GNGTS 2015 - Atti del 34° Convegno Nazionale

the remaining. Regarding the finer silt-clay materials, a consistency ranging from soft to plastic was detected. The Flysch was also classified by the Rock-Quality Designation (RQD) index and, where possible, data regarding sedimentation, fracturing and Joint Roughness Coefficient (JRC) was also collected. The RQD index data revealed that the first metres of Flysch bedrock are characterised by poor quality, which generally moves towards average and, at times, fair quality as further depths are reached. Based on the assessments carried out, a lithostratigraphic model of the area was defined, and several geological sections were drawn. Specifically, the geolithological features are as follows: 1) from 0.0 to -15.80 / -28.80 m below seafloor (mbsf): silt-clay-sand complex; 2) from -15.80 / -28.80 to -18.80 / -32.00 mbsf: altered marlstone-sandstone Flysch; 3) from -18.80 / -32.00 mbsf: unaltered sandstone-marlstone Flysch. Geotechnical laboratory tests were performed on the undisturbed and semi-disturbed samples extracted during the drilling, which allowed for the identification of the principal geotechnical parameters. Lastly, regarding the silt-clay-sand complex overlying the Flysch bedrock, the susceptibility to liquefaction based on grain size was assessed (Sherif and Ishibashi, 1978). The results showed that for four samples there is a possibility of liquefaction. Additional tests were performed based on the Liquid Limit (LL) and Plasticity Index (PI) (Seed et al. , 2003), which revealed the potential risk of liquefaction of some samples. Results and conclusions. The results of the bathymetry survey are shown in a colour-shaded map in Fig. 3. Seaward of the TMT front, the bathymetry shows a smooth, gently sloping to SW with a water depth ranging from about 18 m to 21 m. Some interesting features can observed on MBES data as well as on SSS data: a ship footprint located along the pier and an abandoned pipeline channel with NW-SE direction. SBP data in conjunction with borehole data allow to obtain the depth and the morphology of the top of the bedrock. The assessment of geotechnical conditions was performed mainly on the base of the borehole data and by underwater refraction data. Acknowledgements. TMT personnel for the support and the permission to present these data. ������� ���� ��������� Trieste Port Authority for the permission to access in the harbour area. ��� ������� ������ ��� ��� ������������ ���������� ����� ������� Dr. Roberto Linari for the constructive discussion about seismic refraction data. References Böhm, G., Rossi G., and Vesnaver A., 1999. Minimum time ray-tracing for 3-D irregular grids , J. of Seism. ������ �� Expl., 8: 117-131. Brambati A., Catani G., 1988. Le coste e i fondali del Golfo di Trieste dall’Isonzo a Punta Sottile: aspetti geologici, geomorfologici, sedimentologici e geotecnic. Hydrores Information, vol. 6: 13 - 28. Busetti M., Volpi V., Nicolich R., Barison E, R. Romeo, L. Baradello, Brancatelli G., Giustiniani M., Marchi M., Zanolla C., Wardell N., D. Nieto, and Ramella R., 2010. Dinaric tectonic features in the Gulf of Trieste (Northern Adriatic). ����� ����� ����� ������ ��� ���� �������� Boll. Geof. Teor. Appl., 51, 2-3, 117-128. Busetti M., Zgur F., Romeo R., Sormani L, Pettenati F., 2012. Caratteristiche geologico-strutturali nel golfo di Trieste. Meeting Marino ISPRA, Roma, 25-26 Ottobre 2012. Carobene L., Carulli G.B. and Vaia F., 1981. ������ �� ������ ��� ����������� �� ����� Foglio 25 Udine. In: Castellarin A. (ed.) Carta tettonica delle Alpi Meridionali. CNR ± Progetto Finalizzato Geodinamica Pubbl. 441, 39-54. Carrion P., Böhm G., Marchetti A., Pettenati F. and Vesnaver A., 1993. Reconstruction of lateral gradients from reflection tomography. Journal of Seismic Exploration 2, 55-67. Carulli G.B., Carotene L., CavallinA., Martinis B., Onofri R., Cucchi F. and Vaia F., ����� 1980. Evoluzione strutturale Plio- Quaternaria del Friuli e della Venezia Giulia. In: Contributi alla Carta Neotettonica d’Italia. CNR ± Progetto Finalizzato Geodinamica Pubbl. 356, 488-545. CavallinA., Martinis B., Carobene L., and Carulli G.B., 1978. Dati preliminari sulla Neotettonica dei Fogli 25 (Udine) e40A (Gorizia). In: Contributi preliminari alla realizzazione della carta neotettonica d’Italia . CNR ± Progetto Finalizzato Geodinamica, Pubbl. 155, 189-197. Fantoni R., Catellani D., Merlini S., Rogledi S. and Venturini S., 2002. La registrazione degli eventi deformativi cenozoici nell’avampaese veneto-friulano . Memorie della Società Geologica Italiana, 57, 301-313. Finetti I.R., 1965. Ricerche sismiche marine nel Golfo di Trieste (Profilo sismico a rifrazione “Grado-Miramare”). Bollettino di Geofisica Teorica ed Applicata 7(27), 201-217. GNGTS 2015 S essione 3.2 69