NEHRP Clearinghouse

Title
A Numerical Model for Liquefaction in Sand Deposits.
File
PB298808.pdf
Author(s)
Liou, C. P.
Source
National Science Foundation, Washington, DC. Engineering and Applied Science., April 1976, 221 p.
Identifying Number(s)
UMEE-76R3
Abstract
A continuous model for soil liquefaction in a horizontal or nearly horizontal deposit subjected to ground shaking, as in earthquakes, is described. Information from the numerical model is significant because liquefaction may cause soils to lose their shearing strength or undergo extensive lateral displacements resulting in large scale landslides. Liquefaction involves the change of a saturated granular soil to a liquid state due to increased pore water pressure. A liquefaction model was developed comprising two inter-active parts, the shear wave submodel and the pressure wave submodel. Shear-strain relationships were formulated for the two-phase soil medium, and the governing equations for pressure wave propagation were then developed. A coupling between shear wave propagation and the vertical motion of soil due to changes in its vertical compressibility was developed. Coupled together, these two submodels constitute the liquefaction model. Application of this liquefaction model to case studies related to the Niigata earthquake of 1964 demonstrated the potential applicability of the model to liquefaction. A literature review, glossary, equations, figures, tables, appendix, and references are included.
Keywords
Pore pressure; Earthquake engineering; Sands; Earthquakes; Shear stresses; Soil dynamics; Secondary waves; Earth movements; Liquefaction (Soils); Stress strain diagrams; Liquefaction; Seismic waves