CCLT - Lessons Learned from Geotechnical Failures

Despite advances in geotechnical engineering, failures do occasionally occur because of unknowns, uncertainties, inexperience, miscommunications, etc. However, failures do provide valuable lessons for the profession that can be learned to minimize future failures. This lecture will present three examples of geotechnical failures in British Columbia, in which the author was engaged to carry out forensic engineering. Pertinent details of the geotechnical failures and their causes are described for the following three case histories: (1) the dyke breach at the Stanley Street Pump Station located on the North Arm of the Fraser River in New Westminster; (2) the excessive foundation settlement at the Queensborough Middle School using stone column foundations in very soft soils at the east end of Lulu Island, and (3) the damaging ground movements at the Panorama/Ridgeview Subdivision located on an old landslide or “earthflow” in Chilliwack. Subsequent remedial solutions and lessons learned are also discussed.