1718 ENGLAND AVE 2016-01-01 MF Import

IGcotechnical Gngineering Evaluation England Avenue Lot � Junc 2, 2005 NGA File No.411805 Pagc ]3 � Rockery Construction Rockeries are planncd to support grading cuts along the eastern and western sides of the driveway, �nd on � the western side of the residence. We reconu:iend that thesc rockerics, be conswcted in accordance ��ith the Associated Rockcry Contractors (ARC) guidclincs and appropriate local standards. Rocl•cries should f bear on mcdium densc or bettcr ncdivc subgrade. Any loose or disturbcd soil exposed in the subgrade ! should bc compacted to a non-}�icldinL condition or over-excavated :md replaced with rock spalls. IPreliminary pl�ms indicate that the cxposed hcight uf �he pl:mr� :l rockcries will h�ve exposed heights of I two to five fect. If rockerics of greaten c�ights are planned, we should bc retained to evaluate these rockcrics on a casoby-basc basis. Wc recommend that aIl rockcrics havc a minimum cmbedment of onc I foot below final grade in front of thc rockery for flat surfaces and two feet for sloping ground, as shown on the Cut Rockery Detail in Figure 9. 1Ve recommend that the rockeries be pl,�ced against cuts in medium dense or bettcr native materiaL Gach rock in the base course of rocks should n:casurc at Icast � one-third of the total height of lhe rockery including embedment, in the direction perpendicular ta the � prolected face. Gach rock in successive counes shall bcar on at Ieast two rocks below. Thc rockery Ishould havc a minimum cmbedmcnt of onc foot bclo�e flnal gradc in front of thc rockcry. Thc facc o(thc rockcry should bc battcrcd at approximatcly I li: GV back toward thc cut. I Thc ground surfacc bchind and in front of thc rockcry should bc gra:�cd such th,u surfacc runuff is routcd � away from the rockery :�nd is not allowed to (low over the rockery or pond in the viciniry of the rockery. This could be accomplishecl by desiening appropri�te yard drains or drain;�ge ditches strategically placed ro collect and routc storm runoff inlo die storm.rystem. iA drainage blanket 12 to IS inches in width consisting o(hvo- to four-inch rock spalls should be placed betwcen thc rockcry und thc cat, as shown on the detail. A minirnum four-inch diameter, rigid, perforated, PVC drninpipe embedded in a minimmn of one foot of pca gravel or �vashcd rock and wrappeJ in filtcr fabric should be placed at the bottom of lhe dninage blanket. This pipe should be ( slopcd to drain undcr graviry and ouUct into a penn.ment discharge system. Sur[�cc watcr should not bc allowed to mach this drain by sealing the drainage laycr. This could be accomplished by rcplacing thc Iupper 12 inchcs of tlic drainage laycr with low permcability compactcd till soil. I �'VELSON GEOTECHNICAL ASSOCIATES, INC. I