1997-07-18_REVISION - M1981302 - Laserfiche WebLink

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stood vertically after they were advanced by the 42-inch auger and showed no tendency to cave. Review of the gradation test results of the levee fill show the levee fill was very well graded and quite rocky. Review of compaction test results in Table II shows the percents compaction range, for the 15 compaction tests (two of which were in the foundation ground at the bottom of the fill) from 75 to 103 percent. we believe the wide range in these results and particularly the lower percents compaction are not reflective of the density of the fill but are the result of test error caused by the cobbles in the fill. The efforts it took to dig the density test holes and to advance the "pilot hole" for the nuclear gauge are evidence the fill is well compacted. In our opinion,the levee fill is well compacted but not testable because of the numerous large and closely spaced cobbles (rocks). The Colorado Department of Transportation (CDOT) would call a fill "rock fill' and "not testable" if 50 percent or more of the fill is 1/4-inch in size or larger. Samples of the levee fill showed up to 45 percent retained on the No. 4 sieve. If the gradation tests were adjusted for the large cobble that is "scalped" before the test is run the levee fill would classify as "not testable". Slope Stability Our slope stability analysis is for conditions: a)before the flood; b) for sudden drawdown; c) at the critical flood stage, and c) during an earthquake. The results of our stability analysis are in Appendix A. We assumed the piezometric lines shown on each figure. These lines were selected using our judgment and experience and we believe them reasonable. The assumed lateral acceleration for the earthquake condition used was 0.5 ft/sec/sec. Slope stabilities were analyzed using Slope W, Version 3 by Geo-Slope International, Ltd. FLATIRONS COMPANY LEVEE AT DEEPE FARM PIT CTUT 25,385 4