ABSTRACT
An angle of l/J1 = l/J2 = 40° in Eq. (15.13) means no change of relative density due to pile driving. Values of l/J1 are obtained from insitu penetration tests (with no correction due to overburden pressure, but corrected for field procedure) by using the relationships established between l/J and SPT or CPT values. Kishida (1967) has suggested the following relationship between l/J and the SPT value Ncar as
(15.14) However, Tomlinson (1986) is of the opinion that it is unwise to use higher values for l/J due
to pile driving. His argument is that the sand may not get compacted, as for example, when piles are driven into loose sand, the resistance is so low and little compaction is given to the soil. He suggests that the value of l/J used for the design should represent the in situ condition that existed before driving.
