This paper summarizes the main observations related to geotechnical properties and tool changes that characterize the different tunnel drives in a database of 33 km of EPB tunnel records from the Barcelona area. The data have been examined in detail with regard to cutting tool replacement and performance of the mechanized excavation. The database includes tunnels in soft soils, in hard and medium rocks and in mixed soil-rock conditions; tool changing records and geotechnical properties. Transverse and longitudinal geotechnical heterogeneity are accounted for systematically. Longitudinal heterogeneity is used to subdivide the drives in the database into homogeneous units. Transverse (within section) heterogeneity is described by a set of newly developed impact factors FI.