水涧山隧道衬砌型式受力机理分析

Mechanical Mechanism Analysis of Lining Types in Shuijianshan Tunnel

摘要: 水涧山隧道包含深埋单洞分离式、浅埋小净距两类隧道区段，围岩等级覆盖II、III、IV级，分别配套分离式II级衬砌、分离式III级衬砌、小净距IV级加强型衬砌。为验证各衬砌型式在最不利工况下的结构安全性，依据规范，采用荷载结构法开展运营阶段二次衬砌极限承载验算，结合地层结构法同步验算初期支护、二次衬砌施工及长期运营受力，兼顾衬砌厚度不足病害影响。研究结果表明：三类衬砌在各自控制埋深下安全系数均满足规范要求；深埋II、III级衬砌安全储备充足，浅埋小净距IV级加强衬砌局部存在大偏心受力薄弱区，安全余量偏低；荷载结构法偏保守适用于病害校核，地层结构法贴合围岩–支护协同受力真实状态。研究明确了各衬砌型式适用条件、受力控制部位，可为隧道衬砌设计、施工质量管控及病害治理提供参考。

Abstract: The Shuijianshan Tunnel consists of two types of tunnel sections: deep buried single hole separation type and shallow buried small clearance type. The surrounding rock grades cover level II, III, and IV, and are respectively equipped with separated level II lining, separated level III lining, and small clearance level IV reinforced lining. To verify the structural safety of each lining type under the most unfavorable working conditions, according to the specifications, the load structure method is used to carry out the ultimate bearing calculation of the secondary lining during the operation stage. Combined with the geological structure method, the initial support, secondary lining construction, and long-term operation stress are synchronously calculated, taking into account the impact of insufficient lining thickness and diseases. The research results indicate that the safety factors of the three types of lining meet the regulatory requirements under their respective controlled burial depths; There is sufficient safety reserve for deep buried Grade II and III lining, while for shallow buried Grade IV reinforced lining with small clearance, there are locally weak areas with large eccentricity and low safety margin; The load structure method is conservative and suitable for disease verification, while the geological structure method conforms to the true state of the coordinated force between the surrounding rock and support. The study has clarified the applicable conditions and stress control parts of various lining types, which can provide reference for tunnel lining design, construction quality control, and disease control.