The strength anisotropy of localized compaction: A model for the role of the nature and orientation of cross-beds on the orientation and distribution of compaction bands in 3D

The field observations indicate that the low-angle bed-parallel compaction bands and the high-angle-to-bedding compaction bands occur only in cross-beds with certain range of bedding orientations in the Aztec Sandstone at the Valley of Fire State Park (NV). The hypothesis is that the primary underlying mechanical reason for this phenomenon is the strength anisotropy of localized compaction in anisotropic sandstones. In this paper, we used a quadratic failure criterion to describe the strength anisotropy of localized compaction and compared the results with the field data. The results show a clear relationship among the cross-beds with (or without) compaction bands of certain orientations and the cross-beds with relatively lower (or higher) calculated strength of localized compaction. These findings which are consistent with the published experimental results indicate that (1) the application of the quadratic failure criterion to the formation of compaction bands in anisotropic sandstones is promising and that (2) the strength anisotropy of localized compaction is an important factor controlling the compartmentalized distribution of compaction bands of various orientations in the aeolian sandstones.