基于数值分析的回填型岩溶隧道施工技术研究

为保证那丘隧道特大型溶洞地段主体结构的施工质量与结构稳定性, 在隧道底部溶腔已处治的基础上, 提出了主洞洞身开挖与初期支护施工技术, 并运用FLAC^3D对特殊断面的开挖施工进行模拟, 通过分析围岩位移与结构应力计算结果, 对岩溶整体结构开挖与支护效果进行了评价。结果表明, 围岩最大位移为5 mm, 支护结构应力小于设计抗压强度, 均符合施工设计规范指标。最后, 结合现场监测数据与数值模拟结果, 通过对比分析, 验证了实际施工技术的合理性, 可为类似工程提供参考。

Construction Technology for Backfill-type Karst Tunnel Structures Based on Numerical Analysis

In order to ensure the construction quality and structural stability of the main structure of Naqiu tunnel through the superlarge karst cave section, a construction technology of excavating main body of cave plus supporting at inital stage was proposed after the cavity at the bottom of the tunnel was treated. The excavation for some special sections of tunnel was simulted with FLAC^3D software. The excavation and supporting for the overall carst structure was evaluated based on the analysis of displacement of surrounding rock and calculation of structural stress. Results showed that the maximum displacement of the surrounding rock was 5 mm, and stress of supporting structure was less than the design of compressive strength, which was in accordance with the specifications in the construction design. Finally, the on-site monitoring data and numerical simulation value were taken for comparison and analysis, indicating that such technology is reasonable in the practical construction and can provide a reference for other similar projects.