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*PYCURVE

Data format:

A minimum of two lines lines with three values for the first one, the number of parameters on the other lines will depend on the option

NCUR IANA IOD
PY Y

Status :

Optional

Purpose :

To define the PY curve wrt to the lateral displacement. A PY curve is related to a soil layer.

Details :

Parameter Description
NCUR Identification number of the curve
IANA =0 the PY couples (Pressure (Pa) / Displacement) are the same for static and dynamic calculations.
=1, the PYs couple are different and the static and dynamic values should be given as: PYs1 Ys1 PYd1 Yd1.
If IANA is not provided, the curves are pre-defined curves
IOD if IANA is defined (user defined curves), the displacement is in m (IOD=0) or relative to the diameter of the element (IOD=1)
If IANA is not provided, two types of curves can be used:soft clay or sand. In that case the first line has only the curve identification number NCUR, the second line has 5 or 4 parameters depending on the type of SOIL
ITYP soil type ( 1 : soft clay, 2 : sand)
For soft clay, 4 parameters are read (see API 2A-WSD 6.8.2 and 6.8.3)
* The undrained shear strength for undisturbed clay soil samples (Pa)
* The effective unit weight (N/m3)
J: dimensionless empirical constant with values ranging from 0.25 to 0.
ec : strain which occurs at at one-half the maximum stress on laboratory undrained compression tests of undisturbed soil samples.
For sand, 3 parameters are read
* The weight (N/m3)
* The internal friction angle (in degrees, between 29 and 40)
* Initial modulus of subgrade reaction (N/m3)

Note

You have to create as many *PYCURVE keywords as soil layers; i.e. one curve for each layer.

In case where IANA is not defined, it means the user wants to use API curve. The keyword becomes then:

*PYCURVE NCUR ITYP PARA1 PARA2

If ITYP=1, the soil is made of clay and 4 parameters should be entered:

  • The undrained shear
  • The weight (N/m3)
  • J: empirical constant
  • ec : stress at 50%

If ITYP=2, the soil is made of sand and 3 parameters should be entered :

  • The weight (N/m3)
  • The internal friction angle (in degrees, between 29 and 40)
  • Initial modulus of subgrade reaction (N/m3)

Examples :

*PYCURVE
1
1   0.  20000.   0.5    0.1

*PYCURVE
5
1   4.e3  30000.    0.5    0.1