Laserfiche WebLink
:~ ~ ~ • - <br />L_'-=-? J <br />CTL/THOMPSON, INC. <br />CONSULTING GEOTECNNICAL AND MATERIALS ENGINEEES <br />August 16, 1989 <br />Castle Concrete <br />P.O. Box 2379 <br />7250 Allegheny Drive <br />Colorado Springs, Colorado 80919 <br />Subject: Consulta.ion <br />Slope Stability Analysis <br />Quarry Access Road <br />Snider (Queens Canyon) Quarry <br />Colorado Springs, Colorado <br />Job No. CS-1944 <br />Gentlemen: <br />We have prepared this letter to present our preliminary opini~~ns regard- <br />ing stability of two fill areas adjacent to the quarry access road. The areas <br />are identified as Area 1 and Area 4 on mapping prepared by Oberirg, Wurth & <br />Associates. The major area involved was addressed by Obering, Wurth & As- <br />sociates in a report entitled "Snider Quarry Access Road Slope Stability <br />Report", dated July 1988, Project No. 88106. CTL/Thompson, Inc. w,as retained <br />July 27, 1989 to evaluate stability. <br />We have recently been provided topographic cross-sections of ap- <br />proximately the maximum section of each area. That topography irniicates the <br />slope in question at Area 1 is approximately 90 feet high ami blocks a <br />drainage at the toe. Slopes on much of the face in Area 1 are between 33 de- <br />grees (1.55:1) (horizontal to vertical) and 35 degrees (1.43:1). Area 2 is <br />about 60 feet high and at a slope of about 37 degrees (1.32:1). We understand <br />the slope at Area 1 has been comparatively stable for the last tw~~ years but <br />failed occasionally during the previous 20 years. The slope at Area 4 has <br />remained stable over its life. <br />Our experience indicates the steeper slopes at Area 1 and the slope at <br />Area 4 are at the materials dry, natural, angle of repose irdicating a <br />stability factor safety of 1.0. If the materials become wetted, failure is <br />likely. Flattening will be necessary at both locations to increase stability. <br />We believe flattening can be accomplished by either filling or Icy removing <br />material. Filling may make the toe of the slope extend past the current per- <br />mit boundary. Removing material may necessitate moving the access road fur- <br />ther into the hillside. Moving the road into the hillside could cause some <br />upnill slope stability problems. <br />n <br />/= <br />52ap ;dG Rlt ~t.pLWGBL'iD. ~OLC?AGO SP°'NGS.GOLGRa.D0809!8 !7:9)528-si3CO <br />