PERMFILE54247 - Laserfiche WebLink

Home Browse Search

D~ A. G. WASSENAAR, INC. iii iiiiiiiiiiiii iii 999 ~ ~~,~~ GEOTECNNiCAL CONSULTANTS RNONE 303iT39~Bi00 3i BOS ~vANHOE SUITE] DENVER COLORADO 80333 May 26, 1987 Mr. Al LaSelle 15560 Ee~st 12th Avenue, Suite 301 Aurora, Colorado 80011 Subject: Geotechnical Evaluation Coal Creek on Sections 11, TSS, R65W Arapahoe County, Colorado Project Number 8470 Dear Mr. LaSelle: 14, 24, 25 and 36 As requested, we have completed the geotechnical evaluation of the material along Coal Creek in Sections 11, 14, 24, 25 and 36 of TSS, R65W in Arapahoe County, Colorado. The purpose of this evaluation was to determine the suitability of the material as drain material for the Senac Dam Project and to estimate the quantity of material available. Subsurface conditions were explored by drilling thirteen (13) test borings at the locations indicated on Figure 1. These test borings were drilled in Sections 11 and 14 only. The borings were advanced using a 4-inch diameter, continuous flight auger powered by a CME-45 drilling rig. At frequent intervals, bulls samples of the subsoils were taken for laboratory analysis. The locations of sampling are presented on the Logs of Exploratory Borings, Figures 2, 3, and 4. The Legend and Notes are presented on Figure 5. Our test borings indicate the subsoils, in general, consist of approximately 0.5 to 1.5 feet of topsoil over zero to 17.0 feet of sandy to very sandy clay. This is underlain by 6.5 to 29.0 feet of poorly graded slightly silty sand with scattered gravels and scattered silty to clayey lenses and layers. Medium hard claystone bedrock or very hard claystone- sandstone bedrock was encountered in each test boring at depths of 9.5 to 36.0 feet. Ground water was observed at depths of 1.5 to 12.0 feet in all test borings at the time of drilling. All test borings caved at depths of 1.5 to 13.0 feet. Amore complete description of the subsoil and ground water is shown on Figures 2 through 5. The bulk samples were returned to the laboratory where they were visually classified and appropriate testing assigned to specific samples to evaluate their engineering properti~as. The laboratory tests included nine (9) gradation analysis tests and Atterberg limits tests conducted to evaluate grain size distribution and plasticity of selected samples. These results are presented on Figures 6, 7 and 8. Quantities of the proposed, probable and possible drain material are based on the estimated area determinations presented on Figure 9 and the estimated depth of material shown on Table I. The quantity of material estimated to exist ranges from about 660,000 to 670,000 cubic yards in the area of our test boring locations to about 6,450,000 to