Preliminary Study on Upfloat of PHC Pipe Pile in Xi’an Area and the Prevention

Abstract:

Prestressed high strength concrete drilled caisson (PHC) is used extensively in projects for Xi'an area, the quality problem appearing in construction gradually increases. Project disease of individual project, such as pile capacity largely reducing, and this is often seen in saturated soft soil for south area because of shaft uplift .The paper with Xi'an eastern suburb analyzes the cause and mechanism for heave, shaft uplift, and “hanging foot pile” of static pressure PHC drilled caisson in saturated loess because of squeeze effect and shaft decompression modulus, and key links and precautionary measure has been suggested for drilled caisson construction of saturated loess site.〗Pre-stressed high strength concrete pipe pile (PHC) is extensively used for projects in Xi’an area with the construction quality problems gradually increasing. Engineering disease of individual project, such as pile capacity largely reducing, is often seen in saturated soft soil in south area because of shaft upfloat .The paper analyzes the causes and mechanism of heave by squeezing effect and shaft decompression rebound; “suspending pile” by shaft upfloat with a PHC pipe pile project in eastern suburb of Xi’an. Based on the above, the key links and preventive measures have been suggested for PHC pipe pile project construction in saturated loess site.