Experimental Study On The Crack Principle And Anti-crack Performance Of Secondary Linings Of Highway Tunnel

The cracking of the secondary linings of tunnel is always found in the tunnel construction, which seriously affects the quality and safety of the project. This paper, which is based on the surveys and on-site monitoring to completed and in-progress constructions in Hangzhou City tunnel project, laboratory testing, theoretical research and the lining cracking numerical simulation of research, in-depth analysis and study of the reason, type and material of the secondary linings of tunnel. In this paper, the work undertaken and the achievements are as follows:1. Highway tunnel cracks on-site investigation and analysis. Investigate and survey the home and abroad the secondary linings of Highway tunnel. Make a field survey of the cracking of the secondary linings of tunnel in Hangzhou City. Use the method of classification analysis to study the reason for the cracks.2. In-progress monitoring and data collection of the structure of the secondary linings of tunnel. Monitor and analyses the construction of the tunnel in the rock pressure and displacement, the contact pressure between the lining, and the stress of the secondary linings and the lining's quality.3. Testing the structural material of the secondary linings of tunnel. Male the proportioning test of cement concrete for the secondary linings of tunnel, and focus on the anti-shrinking ability by adding UEA. Making the plate secondary linings concrete shrinkage experiment, and study the effect of the UEA.4. Analyses the structural mechanics of the secondary linings of tunnel. By using nonlinear finite elemental analysis and non-contact element model, and considering the load-temperature shrinkage-dry shrinkage coupling effect, make the analysis mode in difference rock surrounding, based on the breaking strength of the secondary linings of the mechanism of cracking.5. Analyses and sum up the prevention and control technology of the secondary linings of tunnel. The main factor for the cracking of the secondary linings of tunnel are the offset load from the surrounding rock, the temperature changing and the lost of water. To avoid and solve it, we should follow the 'Prevention First' principle.