Reliability Analysis Of Expressway Tunnel Lining

Today reliability method on the basis of continuous medium model plays an important role in illustrating New Austrian Tunneling Method(NATM). In this paper, after 2-D model of tunnel by the great FEM code ABAQUS is established, sensitivity analysis of factors of random variables such as E, c andφinfluencing load effects is studied, reliability of lining structures under ultimate limit state during service period is discussed. The main work is as following:Firstly, based on continuous medium model, a new easy reliability method is available to obtain an explicit expression which can meet practical needs, the method which is put forward differs from Response-Surface-Method(RSM).Secondly, the procedure of tunnel lining based on First Order Second Moment(FOSM) and JC method is presented to calculate the reliability of tunnel lining.Thirdly, with the new reliability method, an excavation of one simple circle tunnel is simulated, then comes to stability analysis of surrounding of tunnel and sensitivity analysis of random variables influencing load effects.Fourthly, after modeling a circle tunnel of 2-dimension with lining, the sensitivity and reliability analysis are discussed for the difference of surrounding grade and depth of burial.Finally, with the FEM code ABAQUS,a large-spaned tunnel and a double-arch tunnel of Baziling off-spur tunnel which belongs to Shanghai-Chengdu expressway are simulated to analyze stability of surrounding and support structure, after this, the reliability of 2th lining structure is studied by the explicit function of load effects about random variables.