Research purposes: At present, the research of diatomite focuses on its physical and chemical properties and genetic mechanism, but the research on its engineering characteristics is less, especially the research on pile foundation treatment technology and dynamic characteristics. In the paper, the dynamic characteristic tests of CFG pile, plain concrete pile and screw pile under natural and immersion conditions are designed respectively, and the stress transfer mechanism, vibration speed, pile strain and settlement law of different pile types are studied, and the pile-soil interaction mechanism are analyzed in depth. Research conclusions: (1) Diatomite has strong structure and is not suitable for the pile forming technology which the soil is disturbed. Screw pile is not recommended because of its large disturbance and poor stability. The disturbance of rotary excavation plain concrete pile is small, the quality of which is the best, followed by CFG pile. (2) Under natural conditions, the stiffness of plain concrete pile is the largest, the speed is the smallest. The dynamic stress and velocity response of screw pile are intense, the strain of which is large. After immersion, the structure of diatomite is destroyed, the stress on the top of pile is concentrated, and the dynamic stress, velocity, settlement and pile strain of single pile composite foundation increase. (3) The system of "rigid-soft-rigid" can dissipate most of the excitation energy and increase the stability. With the increase of excitation frequency, the stress of the top of pile increases, and the dynamic stress of gravel surface and pile plate structure increases exponentially. (4) The research results can provide a reference for the study on dynamic characteristics of diatomite or similar projects.
WANG Fei. , {{custom_author.name_en}}et al.
Experimental Research on the Dynamic Characteristics of Diatomite Single Pile Composite Foundation[J]. Journal of Railway Engineering Society, 2020, 37(12): 44-48
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