1. Lecturer, School of Civil Engineering and Geosciences, Univ. of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, U.K.
2. Emeritus Professor, School of Civil Engineering and Geosciences, Univ. of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, U.K.
3. Engineer, GEOCISA, C/Los Llanos de Jerez 10 y 12, 28820 Coslada, Madrid, Spain.