The mechanical characteristic values of cement-treated Bangkok clay tested under various loading conditions from literature are characterized by the parameter est in Fig. 7. The clay samples in those studies were taken from King Mongkut’s University of Technology Thonburi (KMUTT) located in the southern part of Bangkok, Thailand. These data include the qu from unconfined compression tests (Jongpradist et al. 2010), the yield stress P0y from one-dimensional compression tests (Jongpradist et al. 2011), and the peak undrained shear strength qmax from consolidated undrained triaxial compression tests (Jongpradist et al. 2007). The results of the peak undrained shear strength are normalized with the confining pressure in the figure. Calculation of the parameter est for triaxial conditions must use the after-curing void ratio with the adjusting consolidation process as indicated in Eq. (2).
The figure indicates that, for various mixing components and curing times, the parameter est has been found sufficient to characterize the qu and one-dimensional yield stress. The parameter est has also been proven to characterize the normalized undrained shear strength under triaxial compression conditions at a specific confining
pressure for various mixing components. However, unlike other mechanical properties, the linear relationship between the parameter est and the normalized undrained shear strength cannot be obtained in the semilog space. In future developments, the stress level may be regarded as a second parameter, which, in combination with the parameter developed in this study, will allow a better description of the behavior of cement-treated clay under triaxial loading conditions. On the basis of limited data from only a few clay layers and a few types of experiments in this study, the following relationship has been derived to describe the mechanical characteristics of any cement-treated clay: q0 ¼ AeBest ð7Þ where q0 = any normalized mechanical characteristics, such as qu=pa, P0 y=pa, and E=pa; A and B are dimensionless constants; and pa = atmospheric pressure. On the basis of the results presented, the constants A and B for different mechanical characteristics and different clays are tabulated in Table 5. They depend
on the type of cement and the index and properties of clay, which, in turn, depend on the clay mineralogy and composition. The stress-level-dependent mechanical property at a specific stress level also has a relationship with the parameter, but not in the form of Eq. (7).