pipe flows and other flow patterns can be divided by hydraulic equations. Then in occurrence spheres of flows when air mass existed, its characteristics and occurrence sphere expression of hydraulic moving jump are given as information.

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The purpose of this paper is to evaluate environmental benefits of a rural landscape preservation policy implemented by the Town of Yufuin, Oita Prefecture. Two methods were employed for evaluation; first, the double-bounded dichotomous choice method, and second, the payment card method. We evaluated the residents' willingness to pay (WTP) for the rural landscape at as much as 8, 758 yen a year by the double-bounded dichotomous choice survey and 5, 284 yen a year by the payment card survey. Total willingness to pay can be obtained by aggregating individual WTPs. The estimated total WTP was about 13-22 times as much as the cost shared by the Town of Yufuin to preserve the rural landscape. We showed that a starting point bias could be caused by the double-bounded dichotomous choice method. As for the payment card method, we employed the tobit model to take minus WTPs into account.

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Coupled flow-deformation behaviors of unsaturated porous media (soils) are analyzed by a newly proposed three-phasenumerical model. The proposed model constitutes a new (effective) stress expression, derived by the modern porousmedia theory, to model the deformation behavior and the generalized Darcy's law, ideal gas law, concept ofcapillarypressure and relative permeability to model the flow behavior of fluid phases. Due to the complexities to solve thecoupled field equations of the proposed model by analytically, numerical methods (finite element method and generalizedtrapezoidal method) are employed and research computer code is implemented. To validate the proposed model, hypothetical analyses of the fully coupled consolidation of loaded vertical soil column problem is performed and finally, applicability and limitation of the proposed model is demonstrated by a simulation of a flexible footing resting on a threephasesoil foundation problem.

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Elastic analysis for a semi-infinite homogeneous base is the well known Boussinesq's equation. Research on a homogeneous elastic body with a rigid base and multi-layered elastic body has also been carried out. There exists much research on an axial symmetric multi-layered body, which is used as pavement analysis. However, there is little research on a two-dimensional multi-layered body. The objective of this paper was to come up with analytical solutions for a two-dimensional multi-layered elastic body with or without a rigid base. Using a stress function different from the Airy one, two analytical solutions were shown in this paper. One of these is for a semi-infinite body and the other is for a body constrained in a finite region. Solutions are applicable to both plane strain and plane stress, and are also applicable to both a rough and smooth interface and rigid base. In addition, the finite element method for a multi-layered elastic body with a smooth interface was shown, and the results were compared with the analytical results.

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In water amenity parks, it is not always unclouded how parks are utilized. The parks should be arranged and constructed in consideration with the users opinions and demands in order to bring it maximum utilization. In this paper, facts of angler's opinions and demands on fishing grounds of reservoirs are studied by a questionnaire survey and a case study of the most populer crucian carp fishing in Yamagata Prefecture.From this study, anglers opinions and demands are categrized in five groups, and fishing spots are categorized in three types. Suitable arrangement of fishing spots should be planned based on the three different types.

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In the past, surveys on bottom snowmelt have been conducted relatively often. However, since it is not easy to distinguish between bottom snowmelt and that caused by other factors, long-term surveys or studies have been limited to certain severely cold areas. And it has been very difficult to estimate how the bottom snowmelt affects river runoff. In the meantime, there have been few surveys on bottom snowmelt in forestland, a predominant part of most mountainous basins.
By applying a heat balance-based calculation method of bottom snowmelt at an open site and a deciduous forest site for a snow-covered period, changes in daily bottom snowmelt were estimated, thereby clarifying the different amounts of bottom snowmelt at the two sites. Furthermore, a snowfall simulation was conducted, evaluating how snow depth affects bottom snowmelt. The simulated result qualitatively matched the surveyed one.

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The water quality environment from autumn until early spring with small discharge were discussed in a natural river estuary, Nakasuji River, Japan. Eutrophication processes and longitudinal distributions of inorganic nutrient salts during drought season were observed in detail, and the characteristics of the considerable phytoplankton blooming was clarified. The spatially averaged dissolved inorganic nitrogen concentration in winter becomes four times as large as that in summer in the lower reach of the river owing to the lack of convection effect of river flow. The typical longitudinal distribution of inorganicnitrogen is established; the concentration peak appears at the upstream limit of the sea water intrusion throughout a year and the concentration gradually decreases to the river mouth. The spatial profiles are strongly affected by the mixing and dilution of tidally generated alternating river flow.
The phytoplankton (dinoflagellate) blooming is observed only in winter season. It is formed between the river mouth and the high nutrient salt concentration area. The long term variation of colored water distribution correspondsto the river discharge, and the short term, diurnal variation is strongly affected by the flow conditions governed by the tidal motion. Colored water becomes most conspicuous from the flood stage until the high tide stage while it disappears in the ebb. The convergence and divergence of water body due to tidal motion and the vertical migration of the phytoplankton cells are the primal factors of the short term variation. The phytoplankton blooming in the river is maintained because the growth rate of plankton exceeds the river flow convection and because the inorganic nutrients supporting the plankton growth are continuously supplied from surrounding areas.

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An irrigation dam is considered to show flood mitigation function that reduces the peak flow of flood with its storage function in the course of being utilized as water source for irrigation. Consequently, we investigate the actual conditions of inflow and discharge during floods in the Ohsako Dam and clarify that peak discharge decreases as against peak inflow and that there are some cases of floods where peak discharge does not decrease very much. Further, we analyze discharge as against inflow concerning flood mitigation function of dam by using hydraulics and make it clear that flood mitigation function is created by cutting flood with storage capacity or temporary storage above spillway crest.

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A packed bed type contactor of biological activated carbon was installed to improve performance of submerged biofilter process (SBP). The packed bed type contactor was submerged into the aerobic tank. Performance of a mesh vinyl chloride contactor was also tested to estimate the effect of using the packed bed type contactor. The experiments were carried out under high DO (more than 3.5 mg/L) and low DO (less than 1.5 mg/L) conditions. Rates of nitrification, denitrification and BOD removal were increased by replacing the mesh contactor with the packed bed type contactor. In particular, the effect of using the packed bed type contactor was large under the high DO condition. The reason of the increase of reaction rates could be due to the increase of specific activities of attached growth. The activities of bacteria being attached to the activated carbon was about three times of that to the mesh contactor. In addition, problem with clogging of the packed bed was not observed during the experiment. These results indicate that improvement of performance of the SBP by using the packed bed type contactor of biological activated carbon is possible.

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