forces in the surrounding ground. They are used as:
(1) Reaction piles for pile testing.
(2) Piles to resist uplift forces from ﬂotation.
(3) Anchorage to react to cantilevered foundations, etc.(see Fig. 9.40).
The piles are designed as tension piles transferring their load to the ground by friction, by under-reaming or by bonding into unfractured rock (see Fig. 9.41). It is most important that allowance be made, when anchoring into rock, for the possible damage and shattering of the rock or pile surface during driving.
It is also important to give special consideration to the use of piles as anchor piles for testing if they are to be incorporated as working piles in the ﬁnal scheme.
Fig. 9.40 Anchor piles.
Fig. 9.41 Tension piles.