Response Surface and Importance Sampling Method based Tunnel Lining Structure Time dependent Reliability Research

Abstract:

Because tunnel lining structure limit state function are highly nonlinear, the geometric reliability obtained by a direct adoption of the general method is of a considerable error and an improvement is in need. By combining the response surface method and important sampling methods, the checking point sampling was obtained as an important center of the sample. Then the structure of the reliability indexes were solved. Based on a consideration of the factors of the resistance to decay with time, the Matlab software was resorted to drawing up the time dependent reliability index calculation program of tunnels in the service life period,and a regression analysis showed that the time dependent reliability indexes decreased exponentially with time. By the correlation of durability coefficient and time dependent reliability indexes, the durability coefficient at any time was available, which was key to the durability design of lining structure. The proposed method is suitable for highly nonlinear performance function engineering and it lays a good foundation for structural durability design.