为解决超大断面地下储罐空间的施工开挖及支护技术难题以及克服工效低、工期紧问题，基于某超大跨度地下储罐工程，通过探究本工程的特点与难点，提出2种施工方案及其相应的详细施工支护工艺及支护参数；通过数值模拟，运用生死单元法+软变模量法模拟条形反向挑顶开挖法及环形预留中心岩柱开挖法的罐体施工过程，从围岩竖向位移、结构竖向应力及锚杆锚索拉力方面分析2种施工方式的差异，并经方案比选确认采用条形反向挑顶开挖法开展项目后续罐体施工；然后根据普氏理论和悬吊理论，对预应力锚索的布置进行优化，并通过监测数据及实际施工工期对方案可行性进行验证。结果表明: 1）环形预留中心岩柱开挖法与条形反向挑顶开挖法，以及相应的支护方案与参数，可有效解决大跨度低等级围岩地下空间开挖支护难题； 2）经数值模拟及现场监测验证，条形反向挑顶开挖法及相关锚索支护优化方案对该工程具有良好的适用性。
The excavation and support of ultra-large-section underground storage tank space is challenging, the construction efficiency is low, and the construction period is short. To address these issues, a case study is conducted on an ultra-large-span underground storage tank project, and two construction plans and their corresponding detailed construction support processes and support parameters are proposed based on the characteristics and difficulties of the project. Through numerical simulations, the construction process of the tank body is simulated using the birth death element method and soft modulus method. Furthermore, the differences between the two construction plans are analyzed in terms of vertical displacement of surrounding rock, vertical stress of structure, and tension of anchor bolts and cables. After scheme comparison, it is confirmed that the strip reverse roof excavation method is employed for the subsequent tank body construction. Finally, based on the Platts theory and suspension theory, the layout of prestressed anchor cables is optimized, and the feasibility of the plan is verified through monitoring data and actual construction period. The results indicate that: (1) The proposed construction methods, annular reserved center rock column excavation method and the strip reverse roof excavation method, as well as the corresponding support scheme and parameters, effectively solve the problem of excavation and support in underground spaces with large-span and low-grade surrounding rocks. (2) Through numerical simulation and on-site monitoring verification, the strip reverse roof excavation method and related optimized anchor support scheme have good applicability to this project.
