中文摘要：

高地应力软岩隧道围岩流变效应明显,形变压力导致的仰拱和边墙连接处的应力集中是导致隧道底鼓破坏的重要原因,合理的隧道断面形态有利于减小应力集中,保证隧道长期安全运营。在考虑软岩流变效应的情况下,以有限元软件ABAQUS为平台,通过Python编程实现隧道断面参数化设计和有限元计算,基于结合罚函数的Nelder-Mead函数建立隧道断面优化算法,并以隧道开挖面积,隧道最大仰拱隆起,围岩蠕变损伤区面积,衬砌最大轴力和衬砌最大弯矩为优化目标,对宜-巴(宜昌至巴东)高速峡口隧道断面形态进行优化,为高地应力软岩隧道断面设计提供科学指导。

英文摘要：

When tunneling in high geostress region, the surrounding rock often produces obvious rheological deformation. The deformation would lead to stress concentration at the connection between side wall and inverted arch, which might result in floor heaving during tunnel operation period. So, a reasonable section shape of tunnel which could reduce stress concentration is very important for the long-term stability of tunnel. Considering rheological effect of surrounding rock, the parameterization design of tunnel section is programed into ABAQUS by Python. And a tunnel section optimization algorithm is established based on combination penalty function and Nelder-Mead function. An optimized objective function is established for Xiakou tunnel considering excavation area, floor heaving, creep damage area, axial force and bending moment of supporting system. The optimization results will provide scientific guidance for high geostress soft rock tunnel.