Evolution of geotechnical risk analysis in North American practice - Risk and Reliability in Geotechnical Engineering - page 462

approaches, one sees an emerging number in the 1970s followed by a rapid increase in the
1980s and 1990s.
Like most things in research, interest in geotechnical risk and reliability has followed
economic trends and national programs. Looking back in history, there is a background
phase of interest in geotechnical reliability (as opposed to risk analysis) starting about 1971
and continuing until the mid-1990s. Against this background, various economic or strategic
interests appeared in the 1980s and 1990s, which built on the existing fundamental work
in geotechnical reliability. These included, for example, interest in the nuclear fuel cycle,
offshore energy production, environmental remediation, and dam safety.
We start with the seminal period 1971-1996. This period saw the creation of a geotechni-
cal reliability literature, and the emergence of many of the insights about risk and reliability
in geotechnical practice, which now inform the literature. The second half of the period,
starting about 1980, saw tailored development in a number of economic sectors: mining,
offshore, environmental remediation, and dam safety, among others. Each of these sectors
developed somewhat independent of the others as workers specialized in applications of
their choosings, but each of these led to interesting and different insights. We overview a
selection of these but unfortunately ignore others due to space limitations.
By the early twenty-first century, interest had begun shifting to risks associated with
engineered systems. Perhaps, no development was more critical to this development than
Hurricane Katrina and its aftermath for planning the reconstruction of New Orleans,
Louisiana. Many of the long-time contributors to geotechnical reliability in North America
and to some extent in Europe contributed to the response. A small library of reports and
papers resulted from this effort.
While all this development has been going on, parallel activities have been afoot around
the world. Asia has been a particular hotbed for the development of geotechnical risk and
reliability in the current century. But this chapter has to have bounds; so, it focuses on North
America. We leave the task to others to provide a global review.
12.3 geoteChnICal relIabIlItY (1971-1996)
The period 1971 through 1996 reflects an era during which the focus of probabilistic meth-
ods in geotechnical engineering was principally on the uncertainty in soil properties and
on reliability. Geotechnical reliability concerns itself with the probability that foundations,
earth structures, underground works, and other geotechnical designs perform as required.
The beginning date is that of the First International Conference on Applications of Statistics
and Probability to Soil and Structural Engineering hosted by Professor Peter Lumb in 1971.
The ending date is that of the ASCE conference in 1996 on Uncertainty in the Geological
Environment at which modern risk analysis papers appear in increasing numbers. Toward
the end of this period, the (US) National Research Council report on Probabilistic Methods
in Geotechnical Engineering chaired by Wilson Tang appeared (NRC 1995).
12.3.1 Probabilistic veneer on deterministic models
This was a formative time. In the early years of this period, attention focused on how
uncertainty in engineering models and parameters affected the probability of satisfactory
performance, or its complement, “failure.” In essence, much of this work mostly placed
a probabilistic veneer on traditional deterministic modeling, propagating uncertainties in
loads, soil-engineering parameters, and other factors through design equations, while being
blissfully inattentive to measurement bias and noise, spatial variation, the separation of