Design and Development of Tilt Table-Based In-Flight Simulator for Pseudostatic Loading in a Geotechnical Centrifuge

Abstract In the recent past, failures of many geotechnical structures storing enormous volumes of water and tailings material have been witnessed. These retention type earthen dams and embankments have often been designed for inertial loading considering the pseudostatic method. This paper aims to present the performance of a tilt table-based in-flight simulator for pseudostatic loading (ISPL) in the horizontal direction at enhanced gravity in a geotechnical centrifuge. The developed tilt table-based in-flight simulator consists of a screw jack gearbox-based mechanism with a pivotal hinge to produce a maximum tilting angle of 20° (equivalent to horizontal seismic coefficient of 0.36) with tilting rates varying from 0.2°/min to 0.8°/min at enhanced gravity levels. In the present study, the performance of the ISPL setup was demonstrated on an earthen dam section subjected to upstream water rising and pseudostatic loading at 30 times gravity in a 4.5-m-radius large-beam geotechnical centrifuge facility available at the Indian Institute of Technology (Bombay, India). The data were recorded by pore water pressure transducers and linear variable differential transformers, coupled with front elevations of model earthen dams captured using an onboard digital camera, and analyzed. The results are presented in terms of the development of phreatic surface, pore water pressure, slope face movement, and crest surface settlement before and after earthen dam sections were subjected to hybrid loading (upstream filling and tilting) conditions. In addition, seepage and slope stability analyses of prototype centrifuge models were carried out under hybrid loading conditions. The seepage and slope stability analyses’ results were found to corroborate well with physically observed centrifuge test results.