Abstract
It is of great significance to study the effect of solid contents (SC), binder-to-tailings (b/t) ratio, types and dosage of fly ash (FA) on the viscosity (V) and uniaxial compressive strength (UCS) of backfill. It can improve filling efficiency and reduce filling costs to understand the relationship between SC, b/t ratio, FA dosage and viscosity, and UCS of backfill. Consequently, this paper carried out uniaxial compression tests and rheological tests on five different types of backfill specimens. Experimental results indicate that, with the increase of SC, the viscosity and UCS of all backfill samples increases as a power function. With the decrease of b/t ratio, the viscosity and UCS of all backfill samples decreases as an exponential function. The coupling effect of SC and b/t ratio has a great influence on the viscosity and UCS of backfill samples. The relationship between SC, b/t ratio and viscosity, and UCS is a quadratic polynomial function. The order of the viscosity of the backfill slurry is: pure tailings < backfill slurry mixed with Ordinary Portland Cement (OPC) < backfill slurry mixed with FA1 < backfill slurry mixed with FA2. The higher the FA dosage, the greater the viscosity. The order of the UCS of backfill is: backfill with OPC > backfill with FA1 > backfill with FA2. The higher the FA dosage, the smaller the UCS. The UCS of all backfill samples increased with the increase of curing time (CT). The relations between the viscosity and UCS of backfill present the positively linear functions. It is feasible to use viscosity to predict the UCS of backfill, and the error between the UCS predicted value and the test value is mostly controlled within 10%. Ultimately, the findings of the experimental work will provide a scientific reference for the mine to design the strength of the backfill.
Highlights
At present, underground mining is the main way for humans to obtain metal mineral resources [1,2]
Taking the curing age of 14d and the b/t ratio of 1:4 as an example, when the solid contents (SC) is 66%, the uniaxial compressive strength (UCS) of cemented tailings backfill (CTB) is 0.622 MPa; when the SC increased to 68%, the UCS of CTB is 0.851 MPa, the growth rate is 36.8%; when the SC
Keeping the curing age and the SC constant, the UCS of CTB decreases as the b/t ratio decreases with an exponential function
Summary
Underground mining is the main way for humans to obtain metal mineral resources [1,2]. If the goaf formed by underground mining is not backfilled, in time this may lead to the collapse of surrounding rocks, induce surface deformation, and seriously threaten the safety of underground workers and equipment [7,8]. The tailing slurry is dehydrated to achieve a concentration of 60%~75% [19], and according to the design ratio, it is mixed and stirred with a binder to form a cementing filling slurry. The formed cemented filling slurry is usually transported to the underground goaf by gravity or pump [20,21,22], when it enters the goaf, the filling slurry will gradually hydrate, solidify and produce strength to support the surrounding rock [23,24,25]. Many scholars have carried out a lot of research on slurry viscosity, strength characteristics and influencing factors
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
