Mechanical behavior covers strength, shear strain, resistance to shearing, shrinking, swelling,compaction, volumetric compressibility, deformation, permeability and seepage of water. The clay isstronger than the sand because it can sustain larger suctions: otherwise their behavior is fundamentallythe same. The solid phase interacts whit the fluids which permeate soil pores. Models are best expressedin the concise and terse language of mathematics. Theories for soil mechanics originated around themiddle of the eighteenth century. The theories of soil mechanics apply equally to sands and clays. Soilmechanics can be divided in two branches: mechanical properties and rheological properties. Thescientific considerations relied on a lot of field and laboratory geotechnical studies effectuated in Banatregion. Because water is relatively incompressible, volume changes in soil can occur only if water canflow or out from the pore spaces. If soil is loaded undrained the resulting pore pressures will not be inequilibrium with the long – term, groundwater pressures. As the excess pore pressures dissipate underconstant total stress there will be change of effective stress and volume changes. This process is known asconsolidation. Swelling or shrinking accompanying soil water content change results in verticaldisplacement of the wet soil, which involves gravitational work and contributes an overburden componentto the total potential of the soil water. For a better recognition of vertic and pelic horizons, it can be usedthe next index values: u L – free swelling (vertic horizon: >140%, pelic horizon: 100 - 140%); I p –plasticity index (vertic horizon: >35%, pelic horizon: 25 - 35%), I A – activity index (vertic horizon: >1.25%pelic horizon: 1.0 - 1.25%). The simple theories presented above form the basis for analysis anddesign of engineering works. It must be determined some properties and index as: compressibilitymechanical properties, rheological properties (strength, shearing strength, penetration resistance,permeability, plasticity, consistency, plastic deformation, shear stress consolidation).

compressibility, strength, compaction, consistence, soil

Presentation: oral