Non-uniformity of deformations has always been a concern in interpretation of laboratory triaxial test results due to boundary effects. This paper describes the application of a relatively novel inverse analysis framework, SelfSim (Self learning simulations), which permits the extraction of relevant soil behavior using boundary measurements of load and displacement to triaxial compression tests with frictional ends on a sand specimen. Extracted soil behavior shows increased void ratio towards the middle of specimen. Soil elements along the central axis and mid-plane of the specimen do not experience principal stress rotation during shear while significant principal rotation is computed elsewhere in the soil specimen. The extracted soil behavior is used to interpret a range of mobilized internal friction angles under a variety of loading modes. The analysis provides greater insight into the sand behavior than the simple interpretation of behavior using global measurements of force and displacements.