Behavior of the static drill rooted nodular piles under tension

A series of field tests on static drill rooted nodular piles are conducted to investigate their behavior under tension. A group of destructive field tests are conducted to investigate the load-displacement response of the static drill rooted nodular piles under tension. Moreover, the power function, hyperbolic function and exponential function are used to fit the load-displacement curves of the test piles, respectively. Field tests on the static drill rooted nodular piles instrumented with strain gauges are conducted to investigate their skin friction and mobilized tip resistance. The test results show that the load-displacement curves of the static drill rooted nodular piles under tension are relatively flat, and that the exponential function can be used to fit the curves well. The frictional capacity of the static drill rooted nodular piles is better than that of the bored piles, and the skin friction of the static drill rooted nodular piles is about 1.47~2.11 times that of the bored piles. The existence of the enlarged cemented soil base of the static drill rooted piles can improve the capacity of the tip resistance as well as the frictional capacity of the pile-soil interface close to the enlarged base.