Development and Validation of a Transparent Laminar Box for 1-g Reduced-Scale Physical Modeling: Demonstration Through Tests on Unimproved and Granular-Column-Improved Sand Deposits

Laminar boxes are widely used for reduced-scale dynamic physical modeling. However, detailed observation of deformation remains limited because most sensors generally provide measurements only at discrete locations. This paper presents the development and experimental validation of a transparent, watertight laminar box that combines conventional instrumentation with optical measurements through Digital Image Correlation (DIC). The experimental characterization showed limited boundary interference at the instrumented locations under the investigated excitation conditions. DIC-derived soil displacements were independently compared with displacements obtained through double integration of embedded accelerometer records, resulting in an overall mean absolute error of 0.54 mm. Representative shaking table tests on loose sand, dense sand, and loose sand improved with granular columns were then used as proof-of-concept applications of the experimental system. The combined measurements consistently distinguished the response of the three ground configurations, with the loose sand exhibiting the largest acceleration amplification and accumulated shear strains, the dense sand the smallest, and the granular-column-improved deposit an intermediate response. Overall, the results demonstrate the capability of the proposed system to combine discrete and optical measurements for reduced-scale investigations of dynamic soil behavior and ground-improvement applications.