The elastic undrained modulus Eu50 for stiff consolidated clays related to the concept of stress history and normalized soil properties

The paper presents the results of a triaxial test conducted on stiff, consolidated clays. The standard TXCIU procedure (isotropic consolidation and undrained shearing) was applied in the laboratory soil tests. The undrained elastic modulus Eu50 was de- termined from each test. The Eu50 values were determined for soil samples cut out from different depths and tested under different confining pressures. There was a significant scatter of values with depth, and no relationships between Eu50 modules or other geotechnical parameters (e.g., cu) were observed. This work presents the concept of normalization of Eu50 modulus values using modified normalization SHANSEP (Stress History And Normalized Soil Engineering Properties). This method was first proposed for estimating the value of the undrained shear strength cu normalizing the parameter relative to the in situ effective vertical stress σ _vo and loading history (overconsolidation stress σ _p and overconsolidation ratio OCR) of the soil. The study demonstrated that the concept of normalization of soil properties can also be used for testing elastic modulus Eu50 of con- solidated natural clays and normalized values of geotechnical parameters taking into account the state of stress and load history can be correlated with the value of the overburden pressure.