Horizontal Movements Related to Subsidence

A review of many documented field examples shows that horizontal surface movements often accompany vertical subsidence and that, although these movements may result from a wide variety of different situations, they all appear to follow a well defined pattern. This pattern is the same for horizontal movements associated with mining subsidence; subsidence due to gas, oil or water pumping; or subsidence due to deep consolidation under a heavy fill load such as at an industrial development or an earth dam. A semi-empirical and simple equation is presented which appears to predict the nature and magnitude of horizontal movements correctly provided the vertical subsidence profile is known. An application of the finite-element method of analysis in computing both vertical and horizontal movement is also illustrated. The results of the two methods are compared to data obtained from a laboratory model, a hypothetical earth dam on a compressible foundation, and an actual rockfill dam which settled as the water level rose in the reservoir.