Abstract: In this paper, a new apparatus for expansive property test of the coarse-grained soil is introduced. The instrument overcomes the defect that the existing instrument is not suitable for coarse granular soil. The instrument is used to test the expansive force and expansion rate of the coarse-grained soil. The following conclusions are obtained: (1) the new apparatus can be used effectively and reliably. (2) The coarse-grained soil containing expansive rock and soil has certain expansive properties; (3) The soil samples with more fine particles in the coarse-grained soil have more obvious swelling phenomenon; (4) The expansive property of the coarse-grained soil is similar to that of the fine-grained soil. The new apparatus developed in this paper is convenient in operation, stable in performance, and precise in accuracy, which provides an accurate and reliable test equipment and method for testing the expansibility of coarse-grained soil.

Key words: Coarse-Grained Soils, Test Equipment, Expansive Properties, Swelling Force Test, Swelling Ratio Tests