Review and Investigation on Stress Sensitivity of Naturally Sedimentary Soils

The mechanical behaviour of naturally sedimentary soils generally differs from that of reconstituted soils, due to the soil structure developed during the depositional and the post-depositional processes. It has been well reported that engineering disaster associated with oversize deformation and slope instability often occurs due to the damage or loss of the resistance originated from soil structure. For quite some time, the mechanical behaviour of reconstituted soils has been used as a reference for assessing the role of soil structure in mechanical behaviour of naturally sedimentary soils. This study focuses on the stress sensitivity defined as the ratio of consolidation yield stress of naturally sedimentary soils to the equivalent stress on the uniquely normalized compression line. The start-of-the-art methods of assessing the stress sensitivity is introduced. Based on the best knowledge of the author, the references of evaluating stress sensitivity are analyzed for understanding their advantages and disadvantages. The development of intrinsic compression framework is summarized with examining the related limitations. The unified normalised compression line propsoed by the author and the research team is recomended to investigate the changing law of soil structure resistance during compression. The risk of engineering disaster associated with the soil structure damage or loss is understood to call for high concern in engineering practice. Finally, the trend in development on the approaches of assessing stress sensitivity is discussed. The compression zone of naturally sedimentary soils without soil structure resistance is suggested to be used as a reference for establishing the sensitivity framework in the future.