Influence of Grout's Poisson Effect on Interfacial Shear Stress for Compression Anchor in Rock Mass

The distribution and magnitude of the shear stress at the interface between the grout of a compression anchor rod and rock are strongly affected by the Poisson effect. A new analytical equation of the influence coefficient of the Poisson effect is proposed to quantitatively evaluate the influence of the Poisson effect on the interfacial shear stress. When the Poisson effect is considered, the interfacial shear stress from the neutral point to the bearing plate increases, and the distribution curve becomes steep. However, the interfacial shear stress far from the neutral point is low, and the distribution curve becomes smooth. Overall, the Poisson effect leads to a more nonuniform distribution of the shear stress at the interface of the compression anchor rod. A larger Poisson's ratio, smaller elastic modulus, and smaller diameter of the grout lead to a greater influence of the Poisson effect. Furthermore, a larger elastic modulus of rock leads to a greater influence of the Poisson effect. The Poisson's ratio of rock and that of grout both affect the Poisson effect greatly, but the influence of the variation in the Poisson's ratio of rock on the Poisson effect is negligible. A larger interface friction angle leads to a greater influence of the Poisson effect.