Civil Engineering Reference
In-Depth Information
FIGURE 5.12
Empirical correlation between the standard penetration test
N
60
value, vertical effective
stress, and friction angle for clean quartz sand deposits. (
Adapted from de Mello 1971, reproduced from
Coduto 1994.
)
very approximate and the boundaries between different density conditions are not as
distinct as implied by the table. As indicated in Table 5.2, if it only takes 4 blows or
less to drive the SPT sampler, then the sand should be considered to be very loose and
could be subjected to significant settlement due to the weight of a structure or due to
earthquake shaking. On the other hand, if it takes more than 50 blows to drive the SPT
sampler, then the sand is considered to be in a very dense condition and would be able
to support high bearing loads and would be resistant to settlement from earthquake
shaking.
●
Table 5.3:
This table is based on the work by Tokimatsu and Seed (1987) and is similar
to Table 5.2, except that it provides a correlation between (
N
1
)
60
and the relative density.
