Doctor of Philosophy
School of Civil, Mining, Environmental, and Architectural Engineering
Skin support provides resistance to the shearing and spalling of exposed rock layers/blocks as well as protects the surface from open atmospheric contact. Polymeric liners are one such skin support that can be applied to the roof or sidewalls of excavation to enhance load-deformability behaviour. Understanding the reinforcement mechanism of polymeric liner to the rock/coal blocks in laboratory experiments and numerical models possesses the key to measure its performance for field applications. This thesis focuses on the evaluation of performance parameters mostly in the post yielding regime of rock-like materials and coal when they are coated with the polymeric liner material. These parameters are derived from ductility, energy dissipation, damage characteristics and dilation behaviour of the concrete and coal blocks.
Laboratory tests are conducted to characterise load-deformation behaviour in tension and compression by flexural bending and uniaxial compression testing, respectively. It is found that the polymeric liner application enhances the strength of hydrostone beams by three times, and the failure mode changed from tensile to shear. Also, the load-deformation curves show strain hardening behaviour between yielding and failure. A novel performance index is proposed to quantify the liner performance under tensile loading. A distinct "slight strain-softening zone" is observed in the stress-strain curves of cubical concrete and coal samples when coated with polymeric liner. The dissipated energy density and its rate are also higher in the post-yield regime, indicating effective confinement by the liner. This study analyses the results in terms of elastic strain energy and dissipated energy with and without the liner and provides a performance indicator.
Dondapati, Gopikrishna, Evaluation of Mechanical Behaviour of Polymeric Skin Support for Mining Applications Using Experimental and Numerical Modelling Methods, Doctor of Philosophy thesis, School of Civil, Mining, Environmental, and Architectural Engineering, University of Wollongong, 2023. https://ro.uow.edu.au/theses1/1571
FoR codes (2008)
0999 OTHER ENGINEERING
Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.