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NORRISpN~KNUOShN Gp y~?AN 1. INS. ... _... <br /> <br />0 SB~TdI~I~T51' <br /> <br />.;~:' <br />The first problem in evaluating the stability of the slopes of the re- ' <br />claimed area, having estimated the unit weight of the material, was to . <br />estimate the strength parameters to be used in the analysis. <br />~$~Gs•~~-rha,Jin4 examined the various materials in the spoiNl pile,:aU:conse:rva~ .. <br />tiye~ estimate of the shear strength agri angle of intiernall friction was„;~~',`_ <br />v <br />.~~.: Second,~having observed a failed slope standing at 46 degrees, a =':~ <br />simple calculation was performed for that slope, ~assum~ng a~failure:at-~,0 ~~~ <br />,_tl,- <br />degrees, .. to back-calculate the strength paramete~:~:U These values are' ^"J. <br />believed to be very conservative lower-bound parameters. Third, the prob- <br />~:~. <br />lem was researched in standard references:: The only data was located in <br />the Engineering and Design i4anual, Coal Refuse Disposal Facilities prepared , <br />by E. D'Appolonia Consulting Engineers, Inc., for the Department of the <br />Interior Mining Enforcement and Safety Administration. ,,This referenee~~ <br />r,~eports considerable variations, in reported values, with a minimum cohes~;~~l <br />- of 3.5 pounds per square inch- (approxtmatel~~ snn ~.,~~„~er squa e'~fioo~=~ <br />w <br />a <br />ees. <br />Slopes were examined in the field and by plotting cross sections from the <br />topographic data available. Standard chart solutions were employed to <br /> <br />investigate stability sensitivity to such parameters as slope, height and ' <br />soil strength. The slope condition selected for analysis represented no~t`'~ <br />ryecessaril the stee est slope, but the highest .slope pr~esent~ng.the_grea,,~ <br />.... <br />~e~s.t.: hazard. This is believed to be the north-northwest ~factng s q.p,„~ <br />1 <br />failure of which could threaten Coun y,Road 5 an the mtn s,~o,p,~~ <br />~,., , <br />Because no boring data is available for this area, conservative approxima- .;'.,. <br />-S{ <br />tions of the original ground lines and soil strength parameters were made. ;`;, <br />'~.y,A: <br />Soil properties for the original ground were obtained from the Chen &~:"ttr:, <br />,.,r:~~. <br />Associates, Inc., report for borings nearby. Relatively low values were "~::;~ <br />;.8 <br />used. ~ ° <br />u <br />-4- <br />