Remedial Measures for Houses Damaged by Expansive Clay. Data Supplement

摘要

This report documents laboratory and field investigations of various repair techniques duplicated on two geologic formations whose residual soils are predominantly expansive clay. Ten residences in the Dallas - Fort Worth area were selected; five were founded upon the Eagle Ford Shale formation, and five were founded upon the Taylor Marl formation. Identical stabilization techniques were utilized for both foundation soils. Floor slabs had concave and convex curvatures, with corresponding damage conditions reflected in the superstructure. Using materials and equipment commonly available in industry, researchers evaluated the effectiveness of various repair techniques to mitigate volume change in underlying soils with the slab and subsoil acting as a layered entity. Moisture - temperature cells were installed in boreholes at the midpoint of each side of the house slab and calibrated for existing soil properties. Leveling points were inserted around the slab perimeter, with all peg elevations referred to a permanent benchmark. Data acquisition of soil moisture, temperature, and vertical movement was continued over 4 seasonal climatic cycles, or approximately 2 years; data acquisition for 6 homes was continued for about 3 years. Results indicate damage to a home resulting from swelling and shrinking of foundation soils can be minimized by treating the slab and soil as an interacting system. By establishing the water content of the foundation soil at 2 - 3 percent above the plastic limit of the soil and isolating the soil mass or maintaining this moisture content, the volume change due to seasonal weather cycles would be reduced to a minimum. Many graphs and extensive tabular data are included. Supplementary reports are appended. (Author abstract modified).