A case history: Dock Enlargement at Barcelona Harbour R. Gómez-Escoubès, M. Arroyo & J.M. González Herrero Iberinsa, Madrid, Spain M. Devincenzi Igeotest, Figueres, Spain R. Sáenz de Navarrete Autoritat Portuària de Barcelona, APB, Spain Keywords: Soft clay, Vane tests, CPTU, piezometers, maritime work ABSTRACT: This case history starts, as many geotechnical engineering jobs do, with a tight schedule and poor geotechnical information. The objective was to build a new 325 m dock and passenger terminal within Barcelona harbour. Initial information suggested the presence of a thick soft clay layer above increasingly dense sands. A carefully staged earthwork plan was proposed including new soil exploration by boreholes, CPTu and FVT and ongoing pore pressure monitoring as the work advanced. This proved successful in that the staged earthwork proceeded smoothly and within the time limits. An unexpected result was the discovery of relatively thin clay seams within the sand layer. They were very detrimental to pile bearing capacity, to the point that initially planned dock uses were restricted. Consequently, the piled structure became unnecessary and was substituted by an anchored sheetpile. In-situ tests as well as simple piezometer monitoring proved to be very useful for a multi-purpose goal: a) soil characterization, b) safe recommendations on how and when earthworks should be performed and c) redesigning the whole project. 1 INTRODUCTION Barcelona is now the second port per traffic volume in Spain. It is in the midst of a large expansion plan that will double its current surface. The port expan- sion is directed southwards from its historical loca- tion near the city center. This direction has driven the port facilities closer to the Llobregat delta, whose influence is very marked to the south of the Montjuic mountain. The Llobregat delta is a gener- ally demanding area from a geotechnical viewpoint (see e.g. Arroyo et al. 2004, Devincenzi et al., 2004), and the port expansion works are relying more and more in careful geotechnical exploration and advice. This communication presents an example of how these tools were applied successfully. 2 THE PROJECT APB (Barcelona Port Authority) asked for solutions to cope with a big challenge: construction of a Cruise Terminal in 20 months with no dredging at all, due to environmental restrictions. The project involved reclamation of an area 325m long by 90m wide shouldered on the inner edge of the main breakwater. This area would be initially occupied by the Passenger Terminal buildings. At its waterfront a new 12m deep draught quay was required. The quay may eventually have to serve freight traffic at an un- specified future. Location is shown in Figure 1. 2.1 Available Data Previous geotechnical information was very scarce and consisted in continuous dynamic (Borros type) penetration tests DP, performed several years before from a floating barge. Also available was informa- tion from several boreholes located on the breakwa- ter alignment, but some 300m far away. These bore- holes had discovered 12 to 18m of low plasticity, soft pro-delta clays overlaying granular materials with increasing N SPT figures. Figure 1. Barcelona Harbour. Schematic location of project. Montjüic castle and park appear at the top Preprint : ISC’2, 2nd International Conference on Geotechnical Site Characterization, Porto, Sept. 2004