When a load is applied to piles, a stress distribution corresponding to that load occurs in the soil. In order to study the characteristics of this stress distribution, some model pile tests are carried out on sand. The results of these experiments are compared with the values based on the theory of elasticity.Equivalent depth of application of load is defined as the theoretical location of the load P which, by the theory of elasticity, gives the same stress distribution under the pile as does an actually loaded pile.In group pile tests, the concentration of stresses under the tip of a pile and the application of the law of superposition of stresses to the stress distribution by piles in sand are studied.

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Functional relationships are developed for the load-deflection characteristics of a rigid, vertical pole, embedded in sand and subjected to an applied couple. The study is based on non-dimensional techniques and the physical variables included in the theoretical analysis are the ground-line deflection, depth of embedment, geometry of the pole cross-section, applied couple, time of loading, and soil parameters. The soil parameters used include the density, angle of internal friction, flow characteristics, and relative density of the sand. Non-dimensional techniques in conjunction with small scale model studies are used to determine the explicit form of the interrelationship among the above physical variables for a pole embedded in a very dense, uniform, fine, dune sand of constant properties and subjected to an applied couple. Hyper-bolic prediction equations are given from which the load-deflection characteristics of a prototype pole might be estimated. A failure criterion in the form of a stability number relating the ultimate applied couple to the geometry of the pole-soil system is given and correlated with the failure criterion of the same pole-soil system subjected to a horizontal ground-line thrust. Several illustrative examples are worked.

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A direct shear apparatus for determining the rheological properties of clay soil in simple shear is described. Tests on a remolded Kaolin show that the distribution of strain within the specimen is nearly uniform. The apparatus will be applicable to compacted or undisturbed cohesive soils.

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The secondary compression of undisturbed saturated clay has been attacked triaxially and by standard consolidation test, and it has been found that the variation in void ratio is in proportion with the logarithm of time, though there is a slight undulation on the curve when the specimen is thinner. Also it has been indicated that a larger percentage of secondary compression takes place for thinner specimen.

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The effect of the vibro-compozer method (sand compaction pile) for stabilizing cohesive soils was already presented by Prof. S. Murayama in his successive papers, but there still remain some unsolved problems in design and practice. In this paper, the authors, based on their experiences, have made clear some effects of the method applied to cohesive foundation soils, reaching the following conclusions : (1) By constructing the vibro-compozer piles in the clayey foundation soils, there arises some effect of forced consolidation, and the compound foundation acts against settlement both due to preconsolidation of clay and stress concentration on sand piles.(2) There seems to exist some remoulding of clay around sand piles immediately after driven, but the strength of clay may increase by forced consolidation, which is rather effective for quick stabilization of clay.

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