对高铁隧道二次衬砌钢筋设计问题的思考

On Design Issues of Reinforcement of the Secondary Lining of High-Speed Railway Tunnels

为了研究高速铁路隧道二次衬砌设置钢筋的必要性及配筋设计与钢筋实际受力是否一致问题,文章对比了中国、德国和日本的规范,并依托郑州至西安高速铁路隧道工程,进行了二次衬砌配筋设计与深、浅埋隧道钢筋实际受力现场测试对比分析。研究结果表明:按规范规定的围岩荷载的50%~60%以及按最不利节点,进行二次衬砌配筋设计偏于保守,和现场实测钢筋受力值存在较大差别;现场实测钢筋只有拱顶内侧受拉,受拉值仅为19.5MPa,其余均受压,二次衬砌钢筋压力比较小,最大值在左右边墙位置,为57 MPa。分析认为,进行二次衬砌结构检算时,可适当减小围岩压力的取值;衬砌配筋应通过工程类比及结合规范公式计算综合确定。

In order to study the necessity of reinforcement of high-speed railway tunnel secondary linings, and the consistency between the reinforcement design values and actual stress states of reinforcements, the Chinese, German and Japanese standards are compared. Based on the Zhengzhou-Xi＇an high-speed railway tunnel projects, the comparative analysis is conducted regarding the design parameters of secondary lining reinforcement and the actual reinforcement stress states in deep and shallow buried tunnels. The results show that： 1） the design of secondary lining reinforcements would be conservative at 50% - 60% of the rock loads as stipulated in the specification and the most unfavorable nodes, so there is a big difference between the field measured reinforcement stress values and the designed ones; 2） only the reinforcements at the inner layer of the vault lining are in tension, with tension values of 19.5 MPa; the rests are in compression with small pressure values, and the maximum pressure of the secondary lining reinforcements is 57 MPa at the left and right side walls; 3） in checking the secondary lining structure, the pressure of the surrounding rock can be appropriately reduced; and 4） the lining reinforcements should be determined by engineering analogy and combined with the formula stipulated in the specification.