A Practical Model to Predict Permanent Deformation of Sand Under Cyclic Loading

Sand is the most widely existing granular material for the foundations of extensive constructions which bear various complex cyclic loading such as traffic loading, ocean wave loading and earthquakes. The road pavements and the offshore foundations subjected to cyclic loads tend to produce excessive permanent deformation, which affects the constructions’ normal operation and safety. Nowadays, many engineering projects change from strength controlled criterion to deformation controlled criterion, such as the high-speed railway in China. Therefore, accurately prediction of the settlement due to cyclic loading is essential. Over the years many explicit models have been established to predict the permanent deformation of sand under cyclic loading. Most of these models are more or less empirical and lack of essential analysis of permanent deformation. There are many parameters obtained by fitting the test results in these models which cannot be easily determined in practical engineering use. In this paper, the concept of shear strain amplitude during cyclic loading is put forward to predict the permanent deformation. By introducing the shear strain amplitude, a unified explicit model is established to predict the cyclic permanent deformation of sand, which only contains four empirical parameters. The result shows that the model can successfully predict the permanent deformation under cyclic loading.