This paper presents an example of multiple uses of reliability methods employed by the project management team during the design and construction of the expansion of the Cherry Island Landfill, Delaware.
The landfill expansion involves the installation of prefabricated vertical drains (PVDs) and the construction of a mechanically stabilized earth (MSE) berm over very soft river sediments and dredged materials. The critical nature of this structure and foundation required a high degree of reliability for the characterization of the key engineering parameters on which the design was based. This paper presents the use of reliability methods for the following purposes: (i) to develop geotechnical characterization of the soil parameters; (ii) to perform stability analyses during the design phase; and (iii) to more effectively communicate design scenarios and their associated risks and costs to all project stakeholders during the design process. The use of reliability methods, beginning at the onset of the project led to a better-informed site exploration, a highly-detailed geotechnical characterization, a design with a high degree of reliability, and better- informed stakeholders during the design and permitting of the expansion.