Prediction of shallow salt cavity geometry from surface subsidence configurations

Abstract

Physical model tests are used to simulate surface subsidence induced by shallow salt cavity occurred at the interface between salt bed and overlying soil formation. Uniform fine sand with properties similar to the overburden soil is used in the models. The width and depth of sinkhole or subsidence trough induced under various cavity widths, heights, and depths are measured using 3-D laser scanner. The results indicate that for relatively shallow cavity, the increase of sinkhole depth closely relates to the increase of cavity height. The extent of subsidence area is sensitive to depth and width of the cavity. The maximum subsidence is not sensitive to cavity depth. The physical model results are fitted to empirical equations. They can be used to estimate the cavity height and width from the subsidence configurations under similar geologic conditions.