Introduction, Methods of geotechnical research, Nature and basic characteristics of soils. Soil Classification. Soil Compaction. Seepage and permeability. Settlement of cohesive and non-cohesive soils (Consolidation and immediate settlements). Stress distribution on the Subsoil under the effect of external loads (using Boussinesq method). Mechanical behavior and study of Stress State (Mohr-Coulomb failure criterion). Lateral earth pressures on earth Retaining Walls (Rankine and Coulomb). Bearing capacity of Shallow Foundations (Terzaghi).
The following Laboratory tests are conducted on soils, in order to determine their physical and engineering properties :
- Determination of Water Content and Specific Gravity.
- Atterberg Limits (Liquid limit test and Plastic limit test). The basic behaviour of plastic clay soils can be assessed from The Atterberg Limits.
- Sieve Analysis, to assess the particle size distribution of a soil.
- Soil classification which is the systematic categorization of soils. Both Atterberg Limits and Sieve Analysis are used to identify the soil’ s classification.
- Standard Proctor Compaction Test. A method of determining the optimal moisture content at which a given soil type will become most dense and achieve its maximum dry density.
- Constant Head Permeability Test and Falling Head Permeability Test for coarse and fine-grained soils respectively. Permeability is the measure of the soil’s ability to permit water to flow through its voids.
- Consolidation Test. The main purpose is to obtain soil data which is used in predicting the rate and amount of settlement of
- Unconfined Compression Test. The purpose is to determine the unconfined compressive strength of a cohesive soil sample.
- Direct Shear Test, is used for the determination of the consolidated drained (or undrained) shear strength of soils. Estimates the angle of friction (φ) and cohesion (c) of soils.
- Triaxial Test. Involves subjecting a cylindrical soil sample to radial stresses and controlled increases in axial stresses. Estimates the angle of friction (φ) and cohesion (c) of soils.