01907nam a22001097a 4500082001300000100004200013245011100055260002800166300000800194500155900202700003601761  aR/IMS-19  a Channar, Shabir Ahmeda15-ME(STR)-05  aA Comprarision of End-Bearing and Friction Pile Behavior Due to Excavation iIclude Stress Released in Clay  aNawab shahbQUESTc2019  a28p  aABSTRACT

It  is well  recognised  that superstructure  load  i s transferred to surrounding soil through  pi led  foundation. Consequently, the high  stress regime (stress bulb) is generated surrounding of the pile. On the other hand, the excavation in the ground inevitably results in the ground movement due to induced-stress release. To cope with transportation  problems  in congested  cities in the world  like Hong Kong, Shanghai, London etc, underground transportation systems (involving tunnels for metros, excavations of metro stations and basement to facilitate inhabitants in the buildings for parking)  have  been  developed.  These excavations are sometimes inevitable to be constructed adjacent to existing piled foundations. This condition leads to a big challenge for civil engineers to assess and protect the integrity of piled foundation. This research presents three-dimensional coupled consolidation analyses (using clay  hypoplastic  constitutive  model  which  takes  account  of small-strain stiffness) to investigate the responses of a friction and an end-bearing pile due to adjacent excavation at different depths in soft clay. It was revealed that the maximum induced bending moment in both types of piles after completion of excavation in all the cases is much  less than the pile bending moment  capacity  (i.e. 800 kNm). Moreover  the  end-bearing  piles  were  subjected  to  significant  dragload  due to negative skin friction. In contrast no significant changes in load distribution along friction piles were computed.
  aDepartment 0f civil engineering