超高回填明洞荷载模式优化研究  

A Study on Optimization of Load Pattern of Open-cut Tunnel with Ultra-high Backfill

作　　者：许兴伍 XU Xingwu(China Railway Chengdu Group Co.,Ltd.,Chengdu 610082,China)

机构地区：[1]中国铁路成都局集团有限公司,成都610082

出　　处：《高速铁路技术》2023年第2期19-23,共5页High Speed Railway Technology

摘　　要：超高回填明洞拱顶回填土高度远大于普通明洞,采用传统荷载计算模式时理论与现实存在冲突。本文基于明洞结构施工过程及土压力形成基理,将传统明洞荷载计算模式中侧向压力由主动土压力优化为静止土压力。结果表明:(1)明挖法修建明洞工程,采用传统荷载计算模式时,存在某个极限回填高度;超过该极限回填高度,结构较难满足承载力及正常使用极限状态的要求;(2)明洞结构在回填土荷载作用下,变形量较小,不具备形成主动土压力的变形条件,明洞边墙侧向压力应为自重应力场的静止土压力;(3)案例表明,优化后的荷载计算模式与明洞受力状态更为接近,静止土压力荷载的计算模式合理可行。The backfill height of the arch crown of the open-cut tunnel with ultra-high backfill is much higher than that of the ordinary open-cut tunnels,and there is a conflict between theory and reality when the traditional load calculation mode is adopted.Based on the construction process of open-cut tunnel structure and the formation of earth pressure,the lateral pressure in the traditional load calculation mode of the open-cut tunnel was replaced from active earth pressure to static earth pressure as an optimization in this paper.The results show that:(1)When the traditional load calculation mode is applied for the an open-cut tunnel,there is a certain limit backfilling height;exceeding the limit backfilling height,the structure is difficult to meet the requirements on bearing capacity and serviceability limit state.(2)Under the action of backfill soil load,the deformation of the open-cut tunnel structure is small and does not have the deformation conditions to form active earth pressure.The lateral pressure of the side wall of the open-cut tunnel shall be the static earth pressure of the deadweight stress field.(3)The case shows that the optimized load calculation mode is closer to the stress state of the open-cut tunnel,and the calculation mode of static earth pressure load is reasonable and feasible.

关 键 词：超高回填 明洞 主动土压力 静止土压力 计算模式 

分 类 号：U451.4[建筑科学—桥梁与隧道工程]