Study Of The Influence Of Steel Arch's Local Corrosion On Supporting System Security For Xia' Men Sub-Sea Tunnel

Xiang'an Subsea tunnel was the first tunnel built in China mainland. Geological environment, load model and design theory of the undersea tunnel have different key technologies to general mountain tunnels. The specificity of the undersea tunnel brings some new problems on the tunnel's durability to us. Forasmuch, considering the design and construction experience of the Xiamen Xiang'an subsea tunnel engineering, summary the potential effect factors of subsea Tunnel's durability, and used ansys software to analyzes the impact of the steel arch's local corrosion on supporting system security, which based on the field investigation.Finally study the corrosion monitoring for the steel arch and steel in second lining by combining the tunnel's engineering features. The major work of this research is summarized as follows:(1) reference to the general factors that influence the durability of highway tunnels, and considering the Xiang'an tunnel's engineering environment, design and construction conditions, give a brief analysis on the potential risk factors for the deterioration of the tunnel's durability, which from environmental factors, design, construction and maintenance management, causal factors, other aspects and steel corrosion.(2) Investigate Xiang'an tunnel's shotcrete strength and steel arch corrosion, and then analyze the level of shotcrete strength with the changes of water leakage, and the the condition of steel arch corrosion. Finally got the result that Xiang'an tunnel's preliminary lining exists local corrosion instance.(3) Analyze the the impact of steel arch's local corrosion on supporting system by the means of ansys finite element simulation, which considering bond-slip and bond degradation between steel arch and shotcrete. According to the calculate result of different corrosion part, finally got the result that Arch and side walls corrosion has been the most disadvantageous to the tunnel structure(4) Design the corrosion monitoring system of Xiang'an subsea tunnel, including the choice of corrosion sensors, corrosion section and arrangement of the measuring point, the sensor installation, corrosion, the found of corrosion database, and the management of monitoring system. Finally established the Subsea Tunnel corrosion monitoring and evaluation system, based on field steel corrosion monitoring data,can evaluation the security of Xiang'an subsea tunnel.