Seismic Response Analysis of Shallow Water Tunnel with Concrete Lining

摘要

The water transferring project of Dahuofang reservoir in Liaoning Province is a water supply project with length of 259.13km, which transfers the water in Dahuofang reservoir to Fushun, Shenyang, Liaoyang, Anshan, Panjin and Yingkou cities. In the part of Fushun city, tunnel is the common structure with length of 27.63km. The surrounding rocks of tunnel mainly belong to II or III rock types except that in cleuch mainly belongs to V rock type. Based on the actual construction background of the project and the ground characteristics, a classical section of the shallow water tunnel was selected as the study object in this paper. Considering the interaction between surrounding rock and concrete lining, the finite element digital model was built to simulate the seismic response of this tunnel, the effects of embedded depth, thickness of concrete lining, elastic resistance coefficient and water in tunnel on concrete lining were studied. It is proved that under the horizontal earthquake action, the maximum radial and circumferential tensile stresses of concrete will turn up near the 45° or 135° area of outer half concrete lining and the circumferential tensile stress has the controlling effect. The tensile stresses of concrete will be greatened with the increase of embedded depth till a certain value, after that the stresses will be decreased, but the reducing rate is smaller than the increasing rate. The tensile stresses of concrete will be increased with the decrease of elastic resistance coefficient. The seismic resistance capacity of tunnel will be increased with the increase of the thickness of concrete lining when the surrounding rock is not good, otherwise there are a few influences. The concrete stress is influenced obviously by the water in tunnel, the seismic resistance capacity of tunnel with water is better than that in empty condition. The results can be used as reference for the same kind of engineering in site selection, design, construction and management.