新建隧道小净距下穿已建高铁隧道的安全分析

Safety Analysis of Newly-built Tunnels Underpassing Existing High-speed Railway Tunnels with Small Clear Distance

文章依托巫溪支线柏树林隧道下穿郑万高铁小田坪隧道工程,建立了三维弹塑性有限元模型,分析了下穿段交叉隧道衬砌结构受力情况及结构安全性设计,然后结合交叉隧道夹岩力学理论模型,比较了隧道施工过程夹岩内力变化情况,指出设计上需完善超前支护和支护结构。同时,施工中需采取短进尺、快封闭的支护结构设计理念,最后根据现场实测上部郑万高铁小田坪隧道衬砌结构位移变化值验证了下穿段设计方案的合理性。巫溪支线柏树林隧道小净距下穿在建高铁隧道小田坪隧道工程的成功实施,可为隧道下穿运营高速铁路等相似工程提供参考。

Based on the project of Baishulin tunnel of Wuxi branch line underpassing Xiaotianping tunnel of Zhengzhou-Wanzhou high-speed railway,this paper establishes a three-dimensional elastic-plastic finite element model,analyzes the stress and structural safety design of the lining structure of the cross tunnel in the underpass section.Then,combined with the theoretical model of rock clamping mechanics of the cross tunnel,it compares the internal force change of rock clamping during tunnel construction,and points out that the design needs to improve the advanced support and support structure.At the same time,the support structure design concept of short footage and quick closure should be adopted in the construction.Finally,the rationality of the design scheme of the underpass section is verified according to the displacement change value of the lining structure of the Xiaotianping tunnel on the upper Zhengzhou-Wanzhou high-speed railway.The successful implementation of Baishulin tunnel of Wuxi branch line underpassing Xiaotianping tunnel project of the high-speed railway tunnel under construction with small clear distance can provide references for similar projects such as the tunnel underpassing the high-speed railway in operation.