Stability Analyses in the Ports of Long Beach and Los Angeles

The combined Ports of Los Angeles and Long Beach (Ports) have experienced extensive growth over the last three decades. A main feature of the expansions is the creation of new land by placing hydraulic fill behind rock retention dikes. This paper presents an overview of the recent history and state of practice of slope stability analyses performed for projects related to the expansion of the Ports. The geologic and seismic setting and typical soil conditions are also described. This paper is based on a review of geotechnical reports prepared for projects in both Ports and selected published papers. The various investigators used the current state of the practice analyses, with remarkably close agreement in the basic seismic design criteria. The designs and construction practices have, however, varied significantly, particularly in the configuration of the rock dikes (full section and multilift dikes). The design approaches and construction practices in both Ports have been satisfactory as evidenced by the performance of the facilities. Because of different designs located in the same seismic setting and the abundance of quality geotechnical data, the combined Ports offer an excellent opportunity to install field instrumentation to learn from future earthquakes. The conclusions reached and statements made in this paper are solely those of the authors, and do not necessarily represent the opinions of other parties, firms, or agencies involved in any of the projects referenced

Review of Slope Stability Analysis in the Ports of Long Beach and Los Angeles

The combined San Pedro Bay, California Ports (Long Beach and Los Angeles) have been developed mostly by placing dredged material behind rock dikes to create useable land and the wharfs constructed over the rock dikes. An overview of the stability analysis of the dikes was presented in a 1991 paper that summarized slope stability and seismic criteria prior to 1991. Since that time, deeper channel depths, higher seismic criteria, and higher seismic survivability expectations by the users have resulted in higher levels of analysis. This paper provides an update of a paper presented in 1991 and presents data regarding slope stability finite element/difference method (FEM) analysis completed by different investigators that included the contribution of the wharf piles that extend through the rock dikes to slope stability and reduction of deformation. The conclusions reached and statements made in this paper are solely those of the authors and do not necessarily represent the opinions of other parties, firms, or ports in any of the projects referenced