| dc.description.abstract | Backfilling techniques enable improved ore recovery and structural stability to underground mines
employing a material to fill the voids after the excavation. Fiber-reinforced cemented paste backfill
(FR-CPB) is this material and it consists of mine tailings, cement, mixing, and fibers. After placed
into the underground space (called stope), FR-CPB provides sufficient ground support, enables the
exploration of larger amounts of ore since no orebody pillars are required to sustain the
excavations, and thus enhances mining production. The reinforcement technique has been
considered as a promising approach for the backfilling design. However, regarding that mining
activities may take place at a depth of more than 1000 meters, the geothermal gradient can not
only change the temperature of FR-CPB but also affect its geomechanical behaviors due to its
temperature-dependent characteristics. Therefore, the objective of this research is to
experimentally investigate compression, tension, shear, triaxial, and fracture behaviors of FR-CPB
subjected to different warmer curing temperatures (20°C, 35°C, and 45°C). Moreover, to identify
the mechanisms responsible for the evolution of geomechanical behavior, a series of mold-based
monitoring programs have been designed and performed to measure changes related to matric
suction, electrical conductivity, and temperature in FR-CPB. Additionally, to determine the
progress of binder hydration and associated microstructure change, extensive X-ray diffraction
(XRD) analysis and scanning electron microscopy (SEM) observation have been conducted at the
microscale. The obtained results evidenced that warmer curing temperature can significantly affect
the fiber-CPB matrix interfacial interaction. Correspondingly, the geomechanical (including
tensile, compressive, shear, and fracture) behavior show strong temperature sensitivity from early
to advanced ages. Therefore, the obtained results from the present study can not only improve the
understanding of the geomechanical behavior of FR-CPB but also contribute to the safe design of
backfill structures in underground mines. | en_US |
