地面荷载和衬砌支护作用下浅埋隧道的围岩应力解

为研究地面荷载对有衬砌支护的浅埋隧道围岩应力的影响,在Verruijt研究复杂边界条件下浅埋隧道围岩应力问题的基础上,考虑隧道衬砌支护及地面荷载共同作用对浅埋隧道围岩应力稳定性的影响,求得了浅埋隧道围岩应力解并分析了多个因素对隧道围岩应力场的影响。结果表明:地面荷载越大,隧道腰部环向应力越大、底部环向应力越小;衬砌支护作用越大,隧道腰部环向应力越小、底部环向应力越大。地面荷载和衬砌支护作用不会改变浅埋隧道周边环向应力的分布规律及其受力最不利位置,但会改变其大小及作用方向。开挖过程中隧道拱腰处易出现土体失稳破坏。

Analytical Solutions to Stress of Surrounding Rocks for Shallow Tunnel Considering Internal Pressure and Surface Load

The aim of this study is to probe into the influence of ground load on the surrounding rock stress of shallow-buried tunnel with lining support. On the basis of Verruijt’s research on surrounding rock stress of shallow tunnel under complex boundary conditions, the analytical solution to surrounding rock stress under the combined action of lining support and ground surface load were obtained, and the influences of multiple factors on the stress field were examined. Results demonstrated that greater surface load resulted in larger circumferential stress at tunnel waist and smaller circumferential stress at tunnel bottom; larger internal pressure led to smaller circumferential stress at tunnel waist and greater circumferential stress at tunnel bottom. Ground load and lining support will not change the distribution law of circumferential stress around the shallow tunnel and its most unfavorable position, but will change its magnitude and direction. In the process of excavation, the soil is prone to suffer from instability and damage at the haunch of the tunnel.