1. American Society for Testing and Materials D2166 (1999) Standard test method for unconfined compressive strength of cohesive soils. ASTM Int., West Conshohocken, PA
2. American Society for Testing and Materials D3080 (1999) Standard test method for direct shear test of soils under consolidated drained conditions. ASTM Int., West Conshohocken, PA
3. American Society for Testing and Materials D422 (1999) Standard test method for particle size analysis of soils. ASTM Int., West Conshohocken, PA
4. American Society for Testing and Materials D4253 (1999) Standard test methods for maximum index density and unit weight of soils using a vibratory table. ASTM Int., West Conshohocken, PA
5. American Society for Testing and Materials D4254 (1999) Standard test methods for minimum index density and unit weight of soils and calculation of relative density. ASTM Int., West Conshohocken, PA