关键词: 静压桩, CPTU贯入, 离心模型试验, 沉桩

Abstract: To explore the mechanisms of jacked pile and CPTU penetration, centrifugal model tests are conducted to investigate the variations of earth pressure, excess pore pressure and penetration resistance in the process of jacked pile and CPTU penetration. Meanwhile the installation process of jacked pile and CPTU is regarded as a series of continuous sphere cavity penetration. The cone resistance, the cone side resistance and the excess pore pressure are predicted based on spherical cavity expansion theory. The comparisons between centrifugal model test data and theoretical predictions show that the excess pore pressure and the soil stress around the pile increase with the increase of penetration depth. The excess pore pressure and the soil pressure reach the maximum when the pile tip arrives the measured point. The cone resistance, the cone side friction and the excess pore pressure show linear relationship with the cone penetration depth in saturated clays. The calculated results show a good agreement with the test results, which presents the mechanisms of jacked pile and CPTU penetration well.

Key words: jacked pile, CPTU penetration, centrifugal model test, pile installation