Along the coastline and in particular in the deltaic estuaries of the Netherlands, the occurring of numerous flow slides have been recorded. Analysis of these historical instabilities has resulted in empirical guidelines for verification of occurring of flow slides.

The request to tender for the Engineering & Construct project Dredge Sludge project Hollandsch Diep in the Netherlands prompted the development of realistic design tools which enables the prediction of the initiation of static liquefaction in a reliability based framework. The realisation of a disposal area with a volume of approximately 10 million m³ in a restricted circumference required the excavation up to 38m depth and construction of a ring dike, while designing the required slope with sufficient reliability.

Based on international literature, in-house experience and laboratory and field tests a simplified static liquefaction model based on the critical state framework has been developed. For the reliability assessment a robust method has been adopted using stochastic analysis of the dominant parameters, while using a regional database. Several planned and unplanned failures during the realisation of the dredging activities were successfully analysed using the simplified stochastic approach of the modified state parameter model. The article gives insight into the determination and application of the state parameter approach in the reliability based framework and discusses the practical and academic needs for further developments and research.