Specifies the soil adhesion factor. This option displays only when you select American Lifelines Alliance in the Soil Model Type list and Clay as the Soil Classification.
If no value is defined, the soil adhesion factor is calculated using C - SOIL COHESION OF BACKFILL based upon the following equation:
Alpha = 0.608-0.123C-0.274/(C**2+1)+0.695/(C**3+1)
Where C is in kips/sq.ft.
Possible values are listed in Figure B.2, "Appendix B: Soil Spring Representation"
from the Guidelines for the Design of Buried Steel Pipe by the American Lifelines Alliance