عنوان مقاله [English]
In recent years, the need to make greater use of urban spaces on the one hand and the lack of these spaces in comparison with the ever- increasing demand of urban society are reasons for optimum utilization of available spaces with underground constructions such as tunnels. Most of these excavations with large volume of drilling are located at shallow depths and close to surface which cause displacements in the groundand effect of these movements can be seen as surface settlements in the soil. Surface settlements can be very influential in surface structures such as buildings and facilities that are located in densely populated urban areas and the vicinity of the excavated tunnels. The control of these settlements in order to protect surface structures during tunnel excavation, is the most important issue considered by design engineers. Analytical, experimental, and numerical methods for estimating these settlements were studied and presented by several researchers. However, experimental and semi-experimental methods are not able to include all parameters; so they cannot perform detailed calculation in complex problems. For this reason, the use of numerical methods was developed in order to accelerate and increase the accuracy of calculations, beside methods was developed.In the present work, the effect of tunnel support on surface settlement has been studied by using finite- element method after verification of the model results made with ABAQUS software along with the experimental results and observations of sections s5-28 of the Milan underground line1. As the thickness and length of the concrete lining as geometric parameters that affect the support system stiffness, they can affect the surface settlements caused by tunnel excavation. Therefore, it is important that the support have the optimum size to have the greatest effect on reducing the settlements. Finally, in the present work, the effect of thickness and length of concrete segments installed with EPB-TBM ,has been studied. Keywords: settlement, EPB-TBM, concrete segment, tunnel, finite element.