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07/28/1997 14:15 2�63EFqg73 OTTEN ENGINEERING PAGE 02 <br /> I <br /> Mark T. Otten, P.E. <br /> Engineering consultenc <br /> 3029 NE l:t2nd Slrat <br /> Seaale,WA.98155 <br /> (206)363-9266 <br /> F�.c(206)365-9913 <br /> July 28. 1997 <br /> Mr.Ron Jacobs <br /> 244 Hesther Road <br /> Evemtt,9VA.98203 <br /> Re: Slope Stabiliry Assessment, 244 Heather Road, Everett, WA. <br /> Deat Mz.Jacobs: <br /> This letter presents the results of my teclmical revie.w of the Giles Engineering Associaces,Inc. <br /> C,eotechnical Report and gives concaptual recommendations for slope stabilization. This work <br /> was done in accordance with our Agreement dated July 26, 1997. <br /> I reviewed the Giles Geotechnical Ensinecring Repair Options Report, 244 Heather Road, <br /> Everett,'WA.,project N. 6G-�704016, dated Iune 13, 1997. T observed the site conditions <br /> around the house and on the upper part of the west slope on July 26, 1997. <br /> Review ot Gilee Report <br /> The Giles report is divided into several sections. My comments on the report will be divided by <br /> the Giles scctions. The site conditions and soil types reported in the Site Descriution end <br /> Subsurface Conditions sections are consistent with my observations and my experience with soils <br /> in the vicinity. The repc�rt states that no groundwater was observed in the borings(which were <br /> drilled in May);however,the yazd area was reported to be wet during winter and spring mondis. <br /> 'Che borin;� log for B-2 has a note that seepage was observzd from"drain line backfill:' <br /> H�the Pref minarv Reoai•Recotrunendations section, Giles states that`9andslide is more likely <br /> than not due ta a series of swficisl displacements." I agree with this conclusion. The deeper <br /> soils are dense or hard glacially compacted soil with Uigh strength and them is a low pro6ability <br /> of sliding through the high strength soiis. <br /> '1'he report did not discuss the effect of loose fill soil (1? uld S feet deep in Sorings B-3 and B-4) <br /> un slope stability of the west yazd. It is my understxnding t}�at years after the house was built, a <br /> previous owner impoRed hundreds of cubic yard of fill a�id placed ihe soil in the west yard. <br /> Judging from the low blow cou�ts io Borings B-3 a��d B-4,this soil was not well cumpacted <br /> when it was placed. I.nose silry sand has low strengtU and has a]ow faetor of safety against <br /> sliding wlien place on sloping Browid. Stability of loose fill is further reduced�vl�en the <br /> precipitation in��ltrates into the gound and flqws downs�ope. <br /> 1 �ner» <br /> o�zsi.�x.00c <br />