Civil and Building Engineering.

The processes of solution of limestone and dolomite result in openings and cavities, some of which are extensive and important. The Edwards Limestone in Central Texas is an aquifer that provides water for many of the communities and businesses in the area. During construction of a highway, a drill exposed a cavity and alerted the highway engineers to make careful investigations for bridges in the limestone area. Several caves have been opened in Central Texas as attractions for tourists.

Some of the openings collapsed in the past and are filled with boulders, clay, or surficial soils. The weathering processes are continuing in some areas, with the result that in sections of Florida sinkholes appear suddenly, some of which may be quite large. Investigation of the subsurface conditions in karst areas is especially critical in foundation design. In addition to careful borings of the limestone or dolomite, ground-penetrating radar is sometimes appropriate.

A view of a section of limestone in an area of karst geology excavated for a roadway is shown in Figure 2.3. The cracks and joints in the limestone are evident. Rainwater can penetrate the openings, some of the limestone goes into solution, and a cavity, sometimes quite large, will develop over perhaps centuries.