3800 RIVERFRONT BLVD Geotech Report 2023-05-04

I March 26, 2019 H WA Project No. 2015-061-21 Task 600-7 compaction should only be attempted during the dry summer months. Other types of gas'barrier should be installed in areas requiring construction outside of the dry summer months. If the above-mentioned approved LPSB stockpile is not sufficient quantity to meet the project LPSB needs, laboratory testing will be required to verify that either imported or in-place LPSB meets the intent of the material. For imported LBSB, we recommend that the proposed source location be tested and approved prior to importation of LPSB material. The testing protocol and frequencies for proposed imported LPSB are provided in Table 4. If the in-place soils are to be used as LPSB, testing along the roadway will be required to verify that the soils meet the intent of LPSB and are compacted to a sufficient level to achieve a permeabilityof l x 10-5 cm/sec or p less. The testing protocol and frequencies for in-place soils to be used as LPSB are provided in Table 4. Table 4 LPSB Testing Requirements Required Material Testing Frequencies Imported In Place Test Designation Low Permeability Soil Barrier Low Permeability Soil Barrier (LPSB) (LPSB) Density Test(ASTM Not Applicable 1 test every 200 feet of roadway * D 6938) Gradation 3 initial tests for evaluation by 1 test every 200 feet of roadway* (ASTM D 422) the Engineer prior to placement Moisture/Density 3 initial tests for evaluation by 1 test every 200 feet of roadway* i (ASTM D 1557) the Engineer prior to placement Hydraulic 1 initial test on a remolded 1 test every 200 feet of roadway on Conductivity composite sample, at 1 to 3 a remolded composite sample, at 1 (ASTM D 5084) percent over optimum moisture to 3 percent over optimum content, and compacted to 93% moisture content, and compacted of the uncorrected laboratory to the level determined through maximum drydensity, densitytestingat the subject J determined by ASTM D 1557 location* Moisture Content Daily as processed (ASTM D 2216) * Samples and compaction testing of in place soils to be obtained at the approximate midpoint of the existing layer. Y I Geotechnical Report Revision 3 26 2019.doc 23 HWA GEOSCIENCES INC.