Laserfiche WebLink
Geotechnical Investigation <br />As part of the 2016 design CH2M HILL performed a geotechnical investigation to provide geotechnical <br />recommendations for the system. The geotechnical recommendations for the 2018 design used those <br />determined for the 2018 design, however, given that the location of the system moved to a new location <br />there needs to be confirmation that the geotechnical recommendations stili apply. TC informed CH2M HILL <br />that they would be using a local geotechnical firm to confirm the previous site geotechnical <br />recommendations still apply. The geotechnical firm will do their investigation as part of construction <br />planning. The drawings as provided in this document are issued for review (IFR) given the geotechnical <br />review that is required to take place ahead of construction. <br />3.1 Geotechnical Field and Laboratory Testing Program <br />A geotechnical investigation was performed as the first step of the final design phase in order to assess the <br />stability of the proposed embankments slopes and verify suitability of borrow material for the constructed <br />wetland system. <br />The geotechnical investigation included desktop study and field investigation components. The desktop study <br />included reviews of available geological and soil maps, historical satellite imagery and geotechnical data for <br />the 61VIN Pond down slope of the project. Based on the information gathered during the desktop study and <br />the data required to advance the design, a test pitting program was planned for early March 2016 (Appendix <br />D). Originally 8 test -pits were planned to be excavated with locations selected to optimize data retrieval while <br />assuming that no surface observations would be possible due to snow cover. <br />Due to a delay in site permitting, the field program was conducted in mid-April 2016, at which point the <br />majority of the snow cover had melted and surface conditions could be assessed visually. Based on the <br />consistency observed between test pits and surface conditions, 6 test pits were determined to be sufficient: <br />TP16-1, 2, 3, 5, 6 and 7. Locations of the excavated test pits were selected based upon preliminary wetland <br />areas, as shown on Figure 3-1. <br />TP1G15.� TPtI <br />M. -K <br />:.. - <br />r�i� IP16-. � 6MNPvnd{ -. <br />� 4 <br />r j• <br />% ■ Proposed Test Pit Location <br />Figure 3-1: Test Pitting Locations <br />PEABODY_FINAL_DESIGN_TM_20181010 <br />COPYRIGHT 2Ot2 BY CH2M HILL. INC. • COMPANY CONFIDENTIAL <br />