[en] A mathematical model capable of describing the soil behavior under any loading conditions, monotonic or cyclic, is presented within the framework of critical state soil mechanics. (orig.)

[en] Here, two distinct kinds of reciprocal transformation are employed in conjunction to reduce a wide class of nonlinear moving boundary problems with heterogeneity to analytically solvable canonical forms. These are associated, in turn, with a classical Stefan problem and with one with variable latent heat relevant to the analysis of the evolution of seepage fronts in soil mechanics.

[en] The apparent diffusion coefficient of ³⁶Cl is used to assess pore geometric changes in allophane soil resulting from drying. The diffusion method is based on the boundary condition of a planar source diffusing into an infinite medium. The extent of structural changes accompanying drying was indicated by changes in slope of a plot between geometric and interaction factors versus volumetric moisture content. Structural change was least for freeze drying to be followed by a larger but equal change for air and oven drying. (M.A.C.)

[en] The dynamic-stiffness matrix of the soil appears in the basic equation of motion of the analysis of soil-structure interaction based on the substructure method. This matrix specifies the amplitudes of the forces due to displacements of unit amplitude that are applied at the nodes of the structure-soil interface for harmonic motion. The structure-soil interface of arbitrary shape can be flexible or rigid. Only structures supported on the surface of a layered soil are examined. The soil consists of horizontal layers of visco-elastic material with hysteretic damping which rest on a halfspace with the same material characteristics. The dynamic-stiffness matrix is derived using the boundary-integral method. Its discretized form is the so-called boundary-element method. It requires the evaluation of the flexibility-influence functions (Green functions) of the layered site which are calculated as integrals in the wave-number domain. The dynamic-stiffness coefficients are given for a rigid disc as a function of frequency for a visco-elastic halfspace, a single layer resting on a halfspace and a single layer built-in at its base. The corresponding two-dimensional cases are also examined. Replaced and welded contacts are analyzed. The influence of material damping is also investigated

No abstract available

[en] The material of the scientific work is presented in two articles: “The bearing capacity of the explosive piles’ bases: the bases granular media geomechanics theory” and “The bearing capacity of the explosive piles’ bases: geotechnical design of rational structures”. The foundations granular media foundations geomechanics theory development and the innovative scientific technical problems integrated solution relevance is grounded. The purpose and objectives of the scientific research are defined. The main content of the research presented a brief justification of the results. The theory of geomechanics includes the principles of the theory of nonlinear soil mechanics of granular media of the foundations and non-linear linear mechanics of the soil of granular media of the foundations of single piles. The theory of geomechanics is intended for use as fundamental factors in the development of geotechnical engineering for the design of rational designs of ramming explosive single piles and foundations. (paper)

[en] The problem associated with black cotton and lateritic soils because of the swelling-shrinkage property of their constituent clay minerals were investigated. Samples of black cotton lateritic soils were collected from different parts of Kenya. The samples were analysed for their mineral compositions and later treated with hydrated lime in order to eliminate the swelling shrinkage behaviour. The samples were subsequently tested for their engineering properties in a soil mechanics laboratory using shear box and Casagrande apparatus. It was found that the chemical treatment of the soils with hydrated lime removes their plastic property and improves their shear strength. (author)

[en] A progress report of a project under way at the UFRGS to determine soil properties to be used in dynamic soil-structure interaction analyses, by means of a triaxial dynamic testing machine built at the UFrGS. The objectives of the program and the characteristics of the testing equipament being built at the UFRGS are briefly described. (Author)

[en] For the study of the interaction problems between soil and structures or construction machinery, it is necessary to observe the soil movement around them. And so we have attempted to apply an X-ray radiography method for the visualization of the inner soil movement, which cannot be directly observed. This paper presents an outline of the results of the experimental study on the analysis of inner soil behavior by an X-ray radiography method. (author)

[en] One of the most common hypotheses made for soil-structure interaction analyses is that the earthquake input motion is identical at all points beneath the structure. Several papers have recently shown that this assumption may be overly conservative and that the effect of wave passage is extremely important. These studies typically employ a relatively simple model, namely, the basemat is represented by a rectangular rigid foundation resting on top of the soil and connected to the soil by a continuously distributed set of soil springs. The seismic input is applied at the base of the soil springs and is assumed to be traveling at a constant wave velocity across the site. It ispossible to improve on the soil/structure model by use of finite element methods; however, little is known about how to model the input seismic energy and typically a simple travelling wave is used. In this paper, the author examines the available data to determine: (i) the appropriate wave velocity to use, and (ii) if the currently availble analytic models are adequate. (Auth.)