ABSTRACT
ABSTRACT The surveys of tunnel structures show that many tunnels deteriorated in their early service lives. As important underground infrastructures, the inspections and maintenance costs of tunnel structures are huge, thus the research on scientific tunnel maintenance method is becoming very necessary. Maintenance strategy focuses on the problem of how to allocate maintenance resource to improve maintenance effect in a better way, and it is of vital important in current situation. A state-oriented maintenance strategy of tunnel structure is proposed in this paper. Comparing with traditional maintenance strategy, the major difference of proposed strategy is that it uses dynamic inspection schedule and multi-state oriented maintenance rule, which means tunnel structure in different service states will be inspected by different frequencies and maintained by different levels of maintenance measure. In order to investigate the proposed maintenance strategy with traditional ones, a mathematical framework of maintenance strategy optimization is formulated. Grid exhaustive optimization algorithm is applied to minimize the lifetime maintenance cost of tunnel structure under safety requirement. The results of numerical studies show that state-oriented maintenance strategy is recommended in most cases, which will greatly reduce maintenance cost during the whole service life of tunnel structure.
