FEASIBILITY OF PROBABILISTIC LIQUEFACTION ASSESSMENT IN INDUSTRIAL PRACTICE: IS IT WORTH THE EFFORT?

Earthquake-induced liquefaction has been studied for decades since it poses major challenges for the geotechnical design of building foundations and buried pipes, to name but a few. While in the energy market liquefaction has been mainly investigated for the risk posed to oil and gas facilities, nowadays, it is still a key issue for the growing renewable energy industry. Indeed, it may cause excessive tilting and compromise the holding capacity of wind turbines. The most widely used methodologies in industrial applications are based on deterministic approaches, which evaluate the liquefaction potential along a soil profile for a specific design performance level. Despite the wide acceptance of such method, there are several shortcomings. For instance, they (1) do not provide the annual probability of liquefaction and (2) are based on a single earthquake scenario defined by a PGA for a given probability of exceedance and a characteristic magnitude, usually determined by deaggregation analyses. However, the design PGA is not controlled by a single scenario, but instead by multiple events, and thus it cannot be associated to a unique magnitude value. Nowadays, several methods have been developed within a probabilistic framework to overcome these issues. Nevertheless, the Probabilistic Liquefaction Hazard Assessment (PLHA) is still not common in industrial projects due to the higher computational effort. Should PLHA become standard practice in the near future? Is there a trade-off between complexity and feasibility? To answer such questions, this paper outlines a PLHA procedure for industrial applications, which takes advantage of the OpenQuake-engine. The proposed methodology is applied to different real case studies, which encompass both high and low-to-moderate seismicity areas. Results of the probabilistic approach are compared with conventional deterministic liquefaction procedures to investigate whether the former could provide significant advantages from an engineering point of view.