Research On Evaluation And Treatment Methord Of Tunnel Structural Cracks Disease

With the rapid development of China’s economy, the demand for transportation is growing, which promotes the construction speed of infrastructure projects, including railway, highway, municipal, etc. In recent years, a large number of high-speed railway, highway has been built in our country. In order to ensure a flat line and minimizing the curve as far as possible, when crossing the mountain area, the proportion of bridges and tunnels is huge, some of which is even more than 90%.When put into operation, there are many factors may lead to tunnel concrete lining cracks, such as:vibration caused by high vehicle speed, substantial rapid cooling, heat-expansion and cold-contraction caused by temperature changes, as well as the additional load on the structure because of expansion of special strata, and so on. Cracks will reduce the carrying capacity, durability and water resistance of the concrete structure. If the lining cracks lead to lining concrete impellers, it will threaten the safe operation of the tunnel to a large extent. Therefore, it is very urgent and important to have a research on lining crack disease of tunnel and its control measures.This thesis is based on the previous research, which classified the tunnel lining cracks according to the length and width, considering the trend of cracks and leakage, and has an in-depth study on lining crack disease of tunnel. Finally, it has obtained some achievements, as follows:1. The existing evaluation standard of tunnel cracks is mainly aimed at the length and width of cracks. However, the cause of cracks is complex, and the collection forms are varied. Previous research had a simple classification and quantification about the pattern features of cracks parameter. While, classification standard and the purpose is not clear, and disease parameters is not complete, which can’t accurately describe the basic geometrical and mechanical characteristics of the disease. So it can’t be applied on the defection of tunnel lining cracks directly.2. This thesis combines the trend of cracks and leakage, which are the key factors influencing the characteristics of cracks, and put forward a new assessment standard of tunnel lining cracks.3. Through model test on a different level of cracks, this thesis has found the correspondence of remediation methods on the four levels of cracks for the new evaluation standard, and has introduced in detail.4. This thesis has derived the calculation formula of the safety factor K of remediation methods, which will be used to confirm the regulation effect.5. Relying on the Yaxi high-speed Tu Shan Gang No.1 tunnel, and combining the operation conditions and evaluation standard, this paper through numerical simulation put forward some regulation scheme and confirm.