Modification Effect of Nano-Clay on Mechanical Behavior of Composite Geomaterials: Cement, Nano-Silica and Coastal Soft Soil

To study the modification effect of nano-clay and nano-SiO(2) on cement-reinforced coastal soft soil, the effects of the nano-SiO(2) and nano-clay on the mechanical properties of cement soil were studied through unconfined compressive and unconsolidated undrained shear tests, and the Duncan–Chang model was used to fit the test results. Results show that adding nano-clay and nano-SiO(2) to cement soil improved its compressive and shear strength. The compressive strength and shear strength increased by 18–57% and 3–32%, respectively, with the increase in nano-clay content in a content range of 0–10%. Additionally, nano-clay can enhance the ductility of cement soil. Moreover, nano-clay and nano-SiO(2) improve the shear strength by increasing the internal friction angle by 1°–2° and cohesion of 9–25%, and the cement-stabilized coastal soft soil enhanced by nano-SiO(2) and nano-clay conforms to the Duncan–Chang model well.