Empirical correlation of shear wave velocity (vs) with spt of soils in Madrid

Empirical correlations are usually used as a predictive tool in geotechnical engineering. However, equations calculated for soils very different to the ones to be characterized are frequently used, and so they are not representative of their mechanical properties. This fact, added to the increasing interest of civil engineering in knowing the shear wave velocity (Vs) of the ground, has led to the calculation of different empirical equations to predict the Vs value of the soils of Madrid. In this study this has been achieved by calculating the empirical correlations between the Vs value obtained through the ReMi (Refraction Microtremor) technique and the Standard Penetration Test (500 NSPT values). The empirical correlations proposed are applicable to the whole metropolitan area of Madrid, and have an excellent predictive capability owing to the incorporation of the measurement depth to the equations, which has an important influence in the resistance properties of soils. It is always better to have data collected in the studied site. But often there are too many difficulties to carry out some of these surveys. It may also happen that the surveys take too long or are too expensive to carry out. In these situations, empiric equations can be used to estimate this data. In geotechnical engineering, these empiric correlations are used frequently as a predictive tool, especially in the project’s design primary phases, when vast extensions of terrain are to be characterized in a short period of time, and to define if the soil fits a specific purpose. Because of this factor, there are plenty of estimations published that link between them different types of mechanical properties and geotechnical parameters.