Sharif University of Technology Scientia Iranica 1026-3098 28 4 2021 08 01 Experimental study on the ultrasonic nonlinear damage characteristics of expansive soil during constant amplitude dry-wet cycles 2023 2036 22252 10.24200/sci.2021.55447.4225 EN Z. Huang College of Civil Engineering and Architecture, Key Laboratory of Disaster Prevention and Structural Safety, Guangxi University, Nanning 530004, China B. Wei School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha 410004, China Y. Chen College of Civil Engineering and Architecture, Key Laboratory of Disaster Prevention and Structural Safety, Guangxi University, Nanning 530004, China J. Zhang College of Civil Engineering and Architecture, Key Laboratory of Disaster Prevention and Structural Safety, Guangxi University, Nanning 530004, China Y. Liu College of Civil Engineering and Architecture, Key Laboratory of Disaster Prevention and Structural Safety, Guangxi University, Nanning 530004, China Journal Article 2020 02 15 Dry-wet cycles can cause fatigue damage to expansive soil, and various control parameters of the dry-wet cycles (initial moisture content, number of dry-wet cycles, cycle amplitude, etc.) can affect the development of soil damage. Therefore, it is important to study the fatigue damage characteristics of expansive soil under dry-wet cycles of constant amplitude. This paper considers expansive soil from Baise in Guangxi, China, as the research object. Based on tests of the P-wave velocity and low-stress shear strength of expansive soil under 0-6 constant amplitude dry-wet cycles, the attenuation laws for the P-wave velocity were analysed, the damage variable of expansive soil was characterized by P-wave velocity, and the rationality of this damage variable was verified by measuring the low-stress shear strength values of expansive soil specimens. Based on the experimental P-wave velocity results, a nonlinear empirical model of fatigue damage for expansive soil was constructed. The results illustrate that the P-wave velocity of an expansive soil sample decreases nonlinearly with an increasing number of dry-wet cycles and that the damage degree increases nonlinearly with an increasing number of cycles. The P-wave velocity can be successfully used to define a representative damage variable for expansive soil. https://scientiairanica.sharif.edu/article_22252_349c4d37a8c6850d697a3fff47e36f5d.pdf