$matTag

Unique material object integer tag.

$soilType

soilType = 1 Backbone of p-y curve approximates Matlock (1970) soft clay relation.

soilType = 2 Backbone of p-y curve approximates API (1993) sand relation.

$pult

Ultimate capacity of the p-y material. Note that "p" or "pult" are distributed loads [force per length of pile] in common design equations, but are both loads for this uniaxialMaterial [i.e., distributed load times the tributary length of the pile].

$Y50

Displacement at which 50% of pult is mobilized in monotonic loading.

$Cd

Variable that sets the drag resistance within a fully-mobilized gap as Cd*pult.

$c

The viscous damping term (dashpot) on the far-field (elastic) component of the displacement rate (velocity). Default = 0.0. Nonzero c values are used to represent radiation damping effects.