Research On Reasons For Lining Crack Of Shibiqiao Tunnel

Lining cracking is a very common disease in tunnel, which would affect their normal service, even result in scrappage. Course leading to lining cracking is complicated, such as: geological structure, underground water, uneven pressure, construction quality, etc.This paper takes Shibiqiao Tunnel as a research example. engineering geological condition of the tunnel is investigated, characteristic and amounts of cracks is surveyed. Theoretical analysis is conducted to search the reason for crack; combined with the theoretical results, numerical simulation method is utilized to confirm the course. The main work is stated as following:1.Investigate the geographic and geomorphic conditions, geological structure, meteorological conditions, hydrogeology; investigate the type and characteristic of cracks and add up the amount; assess the level of cracks with qualitative and quantitative assessment index.2. Analyze every negative factor to tunnel, including stratum structure, geological structure, underground water, construction quality, and reached a conclusion that the special stratum structure-weak substrate is the main course to lining cracking. And the underground water softening the substrate would furtherly intensify the lining cracking.3. contrapose the weak substrate, numerical simulation is conducted under three situation: none weak substrate, with weak substrate and softened weak substrate. The results show that the weak substrate is the main course to lining cracking.numerical simulation under the condition of soft weak substrate softened by underground is also conducted, reaching a conclusion that softened weak substrate would furtherly intensify the lining cracking.