| 摘要 |
Site amplification factors, relative to a VS30=1130 m/s site, are computed for 64 base soil profiles based on the equivalent-linear approach using the RASCALS computer program. The base profiles include nine VS30 values (160 m/s, 190 m/s, 270 m/s, 400 m/s, 560 m/s, 760 m/s, 900 m/s, 2830 m/s, and 3120 m/s), up to seven soil depths (50 ft, 120 ft, 250 ft, 500 ft, 1000 ft, 2000 ft, 3000 ft), and four non-linear soil models (EPRI and Peninsular range models for cohesionless soils and Imperial Valley and Bay Mud models for cohesive soils). For each soil profile, the site response is computed for 11 levels of input rock motion: PGA1130= 0.001g, 0.05g, 0.1g, 0.2g, 0.3g, 0.4g, 0.5g, 0.75g, 1.0, 1.25g, 1.5g.
For each base soil profile, the shear-wave velocities, layer thickness and the non-linear soil properties (strain dependence of the G/Gmax and Hysteristic damping) are randomized. Correlation of the velocities and layer thickness variations are considered. For each base profile and each input ground motion level, the median amplification and the standard deviation of the amplification are computed from 30 realizations of the soil profiles and material properties. These results are intended for use by the NGA developers to constrain the non-linear scaling of the site response for the ground motion models. |
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