1Osterberg J. New device for load testing driven piles and drilled shaft separates friction and end bearing [ J ]. Piling and Deep Foundations, 1989:421-427.
1[1]Jori Osterberg. New device for load testing driven piles and drilledshaft separates friction and end beating. Piling and Deep Foundations, 1989.421~427
2[3]Ulrich Vollenweder. Prufung nach dem pfahfusspresserfahren.Zurich: Journey of ETH,1997