Two Slope Function 
The TwoSlope Function dialog contains the equation parameters necessary to mathematically represent the compression curve with a TwoSlope equation. SVSOILS also implements a twoslope equation capable of providing a smooth representation of compression and rebound (or recompression) laboratory data. The TwoSlope equation has the advantage of using the conventional Compression Index, Cc, Preconsolidation Pressure, Pp, and other such variables to represent the compression curve. These variables are found in soil mechanics and as such are familiar to geotechnical engineers. A description of the theory can be found in the SVSOILS Theory Manual.
Compression Index, Cc: The Compression Index field refers to the compression index.
Lambda, L: The Lambda field refers to the slope of virgin compression line in isotropic triaxial test.
Two Slope Fit: The TwoSlope Fit field indicates whether the fit algorithm has been successfully executed on the current data.
Two Slope Error: The TwoSlope Error is the difference between the fitted results and laboratory values in terms of R2.
Rebound Swelling Index, Cr: The Rebound Swelling index field refers to the swelling index as determined from the rebound (or recompression) experimental data.
Kappa, K: The Kappa field shows the slope of the rebound (or recompression) branch of the swelling curve in the isotropic triaxial test.
Rebound Fit: The Rebound Fit field indicates whether the fitted algorithm has been successfully executed on the current data.
Rebound Error: The Rebound Error is the difference between the fitted results and the laboratory values in terms of R2.
