calcareous sediments and experienced severe soil degradations. Construc- 

 tion personnel reported that piles would free drop as much as 6 feet 

 during driving. As a result of these experiences, drilling and grouting 

 the piles may be preferred instead of using an impact hammer to install 

 the piles in calcareous soils. 



Belled pile foundations have been used for a tanker terminal project 

 in Saudi Arabia where calcareous sediments are predominant (Burt and 

 Harris, 1980). This method took advantage of the high end bearing resis- 

 tance in carbonate rocks or highly cemented calcareous soils. 



High capacity, low frequency vibratory hammers were used to drive 

 piles into a calcareous sediment in Saudi Arabia (Fugro Ltd., 1982). 

 Installing piles by such a method appears promising, however, little or 

 no data are available to evaluate the effect of this installation method 

 on the load carrying capacity of piles. 



Axial Pile Capacity 



There are minimal data on the axial load capacity of piles in cal- 

 careous soils. The ultimate axial capacity is determined by the sum of 

 skin friction resistance, Q , and end (tip) bearing resistance, Q , and 

 can be expressed as follows: 



Q = Q+Q=fA+qA (1) 



s p s p 



where: f = unit skin friction 



A = side surface area of pile, which is in contact 

 s . , 



with sediment 



q = unit end bearing capacity 



A = cross-sectional area at pile tip 

 P 



Very few experimental studies have been conducted to investigate 

 the behavior of piles in calcareous sediments. Studies that are avail- 

 able tend to concentrate on skin friction. The results of static tensile 

 pile load tests for driven piles and grouted piles in calcareous soils 

 are summarized in Table 1. Angemeer et al. (1973, 1975) indicated that 

 the axial capacity of driven piles in calcareous soils can be lower than 

 that of piles driven in terrigenous soils. They also found that skin 

 friction for driven piles varied from site to site and thought this vari- 

 ation probably reflected differences in crushability , cementation, and 

 density of the calcareous soil. They concluded that calcareous soils 

 are extremely sensitive to crushing as evidenced by grouted piles yielding 

 a frictional capacity on the order of 3 to 5 times that for driven piles. 

 They applied cyclic loads to a grouted pile to measure the threshold 

 pile friction resistance and observed no significant loss in frictional 

 capacity after about 90 cycles. Contradictory observations, though, 

 have been reported in King et al. (1980) when performing small-scale 

 pile segment friction tests in-situ. King's large displacement cyclic 

 tests (i.e., each cycle displacing the pile to the maximum resistance) 



