NEHRP Clearinghouse
- Title
- LASS-II, Computer Program for Analysis of Seismic Response and Liquefaction of Horizontally Layered Saturated Sands.
- File
- PB281108.pdf
- Author(s)
- Ghaboussi, J.; Dikmen, S. U.
- Source
- National Science Foundation, Washington, D.C. Applied Science and Research Applications., June 1977, 111 p.
- Identifying Number(s)
- UILU-ENG-77-2010
- Abstract
- A new approach to analysis of seismic response and evaluation of the liquefaction potential of saturated sands are presented. Work on the development of a two-phase fluid solid model for quasi-static and dynamic analysis of saturated soils has been extended here by using a nonlinear material model to represent the behavior of solid granular medium. The separate phases of solid granular skeleton and the pore water are modeled individually, and the coupling between these two phases is taken into account. The pore water is allowed to flow with respect to granular solid. This process is assumed to be governed by Darcy flow law with the coefficient of permeability as the material constant. Dynamic analysis of this model allows direct determination of the time histories of pore water pressures and effective stresses. The seismic response of the system to earthquake base acceleration is also determined in the process of dynamic analysis. The material model used is defined in terms of effective stresses. Criteria for the occurrence of initial liquefaction and onset of liquefaction are defined in terms of effective stresses and are included in the material model. (Portions of this document are not fully legible)
- Keywords
- Darcys law; Seismic waves; Computer programs; Earth movements; Ground motion; Earthquake engineering; Soil water; Saturated soils; Liquefaction (Soils); Soil dynamics; LASS-2 computer program; Earthquakes