Abstract：Analysis is made on three types of contrastive tests of 8 super-long cast-in-situ piles with different rock-soil layers at pile end. The piles for contrastive tests are 2 piles plunged into and not into bed-rock，2 piles with and without residua at end，2 piles with residua of different thickness，and 2 piles with and without end postgrouting. The study results are as follows. (1) When pile end rock-soil strata changes from soft to dense，the load-settlement curves change from steep shape to gentle one，the failure changes from plunge failure to integer shear failure，the increment of ultimate bearing capacity consists of the increment of ultimate end resistance，and the kind of pile changes from friction pile to end resistance pile，which indicates that end rock-soil layer has significant influence on behavior of super-long pile. (2) The super-long pile with end postgrouting can be regard as super-long pile with pedestal，so that the ultimate end resistance can be expressed by formula including a parameter of resistance increment，and it can also be expressed by the formula of ultimate end resistance for common pile with pedestal. (3) The super-long bored piles，i.e. the pile with length-diameter ratio of 82，penetrating dense stratum，can be regard as end-bearing friction piles with great potential bearing capacity. It is reasonable to confirm bearing capacity of this kind of pile with greater pile head settlement，and this is practicable as long as unbalance settlement is controlled in a limited range.
