Liquefaction-Induced Lateral Spread Displacement

Lateral ground displacements generated by liquefaction-induced lateral spread are a severe threat to the Navy's shore facilities. During past earthquakes, lateral spread displacements have pulled apart or sheared shallow and deep foundations of buildings, several pipelines and other structures and utilities that transect the ground displacement zone, buckle bridges or other structures constructed across the toe, and toppled retaining walls, bulkheads, etc. that lie in the path of the spreading ground. Port facilities have been particularly vulnerable to ground displacement because they are commonly sited on poorly consolidated natural deposits or fills that are particularly susceptible to liquefaction and lateral spread. This Technical Note presents methods for evaluating liquefaction susceptibility of sediments beneath level to gently sloping sites and for estimating magnitudes of potential lateral ground displacement at those sites. This design guide provides procedures including equations, tables, and charts required to evaluate liquefaction susceptibility beneath level and gently sloping sites and to estimate probable freefield lateral displacements at those sites. Free-field ground displacements are those that are not impeded by structural resistance, ground modification, or a national boundary. This Technical Note does not provide guidance, however, for estimating ground settlements as a consequence of seismic compaction of granular soils or static consolidation of cohesive soils.

Prepared in collaboration with Brigham Young Univ., Provo, UT.