Laserfiche WebLink
AMERICAN ENGINEERING TESTING, INC. AET Project No. 22-00012 <br /> the densification of the soil around and over the pipe. The contractor may have to use special <br /> manual techniques to properly compact the backfill under the haunches of the pipe, in order to <br /> prevent voids and prevent lateral movement of the pipe. The bedding must be in direct contact <br /> with the pipe before the trench is backfilled. <br /> The excavated non-organic soils can be used as backfill for new utility line trenches. We <br /> recommend that each lift of the trench backfill be mechanically compacted to at least 95% of the <br /> maximum Standard Proctor dry density. Within 3 feet of the pavement subgrade elevation, the <br /> compaction should be increased to at least 100% of the maximum Standard Proctor dry density. <br /> Under lawns or landscaped areas, compaction to at least 90% of the maximum Standard Proctor <br /> dry density should be adequate. Cohesive soils used as utility trench backfill should be moisture <br /> conditioned within 2% of optimum water content before placement. The fill should be placed in <br /> lifts thin enough to attain the specified compaction level throughout the entire lift thickness. This <br /> normally requires that fill be placed in loose lifts less than 8 inches thick. <br /> 6.9 Pavements <br /> 6.9.1 Subgrade Preparation <br /> We found soft, compressible non-organic clay in our borings in the new pavement areas. Further, <br /> up to about 3 feet of new fill will be placed to attain the desired grade in the pavement areas. <br /> Pavements constructed over these soils will undergo settlement as the soft soils consolidate <br /> under the weight of the new fill embankment.Areas of thicker fill and deeper soft soils will settle <br /> more than areas of thinner fill and shallower soft soils. <br /> It is typically cost prohibitive to carry out deep soil correction under pavements. One way to <br /> reduce post-construction settlement and associated pavement distress would be to place the new <br /> fill and aggregate base course, and then delay paving, or delay placement of the bituminous wear <br /> course layer until the following Spring. However, please note that heavy vehicle loads traveling <br /> on only one lift of bituminous can lead to excessive distress of the initial bituminous layer, <br /> Page 20 of 28 <br />