Seismic Performance of Deep Excavations Restrained by Anchorage System Using Quasi Static Approach

Soft grounds amplify the earthquake motions and the peak ground acceleration increases when passing through them. Thus, the response of structures constructed on such sites would be more severe than others. The deep excavations are one of the most vulnerable geotechnical structures during earthquakes particularly when performed in soft grounds. Hence, they have to be stabilized and restrained for these circumstances. Using the anchorage system is one of the most common methods to stabilize such excavations. The influence of different factors such as soil characteristics, and anchors' geometry and properties on seismic response of so-called restrained deep excavation is an important issue that needs to be focused on. In the present paper, the results of quasi-static finite element analyses of deep excavations performed in soft and stiff grounds during earthquake loadings have been presented, compared and discussed. The results show that considering adequate values for the anchor parameters (such as; angle, length and distance between the anchors and the amount of pre-stress force in them) leads to accurate and satisfactory design safety and deformation controls of the excavation.