The influence of buildings and ground stratification on tunnel lining loads using finite element method

Urban development and increasingly growth of population have been accompanied by a considerable growth in mechanized Shield tunnelling. Commonly precast concrete segments used as tunnel lining in mechanized tunnelling and include relatively considerable part of tunnelling cost. The optimum design of lining that decreases tunnelling cost needs to accurate evaluation of loads act on lining. In this study. the effects of soil stratification, building's geometry, position and weight on lining loads were studied. A 2D finite element model was applied to simulate the conventional procedure of tunnel excavation and lining using Abaqus software (Ver 6.10). The geometry of tunnel, lining segments, injection grout and around soil properties were adapted from under construction Tabriz urban railway line 2 project. The results show that ground stratification and building properties (especially the position of buildings) have considerable effects on lining loads. From the viewpoint of structural design, the buildings effect on lining is critical when the surface buildings are unsymmetrical.