Shear behaviors of clay-infilled joint with different water contents: experiment and model

• Published in: Arabian journal of geosciences 2021-09, Vol.14 (17), Article 1724
• Main Authors: Zhao, Yanlin, Li, Yang, Chang, Le, Wang, Yixian, Lin, Hang
• Format: Article
• Language: English
• Subjects: Clay; Earth and Environmental Science; Earth science; Earth Sciences; Exponential equations; Infilled joints; Joints (timber); Liquid limits; Moisture content; Original Paper; Rocks; Shear strength; Shear stress; Water content
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-021-08207-8

To better understand the effect of water content on shear behaviors of clay-infilled joint, a series of direct shear experiments were performed on clay-infilled joints prepared by reproducing the standard JRC profiles on a rock-like material and placing the clay infill with various water content inside the joint, and a shear strength model of infilled joints was established. For most of the clay-infilled joints, the shear stress versus shear displacement curve is characterized by gentle type; i.e., the residual shear stress value is close to the peak value, with the absence of a softening phase on the curve. There is a trend to negative correlation between the shear strength of clay-infilled joints and the t/a ratio when t/a is smaller than a critical value ( t/a ) cr . Shear strength of clay-infilled joints decreases with an increase in water content, if water content is below liquid limit of clay infill; however, the shear strength of infilled joint with liquid clay is higher than that of the infilled joint with plastic clay. Based on the JRC-JCS strength criterion, a revised shear strength model of infilled joint is proposed, by the proposed negative exponential equation between friction angle and t/a ratio. The good agreement between experimental results and predictions indicated that the revised shear strength model is capable of estimating the peak shear strength of infilled rock joints.