ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS GEOTECHNICAL LAB
Numerous structures constructed on expansive clay soil experience significant damage from differential heave and settlement. The types of structures most often damaged from heaving soil include highways, foundations and walls of residential and light commercial buildings, canal and reservoir linings, and retaining walls. The leading cause of foundation heave or settlement is change in soil moisture attributed to change in the field environment e.g., climatic changes, prevention of evaporation beneath covered areas, improper drainage following construction and from usage requirements of the structure. This report provides background information for establishing the preliminary design of structures in swelling soil areas based on field studies conducted by the Army Engineer Waterways Experiment Station and experiences of numerous investigators. The overview includes analyses of site and soil investigations, topography and landscaping including drainage and soil stabilization techniques, and selection of the foundation and super-structure. General suggestions for remedial repair of existing structures are provided. Analyses of the movement of cast-in-place concrete piers in swelling soil are included to provide a basis for design of these foundations. Appendices include Determination of soil suction by thermocouple psychrometers and Prediction of pier movement.