This paper presents some examples of such particular deep excavations as pneumatic caissons, open caissons and bored cast-in-place pier foundations. The examples to be quoted here in are limited to those works that the author has been more or less associated with, and that deem to be worthwhile from the viewpoint of soil engineering. In describing these works, emphasis will be placed on the reason why the particular construction techniques were employed and also on the effects of construction on the surroundings.

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The effect of addition of flocculant (Calcium Hydroxide) and dispersant (Sodium Hexameta Phosphate) agents on fine grained soil has been studied with particular reference to residual strength. The type of chemical influences to great extent, the residual strength whereas the strength is independent of the percentage of chemicals. The soil with a flocculant shows a higher peak and residual strength than that with a dispersant. The state of consolidation, viz., normally or overconsolidated does not affect the residual strength, but shows high peak values for overconsolidated soils. Moreover, the change in residual strength for different rates of strain and initial water content is insignificant for the rates of strain adopted.

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The author presents the analytical and the graphical method for determination of the direction and of the stress in the rupture line on one side of the contact between two different non-cohesive media, provided that the following values are known : the shear angles of both media that are assumed to obey Coulomb's failure law, the dilatation angles of both media as well as the stress state and the direction of the failure line on the other side of the contact. The analytical solution has been deduced from the limiting equilibrium conditions for the prismatic contact element whose surfaces are formed by the strain characteristics of both media appearing in the narrow rupture zone in which-according to Bent Hansen-the line rupture develops. The graphical solution can be obtained by constructing the corresponding Mohr's stress circles. The analytical as well as the graphical solution can be used also in order to get the dilation angles provided that the directions of the rupture line at the contact and the magnitude of the normal stress in the contact were determined in appropriate model tests.

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A consolidation test method with constant rates of loading is proposed as an alternative of the standard consolidation test, conventionally used in the laboratory. In the proposed method, a consolidation test is completed between 2 and 3 hours, and the settlement and base pore pressure are automatically measured and recorded. The results obtained from it always show good agreement with those from the conventional test. Test procedures and the theoretical background to the experimental data are described in this paper.

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As a first step in solving the problem of preventing fatigue failures in asphalt pavements, the influence of various factors involved on resilience characteristics of a silty clay and a well-graded sand has been investigated by repeated-load triaxial compression tests. The test results for the silty clay have emphasized the necessity of a sufficiently large number of stress applications and the preparation of specimens having the same water content, dry density, and soil structure as the field soil in determining the actual resilience behavior of this pavement component, and that the resilient modulus varies considerably over the range of axial stress usually encountered in actual pavements. The variations of resilient modulus at 10, 000 stress repetitions of the sand have been expressed by M_γ = kσ₃ⁿ, in which values of k and n vary with the initial dry density, the degree of saturation, and the frequency of stress application.

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Tests were carried out on the decomposed granite soils to examine the influence of properties of soil grains on permeability. The results indicate that the degree of weathering and mineral composition have pronounced effects on permeability, and that the existence of the pores within the grains is essentially important for the permeation of water.

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