隧道衬砌厚度不足对安全性能的影响

Influence of Tunnel Lining Insufficient Thickness on Its Safety Performance

结合荷载结构法和有限元法,建立隧道衬砌多处厚度不足模型,设计多种工况研究Ⅲ,Ⅳ和Ⅴ级围岩隧道衬砌多处厚度不足对衬砌安全性能的影响规律。研究结果表明:当隧道衬砌多个部位存在厚度不足时,隧道整体的承载性能出现减弱,拱顶为隧道衬砌厚度不足最敏感的区域;拱顶衬砌与围岩分离形成脱空区时承担荷载减少,安全系数增加;由于结构、荷载以及缺陷部位均对称,对称部位的安全性能演变规律一致;隧道上部衬砌厚度不足对其他部位的承载特征影响比较小。

The model for multiple insufficient thickness of tunnel lining was established by combing with the load structure method and the finite element method, and various working conditions were designed to study the influence law of the multiple insufficient thickness of tunnel lining in the Ⅲ, IV and V class surrounding rock on lining safety performances. The research results show that the whole tunnel bearing capacity begins to weaken and the vault is the most sensitive to insufficient thickness of tunnel lining when there are insufficient thickness of several parts in tunnel fining, the assumed load decreases and the security coefficient increases when vault lining separates from the surrounding rock and forms the empty area, the safety performance evolution law of symmetrical parts is consistent due to the symmetry of structure, load and defect part, there are insufficient thickness in the upper part of the tunnel, which has a relatively small influence on the bearing characteristics of other parts.