Two static and vibratory Cone Penetration Tests in marine soils at Tauranga Harbor, New Zealand

Piezovibrocones have been developed to evaluate the liquefaction potential of onshore soils, but have not yet been utilized to evaluate the in-situ liquefaction behavior of offshore marine and volcanoclastic sediments. Two static and vibratory CPTu (Cone Penetration Tests) were performed at Tauranga Harbor, New Zealand. The lithology is known from nearby drillholes and the influence of vibration on different types of marine soils is evaluated using the reduction ratio (RR) calculated from static and vibratory CPTu. A sediment layer with high potential for liquefaction and one with a slight reaction to cyclic loading are identified. In addition to the reduction ratio, the liquefaction potential of sediment is analyzed using classic correlations for static CPTu data, but no liquefaction potential was determined. This points to an underestimation of liquefaction potential with the classic static CPTu correlations in marine soil. Results show that piezovibrocone tests are a sensitive tool for liquefaction analysis in offshore marine and volcanoclastic soil.压电振孔锥贯入仪（Piezovibrocones）已被开发用于评估陆上土体的液化势，但尚未应用于近海海洋与火山碎屑沉积物的原位液化特性评价。研究于新西兰陶朗加港开展了两组静力与振动孔压静力触探试验（Cone Penetration Tests，CPTu）。通过附近钻孔可获知试验区域的岩性特征，并利用由静力与振动孔压静力触探试验计算得到的折减比（RR），分析振动对不同类型海相土体的影响。研究识别出两层沉积物：一层具有较高液化势，另一层对循环荷载仅表现出微弱响应。除折减比外，研究还采用经典关联公式对静力孔压静力触探试验数据开展沉积物液化势分析，但未检测到液化势。该结果表明，针对海相土体，采用经典静力孔压静力触探试验关联公式会低估其液化潜力。试验结果证实，压电振孔锥贯入测试是用于近海海洋与火山碎屑土体液化分析的灵敏手段。