Faculty Publications
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Item Model studies on the efficiency of gravity blind backfilling method and evaluation of a pre-jamming indication parameter(CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2016) Pal, S.K.; Mukhopadhyay, S.K.; Panda, S.; Tripathi, A.K.This paper discusses experimental research on a fully transparent scaled model of a section of a Bord and Pillar mine working carried out to study in detail the effectiveness of hydraulic blind backfilling as a solution to reduce subsidence problem above old underground water-logged coal mines. The relative influence of sand and water flow rates on the areas of filling from a single inlet point has been studied in detail. Automatic data acquisition system was installed in the model to continuously record the sand and water flow rates along with the inlet pressure of slurry at the entrance of the model. Pressure signature graphs have been plotted directly with the help of computer. Pressure signature analyses for various slurry flow rates and sand concentrations have been carried out. Investigation has also been carried out on evaluation of a pre-jamming indication parameter, which could be used for indication of the final stage of filling. © 2016 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Comparison of model study with field implementation of gravity blind backfilling method to control subsidence induced disaster in abandoned underground coal mines(World Researchers Associations, 2023) Kumar, P.S.; Akhil, A.; Kumar, T.A.Blind hydraulic backfilling technique is used for subsidence control in underground coal mines. A laboratory size model of underground working was developed to understand backfilling process. Observations from model were utilized for backfilling process in one of the underground mines. This study describes the results obtained in the field investigation at an old abandoned waterlogged underground coal mine of Eastern Coalfields Limited (ECL), a subsidiary of Coal India Limited and their verification with the findings obtained in the laboratory scale model study carried out on a model of underground coal mine worked by board and pillar method. The relative influence of slurry concentration and flow rates on the areas of filling from a single inlet borehole has been discussed. The relative spread of sand in different directions has also been measured using a remotely operated underground vehicle mounted camera. The empirical relationships developed under field conditions have been found to be similar to those of laboratory model. © 2023, World Research Association. All rights reserved.Item Comprehensive Assessment on Utilization of Iron Ore Tailing as Backfill Material in Mechanically Stabilized Earth Wall(Springer, 2025) Satheesh, A.; Sridhar, S.; Packiam, S.World is bestowed with self-sufficient magnetite and hematite iron ores. Huge volume of mining waste, namely iron ore tailings (IOT), is generated during processing of iron ore, leading to environmental concerns. At the same time, due to excessive usage and environmental regulations, there is scarcity of naturally available granular material. This paper presents the detailed laboratory study carried out to ascertain the feasibility of adopting iron ore tailings as an alternate granular backfill material in mechanically stabilized earth wall. A comprehensive study on mineralogical, physiochemical, and geotechnical characteristics was carried out on IOT procured from Lakhya dam, Chikkamagaluru district, Karnataka, India. X-ray fluorescence study indicates the presence of silica as major mineral along with hematite as major iron-bearing mineral. IOT is classified as a poorly graded sand with high friction angle value varying between 44° and 50° under loose and dense states and negligible particle breakage under compaction. The environmental risk connected with IOT was assessed through leaching studies and it was characterized as low contamination low ecological risk material. Design of mechanically stabilized earth (MSE) wall with IOT and granular soil as backfill using tie-back wedge method revealed that identical number of reinforcement layers are required when iron ore tailing or granular soil is used as backfill. Further, finite element modeling of MSE wall with IOT and river sand as backfill was carried out to compare the deformation behavior. MSE wall with IOT as backfill showed 70% reduction in horizontal facing displacement in comparison with sand backfill. © The Author(s), under exclusive licence to Indian Geotechnical Society 2024.Item Performance Assessment of Geosynthetic Reinforced Quay Walls under Concurrent Tsunami and Earthquake Aftershocks(American Society of Civil Engineers (ASCE), 2025) Sajan, M.K.; Sah, B.; Chaudhary, B.; Akarsh, P.K.Coastal structures are built against the dynamic loadings from waves, tides, and storms. However, natural disasters such as earthquakes and tsunamis can impart additional loadings on these structures that might exceed their design specifications. In the past, several earthquakes and tsunamis had resulted in severe damages even on coastal structures engineered to withstand tsunamis. It is reasonable to suggest that the tsunami waves succeeding the earthquake had impacted the coastal structures along with an aftershock, imparting the most critical loading conditions. However, limited studies are available, evaluating the performance of coastal structures when subjected to the combined loading conditions. Among various coastal structures, quay walls stand out due to their distinctive loading patterns, concurrently sustaining vertical live loads, active pressure from retained backfill, and dynamic wave forces from the sea. Therefore, the present study paper puts forth a comprehensive analysis of geosynthetic reinforced quays under the influence of a tsunami withdrawal and an earthquake aftershock. Since the magnitudes of seaward-directed loads during tsunami drawdown are unknown and difficult to assess practically, this study assumes a worst-case loading condition to represent these effects. The analytical approach adopted employs the horizontal slice method, encompassing the influence of outboard seawater, backfill submergence, tsunami impact, and pseudo-static earthquake loads. Results indicate that combined loading conditions substantially increase reinforcement forces, reducing the internal stability of quay walls. Critical parameters influencing stability include the shear strength of backfill soil, quay wall inclination, and surcharge loads. © 2025 American Society of Civil Engineers.