Abstract

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Title:: Influence Range of Soil Around Pile by Extra-tonnage Pile Foundation Static Test

Author(s):: HU He-song; YANG Zhuo; XU Dan; ZHANG Cheng-lin; ZHOU En-hai; CHEN Hang; Guangzhou Institute of Building Science Co., Ltd.

Keywords:: pile foundation; extra-tonnage static test; soil around pile; ground settlement

Abstract:: Based on extra-tonnage pile foundation static load test of bored pile in CBD underground space in Guangzhou, the load-settlement relationship curves and the displacement variation of soil around pile were analyzed. The results show that when the load value is lower than the eigenvalue of vertical bearing capacity of test pile, the vertical rigidity of test pile almost keeps unchanged. When the load value is higher than the eigenvalue of vertical bearing capacity of test pile, the rigidity of pile reduces gradually, but the reduction is less obvious. When the load is lower than the ultimate load-bearing capacity, the settlement of pile tip increases linearly along with the increasing of load, every increment of settlement almost increases linearly too. During the loading process, the closer to the beam of soil, the more obvious phenomenon of unloading rebound, at this time, the soil around pile starts settle due to the shear action. The simultaneous occurrence of both impacts causes upheaval of soil within certain limits around pile. The influence range of soil around pile during loading process can be set to 4d(d is pile diameter). The soil within the scope of the 1.67d-2.22d away from the midpoint of pile behaves heaving after completion of unloading. The soil that beyond the range of 2.78d from the midpoint of pile is in elastic stage during loading process.