A study of the mechanical behaviour of cemented soils via Structured Cam Clay

This thesis describes an investigation of the mechanical properties of soils. A systematic study of the Structure Cam Clay model (SCC) for describing the behaviour of cemented soils is presented. Mode parameters for the different soils are identified and their effects on model performance are investigated. Cementation effects on soil parameters are then investigated. After studying eight groups of experimental data, an empirical equation is proposed to define the relationship between cement content and swelling index. The failure envelope for cemented soil is assessed, based on the analysis of five groups of experimental data. Soils with cohesion including cemented clay and cemented sand are simulated and analysed. Loess could also be analysed as cemented soil with SCC due to its glutinous ingredient, and a special equation for predicting the virgin yield surface for loess is proposed with surface simulation. SCC performance is proved to be better than that of the Modified Cam Clay model (MCC) after a simulation comparison. A study on yield surface was carried out. Defects of SCC yield surface in terms of its shape and the ratio of height to width are discussed. It was found that the extension of SCC to cemented soil failed to take into consideration the breakdown of cementation during a drained simulation. Thus, the decementation equation for drained soil behaviour is proposed to fix this problem. Through the test data and model analysis, it can be determined that the stress paths for cemented soil are usually distorted and SCC is incapable of reflecting sub yielding and decementation before peak stress. Further research in this area is needed. Liu M. D., Liu J., Horpibulsuk S. and Huang W. (2013), “Simulating the stress and strain behaviour of loess via SCC model”, 18th Southeast Asian Geotechnical Conference (Approved).