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��8.B. - Page 130 5-Lot Residentiai Development Decernber 9, 2010 <br /> � <br /> +■`o) <br /> � <br /> Lateral Spread�in� <br /> Th� subject site is located adjacent to a bend in a cl�anneli�ed creek. T�e creek is currently <br /> located witb.in a concrete-Zined channel with an approximate depth of 10 feet. As such, water <br /> wl�ickt may have produced a potential hazard due to saturation of sandier sediments at the site is <br /> no longer present in the site soils. Groundwater was not encountered in auz borings at or above <br /> the level of the creek. Due to the lack of saturated conditions at or above the level of the creek <br /> cha�u�el, the presence of very stiff to hard clay soils in the upper 22 feet, and the nature of the <br /> concrete channel it is ESl''s opinion that the potential fo� lateral spreading to occur at the site is <br /> low. <br /> 6.0 RECOMMENDATIONS <br /> Site Preparat�on and Grading <br /> 1. 'The site should be pzepared £or grading by removing existing vegetation, debris, and <br /> other potentially deleterious materials #'rom areas to receive iinprovements. E�isting <br /> utility lines thar �vi11 not be serving the proposed residences should �e either remov�d or <br /> abar►doned. The appropriate metbod of utilzty abazidonznerzt will depend upon the type <br /> and depth of�e utility. Recozzux�endations for abandonment can be znade as necessary. <br /> 2. Prior to grading operations, the al.d foundation systems for the existing structures should <br /> be removed. Tlae building pac�s for the proposed residences sk�ould be sub-excavated a <br /> miniz�um of 18 inches ar to the top of the expansive clay soil. This sub-exca�ation <br /> shou�d extend at least 5 feet beyond the peri�neter fo�ndation. The exposed ground <br /> sk�ould be observed by the Geotechnical Engineer to determine the need for additional <br /> sub-exca�ation. Ruts oz depzessions resulting from the re�aval of exist.irag utilities, <br /> and/or other foundations, should be properly cleaned out down to undisturbed native soil. <br /> 3. The bottom of the resulti.x�.g depressions should be scarified and cross-scari�ed at least <br /> eight inck�es and recom�acted to a m�nimum of 90 percent compaction relative to the <br /> maximum determined in t�e labaratory using ASTM D1557 at a moist-�re content above <br /> optimum. These depxessions skaould then be backfilled with approved, compacted <br /> structural �ill, as specified herein this zeport. Clearing and backfilIing operations should <br /> be conducted uzader�kEe feld observation ofthe Geotechnical Engi�eez. <br /> 10 <br />