My Understanding of Soil Mechanics

Soil mechanics is defined as the study of engineering behaviour of soil (Powrie W, 2004). Soil mechanics may also be defined as an applied study of soil stress-strain (stress-strain-time) relations of soil under force. Together with Rock mechanics, it is the basis for solving many engineering problems in civil engineering, geophysical engineering and engineering geology. The publication of Erdbaumechanik auf Bodenphysikalisher Grundlage by Karl Terzaghi in 1925 gave birth to new era in the development of soil mechanics. Over the past years, soil mechanics has been developed rapidly and playing an important role in engineering. Some of the basic theories of soil mechanics are the basic description and classification of soil, effective stress, shear strength, consolidation, lateral earth pressure, bearing capacity, slope stability, and permeability.

Foundations, embankments, retaining walls, earthworks and underground openings are all designed in part with theories from soil mechanics. However, various factors on the impact of deformation and stability must be considered in the complex engineering problems. For example, the multi-dimensional load, load changes with time, repeated loading, vibration load, the complexity of the formation conditions and boundary shape, complexity of soil types and structure complexity, physical state changing, existence of seepage and pore pressure, structure-soil interaction(Livaoğlu and Doğangün, 2006), temperature and time effects, etc (Yin Z,1999).

A lot of theories of soil mechanics have been developed because of those factors, such as constitutive theory of soil, strength theory, consolidation theory, rheological theory, earth pressure theory, foundation bearing capacity theory, soil dynamics, environmental geotechnics, etc. Particularly, the theory of strain localization is an analytical theoretical framework in order to deeply research the shear band phenomenon (Bardet, 1991). The analysis of strain Localization was made on by Hadamard as early as 1903, which was further developed by Thomas (1961), Hill (1962), Mandel (1965) and Rice (1976). It was applied in elastic-plastic materials including soil and rock to predict the existence of shear zones, the direction and development of inclination angle of shear band(Rudnicki & Rice,1975; Rice & Rudnicki,1980;Vardoulakis 1979,1980,1981,1988,1989; Mole Kamp 1985; Peric 1990; Yin GZ，1999; Pan,1999,2000,2002).