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.
2[1]Osterberg J. New Device for Load Testing Driven Piles and Drilled Shaft Separates Friction and End Bearing. In: Balkema Rotterdam A A Edition. Piling and Deep Foundations. Netherlands:1989.421～427
3[2]_lrich Vollenweider. Prfung Nach dem Pfahlfusspresserfahren. Journey of ETH, Zrich, 1997
