Characterizing the Soft Clays in the Texas Gulf Coast Using the Texas Cone Penetrometer (TCP)

In this study, properties of soft clay soils (undrained shear strength (S_u) ≤ 25 kPa) from three locations along the Texas Gulf Coast were investigated using laboratory and field tests. The data and samples for this study was obtained from 46 boreholes in three counties along the Gulf coast. The soils were characterized based on their geotechnical properties including undrained shear strength using statistical methods. The field tests were performed using the Texas Cone Penetrometer (TCP), which is a dynamic method using a cone of 3-in (75 mm) in diameter. Both CL and CH soft soils were present in these locations and there was large variation in the index properties of the soils. Physical, index and strength properties of CL and CH soft soils were quantified using mean, variation, coefficient of variation and probability distribution function. The natural moisture content of 95% of the soft clays was lower than the liquid limit and the coefficient of variation for the Su of CH soil was about 25%. Based on available data the undrained shear strength of soft clay soil (S_u) was related to the TCP blow count.