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1 <br />' Table 1. -Soil Properties <br />I <br />1 l <br />-~ <br />1 <br />1 <br />1 <br /> <br /> <br />1 <br />1 <br /> <br />-~,1,~. ~,- . ,k <br />Description Max dry density <br />(pcf) Saturated Density <br />(pcf) Cohesion <br />(pst) Direct Shear <br />(Friction angle) <br />SiltstoneClaystone ]28 140 300 45 <br />Embankment I15 128 200 I8 <br />Silry Sand <br />Overburden I10 122 125 16 <br />Clayey Sand <br />Overburden ]12 125 150 ]8 <br />Alluvium 126 138 0 32 <br />Liner Core 118 130 200 16 <br />EMBANKMENT DESIGN <br />Based on the results of the geotechnical site investigation, it was decide that the <br />embankment would be constructed of a mixture of the siltstone /claystone bedrock and <br />the silty/sandy clay overburden located on the site. The embankment will not extend <br />above the ground surface and will extend down into bedrock. <br />DESIGN ANALYSIS AND CRITERIA <br />The proposed reservoir embankment was analyzed using the XSTABLE v5.lO5a <br />computer program. XSTABLE was designed to analyze the slope stability of earth <br />embankments subjected to several critical situations that may occur during the life of the <br />embankment. For this project, seven situations were identified as critical. <br />Case 1 - Miniug Conditions - "O" Street. A 75 foot setback has been proposed <br />from the Public R.O.W. for this location. An Ei.S. 20 highway loading with a 1.3 <br />impact loading factor has been added to the stability model <br />Case 2 -Mining Conditions - 71`t and 83r" Ave. A 40 foot setback has been <br />proposed from the Public R.O.W. for this location. An H.S. 24 highway loading <br />with a 1.3 impact loading factor has been added to the stability model <br />Case 3 -Mining Conditions -Cache La Poudre River. A minimum 100 foot <br />`~ setback has been proposed for this case. <br />' Case 4 -Mining Conditions -Surrounding private homes. There are several <br />private homes that surround the proposed site. A minimum 100 foot setback has <br />' been proposed for this case. Typical foundation loading has been added to the <br />stability model for this case. <br />' Case 5 -Mining Conditions -Fish Hatcheries -There are several existing fish <br />hatcheries adjacent to cell 4. A minimum 100 foot setback has been proposed for <br />this case. A 5000 psf loading has been added to the stability model. <br />1 <br /> <br />