基于随机有限元的隧道锚喷支护可靠度方案优化设计

根据剪切滑移理论, 建立了隧道围岩-支护结构功能函数, 提出了基于随机有限元的隧道锚喷支护方式的可靠度分析方法。以广州某区间隧道工程为例, 在分析支护方案的内力及可靠度参数基础上, 确定优选方案并采用JC法从抗压、抗裂方面验算了其可靠性。研究结果表明:9种工况中喷层的最大轴力为923.67 kN, 最大弯矩为10.12 kN·m, 最大剪力值为47.62 kN, 锚杆的最大轴力为48.06 kN; 以柔性支护和组合梁理论, 初选喷层厚度取值为6 cm或10 cm, 锚杆间距1.4 m, 以可靠度β=3.35为判断标准和耐久性原理, 确定喷层厚度10 cm, 锚杆间距1.4 m的支护参数为最优方案。

Optimal Design for Reliability of Tunnel with Bolt-shotcrete Support Based on Stochastic Finite Element Method

Based on the performance function involving tunnel surrounding rock and support structure obtained according to the shear slip theory, a reliability analysis method based on stochastic finite element was proposed for tunnel with rock bolt and shotcrete support. For a tunnel project in Guangzhou area, an optimal tunnel support program was determined based on the stress analysis and reliability assessment and its reliability was verified by JC (method) in terms of its resistance to stress and crack. Research results show that in 9 kinds of work conditions, the rock bolt and shotcrete layer has the maximum axial force of  923.67 kN, the maximum bending moment up to 10.12 kN·m, the maximum shear no more than 47.62 kN and the maximum axial force of anchor at 48.06 kN. With the flexible supporting effect of shortcrete and effect of composite beams taken into consideration, the primary tunnel support with the shortcrete thickness at 6 cm or 10 cm, with the bolt spacing at 1.4 m was determined. With reliability β=3.35 as criteria, together with reliability theory, a rock bolt-shotcrete supporting program with a shotcrete thickness of 10 cm and bolt spacing at 1.4 m was finally regarded as the optimal method.