title: Pipe flow of pumping wet shotcrete based on lubrication layer.
abstract: Wet shotcrete can reduce dust and improve supporting strength, however, safe and efficient pipage is a key technical part of wet shotcrete process. The paper studied the pipe flow law of wet shotcrete based on lubrication layer by build the experimental pumping circuit of wet shotcrete that can carry out a number of full-scale pumping tests. The experimental results show there was a linear relationship between pressure loss and flow rate. Combined with the Buckingham rheological equation, the computing equations of the yield shear stress and plastic viscosity were deduced through linear regression. A simple analytical method allowing for a rough estimation of the pumping pressure was proposed and used when considering the lubrication layer of wet shotcrete in pipes. In addition, two kinds of particulate distributive models were established along the time axial to analyze the formation of lubrication layer which is related with particles migration. By computational fluid dynamics simulation, the lubrication layer thickness of different mix proportions was estimated. A new method for measuring the thickness of lubrication layer was proposed to verify it by binarization processing. Finally, according to the comparative analysis of experiments, simulation and computed value, it can be seen that the lubrication layer plays a key role in the process of wet shotcrete flow and with the increase of lubrication layer thickness pipe pressure declines gradually.
authors.affiliation: State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao, 266590 China ; College of Mining and Safety Engineering, Shandong University of Science and Technology, Qingdao, 266590 China.
authors.forename: Lianjun
authors.initials: L
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao, 266590 China ; College of Mining and Safety Engineering, Shandong University of Science and Technology, Qingdao, 266590 China.
authors.forename: Guoming
authors.initials: G
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao, 266590 China ; College of Mining and Safety Engineering, Shandong University of Science and Technology, Qingdao, 266590 China.
authors.forename: Weimin
authors.initials: W
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao, 266590 China ; College of Mining and Safety Engineering, Shandong University of Science and Technology, Qingdao, 266590 China.
authors.forename: Gang
authors.initials: G
authors.lastname: Pan
keywords: Lubrication layer; Particles migration; Pipeline transport; Pressurel loss; Wet shotcrete