Foundation Densification for Fossil Plant Loads

A case history is presented in which foundation soils in excess of 50 ft (15 m) deep, were densified in place to the degree required to support the loads of a coal‐fired electric generating plant. The use of drop‐weight compaction and compaction grouting techniques resulted in a significant savings when compared to a more conventional pile foundation system. The application of deep densification techniques has gained increased popularity in recent years. However, even when the soil conditions on a major project are appropriate for in‐place densification, the implementation of a deep densification foundation plan may be difficult. A large portion of this difficulty is attributed to the required deviation from the traditional methods of site investigation, contract preparation and construction management. The case history considers how the foundation plan was developed to allow deep densification to be a viable foundation preparation alternative and, ultimately, part of a successful foundation system.