Reliability Analysis And Durability Evaluation Of Inservice Heat-supplying Underground Structures

With the service time of engineering structures goes on, a large number of concrete structures got into aging stage. The decrease of reliability of buildings or structures that due to durability damage is bringing more and more economic loss, which makes the durability damage of reinforced concrete structures become an urgent problem, especially the durability damage of heat-supplying engineering. However, urban underground engineering that mainly include heat-supplying engineering(brick structure, reinforced concrete structure, undercut tunnel and the annex) lack in systematic study of structural disposal. The revision and transformation of old urban underground structures are still lack of theoretical basis in decision of structural disposal. In this paper, the reliability calculation and durability evaluation of heat-supplying tunnel have been done through field test and numerical analysis, the specific research are as follows:(1)According to the type of structures, brick and reinforced concrete cover combination structure, concrete structure and injection of concrete structures were field test and statistical analysis respectively, the technical conditions of different structure types and statistical law of test items were obtained.(2)Introducing response surface method, modeling calculation of chamber and tunnel structures were completed using Midas/Gen, which obtained the statistical characteristics of load effect, and then the reliability index of structure is calculated by using the optimization toolbox of Matlab.(3)The durability of structure is divided into two levels by using fuzzy evaluation method, and the weight set of each influence factor is established by the method of analytic hierarchy process.Finally, the durability of thirty sites is obtained according to the nearness degree method.(4)Based on the result of fuzzy evaluation,combined with the concept of Markov process,the remaining life of HuaNeng 10 structure is predicted, which provides the theoretical basis for maintenance and reinforcement of the tunnel in the future.