2024 年 10 巻 28 号 p. 1029-1034
1-D site response analysis of horizontally layered soil profiles is commonly used to generate site-specific earthquake ground motions. While there are many existing methods, both equivalent-linear and nonlinear type, to simulate the response in small to medium strain range, application to large strain range is often considered questionable. The accurate representation of soil strength in the selected nonlinear model is the key to simulate response beyond the medium strain range. This paper presents a new analytical solution by combining a recently proposed double hyperbolic model with Mohr-Coulomb strength model. The paper describes the mathematical formulation of the new model and demonstrates a practical implementation using DYNES3D, an open-source site response analysis tool.
The application of the proposed strength formulation with double hyperbolic model is investigated by analyzing the response for an arbitrary soil profile and comparing with conventional hyperbolic model. Results indicate that using the proposed model could lead to smaller shear strains at shallow depths, potentially leading to larger surface accelerations and higher response acceleration in the shorter period range. A python package developed to interact with DYNES3D and analyze with the proposed method is also made available on GitHub.