In order to adapt to dry and wet environment in mine roadways and improve the performance of sealing materials under different environmental conditions, this study selected the materials based on their ability to spray and found that the materials with a viscosity of 1500–6000 MPa·s can achieve a balance between performance of spray and wall-hanging performance. Next, by selecting high-elastic polyacrylate emulsion and ordinary Portland cement as the film-forming agent and gel, respectively, mix proportion factors of the nonreactive thin spray-on liner (TSL) were analyzed by using the Taguchi method. Moreover, fluidity, setting time, sealing properties, compressive strength, bending strength, and bonding strength of those materials were measured. It was disclosed that addition of an appropriate amount of polyacrylate emulsion can enhance the effects of fibers. By observing the morphologies of the materials’ bonding surfaces and comparing the factors influencing bonding strength between both dry and wet walls, it was uncovered that the adhesive property of cement-based sealing materials was mainly affected by the water-cement ratio. Eventually, bonding strength and sealing properties were selected as primary optimization indexes, while setting time, bending strength, and compressive strength were selected as secondary optimization indexes. The appropriate proportions of two types of TSLs for dry and wet walls were (W/C = 50%; P/C = 6%; F/C = 1%; T/C = 0.2%) and (W/C = 45%; P/C = 6%; F/C = 1%; T/C = 0.4%), respectively. A prepared TSL can be used for filling rock fractures in mine roadways. In addition, TSL exhibited a great performance for dry and wet walls under different environmental conditions. The present study may provide an insightful guidance and reference for the investigation of TSL sealing materials applied in the mine roadways.
In order to explore the pressure change law of mining wet shotcrete in pipes, the rheological model was built based on rheology principle, and the computational formula of rheological parameters of wet shotcrete was deduced with the linear regression. 100 m full-scale pipeline platform of wet shotcrete was designed and built to study the relationship of pressure and other factors including flow rate, water cement ratio, mix proportion, and pipe bends. Results show: pipe pressure increases with the increase in flow rate and declines with the increase in water-cement ratio, the pressure may fluctuate with a high water cement ratio which can cause cement overhydration and bleeding separation. It will be more beneficial to transport materials if the continuous grading and straight pipe were considered. According to the tests of mix proportion 1:1.5:2.25, the pressure drop is 0.032 MPa·m−1 and the bend pressure drop is 1.3 times higher than in the straight line. We also conclude that solid phase pressure is bigger than liquid phase pressure and they both decline along the pipe based on FLUENT simulation. Finally, the formula of on-way resistance used in mine production was deduced.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.