11731 AIRPORT RD Geotech Report 2018-01-02 MF Import

�8/18/2005 15:27 4257478561 GEOTECH PAGE 05 Lucia Development, LLC JN 05233 August 18,2005 Page 4 • Fill to the desired ske gredes several months prior to constructing on-grade slabs, walkways, and pavements around the buildings. This aHows the underlying soils to undergo some consolidation under the new soil loads before final grading is accomplished. • Conned all in-ground utilities beneath the floor slab5 to the pile-supported floors or grade beams. This is intended to prevent utilities, SUCh as sewers, from being pulled out of the floM as the underlying soils settle away from the slab. Hangers or straps can be poured into the floors and grede beams to carty the piping. The spacing of these suppotting elements will depend on the distance that the pipe material can span unsupported. A slgn�cant geotechnical eonsideration for developmerrt of thfs aite Is the ove�ly moist to wet condition of the silty sals and the potential for the siltier sands to become werly wet due to rainfall or grourxJwater. Based on our observatlons, the molsture coMents of the on-site silt soils are above the optimum moisture corrtant. Therefore, these sift soils will be unstable under vehide traffic and will 6e subjeCt to pumping under equipmeM and compacted fills. It may be prudent to cover these soils wiih a layer of granular (crushed rock) fill to proted them from disturbanee from vehicle and foot trdffic. Due to their poor compaCtability and organic conteM, the on-site silty soils should rat be rausad aa structural fill. Imported granular is recommended for all structural fill on the praject. UtiGty trenGh baCkfill in structural areas, such a5 pavements, should also consist af imported structural fill. Improper compaction of backfill in utflity trenches and around control strudures is a common reason for pavement distress antl failures. Due to the loose, near-surface soil conditions, we recommend that asphalt parking areas be supported on a minimum 1-foot layer of imported granular sttuctural fill. Additional pavement recommendations are provided in the PavemeMAreas seetion of this report. The erosion cortt�ol m�asures needed during the site development will depend heavily on the weather cond'Rions that x�r. encountered. While Site dearing will expose a large area of bare soil, the erosion potential on the site is relatively low due to the gentle slope of Me ground. We anticipate that a sift fence will be needed around the doumslope sides of any deared areas. Rocked construction aecess roads should be extended into the site to reduce the amount of soil or mud caRiPd oH the property by t�uoks and equipment. Wherever possible, these roads should fallow the alignment of planned pavements, and trucks should not b.� allowed to drive off of the rock�overed areas. Existing catch basins in, end immediately downslope of, the planned work areas should be pmtected with pre-manufadured silt soaks, Cut slopes and soil stockpiles should be covered with plastic during wet weather. Following rough grading, it may be necessary to muleh or hydroseed bare areas that will not be immediately wvered with landscaping or an impervious surface. Additional erosion wntrol measures may be required due to condkions encountered during construetion. Geotech ConsuRants, Inc. should be allowed to review the final development plans to verify that the recommendations presented in this repor! aze adequately addressed in the design. Such a plan review would be addkional woric beyond the cunent scope of work for this study, and it may inelude revisions to our recommenaations to accommodate site, development, and geotechnical constraints tfiat become more evident dunng the review process. We recommend including this report, in its entirery, in the project contract documents. GEOTECH CONSUITANTS,INC. J