SPT: Standard Penetration Test (SPT) Corrected N-values

In geotech: Geotechnical Engineering

Description

These functions are used to calculate corrected blow counts (N-values) for the Standard Penetration Test (SPT). Function N60 calculates corrections for field procedures, and function N160 calculates corrections for field procedures and overburden pressure.

Usage

N60(N, Lr, Db, SS = TRUE, E = 0.60, metric)
N160(N60, sigma, metric)

Arguments

N	raw SPT N-value
Lr	rod length (ft or m)
E	hammer efficiency as a decimal (default: 0.60)
Db	borehole diameter (in or mm)
SS	logical variable: TRUE for standard sampler [default]; FALSE for sampler without liner
N60	SPT N-value corrected for field procedures
sigma	effective vertical stress at the depth of interest (psf or kPa)
metric	logical variable: TRUE (for metric units) or FALSE (for English units)

Value

• N60 = SPT blow count (N-value) corrected for field procedures, after Skempton (1986)

• N1,60 = SPT blow count (N-value) corrected for field procedures and overburden pressure, using the Liao and Whitman (1986) stress correction

Author(s)

James Kaklamanos <[e-mail]> and Kyle Elmy <[e-mail]>

References

Liao, S.S.C., and Whitman, R.V. (1986). "Overburden Correction Factors for SPT in Sand", Journal of Geotechnical Engineering, Vol. 112, No. 3, pp. 373-377, ASCE.

Skempton, A.W. (1986). "Standard Penetration Test Procedures and the Effects in Sands of Overburden Pressure, Relative Density, Particle Size, Aging, and Overconsolidation", Geotechnique, Vol. 36, No. 3, pp. 425-447.

Examples

##  Example code for SPT blow count (N-value) corrected for field
##  procedures
N60(N = 11, Lr = 25, Db = 4, E = 0.50, SS = TRUE, metric = FALSE)

##  Example code for SPT blow count (N-value) corrected for field
##  procedures and overburden pressure
##  In English units
N160(N60 = 8, sigma = 1500, metric = FALSE)
##  In SI units
N160(N60 = 8, sigma = 90, metric = TRUE)

geotech documentation built on May 1, 2019, 9:09 p.m.