DEEPSOIL is a one-dimensional site response analysis software developed by the University of Illinois at Urbana-Champaign. It is widely used in geotechnical and earthquake engineering to simulate the dynamic behavior of soil layers subjected to seismic loading. The software is freely available for academic and professional use and is particularly suited for modeling total stress response under various ground motion scenarios.
Main features of the software include:
The primary function of DEEPSOIL is to evaluate how seismic waves propagate vertically through soil profiles. This is done through time-domain or frequency-domain analysis methods that capture key soil behaviors such as amplification, stiffness degradation, and hysteretic damping. DEEPSOIL supports both linear and nonlinear analysis types, allowing users to model elastic response or incorporate soil nonlinearity through modulus reduction and damping curves.
The software can accommodate multiple soil layers, each defined by parameters such as thickness, unit weight, shear wave velocity, and damping ratio. Users can assign site-specific or empirical modulus reduction models, choose from a selection of constitutive models, and apply custom or database-sourced ground motions.
DEEPSOIL features a graphical user interface that guides users through each stage of model development. The process includes defining the soil profile, selecting input motion, configuring analysis parameters, and reviewing the output results. Analysis options include:
Output results include acceleration time histories at different depths, response spectra, shear stress-strain loops, transfer functions, and excess pore pressure ratios (if applicable). These outputs are critical for evaluating ground shaking intensity and understanding how subsurface conditions influence seismic response.
DEEPSOIL is commonly used in both research and applied engineering contexts, including seismic hazard assessment, site classification, and foundation design. Its balance of analytical depth and usability makes it a practical tool for engineers seeking to evaluate local site effects.
The tutorial
We are demonstrating a full DEEPSOIL workflow using a 15-meter layer of loose sand over a rigid bedrock base. The example includes input motion selection, linear analysis configuration, and results demonstration.
In the video tutorial, we completed a full linear site response analysis using DEEPSOIL. We defined a 15-meter loose sand layer overlying rigid bedrock, applied a real earthquake ground motion, and reviewed the key outputs including acceleration time histories, stress-strain behavior, and spectral response.
This example demonstrated how soil properties and boundary conditions influence seismic wave amplification. The observed spectral peak highlighted the importance of site-specific analysis in assessing surface shaking intensity.
The workflow shown here can be expanded to nonlinear cases, damping models, and pore pressure generation depending on project needs.
References
University of Illinois at Urbana-Champaign. (2019). DEEPSOIL User Manual, Version 7.0. Department of Civil and Environmental Engineering. Retrieved from: https://deepsoil.cee.illinois.edu/
DEEPSOIL is a 1D site response analysis program with graphical user-interface that can perform both: 1D Nonlinear analysis 1D Equivalent li...
