Effects of deep excavation on uplift capacity of piles by centrifuge tests

The stress state of the soil around piles and the bearing capacity of uplift piles will be changed by deep excavation. Through centrifuge tests, the effects of ultra-deep excavation on the bearing capacity of uplift piles are analyzed. Using the finite element numerical simulation analysis method which takes the effects of over consolidation into account, the centrifuge tests are calculated, and the mechanism of the effects of ultra-deep excavation on bearing characteristics of uplift piles is analyzed. The results show that under the influence of over consolidation of base soil, the coefficient of earth pressure, the pile-side ultimate friction resistance and the bearing capacity of uplift piles are larger than those under normal consolidation. If the effects of pit excavation on stress level of soil are not considered, it will be unsafe to take the bearing capacity as design value. If the effects of pit excavation on stress level of the soil around piles are taken into account, while the capacity of over consolidation is not considered, the bearing capacity of uplift piles will be underestimated.