Research progress in ecological treatment of expansive soil

The expansive soil is a kind of problematic soil that rapidly expands and deforms when encountering water and rapidly shrinks and cracks when losing water. It needs to be treated to meet the engineering requirements. The newly developed ecological treatment materials for the expansive soil in recent years are summarized and categorized, and the are classified according to their components and characteristics into-geopolymer, ion curing agent, organic polymer material, microorganism and enzyme, and biopolymer. The material characteristics, treatment effectiveness, and stabilization mechanisms of various treatment materials are elaborated, and they all meet the requirements of the new era and can be widely promoted and applied as a sustainable, environmentally friendly and versatile technology. Finally, the urgent issues that need to be addressed from the perspectives of ecological governance and promotion are discussed.