裂缝对衬砌结构承载力影响与评价方法研究

Study on the bearing capacity and the evaluation method of the cracked lining structure

为了研究裂缝对衬砌结构承载力的影响和弥补现行《公路隧道养护技术规范(JTG H12-2015)》没有提供基于力学分析的结构承载能力评价方法,利用Abaqus扩展有限元软件,对纵向裂缝以不同深度单独出现在不同衬砌部位时的各工况进行了仿真模拟。通过承载力衰减率和安全系数衰减率,分别反映不同工况对衬砌结构承载力和安全性的影响程度。研究结果表明:随着裂缝深度的增加,衬砌结构的承载力和安全性会随之下降。裂缝出现在拱顶时对衬砌结构承载力和安全性的影响最大,其次为拱腰和边墙。根据建立的“衬砌安全性评价标准”,提出了各工况的安全等级、安全类别以及相应的处治措施。

In order to derive the effect of cracks on the bearing capacity of the lining structure, and make up the lack of method for evaluating the bearing capacity of the structurel based on mechanical analysis in current “Technical Specifications for Highway Tunnel Maintenance (JTG H12-2015)”, Abaqus extended finite element software to separately appear longitudinal cracks at different depths is used. Simulations were carried out under different working conditions for different lining parts. The defined bearing capacity attenuation rate and safety factor attenuation rate were used to reflect the influence of different working conditions on the bearing capacity and the safety of the lining structure. The results show that with the increase of crack depth, the bearing capacity and safety of the lining structure can decrease. When the crack appears in the vault, the bearing capacity and the safety of the lining structure can be the most important, factor followed by the arch waist and the side wall. According to the established “lining safety evaluation standard ware derived in this article”, the safety level, safety category and corresponding treatment measures for each working condition are proposed.