Karst Development In Coastal Plain Sands: A "New" Problem in Foundation Engineering

Abstract

Settling of a home located on clayey sands of the Plio-Pleistocene Citronelle Formation in Mobile, Alabama was identified as being caused by the incongruent dissolution of kaolinite to form gibbsite. On a molal basis, the transformation causes a volume loss amounting to nearly 35 percent. Sufficient kaolinite is present in the formation to account for small sinkholes in a homeowner9s yard and the settlement of his home. A damage suit was successfully filed by the homeowner against his insurance company for breach of contract because it was shown that he was entitled to compensation under a clause of the contract covering damage caused when “settlement or collapse results from subterranean voids created by the action of water on limestone or similar rock formations.” Arguments are presented to show that the clayey sands are, in fact, undergoing dissolution and, therefore, are behaving similar to limestone by the fact that water was dissolving a mineral and causing the formation of void spaces.