Modified Soil Tests for Scour Analysis on Offshore Windfarm Foundations

Abstract

The analysis of the scour processes following the pile driving procedures in offshore wind platforms is one of the major problems associated with this new form of clean energy generation. At present there are no scaled studies carried out analyzing the mechanical and deformational behavior of both the material of which the pile supporting the engine and the wind shovels is made (large steel hollow piles with a diameter of 8 m and a thickness of 15–20 cm) as well as the soil where the pile is driven. Usually these elements are installed on a very low granulometry sand displaced from the limits of dry beach– wet beach towards the offshore limits and where, due to this, it cannot return back to its natural state in its previous location. In addition, the few scaled studies carried out on dry soil similar to the existing one in the area of installation of the turbines has not considered a fundamental aspect such as the presence of seawater. This paper presents results obtained from tests to analyze the behavior of the base material on which the turbines are installed (degraded sands). These tests are the direct shear testing and a modification of the California bearing ratio (CBR) test to be carried out on completely submerged samples. The objective is to compare the results with those obtained in standard tests and analyze their suitability for field studies in offshore windfarms.