| In the 21 st century, China’s level of scientific research and technology in soft clay foundation engineering field has been developed rapidly. Meanwhile, some prominent theoretical results have been made greatly. However, when the pipe piles are applied in the soft clay area, the problems, such as pile inclination and breakage, inhibit the progress of construction in the process of foundation excavation, which has arisen a wide concern between technicians and researchers.In this paper, contrary to the insufficient theoretical studies of pile excavation pit under soft clay quality conditions, the excavation of excess pore water pressure on the pile and soil- structure interaction effects are focused on. In terms of engineering examples in Qingdao, major in PHC pipe pile foundation, displacement and mechanism of pile breakage during pipe pile foundation excavation on soft clay are investigated through theoretical analysis and FEM simulation. Besides, technology of pipe pile foundation excavation in soft soil region is proposed.Firstly, formation, definition, features, physical and mechanical factors are overviewed briefly. Mechanism of pore pressure in soft clay is analyzed, and fundamental form, mechanical properties and relative construction methods are summarized.Secondly, application of pipe pile on both piling and excavation is overviewed. Displacement during piling and mechanism of pore pressure during excavation are analyzed. Besides, a practical engineering is studied for further understanding on features of Qingdao soft clay region foundation excavation.Finally, the finite element software PLAXIS is utilized to simulate a construction in Qingdao. Based on characteristics of soft soil foundation and pipe pile construction, pore pressure and displacement of pile are analyzed from the fields of angle of excavation, machines and geological conditions. Furthermore, pile-soil interaction is analyzed to select technique of excavation and machines. |
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