7431 EVERGREEN WAY TACO BELL 2018-01-01 MF Import

( GEOTECfINICAL ENGINEERING STUDY Taco Bel! Corporation April 29, 1993 E-6140 Page 8 magnitude of such seepage, it may also be necessary to interconn�ct the sump pits by a system of connector trenches. It is recommended that the appropriate locations of subsurface drains, if needed, be established during grading operations by this office, at whic`i time the ssepage areas, if present, may be more clearly defined. The site should be graded so that surface water is directed off the site. Water should not be allowed to stand in any area where buildings, slabs or pavements aro to be constructed. During construction, loose surfaces should be sealed at night by compacting the surface to reduce the potential for moisture infiltration into the soiis. Final site grades shouid allow for drainage away from the building foundations. The ground should be sloped at a gradient of three percent for a distance of at least ten feet away from the buildings in landscape areas. In pavement areas, this may be reduced to one percent. Footing drains should be installed around the perimeter of the building just below the invert of the footing with a gradient sufficient to initiate flow. Under no circumstances should roof downspouts be connected to the footing drain system. Cleanouts should be installed st several accessible locat'ons to ailow for the periodic maintenance of the footin� drain and downspout tightiine systems. ��Aiii: � � � • � : , , : Based on the conditions encountered in our test pits, the soil expected to be exposed by utility trenches should provide adequate support for utilities. Utility trench backfill is a concern in reducing the potential for settlement along utility alignments, particularly in pavement areas. It is important that each section of utility line be adequateiy supported in the bedding material. The material should be hand tamped to ensure support is provided around the pipe haunches. Fill shoUld be carefully placed and hand tamped to about twelve inches above the crown of the pipe before any heavy compaction equipment is used. The remainder of the trench backfill should be placed in lifts having a loose thickness of less than twelve (12) inches. A typical trench backfill section and compaction requirements for load supporting and non-load supporting areas is presented on Plate 3. Trench backfill beneath building, parking, and roadway areas may consist of existing on-site granular fill soils or imported granular mate�ials provided they are placed near optimum moisture content. The native silty sand and silt with sand encountered in our test pits contain a significant amount of fines (13 to 43 percent) and were slightly above optimum moisture. Therefore, unless the moisture content of the native soils can be reduced, it will be necessary to import a granular soii for use as iitility trench backfill. Earth Consultants, Inc.