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Viscous behaviour is a significant characteristic of soil, and to accurately capture this behaviour, a piecewise-linear model called ACLC has been developed specifically for modelling one-dimensional large-strain consolidation of soft clay. ACLC takes into account both the long-term deformation and anisotropy of the soil. Furthermore, it incorporates various factors such as soil heterogeneity, self-weight, time-dependent loading, vertical flows, and seepage force. In ACLC, the settlement of the soil layer is a result of both the net outflow of fluid from the soil element and the development of soil creep. To describe the creep behaviour of the soil, ACLC employs two yield surfaces: the Current State Surface (CSS) and the Normal Consolidation Surface (NCS). The creep rates are calculated based on the associated flow rule. To ensure the accuracy of ACLC, it is validated using the enhanced CS2 model, oedometer tests conducted on Xiaoshan soft clay, and observed data from the Murro test embankment. Finally, the influence of ACLC parameters on the consolidation behaviour of clay is thoroughly investigated. This analysis helps to understand the role of these parameters and their impact on the overall consolidation process. [ABSTRACT FROM AUTHOR]

Abstract This paper studies the long-termed displacement of a tunnel boring machine (TBM) resting on soft clay during its unscheduled stoppage for 100 days. It is based on a real case of tunneling in a coastal city of Ningbo in China. The numerical prediction is carried out by using different soil models in the software PLAXIS, and the prediction is compared with on-site measurement of the displacement. Different factors are considered in the prediction, including soil creeping and the disturbance to the soft clay during the tunneling. The study indicates that the consideration of disturbance is essential to the accurate prediction. While advanced soil models including the soft soil model and soft soil creep model are not able to accurately predict the TBM displacement, the consideration of soil disturbance leads to a very good agreement with the measurement. The accurate prediction of ground settlements also justifies consideration of the disturbance in the study of tunneling. [ABSTRACT FROM AUTHOR]