| Liquefaction-induced lateral spreading is defined primarily as the lateral displacement of a soil mass in the direction of gravity-induced "driving" shear stresses as a result of seismically-induced soil liquefaction. Lateral spreading, and resultant ground displacements and deformations, can damage bridges, buried utilities and lifelines, conventional structures, port and harbor facilities, and other works.; The objectives of this research effort are to develop improved engineering tools for prediction of liquefaction-induced lateral spreading displacements. A semi-empirical approach is employed, combining mechanistic understanding and data from laboratory testing with data and lessons from full-scale earthquake field case histories. A formally probabilistic approach is taken to development of the final predictive model to: (1) take fullest advantage of the data available and to deal with the inherent uncertainties intrinsic to the back-analyses of field case histories, and (2) develop predictive tools that will optimally interface within the probabilistic framework of probabilistic seismic hazard analyses.; This research separates the issue of magnitude of liquefaction-induced lateral spread displacement on a lateral spread feature from the spatial distribution of displacements across a lateral spread feature. Magnitude prediction was accomplished by the development of probabilistic predictive models for the estimation of the average and maximum liquefaction-induced lateral spread displacement. Two approaches were developed for prediction of the distribution of lateral displacements across a given spread feature. The first was to define the distribution of displacements at progressively larger distances from the location of maximum displacement, and the second involved assessment of localized strain potential indexes and correlation of these (as well as driving shear stresses and duration of strong shaking) with observed local displacements. Both approaches yielded valuable insight, and the combination of these provide engineering tools for site-specific prediction of liquefaction-induced lateral spreading displacements. |
