隧道二次衬砌全环拆除技术

The Whole Ring Demolition Technology of the Tunnel Second Lining

隧道二次衬砌边墙处连续区域经回弹检测及取芯验证为二次衬砌强度不合格,经研究确定需全环拆除,施工风险高,施工难度大。整板拆除一般采用爆破方式,因会较大程度的扰动初支及两侧已浇筑成型的二次衬砌,故改为采用打孔划区域、从拱顶到边墙逐段拆除的方式,把二次衬砌全部凿成蜂窝状,采用竖向支撑有效的避免大块掉块风险,避免了对初支及两侧已浇筑段二次衬砌的影响。施工实践证明安全可靠。

The strength of the secondary lining in the continuous area of the side wall ofthe tunnel is not qualified by rebound test and core-taking.The study shows that the whole ring demolition should be carried out, which is high risky and difficult for the construction.The whole slab is demolished generally by blasting, but it will disturb the initial support and the formed secondary lining on both sides largely, so the method of drilling and dividing the area is adopted instead, and the whole slab is demolished section by section from the vault to the side wall, the secondary lining is chiseled into honeycomb shape, the vertical support can effectively avoid the risk of large block dropping.Consequently, the adopted method avoid the influence on the secondary lining of the initial support and the poured sections on both sides. The construction practice proves that it is safe and reliable.