Spatial variability of seabed liquefaction in the Yellow River Subaquatic Delta based on CPT

Abstract

The soil composition in the Yellow River Subaquatic Delta is complex, and soil liquefaction is a serious threat to the safety of offshore projects. Two-dimensional soil liquefaction evaluation cannot meet the practical needs of engineering. In this paper, in-situ cone penetration tests (CPT) were used to investigate the classification and distribution of soils. Liquefaction variability prediction analysis was performed for the region by the inverse distance weighting (IDW) and full-cokriging methods using the liquefaction vulnerability index (LVI) and cone tip resistance as sample parameters. The results show that: (1) the overall soil grain size in the offshore direction is coarser than that in the far shore, with the clay content less than 18% at Station S1 in the near shore, but more than 90% at Stations S10 and S5 in the far shore; (2) using IDW to predict the liquefaction potential, which first decreases and then increases in the offshore direction, the one-dimensional reconsolidation settlement (SV1D) predicts better than the other two LVIs; (3) a full-cokriging method with normalized cone tip resistance as the main variable and sleeve resistance (fs) as the auxiliary variable is proposed, and its prediction accuracy is better than that of the ordinary kriging (OK) method.