This book presents the select proceedings of the 26th Annual Symposium organized by the Sydney Chapter of the Australian Geomechanics Society (AGS). The symposium brought together key stakeholders of the Australian geological and geotechnical community. This book showcases state-of-the-art practices, new research findings, and case histories that demonstrate reliability-based designs and assessments. The papers on reliability-based approaches cover various aspects of site investigations, interpretations, designs, specialized testing, and technologies. This book presents recent innovations, trends, and concerns, as well as practical challenges encountered, and solutions adopted in the field. This volume will be a useful guide to those in academia and industry working in the fields of geotechnical engineering.