Fig. 17.
The scatter plot plots beta, f 0 over f str, against effective stress sigma prime v in kilopascals. Effective stress ranges from 0 to 90 kilopascals and beta ranges from 0 to 1.0. Q Z 1 model values increase from about 0.40 at 0 kilopascals to about 0.59 near 53 kilopascals. Q Z 2 model values increase from about 0.40 to about 0.70 across the same range. Futai et al. 2018 and 2021 values increase from about 0.29 near 0 kilopascals to about 0.53 near 83 kilopascals. Fitted equation curves for all datasets increase gradually with effective stress. A horizontal reference line marks f n and f str at 1.0.Variation of the β soil–structure interaction parameter with vertical effective stress