Laserfiche WebLink
E-20 <br />MOUND DESIGN T-20CEDURE (Continued) <br />(For Flows up tt 1200 gpd) <br />G.3. Calculate basal width ratio <br />by dividing rock layer <br />loading rate of '' .21 gpd/ft^ <br />by allowable soil loading <br />rate; <br />1.20 gpd/ft2 1 g,j^gpd/ft2 = 2.0 <br />Check this value on page E-16. <br />4. Multiply basal width ratio by <br />rock layer width to get <br />required basal width; <br />2.0 0 X 10 f t = t <br />H. Downslope Dike Width <br />1. If landslopc is 3% or more, <br />subtract rock layer width <br />froni basal width to obtain <br />nininum doOTslopo dike toe width <br />20 ft - 10 ft = /g> ft <br />2. Calculate mound height at edge <br />of rock layer on downslope side; <br />a. Determine depth of clean sand <br />fill at upslope edge of rock <br />layer: / feet <br />b. Multiply rock layer width by <br />landslopc to determine drop <br />in elevation; <br />/ X 3 7. 4 100 = 0.3 ft <br />c. Add drop in elevation to depth <br />of clean sand at upslope edge <br />of rock layer to get depth of <br />clean sand at downslope edge <br />of rock layer. <br />0,3 ft + / ft = /.3 ft <br />d. Add depth of clean sand at down- <br />slope edge to depth of rock <br />layer to depth of soil backfill <br />to get mound height at downslope <br />edge of rock layer; <br />A 3 ft +0.75 + A25ft = 9^3 ft <br />e. Enter table on page E-18 with <br />landslope and downslope dike <br />ratio. Select dike multiplier <br />of 3. 30 <br />H.2.f. Multiply dike multiplier by <br />do\.mslopo mound height to get <br />downslope dike width; <br />3.20 X 2,3 = /o.7ft <br />g. Compare the values of step II. 1 <br />and step H.2.f. Select the <br />greater of the two values as <br />the downslope dike width; <br />/«?. J feet <br />h. Calculate upslope dike width <br />using upslope mound height <br />and upslope dike multiplier <br />f,rom pa^-18; ^ <br />i. Total mound width is the sum <br />of upslope dike width plus rock <br />layer width plus downslope dike <br />\7id th; <br />+ /O ft +/ojft Z9.2ft <br />3. If landslope is 2.9 percent or <br />loss, basal width includes both <br />the upslope and downslope dike <br />widths. <br />a. Calculate do:^islope dike width <br />using steps II.2.a. through <br />H.2.f; _ _ _ _ _ _^feet <br />b. Calculate upslope dike width <br />using upslope mound height and <br />dike multiplier from Page E-18; <br />_ _ X _ _ft = _ _ _ft <br />c. Add dovTnslope dike width to <br />upslope dike width to rock <br />layer width to get total mound <br />wid th; <br />_ _ft +_ _ft +_ _ft = _ _ft <br />d. Compare total mound width to <br />required basal width from step <br />G.4. If total mound width is <br />greater than required basal <br />width, use calculated dike <br />widths. If required basal <br />width is greater than total <br />mound width, increase downslope <br />dike width.