Effect of Nail Layout Variability on Soil Nailed Wall Analysis: Fid-Bau Portal

Effect of Nail Layout Variability on Soil Nailed Wall Analysis

Yazdi, J. Sadoghi / Rahman, M. M. / Cameron, D. A.

This paper focuses on the effect of nail layout on soil nailed wall analysis (SNWA). SNWA relies upon proprietary commercial software. Evaluation of the effect of variations of nail length on stability requires numerous time-consuming calculations. This study has as an objective to develop a reliable open source program with fast searching algorithm for finding the critical slip surface of a soil nailed wall with variable nail layout. For this example, it is shown that factor of safety is sensitive to nail length, and sensitivity increases with ultimate bond strength. The simplified Bishop method is commonly used for calculation of the factor of safety for the stability of nailed slopes. MATLAB® was adapted for SNWA based on Bishop's method. To reduce time consumed in searching for the critical surface, the major command loops in the code were vectorized using the "array operations" in MATLAB. The fast MATLAB program for calculation of soil nailed walls (SFSNW) was compared with commercial software, and the SFSNW outcome is shown to be more precise. Nail variability was introduced using Monte Carlo simulation to generate a set of a hundred combinations of different nail lengths for seven nails in an example of a 10 m high wall. Some restrictions on nail length were enforced. The generated nail length data was fed into SFSNW to compute factors of safety.