1. Part 2 COMBATING SOIL HEAVE

2. Expansive soils can either absorb moisture or dry out and desiccate. These CPT soundings show the startling change in material properties with time, caused by desiccation and landscape watering of an urban fill.

3. The percent swell (heave) is usually a function of effective normal stress. Soil expansion is retarded at increasing depth. Usually no significant expansion at depths > 50 feet.

4. The key factor is controlling moisture at the time of initial compaction.

5. Wetter the better For highly expansive soils, the wetter the soil is during initial compaction, the less heave can subsequently be expected to occur. Particularly important in uppermost 10 feet of urban fill embankments