SPT data

No.

Interpreted

Parameter

Description

Equation

Refs

0

(ft)

Layer bottom depth

1

(ft)

Layer middle depth

2

(pcf)

Unit weight

Measured

For Saturated Soil Materials:

       (kN/m3, m/s, m)

       (kN/m3, m/s, m)

Maybe et al. (2001)

Maybe et al. (2009)

For Saturated Soil Materials:

       (kN/m3, m/s, m)

Yi (2009)

3

Blowcounts

Energy ratio:

Borehole diameter:

  Use inner diameter for hollow-stem augers

SCEC (1999)

Rod length:

Sampler (see 12)

4

(%)

Measured fines content

5

(%)

Measured clay content

6

USCS classification

7

Friction angle

Measured or

8

(tsf)

Cohesive strength

Measured or

, clay-like soil

, sand-like soil

9

Total overburden pressure

10

Effective overburden pressure

11

Overburden pressure correction

<1.7

Liao & Whitman (1986a)

       ,

Idriss & Boulanger (2008)

12

Liner correction

Split spoon without room for liners ():

Split spoon with room for liners but with the liner absent ():

Split spoon with room for liners but with the liner absent ():

Seed et al. (2001)

13

Normalized

14

Normalized clean sand

Youd et al (2001)

Idriss & Boulanger (2004)

15

(%)

Relative density

Idriss & Boulanger (2008)

Terzaghi

Tokimatsu & Seed (1987)

Equation by Yi

16

(m/s)

Shear wave velocity

Andrus et al. (2004)

17

(ft/s)

Shear wave velocity

18

(kPa)

Initial shear modulus

in kPa (ρ in t/m3)

19

(tsf)

Initial shear modulus

in (psf)

20

Preconsolidation stress

For clay,

, (m/s, tsf)

Maybe et al. (2001)

For sand,

21

Overconsolidation ratio

For clay-like soil,

, (m/s, tsf)

Maybe et al. (2001)

For sand-like soil,

Maybe (2007)

22

Undrained shear strength ratio

For clay-like soil,

Maybe (2007)

23

Coefficient of lateral earth pressure at rest

Maybe & Kulhawy(1982)Mayne (2007)

24

Stress reduction coefficient

Liao & Whitman:

       , for

       , for

       , for

       , for

Liao & Whitman (1986)

NCEER/NSF (2001)

Blake:

Blake (1996)

Idriss:

       , z in ft

Idriss (1999)

25

MSF

Magnitude scaling factor

NCEER Workshop lower bound (Idriss)

NCEER Workshop up bound (Andrus & Stokoe 1997)

Yi (revised)

Yi (revised)

Sand-like soils

Clay-like soils

Boulanger & Idriss (2004b)

Boulanger & Idriss (2004b)

26

Correction for overburden pressure

,

Hynes & Olsen (1999)

       , or

Idriss & Boulanger (2004)

27

Correction for initial (static) shear stress

Idriss & Boulanger (2004)

28

Cyclic stress ratio

Seed & Idriss (1971)

29

Cyclic resistance at M=7.5

Sand-like soil:

Youd et al (2001)

Idriss & Boulanger (2008)

Clay-like soil: 

Boulanger & Idriss (2004b)

Clay:

       n/a (nonliquefiable)

30

FS

Factor of safety for liquefaction

31

Average cyclic shear stress

32

Average stress

33

or

Shear strain

Dry sand:

       ,

Pradel (1998) (for dry sand)

Saturated sand:

, if

                               if

, if

Idriss & Boulanger (2008)

34

Shear modulus ratio

35

Volumetric strain

Dry sand:

Pradel (1998) (for dry sand)

Idriss & Boulanger (2008)

Saturated sand:

Tokimatsu & Seed (1987)

36

Seismic settlement increment

Dry sand:

Saturated sand:

Pradel (1998) (for dry sand)

Zhang et al (2002)

37

Cumulated seismic settlement

38

Lateral displacement increment

Saturated sand:

Zhang et al (2004)

39

Cumulated lateral displacement

and :

Gently sloping ground without a free face:

       ,

Level ground with a free face:

       ,

Gently sloping ground with a free face:

Zhang et al (2004)

Original Pradel method

40

or

Shear strain

Dry sand:

       ,

Pradel (1998) (for dry sand)

41

(tsf)

Initial shear modulus

Seed & Idriss (1970)

42

Shear modulus ratio

43

Volumetric strain

Dry sand:

Pradel (1998) (for dry sand)

44

Seismic settlement increment

Dry sand:

Pradel (1998) 

45

Cumulated seismic settlement

46

Preconsolidation stress

Other methods:

Mayne (2005)

47

Overconsolidation ratio

48

Preconsolidation stress

        for clean quartzitic sands;

        for silty sands to sandy silts;

        for intact “vanilla” clays to clayey silts

Mayne (2006)

49

Overconsolidation ratio