1910 MERRILL CREEK PKY 2018-11-15

Mr. Darren Peugh January 19, 2004 Site Preparation and Gradin� To prepare the site for construction, all vegetation, organic surface soils, and other deleterious materials should be stripped and removed from the site. Based on our observations, we expect that only stripping to remove existing vegetation will be required to expose soil conditions suitable for use as fill material, or for support of new fill and building elements. Stripped vegetation debris should be removed from the site. Once clearing and stripping operations are complete, cut and fill operations can be initiated to establish desired building grades. Prior to placing fill, all exposed surfaces should be proofrolled to determine if any isolated soft and yielding areas are present. Proofrolling should aiso be performed in cut areas that will provide direct support for new construction. If excessively yielding areas are observed, and they cannot be stabilized in place by compaction, the affected soils should be excavated and removed to firm bearing and grade restored with new structural fill. In pavement areas, if the depth of excavation to remove unstable soils is excessive, use of a geotextile reinforcing/separation fabric, such as Mirafi SOOX or equivalent, can be considered in conjunction with structural fill. Our experience has shown that, in general, a minimum of 18 inches of a clean, granular, structural fill over the geotextile fabric should establish a stable bearing surface. Our study indicates that the native soils contain a sufficient percentage of fines (silt and clay size particles) that will make them difficult to compact as structural fill if they are too wet or too dry. Accardingly, the ability to use native soils from site excavations as structural fill will depend on their moisture content and the prevailing weather conditions when site-grading activities take place. Native soils that are too wet to properly compact could be dried by aeration during dry weather conditions or mixed with an additive such as cement, cement kiln dust (CKD) or lime to stabilize the soil and facilitate compaction. If an additive is used, additional Best Management Practices (BMPs) for its use wil] need to be incorporated into the temporary erosion and sedimentation control plan (TESC) for the project. If grading activities are planned during the wet winter months, or if they are initiated during the summer and extend into fall and winter, the owner should be prepared to import wet weather structural fill. For this purpose, we recommend importing a granular soil that meets the following grading requirements: U.S. Sieve Size Percent Passin 6 inches 100 No. 4 75 maximum No. 200 5 maximum* *Based on the 3/4-inch fraction. Prior to use, Terra Associates, Inc. should examine and test all materials imported to the site for use as structural fill. Structural fill should be placed in uniform loose layers not exceeding 12 inches and compacted to a minimum of 95 percent of the soil's maximum dry density, as determined by Amencan Society for Testing and Materials (ASTM) Test Designation D-698 (Standard Proctor). The moisture content of the soil at the ti�ie of compaction should be within two percent of its optimum, as determined by this ASTM standard. In non-structural areas or for backfill in utility trenches below a depth of 4 feet, the degree of compaction can be reduced to 90 percent. Project No. T-5471 Page No. 5