Research Projects

Dredging is a severe plastic deformation process that has myriad applications in the infrastructure industry. With the reservoirs and other inland waterways in India reaching their design life, refurbishment is often critical, which would involve dredging of reservoirs and other waterways to remove silt and enhance the capacity. The project presented in this proposal is an extensive experimental and computational study of the mechanics of dredging especially in soft sediments. The problem of dredging of soft sediments can be simplified to one of orthogonal cutting of soft clays. The proposal has two closely inter-related but complementary research thrusts. First, we seek to develop a series of physical model tests that offer under both 1g conditions and geotechnical centrifuge tests a comprehensive idea on the kinematics of dredging in soft clays. Extensive rheometry of the model sediments, geomechanical characterization of the model sediments would set the stage for the experiments in this research work. Further, the first part of the model testing would involve a program for specimen reconstitution, followed by a series of physical model orthogonal cutting experiments on the reconstituted specimens. Similar cutting experiments inside a geotechnical centrifuge will follow the dredging experiments. The centrifuge experiments will complement the 1 g tests, in effect providing a comprehensive view of the stress states in situ. These centrifuge tests will provide a path towards understanding the efficacy of the controllable parameters in dredging operations. Second, we seek to demonstrate the basic kinetics of the problem through photoelastimetry. This approach will provide unprecedented access to insights into the microstructure and force propagation in a large deformation process such as dredging. Successful accomplishment of either of these research thrusts will offer new opportunities in a deeper understanding of the mechanics of dredging and the potential for extending this understanding for refining and optimizing processes in the field. These experiments will also serve as a strong underpinning for a suite of simulations using material point method (MPM) for potential applications. These results will serve as a framework for a comprehensive understanding of the physics and mechanics of dredging but also in designing optimal tools for real world application. As a part of this research stakeholders such as the dredging corporation of india, companies like Boskalis will be contacted and the results will be disseminated with them. The feedback from the industry will be critical in refining the research through the progress of the project.