Laboratory model tests for ultimate bearing capacity of rough rectangular surface footings in dense sand are presented. These tests were conducted to study the variation of the ultimate soil bearing capacity when a rigid rough base is located at a shallow depth from the bottom of the footings. The length-to-width ratios of the footings used for the model tests varied from one to six. The deducted experimental values of the modified bearing factor, N_γ', and shape factor, λ_s', have been compared with theoretical values proposed by Mandel and Salencon (1972) and Meyerhof (1974), respectively. The experimental modified shape factor, λ_s', compared reasonably well with the approximate relation given by Meyerhof. When the rough rigid base is located at a very small depth, i.e., H/B less than about 0.6, grain crushing takes place at around the ultimate load and also the deduced N_γ' is lower than that predicted by the theory based on the internal angle of friction of soil determined from standard triaxial tests.

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The purpose of the study is to find out the factors relating to the permeability of the decomposed granite soil with special consideration on the physical properties of soil particles. Specific surface area was taken first for a criterion of the degree of weathering and was determined by means of Nitrogen adsorption test. The relationship between specific surface area and free energy level of soil water was examined in detail.The permeability test was also carried out on the soil specimens to find the influence of the physical properties on permeability.In conclusion, fundamental properties of soil particles have a close connection with specific surface area by Nitrogen adsorption, which gives a strong effect on water retertion capacity of the soil mass. Soil water with pF value higher than 3.3 is assumed to be firmly held within or around the soil particles and is not involved in permeation of water. Coefficient of permeability can be examined in detail by such parameters as void ratio, specific gravity, apparent specific gravity and medium grain size.

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Many kinds of pipelines are buried underground in a city and the earthquake often brings the damage to these pipelines. The purpose of the present study is to propose the decision method of the optimum kind of pipe (i.e. the optimum material of pipe) against the earthquake damage by using the reliability theory. This paper firstly describes the actual conditions of the earthquake damage of pipelines and the results of the factorial analysis in relation to the type and state of the ground and the materials of pipes forming a pipeline. As a result, it is shown that the earthquake damage of pipelines is strongly influenced by N-value of a surface layer up to 5 m in depth and the kind of pipe. Secondly the probability of failure of pipelines are calculated by using the past data of the actual damage and the decision method of the optimum kind of pipe is discussed with many numerical examples. The numerical study gives the results which agree with the common-sense presumption.

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Comprehensive tests on a clean sand were performed to evaluate the effects of the methods of sample preparations on shear moduli and hysteretic damping ratios of sands with use of a resonant-column apparatus and a static torsional shear device. All of the tests were conducted under the fully drained condition. Specimens for resonant-column tests were solid cylindrical and those for torsional shear tests were hollow cylindrical. These specimens were sheared torsionally and cyclically. It was found that for a wide range of shear strain the shear modulus and the hysteretic damping ratio of the sand tested by cyclic drained shear tests are quite insensitive to the methods of sample preparations adopted in this investigation. These include the different methods of pouring, compacting, moistening, saturating, unsaturating or so.

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The approximate solution of unsteady groundwater flow toward a partially penetrating well in an anisotropic confined aquifer is described and a method for analyzing field data with a partially penetrating well in an anisotropic confined aquifer is given.A distinction of this method is that anisotropic coefficients of permeability can be easily determined by using graphical techniques. An application of this method is illustrated by analyzing data from groundwater basins in Okayama City in Japan.

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A three-dimensional isotropic stress-dilatancy model is proposed. The model is formed on the basis of the basic hypothesis that the shear deformation of granular materials results mainly from the sliding between grains. The model is also based on such a new concept relating to shear mechanism that the position of sliding contacts is closely related to the applied stresses and accordingly shifts in turn as shearing proceeds. The general stress-strain increment relations obtained from the model contain the influence of stress path in a general form. It is verified that the stress-dilatancy equations derived from the model agree weel with the experimental results under the conventional and true triaxial stress conditions.

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The main purpose herein is to present a method of the identification and classification of pyroclastic flow deposits distributed in southern Kyushu, Japan, from the viewpoint of soil engineering. Since the deposits have a hardness ranging from soft soil to hard rock, their hardness can be used as a criterion of the identification and classification for engineering purpose. It is proposed that the hardness is given by the index hardness of matrix of the deposits and is measured by applying Yamanaka's soil hardness tester. Here the author investigated the hardness at 145 locations in southern Kyushu and classified the deposits into five distinct groups as soft decomposed Shirasu, decomposed Shirasu, proper Shirasu and welded tuff. The propriety of proposed method is ascertained statistically by X²-, F- and t-tests. The correlations between hardness, dry density and water content are also obtained. Finally a chart of the identification and classification of pyroclastic flow deposits is establiched on the basis of the relationship between hardness and dry density.

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