Study On The Effect Of Construction Defects On The Stability Of Tunnel By Laboratory Tests

With the rapid development of our national economy and the continuous development of highway construction, the quantity of road tunnel is increasing quickly. The tunnel construction are not only highly cost, but also very important for the control of the construction period of the highway project. Therefore, we must assure the tunnel construction safety, economy and applicability. Due to the tunnel construction process is various, it is very easy to form construction defects during the construction. And these defects would form tunnel damages. These diseases influenced the function of tunnels, we should pay a lot of money on reinforcement. The more serious it is unsafe. Therefore, to analyze the influence of the tunnel construction defects on the tunnel stability is extremely important.This thesis would take the Haitangshan tunnel project in Liaoning as an example to analyze the influence of the tunnel construction defects on the tunnel stability, so as to provide a reference to this project. At present, more and more researchers and engineers pay much attention to the study of the stability of the tunnel by construction defects. Most of studies are carried out with the method of numerical simulation, but model test studies in these fields are rarely seen. Therefore, in review of the advantages of model test, such as authentic visual and comprehensive, on the base of the presently laboratory conditions of NEU, this thesis would take model test studies as the main method, and numerical simulation as the assistant method.This thesis would carry out the main research work:(1) The review and analysis on the tunnel stability by the empty:the empty between the surrounding rock and lining produce the uneven contacts.These contacts cause stress concentration, making lining inside tensile, lateral compression.The stress modes seriously influence the stability of surrounding rock and structure.So the empty would effect on the tunnel stability.(2) Models with the empty in different range and in different positions are carried out to study the influence of the tunnel construction defects on the tunnel stability.The comparability that controls all physical and mechanical parameters in elastic condition is realized by the similarity criterion. Then proportioning test is proceeded. Tunnel models are manufactured.At last to make the loading test and data measurement. We obtain the construction of the effect on the stability by different tunnel defects.(3) On the basis of the model test results, the thesis makes the numerical simulation analysis with the MIDAS. Through the finite element analysis, the thesis would analyze the deformation and stress of surrounding rocks in the different situation from the displacement and stress analysis. The numerical simulation results are adopted to verify with the model test results. This thesis puts forward the directive construction suggestions.(4) According to the model test and numerical analysis, the thesis puts forward some construction defect prevention measures for the Haitangshan tunnel project.