Microstructural and Geotechnical Properties of Houston-Galveston Area Soft Clays

Rapid growth in the urban areas such as Houston and Galveston in Texas is leading to construction of civil infrastructure facilities, including bridges and highways on soft clays. In this study, soft clays are characterized based on their mineralogy, physical and mechanical properties. The X-ray diffraction (XRD) and scanning electron microscope (SEM) studies were performed to investigate the mineral composition and microstructure of the clays respectively. Both CL and CH soft clays are present in the Houston area. Based on over 100 data sets, statistical mean, standard deviation, variance and coefficient of variance and distribution of properties and property correlations for the CL and CH soft clays have been developed. The natural moisture content of 97% of the soft clay was lower than the liquid limit. The undrained shear strength of the soft soils was related to the natural moisture content of the soils. The CL soil showed greater variation in the undrained shear strength compared to the CH clay. XRD and TGA analyses with the plasticity index chart confirmed the presence of illite in the soft CL clay.