Numerical investigations of mitigation techniques for damage to structures subjected to mining subsidence

Structural damage induced by mining subsidence is a major problem in regions which are heavily mined for coal. As a result, several mitigation techniques have been proposed to alleviate these damages. This research utilizes numerical analysis to evaluate the performance of certain mitigation techniques. The idealized subsidence trough to which the foundations arc subjected was derived from a survey taken above a previously mined longwall panel. The foundations analyzed are: plain concrete, post-tensioned concrete, and reinforced concrete with various amounts of reinforcing. Vertical loads were applied to the foundations to simulate a typical house load.

It was found that the post-tensioned concrete foundation performed better than the other foundations considered by remaining structurally intact and minimizing the amount of angular distortion, and thus potential superstructure damage. Further investigations pertaining to the use of post-tensioning as a mitigation technique are warranted to determine the optimum amount of prestressing to be incorporated. Reinforced concrete footings remained well below the yield moment but resulted in higher angular distortions.