Field tests on bearing capacity of pre-bored grouted planted piles under compression and tension

A series of field tests are conducted to study the compressive and uplift bearing capacities of pre-bored grouted planted (PGP) piles in the same test site, and the test piles are all loaded to the ultimate state. The compression and uplift bearing capacities of the PGP piles are also compared based on the field test results. The test results show that the compressive bearing capacity of the PGP piles is significantly improved compared to that of the bored piles, and the ultimate skin friction of the PGP piles in different soil layers in this research is about 1.49~3.21 times the ultimate skin friction of the bored piles recommended by the local specification. The uplift bearing capacity of the PGP piles is also better than that of the bored piles, and the ultimate skin friction of the PGP piles under tension is 1.52~1.55 times that of the bored piles under tension recommended by the local specification. Moreover, the ultimate skin friction of the PGP piles under compression is obviously smaller than that under tension, and the uplift coefficient of skin friction is also needed for the PGP piles.