Study on Construction Technology of Composite Pile Made up of Jet-mixing Cement-soil and PHC with Core Concrete

摘要

Construction technology of composite pile made up of jet-mixing cement-soil and PHC with core concrete (CPCP) is a national grade normalized construction method, which has been granted invention patent by China. CPCP consists of an external jet-mixing cement pile and a PHC in the inner core. The external cement-soil pile is constructed using the method combined the jet grouting with the mechanical mixing. The inner core PHC is driven into the external cement-soil pile. Construction equipments and construction process are first introduced in this study. Key construction techniques of grouting process, reasonable time of driving PHC and controlling method of CPCP offsetting are then discussed. Two buildings using CPCP as foundations in Liaocheng, Shandong Province, China, are presented. The results show that vertical bearing capacity and offsetting of CPCP, settlement of buildings all meet requirements of design. Construction efficiency of CPCP is equivalent to that of bored cast-in-situ piles with the same size in soft soil, and engineering cost using CPCP decreases by more than 35%. Construction technology of CPCP has the advantages such as safety, economics and reliability, and therefore has great promotion values in soft soil.