Simplified Analytical Method for Calculating the Maximum Shear Stress of Nail-Soil Interface

This paper describes a simplified analytical method that considers postinstallation normal stress, normal stress due to soil dilation, and grouting pressure when calculating the maximum shear stress of the nail-soil interface. Systematic test results from two previous publications were used to verify the accuracy of the proposed method. The Hong Kong design method was also used to determine the maximum shear stress of the nail-soil interface. These analyses confirmed that the experimental data were more accurately predicted by the proposed analytical method. An extensive parametric study was conducted to examine the effects of several key parameters on the maximum shear stress. It was observed that when there was no grouting pressure, maximum shear stress increased with increasing overburden pressure, failure surface distance, dilation angle, or decreased drill hole radius. Analysis using the proposed model also demonstrates that grouting and overburden pressures share an interactional effect. The larger the grouting pressure, the greater the influence of the overburden pressure; and, consequently, the larger the maximum shear stress at the nail-soil interface.