Liquefaction assessment of silty soils using field tests
Liquefaction means for water-saturated sediments or soils to suddenly lose strength and become a liquid, typically as a result of earthquake. The phenomenon came to scientific awareness in 1964, and has since been extensively studied, though uncertainties remain about the dominant screening method. The method is the cone penetration test (CPT), which measures the penetration resistance and excess pore water pressure of the soils. The EU-funded LIQUEFACTION project aimed to evaluate the liquefaction screening by CPT, and detail the effects of low-plasticity fine sediments on cone penetration resistance and liquefaction resistance. The four-year investigation concluded at the end of 2013. To obtain the needed field data, the project investigated 20 test locations in the Izmir Gulf, on Turkey's western coast. The sites were chosen by sediment type and propensity to liquefaction. Five tests were conducted at each location, establishing the drainage characteristics and strength of soil. Additionally, the study constructed a shake-box equipped with monitoring sensors, then filled the box with various kinds of soil that were experimentally shaken. The tests provided data valuable to the broader seismic research community. Project activities included the training of graduate students, who will help to fill a skills shortage in Europe. As a result of LIQUEFACTION, the currently used liquefaction assessment by CPT method is better understood. Hence, people and structures will be better protected from the destructive effects of earthquakes.
Keywords
Liquefaction, soils, earthquake, sediments, cone penetration test, low-plasticity, seismic research
