Abstract:

The vertical static load test is adopted to investigate 4 super-long bored piles in loess, in which the variation of axial force in piles is tested by vibrating wire strain gauge. Hence, the bearing capacity behavior, load transfer mechanism, the lateral friction and end bearing capacity are researched. With the increasing of vertical static load, the results indicate that: (1) shaft force distribution of bored pile is different from that of original cases; and this difference mainly concentrates on top of 1/3 pile length; (2) enhancing effect of static lateral friction and degradation effect of static lateral friction are obtained in sand soil; (3) the vertical static loading can induce decreasing of axial stiffness of single pile; and (4) axial stiffness of single pile reduces about 40 %-70 %.

Key words: high-speed railway, super-long bored pile, bearing capacity behavior, lateral friction, axial stiffness of single pile