Abstract

Based on the collection of many data coming from a large survey carried out in the Ravenna Port channel, this paper focuses on the dynamic properties of the 30 m thick soil deposit whose poor geotechnical characteristics make the design of infrastructures in the area particularly challenging. The study included specific seismic in-situ investigations (e.g. Seismic CPTu and CH), laboratory tests on undisturbed bored samples (e.g. Resonant Column Test) and common in-situ testing (e.g. CPTu, DMT). The main objective is the estimate of the very small strain shear modulus and its decay with strain level (i.e. curves G0-gamma) for dynamic characterization. This is a fundamental aspect to consider for numerical modelling of geotechnical engineering problems considering soil-structure interaction under working loads and site response analysis. The availability of direct and indirect measurements of the dynamic soil properties allowed the comparison between the different estimates and an evaluation on the applicability of the correlations between the outcomes from possible in-situ investigations.

Abstract

Based on Cone penetration tests (CPT) data, a number of soil’s physical and mechanical parameters can be interpretated, like shear wave velocity, etc. Even though various studies have been conducted and methods are proposed, uncertainties still exist and the applicability of each method needs be further clarified. A case study on the interpretation of CPT results is performed which based on the measured data from an offshore site close to East Sea, China. This paper focus on clayey soil layers and presents an assessment of CPT data interpretation methods for the derivation of clayey soil’s shear wave velocity. It shows that Long’s method proposed in 2010 (C1) and Cai’s method proposed in 2014 (C2) provide better predictions of shear wave velocity. Additionally, values of soil unit weight used in the shear wave velocity derivation can also be interpretated from CPT data since it shows ignorable effect on the interpretated velocity profile.