Abstract: With the gradual development of the Great Bay area of Guangdong, Hong Kong and Macao, the expansion project of Guangdong, Hong Kong and Macao has the characteristics of large scale and complex stratum. Especially in the soft soil area near the sea, there are always complicated engineering geological problems. Taking the foundation treatment project of Terminal 4 of Shenzhen Airport as the background, aiming at the damage of the cavity after shield tunneling around the site of the proposed Terminal 4, the general shape and orientation of the cavity are detected by the appropriate ground penetrating radar, and the formation causes are analyzed combining with the site conditions, which are mainly related to the construction technology, lining concrete materials, shield equipment and the influence of site ground stress. Sleeve valve pipe grouting was used to deal with the cavity damage, and the effect of cavity treatment was tested on site, so as to provide a reference for the cavity treatment in Guangdong, Hong Kong, Macao and other similar areas in China.