Equivalent Expansive Force and Its Evaluation on Stability of Unsaturated Expansive Soil Slope

摘要

The instability of unsaturated expansive soil slope is a security threat that urgently needs to be evaluated in geotechnical engineering. In this study, in order to investigate the equivalent expansive force corresponding to matric suction a newly testing device was developed. Firstly, the internal relations between matric suction and the corresponding equivalent expansive force of unsaturated expansive soil were analyzed and compared. Then, the equivalent expansive force was introduced into the calculation analysis for the stability of unsaturated expansive soil slope. Finally, the equivalent effects of the matric suction and the equivalent expansive force on evaluating the stability of unsaturated expansive soil slopes were compared and analyzed. Research results show that the newly testing device significantly improves the accuracy of expansive force test and shortens testing time, and the correlations between matric suction and the equivalent expansive force with the change of initial water content are obvious. Because the macro contributions of matric suction to unsaturated expansive soil can be reflected by the equivalent expansive force, the stability of unsaturated expansive soil slope will be analyzed and evaluated by means of the equivalent expansive force in future.