The potential of internal stability of granular soils can be evaluated using the three commonly used semi-empirical criteria: Kezdi (1969), Sherard (1979), and Kenney and Lau (1985). However, some issues exist and need to be addressed. 1) Only limited particle size distribution (PSD) data can be obtained using sieving analysis technique. 2) Some specific PSD data is necessary but difficult to be obtained through sieve analysis. 3) The secant slopes of PSD curves only can be computed manually.

Therefore, a software package named Analysis Software for Internal Stability of Granular Soils (ASISGS) was developed to address these problems. The ASISGS program was divided into two parts: ① Calculation Program for Parameter Values of PSD Models (CPPV), which is used to develop an optimal parametric model for representing the PSD curves of granular soils based on limited experimental data. ② Calculation Program for Secant Slope of PSD Models (CPSS), which can be used to calculate automatically the secant slopes of PSD curves according to the three commonly used semi-empirical criteria, so that the internal stability of granular soils which mainly depend on soil PSDs can be evaluated.