Time-dependent capacity increase of jacked piles is caused by the timeliness of shaft resistance and is affected directly by the character and mobilization of shaft resistance at the end of pile installation. However

the previous researches on the time-dependent capacity always relies on the correlation study between the pile installation resistance and its bearing capacity tested by load test

while the influence of the total shaft resistance at the end of pile installation on timeliness has been seldom considered . In this paper

jacking installation tests of model piles and load tests after installation are conducted to study the influence of base resistance on shaft resistance and further influence on the timeliness of bearing capacity of jacked pile with the theory of tribology in the Pearl River Delta. The study reveals that the friction at the pile-soil interface changes between lubricated friction and unlubricated friction during the whole pile installation. This phenomenon is caused by the change of installation velocity of the jacked pile when inserting different soil layers. If the pile shaft friction is unlubricated friction

then there is almost no timedependent capacity increase

if the pile shaft friction is lubricated friction

then the timeliness of bearing capacity is very significant. That means the shaft friction condition of pile can be used to prediction the timeliness of bearing capacity.