Soil Engineering and Foundation

›› 2019, Vol. 33 ›› Issue (2): 232-235.

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Centrifuge Tests for Peak Penetration Resistance of Spudcan Footings in Hard Crust Layer Overlying Clay

JING Shaodong1, CHEN Xiao2, SUN Yongfu3, ZHANG Minsheng2, KOU Hailei2, WANG Dong2   

  1. (1.Sinopec Petroleum Engineering Corporation, Dongying 257026, China; 
    2.Ocean University of China, Qingdao 266100, China;
    3.The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China)
  • Received:2019-03-20 Revised:2019-03-24 Online:2019-04-20 Published:2019-04-22

Abstract: The “hard crust layerclay” layered soil is spread widely in shallow waters near Chengdao, Dongying. When they are installed in such stratigraphy, the spudcan footings of jackup rigs are vulnerable to punchthrough failure. A number of centrifuge tests were conducted to explore the penetration resistance profile of spudcans in hard crust layer overlying clay. The approaches recommended in the ISO guidelines and other two representative approaches are compared, in terms of the magnitude of peak resistance and its corresponding depth. It is found that hard silty sand layer can be regarded as a strong clay layer under undrained conditions, then the peak resistance may be estimated through previous approaches for “stiffoversoft” clays.

Key words: spudcan, silty sand, punchthrough, undrained strength, drainage conditions