Application of Digital Image Cross Correlation to Study Sinkhole Collapse

This paper presents the results of a study using a transparent soil experimental technique and numerical modeling to detect 3D deformations resulting from submerged cavities that lead to a sinkhole. Excessive deformations from underground activity beneath highway pavements could lead to sinkhole collapse. The formation of a sinkhole is often sudden and can lead to extensive damage and loss of life, especially in urban areas. The use of transparent soils permitted the visualization of internal ground deformations which allowed for comprehensive evaluation of the extension of failure. A series of finite element analyses have also been carried out for the tests conditions. The observed sinkhole, at the surface, is found to be a small indicator of the final size and magnitude of the internal deformations as a subsequent funnel-shaped depression developed with a hole at the center. The modeling results emphasized the need to extend the repair zone following sinkhole collapse by a minimum distance that equals twice the cavity diameter away and ahead of the developed hole. Results of this study are believed to be of practical interest for predicting surface and internal ground deformations following sinkhole collapse which could be useful for the stability assessment of underground utilities and the development of a restoration plan after collapse occurred. The results also provided approximate bounds to areas affected by the sinkhole allowing for collapse risk to be assessed.