Investigation of the Expansion Deformation Characteristic of Compacted Predisintegrated Shale

ABSTRACT To investigate the expansion deformation of predisintegrated shale as subgrade soil and develop a calculation model to describe its expansion characteristic, the nonloaded and loaded expansion tests as well as expansion force tests were conducted on the typical predisintegrated shale under varying conditions. The results show that the expansion rate of compacted predisintegrated shale is greatly affected by initial water content, dry density, and overburden load, and that its expansion characteristics can be divided into three stages. After compaction, the expansion force of predisintegrated shale has a strong correlation with the initial dry density and initial water content, and 1.45 g·cm−3 can be used as threshold density for the rate of expansion force growth. Moreover, a comprehensive calculation model for the expansion rate and expansion force considering the coupling effects of various factors was proposed. This study proposes an alternative subgrade material using shale, which can efficiently save land resources and reduce engineering costs.