Search

As complexity and unpredictability exist in nature, careful observations and interpretations of what can be measured in the field become prerequisites for geotechnical engineers to conduct safe and economical construction works. Observational methods have evolved from basic visual procedures, conducted on site, to sets of sophisticated procedures using modernized measuring instruments and computer-based back analysis techniques. From the wide range of procedures available for modern tunneling engineering in this field, the present paper tries to address a series of back analysis procedures in which the identification of strain distribution is sought as the primary goal in order to achieve a solid and reliable routine of observations and data interpretations. The discussion starts by identifying structures and flows of forward and back analyses; and it is then expanded to cover several back analysis procedures, including application examples, formulated for linear and non-linear material behaviors. The current status and limitations of the procedures available are also discussed.