Shear stiffness modeling of cemented clay

The shear modulus and damping of cemented clay are investigated using ultrasound transducers, bender elements, and a resonant column device. The model SimSoil-CC, based on the Pestana and Salvati (published in 2006) model SimSoil, is proposed to represent the maximum shear modulus and stress-strain behavior (under cyclic loading conditions) at small strains for the cemented clay. The model can also be used for uncemented clay when the cementation parameter is set to zero. Model parameters are determined for three types of clay (kaolinite, bentonite, and the equal mix of kaolinite and bentonite) and two types of cementation agents (type III Portland cement and gypsum). The model SimSoil-CC is validated using the laboratory test data of this study and data from other studies in literature. The SimSoil-CC model can be very useful for performing earthquake site response analysis for naturally cemented clay sites or sites that have been improved by cementation. In addition, a relationship between the cementation parameter a(cc)(CC)(2) (a(cc), cement material constant; CC, dry cement content) and the unconfined compression strength is proposed. The relationship simplified modeling for naturally cemented clay soil or cemented clay whose cement contents and cementation type are otherwise difficult to determine. This research advances the understanding of cemented clay by providing a database of test results and creation of a model that can be used to predict the response of cemented clay soils to dynamic loads.