September 9, 2022

Bob Bachus to Present on Settlement Analyses at GeoCarolinas 2022

Robert Bachus, Ph.D., P.E., D.GE (Georgia) will present "Accounting for Uncertainty in Settlement Analyses" at GeoCarolinas 2022 at the Mint Museum in Charlotte, North Carolina at 2:10 p.m. ET on September 13, 2022.

Geosyntec's Weston Shin, P.E. (South Carolina) will also be in attendance.

Robert Bachus is a Senior Principal engineer based in Georgia with more than 30 years of professional experience focused on geotechnical engineering, geoenvironmental engineering, waste by-product characterization, and the permitting and design of waste containment facilities.

GeoCarolinas 2022 will feature invited technical presentations by leaders in the field of geotechnical engineer as well as a conference reception, exhibits, a Student Poster Session, and an employee recruitment event.

The Carolinas Chapter of the Geo-Institute (GeoCarolinas) was formed to serve the interests of the geoprofessional community of North Carolina and South Carolina. The primary objectives are to organize the GeoCarolinas Conference on an 18-month cycle and support the North Carolina and South Carolina American Society of Civil Engineers Sections in developing geotechnical programs for their conferences.

Presentation Information

Assessing Uncertainty in Consolidation Settlement Calculations
Presenter: Robert Bachus, Geosyntec Consultants
Date and Time: 2:10–3:00 p.m. ET on September 13, 2022

In his seminal paper titled Factors of Safety and Reliability in Geotechnical Engineering (Duncan, 2000), Professor Duncan reported that… "Simple reliability analyses, involving neither complex theory nor unfamiliar terms, can be used in routine geotechnical engineering practice. These simple reliability analyses require little effort beyond that involved in conventional geotechnical analyses." In the paper, Professor Duncan applied reliability analysis to a cantilever retaining wall to assess the uncertainty associated with calculated factors of safety. The methods have also been applied successfully to assess the uncertainty of slope stability calculations for the factor of safety. This analysis approach considered potential variability and uncertainties in the analysis parameters and the associated reliability of the calculated factors of safety, essentially demonstrating little correlation between the calculated factors of safety and the probability of failure.

The Federal Highway Administration (FHWA) has proposed analysis techniques to assess variability in engineering parameters in its publication Geotechnical Site Characterization, Geotechnical Engineering Circular No. 5 (GEC 5). This presentation will build on the techniques presented in these two documents and apply the concept of reliability analysis to a very common geotechnical analysis problem, specifically one-dimensional consolidation settlement. Although the calculation of consolidation settlement does not involve a calculated factor of safety, the design engineer can apply reliability concepts to assess the reliability of the predicted settlement. As will be described in this paper and presentation, the most important contribution of this application is that it is possible to assess the relative importance of specific analysis parameters, considering the potential epistemic and aleatory uncertainties associated with each parameter. The results can inform the designer regarding site characterization strategies that will explicitly improve the confidence in settlement calculation results. This methodology can be readily included in geotechnical education and training classes to facilitate adoption of reliability analysis in current curriculum.

More Information

About the event: GeoCarolinas 2022
About the Carolinas Chapter of the Geo-Institute: https://www.carolinasgeoinstitute.org/
For consultation regarding geotechnical engineering, contact Bob Bachus at This email address is being protected from spambots. You need JavaScript enabled to view it.
Learn more about Bob: Robert Bachus | Geosyntec Profile