Portland State University. Department of Civil & Environmental Engineering
Diane M. Moug
Term of Graduation
Date of Publication
Master of Science (M.S.) in Civil & Environmental Engineering
Civil and Environmental Engineering
1 online resource (x, 43 pages)
The piezocone penetration test (CPTu) is a commonly used method of geotechnical site investigation. The CPTu is especially useful because it provides a nearly continuous data profile of in-situ soil behavior, which can be correlated to useful engineering parameters. However, limitations exist for interpretation of geotechnical properties from CPTu data and for numerical analysis of cone penetration problems. The research presented in this thesis examines interpretation of coefficient of consolidation from CPTu dissipation test data and implementation of an algorithm to advance numerical simulation of cone penetration problems.This thesis presents analysis of CPTu dissipation responses from field-measured and numerically simulated dissipation tests and their interpretation, according to four published methods. The performance of these methods in interpreting assigned model properties is examined under various conditions of vertical and horizontal hydraulic conductivities and OCR. The analysis indicates that existing methods of interpreting coefficient of consolidation from dissipation tests fall short in two areas: improper interpretation of non-monotonic dissipation and inaccurate neglect of the role of vertical pore pressure migration during dissipation testing. A useful tool in studying CPTu site investigation and dissipation testing is high quality numerical simulation of CPTu testing. Moug (2017) described an ALE model for steady-state simulation of cone penetration at a single depth using the MIT-S1 constitutive model, which accurately represents clayey and silty behavior well, including anisotropic loading of clay. This is especially important because of the complex anisotropic stress conditions that exist around the cone (Moug, et al. 2019). However, due to its remeshing step, the Moug (2017) model is limited to simulation of a single soil layer at a single depth. This thesis describes the implementation and verification of a linear elastic finite-element adaptive remeshing algorithm that, when integrated with the Moug (2017) model, provides a numerical scheme capable of simulating penetration through depth in a soil profile, while retaining the valuable constitutive performance of the original model.
© 2020 Andrew Phillip Eugene Huffman
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Huffman, Andrew Phillip Eugene, "Numerical Simulation of Continuous Cone Penetration and Interpretation of CPTu Dissipation Tests" (2021). Dissertations and Theses. Paper 5639.