层状围岩隧道裂缝机理分析与防治技术

Mechanism Analysis and Prevention Technology of Layered Surrounding Rock Tunnel Crack

摘要:

依托在建公路隧道仰拱填充顶面及二次衬砌纵向裂缝病害，采用理论分析、数值计算等方法对隧道出现裂缝及其分布范围的机理进行分析，通过理论推导可得到层状节理岩体中破坏塑性区的近似分布特征，利用有限元软件对二次衬砌、仰拱及仰拱填充进行受力分析，分析结果表明：倾斜岩层存在的情况下，隧道衬砌结构内力显著增加；仰拱填充内设置中心水沟改变了填充顶面的应力分布；层状围岩的破坏塑性区分布受岩层倾角影响较大，与裂缝分布范围相吻合。根据倾斜岩层受力特征制定锁脚及系统长锚杆的方案，为隧道病害处治以及支护方案优化提供了依据。

Abstract:

Relying on the longitudinal cracks on the top surface of invert filling and secondary lining of the highway tunnel under construction, the mechanism of cracks and their distribution range of tunnels are analyzed by the methods of theoretical analysis and numerical simulation. Through the theoretical derivation, the approximate distribution characteristics of the failure plastic zone in the layered jointed rock mass can be obtained. The finite element software is used to analyze the stress of secondary lining, invert and invert filling. The results of the analysis show that the internal force of the tunnel lining structure increases significantly in the presence of inclined rock formations. The central ditch set in the invert filling can change the stress distribution of the top surface of the filling. The distribution of the failure plastic zone of the layered surrounding rock is greatly affected by the dip angle of the rock layer, which is consistent with the distribution range of cracks. According to the stress characteristics of the inclined rock formation, the schemes of locking foot and system long bolt are formulated, which provides a basis for the treatment of the tunnel disease and the optimization of the supporting scheme.