Predictions and Performance of Uplift Piles in Soft Ground

摘要

Predictions and performance of uplift piles embedded in soft ground have recently receivedrnmuch attention due to extensive use of uplift piles in underground structures. Shanghai World Expo 500kVrnUnderground Transformer Substation and Shanghai Hongqiao Comprehensive Transportation Hub are typicalrnexamples. Both uniform-section piles with side-grouting and enlarged base piles have been extensively usedrnin the engineering practice. Despite of their extensive applications, theoretical and laboratory experimentalrnstudies have lagged far behind engineering practice. In this paper, a comprehensive study on three key issuesrnfaced is presented, including the predictions of the ultimate bearing capacity of base enlarged base piles, loaddisplacementrnresponses of side-grouted piles, and bearing capacity loss of uplift piles after deep excavation.rnCentrifuge tests were conducted to further demonstrate the performance of side-grouted piles and enlargedrnbase piles before and after deep excavation. Present theoretical and experimental studies have provided a deeprnunderstanding in the design issues of uplift piles used in soft ground.