深埋砂层隧道欠厚二衬安全性及加固效果分析

为研究隧道二次衬砌厚度局部不足对隧道结构受力的影响及加固效果，依托蒙华铁路某隧道，运用有限元软件建立隧道二次衬砌局部厚度不足荷载-结构模型，对衬砌缺陷位置、缺陷厚度及缺陷范围对二衬结构安全性能的影响进行了分析，并结合现场加固方案对其加固效果进行评价。结果表明:衬砌厚度不足对其所在缺陷部位的安全系数影响最大；拱顶安全系数相对最小，拱脚对缺陷厚度最敏感；衬砌欠厚时对结构轴力影响很小，但会造成欠厚位置弯矩值的大幅度降低；对衬砌加固后，结构弯矩值能得到有效改善，安全系数显著提高。

Analysis on the Security and Reinforcement Effect of the Partial Defect Lining in Deep Sandy Tunnel

In order to study the effect of local insufficiency of secondary lining thickness of tunnel on the stress of tunnel structure and its reinforcement effect, this article relies on a tunnel on the Menghua Railway, using Finite Element Software to Establish the Local Thickness Deficient Load-Structure Model of Tunnel Secondary Lining, analyzing the effect of the position of the lining defect, the thickness of the defect and the defect range on the safety performance of the secondary lining structure and combining with on-site reinforcement program to evaluate its reinforcement effect. The results show that insufficient lining thickness has the greatest impact on the safety factor of the defect site; vault safety factor is relatively minimum, arch feet are most sensitive to defect thickness; when the lining is under-thick, the axial force of the structure has little effect, but it will cause a significant decrease in the bending moment value of the under-thickness position; after the lining is reinforced, the bending moment value of the structure can be effectively improved and the safety factor is significantly improved.