Date of Award


Degree Type


Degree Name

Master of Engineering Science


Civil and Environmental Engineering


Dr. Sean Douglas Hinchberger


In this study, the stability of tunnel headings is assessed using 3-dimensional finite element (FE) analyses. First, new tunnel face stability factors are derived corresponding to limit state or collapse of tunnel headings in homogeneous clay. In addition, stability factors corresponding to limited face displacement are developed for the serviceability condition since large face displacements can cause excessive surface settlements. The stability factors are presented as functions of tunnel cover thickness in design charts, the new factors are compared with some of the published works of Davis et al (1980) and Mair (1979). The second area addressed in this study is the stability of circular tunnel headings in non homogeneous clays. Again, stability factors are derived using FE analysis corresponding to the limit state (collapse) condition as well as the serviceability condition. For the serviceability limit state, the stability factors corresponding to ten percent plastic departure of the face. The results have been presented as design charts which should help design engineers to asses the risks associated with tunneling in non homogeneous clays. To conclude this study evaluates drained stability factors for circular tunnel headings in loose sand using 3 D finite element (FE) analysis. Again, stability factors have been derived corresponding to collapse (limit state) and yield (serviceability) are presented and compared with work of Leca and Dormieux (1990)



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