CORRELATION BETWEEN STANDARD PENETRATION AND DYNAMIC CONE PENETRATION TEST VALUES FOR DIFFERENT TYPES OF SOILS

Abstract

Soil has been used as a foundation and Construction material since the earliest days of recorded history. In order to be used as a foundation material, we should have a fair idea about the properties of soils as it exists insitu. The properties of soils can be determined by conducting labo-ratory and field tests. For laboratory tests, undisturbed semples are required which are nearly impossible to obtain for cohesionless soils, so for all practical purposes field tests are prove to be more effective. The standard penetration test and dynamic cone penetration test are a suitable field test which gives a general idea about the soil stratification and soil characteristics of compactness and firmness up to a desired depth. The standard penetration test though it is costly, time consuming and difficult to carry out is standardised. Several correlations are established between standard penetration resitance 'N' and properties of soils to determine the bearing capacity and allowable soil pressure of footings on cohesionless as well as cohesive soil. The dynamic cone penetration test though it is simple, cheap, quick and easy to carry out is not standardised. Stand-ard correlations are also not yet established between dynamic cone penetration resistance 'N and properties of soils. (iv) There is a need to establish a correlation between Nc and N values for different types of soils, so that Nc values can be indirectly utilised to evaluate the various properties of soils by using the standard correlations established with N values. The author has studied in detail the several existing correlations developed by various scientists in India and abroad between Nc and N values. The author has developed a correlation between Nc and N values by taking 30 locations where both SPT and DCPT tests were carried out. Correlation between Nc and N values are established for non cohesive and cohesive soils by using the observed as well as corrected values of standard penetration resistance 'N'.