Mechanism Study On Longitudinal Deformation Of Secondary Lining Of Highway Tunnel In Cold Regions

Influenced by temperature, circular cracks of secondary lining of highway tunnelwhich in use has been found in different degrees, especially in cold area. Circularcracks is the passageway of leaking water, which causes corrosion of reinforcementand decreases the reliability of the structure. Nowadays, the study on mechanism ofthe longitudinal deformation of secondary lining influenced by temperature, boundaryconstraint conditions, waterproof performance and measures of crack control is notmature.This paper introduces the concept and types of temperature stress. Based on thetheory of the long wall on foundation, this paper analyzes temperature stress ofsecondary lining of highway tunnel which in cold area and the law of crackpropagation, gets the analytical formulas of the temperature stress, the space betweentwo cracks and the width of the cracks. This paper finds out that temperature stress,the space between two cracks and the width of the cracks are majorly influenced bythe difference in temperature, the length of forging and the horizontal resistancecoefficient of foundationshear tests of six combinations of waterproof material, PVC, EVA, compoundPVC, compound EVA, PVC+buffer layer, EVA+buffer layer are done through thepreparation of small shear test instruments indoor and large shear test instruments in acavern. For simulating the working condition of compound lining of tunnel. Thispaper determines horizontal resistance coefficient of foundation of differentcombination under different surrounding rock pressure, presents the function ofhorizontal resistance coefficient of different material and surrounding rock pressure.The tests show a big difference between horizontal resistance coefficient got by testsand calculated based on the theory of the long wall on foundation. Then evaluate the two kinds of materials, PVC、EVA based on the result of tests.This paper investigates the temperature field and circular cracks of secondarylining of Huan Xi Ling tunnel, analyzes the law of temperature change and Crackpropagation and influence factors. Calculate the stress and cracks of Grade Ⅳ zone ofHuan Xi Ling tunnel using horizontal resistance coefficient got by tests, the contrastof the theoretical calculation and the actual situation shows that the results areconsistent.Shear test results of the waterproofing material of secondary lining provide areference for the design of highway tunnel, code-setting of maintenance. This studyhas important realistic meaning and academic value.