跨断层深海隧道衬砌变形规律及加固措施研究

Deformation Law and Reinforcing Measures of Lining in Deep-sea Tunnels Crossing Faults

断层破碎带岩体强度低、易渗透、松散性强,跨海隧道的修建极易遇到断层破碎带,如果不施加相应的预加固措施,很有可能造成隧道衬砌发生扭转和剪切破坏。这项研究依托某段跨海隧道工程,采用数值模拟建立了详细的三维数值模型,该模型考虑了注浆压力、顶推力、注浆时效硬化等问题。模型模拟了管棚法和径向注浆法两种加固措施,分析了两种预加固措施对于抑制断层错动和稳定隧道的效果,最后用解析解对数值模型进行可靠性验证。主要研究结论如下:隧道穿越断层破碎带时,衬砌的危险位置主要与断层的倾角、宽度和倾向相关。以72°的走滑断层为例,隧道施工时衬砌的危险位置主要为左拱顶和右拱底,这两处位置受到断层的挤压,极易发生剪切破坏。管棚法和径向注浆法均能有效的减小隧道的最大变形,但管棚法对于抑制断层的效果要强于径向注浆法。

The construction of cross-sea tunnels is very likely to encounter fault fracture zones,which have low rock mass strength,easy permeability and strong looseness.If the corresponding pre-reinforcement measures are not applied,it is likely to cause torsional and shear damage to the tunnel lining.In this paper,a detailed three-dimensional numerical model is established by numerical simulation based on a certain section of the sea-crossing tunnel project.The model considers grouting pressure,jacking force,grouting age hardening and other issues.The model simulates two reinforcement measures,the tube shed method and the radial grouting method,and analyzes the effects of the two pre-reinforcement measures on restraining fault dislocation and stabilizing the tunnel.Finally,the reliability of the numerical model is verified by analytical solutions.The main research conclusions are as follows.When the tunnel passes through the fault fracture zone,the dangerous position of the lining is mainly related to the dip angle,width and inclination of the fault.Taking the strike-slip fault of 72°as an example,the dangerous positions of the lining during tunnel construction are mainly the left vault and the right vault bottom.These two positions are squeezed by the fault and are prone to shear failure.Both the pipe roof method and the radial grouting method can effectively reduce the maximum deformation of the tunnel,but the effect of the pipe roof method on suppressing faults is stronger than that of the radial grouting method.