 • Date:29 Jun 2020
• Views:5
• Pages:15
• Size:382.30 KB

Share Pdf : Procedure For Determining Rock Weights Sizes And Gradations

Report CopyRight/DMCA Form For : Procedure For Determining Rock Weights Sizes And Gradations

Transcription:

Some measurement precautions are necessary to obtain the best results from this procedure. They are as follows, 1 The graph in Figure 3 and formulas are for rock that has a specific gravity of 2 65 165. pounds per cubic foot Use this graph or formula unless the actual specific gravity Gsa is. known and varies more than 5 percent 0 13 from 2 65. To correct to the actual weight Wa use this formula. Wa W from Figure 3 2 65 x Gsa, 2 When measuring the major and minor perimeters do not measure sharp peaks protrusions. or valleys Move the tape slightly off the 90 angle or adjust the measurement to represent. the rock s general shape, 3 The approximate formula 0 335 P1 P2 3 Weight of rock W in pounds can be used To. obtain the equivalent d use this formula,d inches 2 4 x W. Use the following procedure for the perimeter measurement method. 1 Place the rock in its most probable at rest laying position. 2 Imagine two vertical cutting planes passing through the rock at nearly right angles to each. other Measure the two resulting perimeters in feet and add them together. 3 Enter the graph in Figure 3 at the measured P1 P2 and follow horizontally to the intersection. with the line labeled Weight of Rock W Follow down the chart and read the approximate. weight in pounds on the bottom scale, 4 To determine the equivalent d enter the graph at weight at the bottom of the chart.
Proceed vertically to the intersection of the line labeled Size of Rock d and move. horizontally to the right to read d, 5 To determine the weight of small rock and sand gravel determine the volume in cubic feet. and multiply by 100 pounds See Figure 4,Note The volume of a cone is V 3 14 b2h. Where V Volume in cubic feet,b Base in feet,h Height in feet. EFH Notice 210 WI 106, After the weight and d of each rock except small rock gravel are determined they need to be. accumulated into sizes that would be held on a particular screen size such as 1 5 D50 D50 etc. The weights of the rocks that have a d greater than the screen size are accumulated and. considered retained on the screen The cumulative percentage is subtracted from 100 percent to. obtain the percent passing See Examples 1 and 2, Comments on Example 1 are D50 6 inches Dmax 12 inches Note 3 rocks which have a d.