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• of erosion, creep and shallow slope failures could be accommodated. Steeper fill slopes will <br />require selected rock fill or mechanical stabilization. All fills will be placed on ground that is <br />benched and cleared of all vegetation matter and where available boulder rubble will be used as a <br />starter fill to increase strength and drainage. All fills wilt be approved by an on site geotechnical <br />engineer and placed in appropriate lifts, thicknesses, and moisture then compacted with the <br />appropriate equipment to the recommended density. Reclaimed fill slopes should not be steeper <br />than 2:1 and should be benched to control drainage and promote revegetation. <br />Boulder rubble fill is discussed in the preliminary report. The preliminary report states in part: <br />"Where available, boulder rubble with a wide range in sizes would be acceptable for use as a <br />starter fill at the toe of the fill. This is an excellent use for such a material because of its strength <br />and drainage capability". This section of the report was clarified by a letter from Maxim dated <br />October 17, 1996 which states in part: "Where boulder rubble fill is used as a drainage feature <br />beneath a fill, it should be protected from fines migration by either a filter fabric or a suitable filter <br />course. If boulder rubble fill is placed in areas not intended for drainage, it is important the rock <br />be incorporated into a soil matrix to insure that any voids between rock are filled to prevent <br />migration of fines. In this later case a filter course or fabric would not be requ'ved". <br />Boulder rubble fill may or may not be available when needed during construction. Boulder rubble <br />fill would be beneficial if a slope or underdrain were determined to be the appropriate remediation <br />technique for a wet slope or fill. The benefit would be the use of on site materials to construct a <br />• drain. However, if the geotechnical observer mentioned in following sections of this report <br />determines a drainage feature is required, it will be constructed utilizing boulder rubble or other <br />materials determined by proper engineering principles and practices. <br />If boulder rubble fill is used as an drain, it is important the voids between the rock be filled with a <br />well graded filter blanket with the following gradation: <br />Sieve Size Peroen[ Passing <br />3" 75-100 <br />2" 60-80 <br />1" 4510 <br />1/2" 30-45 <br />4 20-30 <br />8 15-30 <br />l00 0-]0 <br />Soundness = 21%or less <br />u <br />-2- <br />