Laboratory Apparatus Development Designed, developed, and performed experiments on several advanced laboratory apparatus for geotechnical engineering research: A large direct shear testing apparatus was developed to study the effects of geotexiles in the railway track system and the interface behavior between the ballast and the supporting subgrade soil. The shear box received a 30.5 cm x 30.5 cm (12 in. x 12 in.) sample. This apparatus is in the geotechnical engineering laboratory of IIT. A directional shear cell (DSC) was developed at the University of Colorado to study the behavior of stress induced anisotropic soil under the effects of rotation of the principal stress. The DSC is capable of applying independent normal and shear stresses on the four faces of a cubical sample in plane stress or plane strain conditions. By controlling appropriate combinations of normal and shear stresses applied on the faces of the cubical sample, the magnitude and the orientation of the principal stress can be controlled as desired. the DSC received a 20 cm x 20 cm x20 cm (8 in. x 8 in. x8 in.) cubical sample. A True Triaxial Cell apparatus is used to investigate the behavior of soil under static and dynamic loading under three independently controlled principal stresses. It is a stress controlled device where stresses are applied to the specimen through the flexible membranes. This apparatus is at IIT. A large dynamic Torsional Hollow Cylinder Testing apparatus to study the effects of principal stress rotation on anisotropic soils. The axial and shear stresses are applied independently. The shear stress is applied through the double acting pneumatic cylinder. This apparatus is at IIT.