Analysis of helical soil-nailed walls under static and seismic conditions

The present study investigates the behaviour of helical soil-nailed wall in a dry cohesionless medium under static and seismic conditions. Initially, results from laboratory pullout tests are used to develop a pullout capacity equation, which is subsequently used for stability analysis of helical soil-nailed wall. A detailed parametric study is conducted to evaluate the effect of angle of internal friction of soil, nail inclination, vertical spacing of nails, number of nails, helix size, number of helices, and the face angle on the stability of the soil-nailed wall. Results from the present method are compared and validated with similar existing methods available in the literature. The results suggest that for the given input parameters, the factor of safety (FoS) values from the present method are lower than the pseudo-static and pseudo-dynamic values. Further, the study clearly highlights the significance of input excitation frequency on the FoS of helical soil-nailed walls. In addition, the effects of strain-dependent dynamic properties (shear modulus and damping ratio) on the stability of helical soil-nailed walls are studied using the newly proposed equivalent linear analysis approach. The results computed from the proposed linear and equivalent linear analysis are also compared and discussed in detail.