Page - 516 - in Book of Full Papers - Symposium Hydro Engineering

Figure 14. Soil Cement Placement on Primary Embankment. Source :Hazama Ando-Wika JO Drone Step 4: Finally after the soil cement is completed the top layer is covered with soil and the project waits till next year before the DMSI can commence. The soil cover used to prevent the Hexavalent Chromium leaching from cement into the water. 2.3. Stage 2. Deep Mixing Soil Improvement,– Second Construction Season (2018) After the water level decreased in the second construction season, the start the DMSI works will commence. There are planned for approximately 4,300 columns up to 24 m depth. Each column is a column pair made from twin 1-m screws with 20cm overlap. The column pairs will be placed in sections, with 21 column pairs with 2.2 m Centerlines for section width of 45.8 m. Each section along the axis of dike will be placed at 2.2 m intervals. As mentioned earlier, the DMSI equipment and support facilities are heavy and not quickly moved. Coupled with the very short construction season of less than 5 month the logistics of completing all the work within a single season is a challenge. Originally, it was planned to use six complete DMSI teams (mixing machines with their cement slurry supply plants) but the Contractor has proposed to utilize 3 DMSI groups working double shifts. After DMSI works have been completed the tops of the DMSI Columns will be covered with soil again to prevent the Hexavalent Chromium leaching from cement into the water. The Project site will then have to wait until the following year to complete the closure Dike. 516