This research was aimed at studying the settlement behavior of road surfaces caused by the dissolution of salt layers that in turn create cavities. The dissolution can happen naturally or occur from salt mining. The proposed project's site was Highway 2229 from km 4 + 066 to km 4 + 275 , Kud Ruakham Subdistrict, Ban Muang District, Sakonnakhon Province. The 2015 soil layer drilling survey revealed layers of hard clay and compact soil or shale with low plasticity. Cavities were found at the depth of 42 meters over sand stone layers. The analysis of road surface settlement was based on the Empirical Method and theories of Peck 1969 ( ), O'Reilly and New 1982 ( ), and Rankin 1969 ( )to determine the i and Vs parameters based on Smsx from the surveys of road surface settlement from 2013 to 2018. Using the survey results, the analysis by the theory of O'Reilly and New 1982 ( ) showed i at 21 m and Vs ranging from83.24%to85.14%of Vs. The analysis based on the survey data and Rankin's theory 1969 () showed i equal to 19.16m and Vs between 91.23% %and 93.32%of Vs. The analysis of the surveyed data showed the end of surface settlement in 2016, which was consistent with the drilling survey in 2017 from which no cavities were found on the sand stone layers.