Author(s)

Cheng Shufan ^1,2

Affiliation(s)

¹ Hubei Province Road and Bridge Co., Ltd., Wuhan, China
² School of Civil Engineering, Wuhan University, Wuhan, China

Corresponding Author

Cheng Shufan

ABSTRACT

Gansu clay-sulfate rock is a special red-bed rock that formed in an evaporation environment with strong oxidation. In this study, a loadable cyclic drying-wetting instrument was designed to simulate the occurrence of the surrounding rock mass of a tunnel experiencing a periodic change in groundwater level. Firstly, a series of drying-wetting cycle tests with different normal pressure were carried on to obtain the expansion regulation of clay-sulfate rock. Then, computed tomography (CT) and scanning electron microscope (SEM) tests were carried on to explain the corresponding mechanism in mesoscopic. The test results show that large expansive deformation was generated in the first water immersion and only part of the deformation can be recovered during the later drying process. Meanwhile, the degeneration of the clay-sulfate rock was observed in the first cycle by the CT and SEM test. It indicates the clay rock, in large part, degenerated to clay soil during the first drying-wetting cycle. Structural degradation and hydration of anhydrite is the main source of irreversible expansive deformation. Moreover, normal stress and confined restraint can reduce or even eliminate the expansive deformation, however, cannot avoid the degeneration of mesostructure.

KEYWORDS

Expansive Rock, Coupling Effect, Meso-Structure

CITE THIS PAPER

Cheng Shufan, Experimental Investigation on the Expansive Characteristics of Clay-Sulfate Rocks Subjected to Confined Compression and Cyclic Drying Wetting. Journal of Civil Engineering and Urban Planning (2025) Vol. 7: 7-12. DOI: http://dx.doi.org/10.23977/jceup.2025.070302.

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