Distinctive and critical elements in geotechnical risk and reliability

Although geotechnical risk and reliability build on many general principles of structural reliability, it is gradually evolving as a distinct discipline that contains some critical elements that are distinctive from structural reliability. An example of these elements is the potentially large variability of geotechnical design parameters, because soils and rocks are natural materials with inherent spatial variability but the geotechnical design parameters are often estimated from limited observation data. This leads to substantial statistical uncertainty in the estimated design parameters, in addition to the inherent spatial variability. Scarcity of geotechnical data, particularly the lack of site-specific test data for generating meaningful soil or rock property statistics, is a major difficulty in implementing probability-based analysis in geotechnical practice that requires such statistics as input. Model uncertainty is another example of distinctive and critical elements in geotechnical risk and reliability. To carter for the diverse property, load and resistance evaluation methodologies and diverse site conditions in geotechnical practice, many different calculation models have been developed and adopted in geotechnical practice. Uncertainty associated with these calculation models is generally significant and has important effect on the assessment of geotechnical risk and reliability. A fair amount of research attention has been attracted recently to identify and deal rationally with these elements. This special issue, entitled “Distinctive and critical elements in geotechnical risk and reliability”, aims to stimulate discussions on what constitutes the distinctive “geotechnical” aspects in risk and reliability and reports recent research progress on these aspects. The special issue appears as Volume 10, Issue 4 of Georisk, and it contains six papers from Taiwan, Singapore, the USA, Japan, Hong Kong and China. Various topics are covered in this special issue, including model uncertainty in soil property correlation and liquefaction triggering assessment procedure, levee failure case studies in Taiwan considering uncertainty in different parameters, reliability-based design of foundations under serviceability limit state, evaluation of spatial distribution of strength inside earth-fill dams using both Swedish weight sounding and geophysical tests, and a user friendly Excel-based software for estimating meaningful soil or rock property statistics from limited site-specific data. Last but not the least, we would like to thank all the authors for contributing the papers, all the reviewers for reviewing the papers and the Georisk editor-inchief (Professor Limin Zhang) and editorial office staff for their supports. Without their contributions and efforts, the special issue would not be possible.