Field test on Ultimate bearing capacity of Composite Pile made up of Jet-mixing Cement and PHC Pile with Core Concrete

Abstract

Composite pile made up of jet-mixing cement and PHC pile with core concrete (CPCP) is a new kind of pile. It is formed by inserting PHC core promptly into the cement soil mixing pile. According to the single pile static load test and PHC pile cement soil bond strength test, differences between CPCP and pipe pile in bearing capacity and coordination deformation mechanism are studied. The results show that presence of peripheral cement soil has greatly improved the bearing capacity of CPCP. Three different loading modes have no obvious effect on CPCP bearing capacity, but the more significant effects on settlement. When the cement soil and soil interface destroyed, pile and cement soil interface friction resistance is much smaller than the bond strength, indicating that the bond strength can ensure coordination between the pile and cement soil. On this basis, the design formula for calculating the bearing capacity of CPCP pile is proposed. Comparing calculated values with field measured values, it has been found that the results are less error and the formula has a certain reliability in the calculation of vertical ultimate bearing capacity of CPCP pile, providing a certain reference for the design and calculation of this type of piles.