Transactions . llowance is to be made for corrosion it canbe applied to the results calculated as above. Such an allowanceshould be added to t; w and / being left unchanged. 31.—Magnitude of the Pressure.—The pressure which the tubbinghas to withstand is usually calculated as that due to a column ofwater of a height equal to the depth of the tubbing. When,however, there are water-bearing strata between beds of im-pervious rock, it may be necessary to measure the depth ofthe shaft from the outcrop of the water-bearing strata. It is perhaps possible, with certain soils, to encounter pressuresgre
Transactions . llowance is to be made for corrosion it canbe applied to the results calculated as above. Such an allowanceshould be added to t; w and / being left unchanged. 31.—Magnitude of the Pressure.—The pressure which the tubbinghas to withstand is usually calculated as that due to a column ofwater of a height equal to the depth of the tubbing. When,however, there are water-bearing strata between beds of im-pervious rock, it may be necessary to measure the depth ofthe shaft from the outcrop of the water-bearing strata. It is perhaps possible, with certain soils, to encounter pressuresgreater than that due to an equal head of water. In such casesProf. Rankines formula may be used. Thus, if h be the depthin feet, iv the weight of a cubic foot of the earth, and 6 the lie Tnstif-utiorv of Mining Engineers VomJLKXIK PLATE II Transeu>tioTusJ9071908. 7b il/ustrafe I)rJ.+yorrowsFaperon T/k Strength ofOzst^vn Tubbing for Prep Shafts. Fig. 1. Fig 2. nrnnnaizzicHzi Scale, 3 Feet to 7 Inch. Fig. Fig. 4. 9
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Keywords: ., bookcentury1800, booksubjectmechan, booksubjectmineralindustries
