SREL C3 – Construction Challenges and Solutions

This paper discusses the challenges encountered and solutions adopted during the construction of 3,876 feet of deep mixing method (DMM) cutoff wall, 7,116 feet of soil-bentonite (SB) wall, 1,100 feet of Slag-Cement-Cement-Bentonite (SCCB) wall, and earthwork during reconstruction of the levee after cutoff walls were constructed. The DMM wall encountered challenges due to use of air pressure through the drill stems, multiple instances of stuck augers in the ground, and impact on mixing index due to a broken paddle on the auger. The challenges with open trench soil-bentonite (SB) and Slag-Cement-Cement-Bentonite (SCCB) walls included confirmation of the tie-in layer, interpretation of trench sounding data, a slurry leak, and quality control issues. The paper emphasizes the importance of construction sequencing and challenges encountered at the tie-in locations of different walls. The paper also discusses the challenges to reconstruction of levee embankment and the solutions adopted to overcome the varying stratigraphic conditions at the degrade elevation and different cutoff wall types creating varying challenges to the reconstruction of the levee.