Civil and Building Engineering.

The behavior of the soils supporting the foundation is influenced strongly by the stress and groundwater conditions present in the soil and rock profile.

Thus, it is important to consider what conditions existed in the soil and rock profile when the soil investigation was conducted, what changes might occur in the future as a result of construction, and what changes might occur in the future due to additional nearby development or other causes. Often, this requires guesses about a possible worst-case scenario or a reasonable-case sce-nario for the future.

The principal factors of concern for changes in conditions that might occur during construction are any addition or reduction of overburden to the soil profile during the project and changes in the elevation of the water table. Any change in the overburden stress will directly affect the shearing properties of the soil and may affect its deformation properties as well. The position of the water table can be changed locally by the removal of some varieties of trees and by the amount (or lack) of irrigation or landscaping at a project.
The changes in soil conditions at a site are important factors to consider.

History provides many examples of successful foundation designs rendered unsuccessful by changes in soil conditions. A few of the examples are well known, but many others are known only locally because the structure did not survive and was taken down or suffered minor or repairable damage. Foundation design engineers strive to provide trouble-free foundations because repair of defective foundations is very costly and inconvenient or the damage may be hidden and the structure sold to another party.