27-07-2012, 12:38 PM
Soil Classification
Soil Classification.ppt (Size: 3.42 MB / Downloads: 138)
Introduction
Object:
To keep various types of soils into groups according to their properties
Soil consisting of similar characteristics Can be placed in the SAME Group
Need:
To find the suitability of the soil for construction of dams, highways and foundations
Types of Soil Classification
Partcle Size Classification
Unified Soil Classification System (USCS)
Textural Classification
Public Roads Administration Classification (AASHTO, 1978)
Unified Soil Classification System (USCS)
Origin of USCS:
This system was first developed by Professor Casagrande (1948) for the purpose of airfield construction during World War II. Afterwards, it was modified by Professor Casagrande to enable the system to be applicable to dams, foundations, and other construction.
Liquid Limit - LL (or wL)
Casagrande Method
Professor Casagrande standardized the test and developed the liquid limit device.
Cone Penetrometer Method
This method is developed by the Transport and Road Research Laboratory, UK.
Public Roads Administration Classification System
(AASHTO 1978 System)
Based on both particle size composition and plasticity characteristics
GROUP INDEX of the soil is determined in order to rate the soil as a SUBGRADE MATERIAL for PAVEMENT construction
HIGHER the value of GROUP INDEX, POORER is the QUALITY of the SOIL.