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DEC-20-2005 TUE 03:26 PM HWA GEOSCIENCES FAX NO. 4257742714 P. 04 <br /> 5 <br /> December 20,2005 <br /> HWA Proposal No.P 5525 <br /> Pavement cores will he cut before hollow-stem auger drilling commences,so that the existing <br /> pavement section at the boreholes may be accurately measured, Standard Penetration Test(SPT) <br /> samples will be obtained at 21-foot intervals in each boring. Soil cuttings generated during <br /> drilling will be placed in steel drums and disposed of off site. An HWA engineering geologist <br /> will monitor and log the borings,and will collect soil samples at selected depth intervals for <br /> classification and laboratory testing. Based on our present understanding,ground water is not <br /> anticipated to be encountered and,accordingly,we did not include piezometer installation in this <br /> proposed scope. Upon completion,all borings will be backfilled with bentonite chips in <br /> accordance with Ecology requirements. <br /> The test pits will bc excavated 5 feet below the sewer invert,or to a depth of 12 feet,whichever <br /> is shallower. An HWA engineering geologist or geotechnical engineer will monitor and log test <br /> pit excavation. The City will need to provide a backhoe capable of digging at least 12 feet. <br /> Upon completion of the test pits,the excavated soils will be backfilled and tamped in placed <br /> using the backhoe bucket. There will bc some ground disturbance at the test pit areas,and the <br /> test pit backfill will settle somewhat after completion. We have not allowed for site restoration <br /> or future maintenance associated with such disturbance and future settlements, and it is assumed <br /> that the City will look after this as required. <br /> Task 4. Laboratory Testing: We will perform laboratory tests on selected soil samples retrieved <br /> from the borings and test pits to characterize engineering and index properties of the site soils. <br /> Tests will be selected based on the soils encountered, and will include natural moisture content, <br /> grain size analysis,and plasticity index(if cohesive soils arc encountered), and moisture-density <br /> (compaction)relationships for hulk samples retrieved from the test pits. <br /> Task 5. Engineering Analyses: We will analyze the data acquired from our subsurface <br /> explorations and laboratory testing with respect to temporary excavation stability,pipe <br /> foundation support,re-use of on site soils for trench backfill,and the suitability of pipe bursting <br /> at selected areas. <br /> Task 6. Draft and Final Reports: We will prepare draft and final geotechnical reports <br /> presenting the results of our study. We will include a site map showing our exploration <br /> locations,boring and test pit logs,and graphs and charts of laboratory test results. Our report <br /> will include design and construction recommendations pertaining to the following: <br /> a) Temporary excavation support and recommendations for design of temporary <br /> shoring,if required. <br /> h) Recommendations for pipe foundation support,pipe bedding, and trench backfill <br /> material and compaction,in accordance with Everett Standard Specifications. This <br /> includes evaluation of the suitability of on-site soil for re-use as trench backfill. <br /> c) Design recommendations for below-grade structures including lateral earth pressures, <br /> vertical load on buried pipes, and buoyancy considerations. <br /> Y5525 v3 due 3 HWA GEOSCIENCES INC. <br /> 25 <br />