| The liquefaction assessment method in Japan has been developed based on the standard penetration test (SPT). A drawback of SPT is that the number of blows (N-value) is influenced sensitively by particle size and fines content. This caused underestimation of liquefaction resistance of sandy soil with non-plastic fines during the 2011 off the Pacific coast of Tohoku Earthquake (Tohoku) Earthquake. On the other hand, the cone penetration test (CPT) is also used worldwide where cone resistance, skin friction and pore water pressure can be measured. A potential drawback of CPT for the purpose of liquefaction assessment is that the undrained cyclic resistance of soil, which is a dynamic property of soil, is measured indirectly in a static manner. To overcome these limitations, this contribution proposes a vibratory cone penetration test (VPT) for in-situ liquefaction assessment using a novel vibratory cone probe that vibrates horizontally with varying amplitude of acceleration. The vibratory cone probe can be driven at a constant rate in the same manner with CPT, and the horizontal vibration of the probe can be conducted at any depth in which horizontal acceleration, cone resistance and pore-water pressure can be measured. This contribution presents a case study of VPT using the novel vibratory cone probe, and demonstrates representative field test data where the cone-tip resistance drops sharply when the horizontal acceleration exceeds a threshold value in liquefiable subsoil, while such drop does not occur in non-liquefiable subsoil. |
