Effect of strain rate, sampling technique and aging on the soil properties used in the reassessment of pile foundations performance in the Bay of Campeche

After the Hurricane Roxanne passage over the Bay of Campeche in 1995, a reassessment and requalification of the offshore infrastructure was required. In order to represent better the real behavior of the platforms under current, wind and wave forces for the reassessment, effects such as soil sampling, strain rate and aging on the soil properties were incorporated in the analysis. The use of static parameters of the soil is an assumption very conservative for the analysis of reassessment of existent structures and for better geotechnical characterization the effect of strain rate, sampling technique and aging are considered. The consideration of these effects on the properties of soil were evaluated in 15 sites. The laboratory results for soils with strain rate of 10^-4% hour, which corresponds to the wave forces, show a mean value of increment of 35% in the shear resistance of the soil. The push sampling technique showed an increase of 20% in Su versus the wire line technique. For including aging effect, triaxial and direct shear testing is being carry out on samples of different sites of the Bay of Campeche. The reassessment of the offshore structures is optimum if the analysis includes the mentioned effects since the assumptions of the geotechnical characteristics are more realistic.