Numerical modeling and analysis of reinforced residential foundations subjected to mining-induced subsidence

Numerical techniques are used to investigate the behavior of reinforced residential foundations subjected to mine- induced subsidence. The foundation and subsidence event are modeled after test foundations constructed near West Frankfort, Illinois. Parametric analyses are performed to evaluate reinforcing amounts and location within the footing, soil-structure interface, the thickness of the footing, and masonry wall construction techniques.

The finite element analysis established that the combination of the masonry wall and footing contribute greatly to foundation response. There was no reduction in damage and curvature for increased amounts of reinforcing placed in the footing. More damage occurred in the reinforced footing as its depth was gradually increased; however, larger increases of footing depth reduced damage. If typical masonry is used for foundation wall construction, only one layer of reinforcing in the top of the footing is required. Cracking and curvature can be reduced if a bond beam is utilized in the masonry wall or if the masonry wall is replaced by a reinforced concrete wall. Decreasing the friction angle at the interface resulted in larger amounts of tension and curvature in the footing.