Numerical Modelling of Creep Behavior of Excavations Stabilized with Anchors with a Case Study in Tehran

Some excavations need to be designed for a long time or sometimes they are left for a long time. Stabilization of most of the excavations has been done using anchors. Field surveys of these excavations show that in some cases, deformation of the excavations increases over time, and the locking force of anchors decreases, leading to dangers. Therefore, it is very important to know the long-term behavior of stabilization systems by an anchor and reduce the anchor load. The main purpose of this study is to evaluate the changes in anchor load in excavations. Numerical modeling of the long-term behavior of soils has many complexities and may not correspond to reality. Therefore, in this study, data on the long-term behavior of an excavation project in Tehran were collected and then numerical modeling in finite difference software was used to study the long-term behavior of this system. Also, using the back analysis method, the input creep variables of the rheological model of the time function in the numerical model were determined and used. Comparison of the results of this research and field survey results confirms the time function behavior of the numerical model performed in software. The results of this research show that in an anchor installed in the middle depth of the excavation project, a 7% reduction in load occurs one year after prestressing. Also, during the creep time, the maximum horizontal deformation of the excavation walls increases by 13% during one year.