3412 BELL AVE 2016-01-01 MF Import

.. DAVID L.NELSON AND ASSOCIATES,INC. — � ConsultingEnginecrinqGeology January 26, 1987 ProjE�ct No. 9387 Page two As approximately shown on thz enclos�d she��t M-1 , the block 'wall' has been constructed against the existingtfill soils, but hconcbrete drivewayloccurs some in front of and behind the 'wall . The existing distance from the 'wall' , and an exposed s�il area occurs up to the 'wall' . Presently, the surface of :he exposed soil area drains over the 'wall ' , but the concrete driveway drains into constructed drains which outfall into the approved o�tfall drainage system. The block 'wall ' censists of conventional 2'x2'x6' concrete ecology blocks, with concave and convex ribs, bottom and Lop. The 'wall' created by placing these blocks on top of �ach other generally makes up the northerly property line. Rockery rock has been placed alo�g the downslope side oP the 'wall' along the northeastern side. 7he 'wall' area created by the block ` stacking appears to have only a slight batter into the slope, if any. Opinions The use of ecology blocks is. generally limited to slope areas of marginally stab:e, to st�ble slopes, which are well dralned. If the slope areas are found to be marginally unstuble to unstable, the ecology blocks 9re not recommended. The natural soils wlthin the site appear Lo consist of dense glacial soils (glacial till) , whicti are considered normally stable. However, the artificial fill placed along the slope is not considered stable, since no evaluation or inspect!on for structural fill �as performed. We wouid consider tmis are to be marginally stable, with some question, since geotechnical evaluation was not performed. Based upon the understood development within the area, it appears that some rea�onable effort should be made to increase the suspected marginally siable and questionable fill area stability. Snort nf removal and replacement of the block 'wall' and total re-development, we anticipate that removal and replace- ment of the fil] soils behind the !.wzll ' •and adequate drainage be anticipated. ' To achieve a reasonably stable ecology block 'wall ' area, it appears that some specific improvements to the area should be made. Recommendatinns Rs shown on sheet �4-3, an extention of the existing concrete driveway is Dro- posed, together with regrading and erosion protection of the exposed soil areas.