Engineering-geological model of the Segura River flood plain (SE Spain): a case study for engineering planning J. Delgado a, * , P. Alfaro a , J.M. Andreu a , A. Cuenca b , C. Dome ´nech c , A. Este ´vez a , J.M. Soria a , R. Toma ´s d , A. Ye ´benes a a Dpto. Ciencias de la Tierra, Universidad de Alicante, Ap. Correos 99, 03080 Alicante, Spain b Laboratorio de Carreteras, Generalitat Valenciana, Ctra. De Madrid s/n, Alicante, Spain c ITC S.A., Av. Elche 131, Alicante, Spain d Dpto. Expresio ´n Gra ´fica y Cartografı ´a, Universidad de Alicante, Ap. Correos 99, 03080 Alicante, Spain Received 17 October 2001; accepted 4 September 2002 Abstract This article presents a sedimentological and geotechnical study of the surficial sediments in the Segura River valley (SE Spain). We formulate an engineering-geological model consisting of four zones, each characterized by its geotechnical properties and by various geotechnical problems (namely low bearing capacity, significant ground settlement and liquefaction of sandy sediments). The model quantifies the geotechnical properties and potential problems in each zone. It serves as a useful tool for preliminary geotechnical investigations. The model also enables a better design of field surveys as well as optimal selection of geotechnical investigation techniques for future civil engineering works. D 2002 Elsevier Science B.V. All rights reserved. Keywords: Engineering-geological model; Bearing capacity; Ground settlement; Liquefaction 1. Introduction When civil engineering projects are based on limited site geological conditions, geotechnical prob- lems frequently arise and the work suffers cost increases and delays. To reduce such problems, inves- tigation is recommended to correctly characterize the site and define land units with similar behaviour (Anonymous, 1972, 1976). This information allows the engineering geologist or the geotechnical engineer to develop a conceptual geological model (Fookes, 1997), useful to the site-specific project or to others in the same geological terrain. This model helps to understand site geological conditions, to identify the main geological problems, and to make realistic esti- mates of material properties. If the model is well done, further site investigations may generally confirm or complement the model. Examples of such geological models are those proposed by Mollah (1993) for the alluvial plains of Bangladesh, and by Bozzano et al. 0013-7952/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII:S0013-7952(02)00226-0 * Corresponding author. Tel.: +34-965-903-400; fax: +34-965- 903-552. E-mail address: jose.delgado@ua.es (J. Delgado). www.elsevier.com/locate/enggeo Engineering Geology 68 (2003) 171 – 187