Numerical analysis on the interaction of shotcrete liner with rock for yielding supports

• A new interface model of the liner–rock interface is used.
• The characteristics of yielding support are analysed.
• A sensitivity analysis of support parameters of yielding support is conducted.

The yielding supports have been successfully used in excavation in squeezing rock. For yielding supports the shotcrete liner is often divided into several segments, and the HDEs (highly deformable elements) are installed between the segments. Compared to the shotcrete, HDEs have a considerably lower compressive strength and a higher deformation ability. To study the influences of HDEs on the liner–rock interaction, a number of numerical analyses were conducted. In all of these numerical analyses, an interface model that can reflect the failure behaviour of the liner–rock interface was employed. According to the numerical results, after the installation of the HDEs, the compressive and shear failures of the liner decrease sharply; however, obvious shear failure on the liner–rock interface and tensile failure of the liner are observed, which may result in the liner failing to provide sufficient support load. In this condition, reinforcement of the TH profile steel sets, which can decrease the shear failure of the liner–rock interface and the tensile failure of the liner, is suggested instead of thickening the shotcrete liner.