SLIQ2D is a 2D computer program which calculates whether a submerged slope of sand or silt may liquefy or not, based on slope geometry, relative density and material properties of the sand or silt. The first version of the program was developed by Grondmechanica Delft in 1994, commissioned by Rijkswaterstaat. Background information can be found in for example Handboek Zettingsvloeiingen
Background informations about SLIQ2D can be find in the User Manual of SLIQ2D.
Determination of the imaginary surface
In this program, the fictive slope height and the fictive slope inclination are determined using the following steps:
Step 1: Determination of the fictive height
The height of the part of the slope above water (h1) is increased until h2 with a factor equals to the ratio between the soil unit weight above water table and the soil below water table:
h2 = (1 + w) . γs . h1 / (γs – γw)
Step 2: Determination of the fictive slope inclination
By means of the least squares method, the submerged slope (red line in the figure below) compared to the fictive submerged slope is determined and subsequently the fictive slope inclinaison (αR)
