An Experimental Study of Water Saturation Effect on Chipping Efficiency of a Chisel Pick in Cutting Some Low- and Medium-Strength Rocks.

Water saturation of rock plays an important role in chipping efficiency and productivity of mechanical excavators. In this study, small-scale linear rock-cutting experiments were performed with a chisel pick on five sandstones, four gypsums, and three synthetic specimens under dry and water-saturated conditions at cutting depths of 1, 3, and 5 mm in order to investigate the mechanical effect of water on the rock-cutting process. In addition, chipping efficiency and cutting particle size distribution in both dry and saturated rock conditions were investigated using sieving analysis and particle size distribution indices. In addition, a new indicator was introduced for evaluating chipping efficiency. Analysis on cutting test results showed that water saturation causes (1) a reduction of production capacity of chisel pick ranging from 1 to 35%, (2) a reduction of chip size and parameters of particle size distribution, and (3) an increase in the proportion of fines produced from rock cutting. The results showed that the reduction of chisel production capacity is greater in saturated rock samples with higher porosity and water content when compared to the same dry conditions. The results of the sieving analysis revealed that all the size parameters of rock debris are reduced in saturated conditions compared to dry conditions. Highlights: Chipping efficiency was investigated in dry and saturated rock cutting with a simple chisel pick. The production capacity, chip size, and weight percentage of large chips were found to be lower in saturated cutting conditions. The proportion of fines was found to be higher in saturated rocks. The reduction of chisel production capacity was greater in saturated rocks with higher porosity and water content when compared to the same dry conditions. There was a strong correlation between cuttings size descriptors and production capacity in both dry and saturated conditions. [ABSTRACT FROM AUTHOR]