Large-scale Cyclic Triaxial Testing of Soft Clay

The behaviour of saturated soft clays subjected to cyclic loading is of considerable importance in railway engineering. The use of prefabricated vertical drains (PVDs) with surcharge preloading is one of the popular methods of soft ground improvement as they accelerate the consolidation by shortening the drainage path. In this paper, the behaviour of a soft clay from North-eastern NSW subjected to cyclic loads is investigated using large-scale triaxial testing. Cyclic triaxial tests on remoulded soft clay samples with vertical drains were carried out using a large scale triaxial apparatus designed and built at the University of Wollongong, using samples of 300 mm in diameter and 600 mm in height. The samples were anisotropically consolidated under ko condition to simulate the in situ stress history. Stress-controlled cycles were then applied to the soil samples. The results of the excess pore water pressure and settlement of the soft clay are presented. The advantages of soft subsoil stabilization with PVDs under cyclic loading conditions are discussed.