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In one case study, vibroflotation was found to be one of the most economical remedial solutions compared to other common ground improvement techniques. Concluded in 1999, the study examined possible design solutions for Croton Dam, which was found to be susceptible to damage due to earthquake shaking. Although, it is located near Muskegon, Michigan, it is considered a “high-hazard” dam so it must be designed to account for large ground accelerations. The dam consists of two earth embankments, a gated spillway, and a concrete and masonry powerhouse. The earth embankments are composed of a hydraulically placed sand fill with concrete cores. A seismic analysis of the embankments found that they were likely to liquefy in the event of a magnitude 6 or greater earthquake. It was determined that adequate strength to resist liquefaction could be achieved by compaction (Uddin & Baltz, 2004). Table 1 displays the possible remediation techniques examined in this study, along with associated costs. Compared to the other two ground improvement methods (jet grouting and compaction grouting), vibroflotation proved to be the most economical solution for this case.

Table 1: Comparison of costs at Croton Dam (Uddin & Baltz, 2004)

Table 1: Comparison of costs at Croton Dam (Uddin & Baltz, 2004)

The three ground improvement techniques examined (vibroflotation, jet grouting, and compaction grouting) were quoted by contractors based on the “maximum plausible area” of improvement. This was taken to be 70% of the maximum possible area of improvement. While vibroflotation was judged to have the greatest increase on material strength, it was also considered to cause significant damage to existing surficial structures (Uddin & Baltz, 2004).

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