| Abstrakt: |
Backfilling is critical to deep and high-stress mining in order to minimize stress redistributions in the host rock, which can lead to mining-induced seismicity and underground excavation collapse. Cemented paste backfill (CPB) is the most popular backfilling material in the mining industry; it is a mixture of mine tailings, binder, and water, which tightly fills the mined-out space, providing optimum regional ground control. This paper presents the results of a laboratory study of the evolution of the coefficient of at-rest earth pressure (K0) of a typical CPB material. The impact of parameters such as cement content and curing time on K0 and one-dimensional behavior of a CPB in stresses up to 1.8 MPa was studied. In general, K0 behavior is characterized by three regions: elastic, transitional, and posttransitional. Fitting functions are proposed to predict evolving K0 based on cement content, specimen curing time, and unconfined compressive strength (UCS) as the most common laboratory test in geomechanical engineering practices. Although the calibrated functions are specific to the material tested, the testing approach can be used to characterize other mines' backfills. [ABSTRACT FROM AUTHOR] |
