Experimental investigation and mathematical strength model study on the mechanical properties of cemented paste backfill

Abstract

Quantifying the properties of cemented paste backfill (CPB) is essential for the design of cost-effective, safe and durable cemented backfill structures. In this paper, physical and mathematical modeling were integrated to develop a scientific and reliable approach to represent the mechanical properties of CPB. An experimental investigation was firstly carried out to highlight the effect of cement-tailings ratio (c/t) and slurry concentration (SC) on the UCS of CPB at different curing times. It was found that both of them produced beneficial effects on the strength behavior of CPB. The power and linear functional relationships were exhibited between the UCS of CPB specimens and the corresponding c/t and SC, respectively. Their coupled effects were complicatedly and continuously dominate the development of UCS over time. On basis of these, three time-dependent mathematical strength models were further derived to represent the coupled effects of c/t and SC on UCS. Results showed that the strength expressions for curing times of 7, 14 and 28 days were successfully deduced with ideal accuracy and reliability. The corresponding strength surfaces and contour plots could provide a useful guideline for backfill design and safety management of underground engineering.