摘要
针对V级围岩条件下单洞4车道(双洞8车道)隧道采用双侧壁导坑法施工时存在的机械作业空间受限与施工步距矛盾问题,提出了基于机械化施工适配性的工艺优化方法。通过理论计算和监测分析发现,传统工法导坑长度不足导致大型设备(如挖掘机、拱架安装台车)操作空间欠缺,是制约施工效率与安全性的关键因素。基于此,创新性地建立了以机械最小转弯半径为控制参数的导坑长度准则,并提出了“延长导坑长度至25 m+非对称开挖侧导坑+动态调整主洞中导坑台阶间距”的改进工艺。以某双向8车道隧道(最大净宽为18.762 m,最大净高为11.542 m,V级千枚岩)为工程载体,采用Midas软件建立了三维数值模型,对比分析表明:优化后的的施工方案,拱顶沉降值降幅为24.6%,边墙收敛位移降幅为26.3%,支护结构内力重分布效应可控(轴力波动<6%,弯矩峰值降低了24.3%),方便了大型机械化施工设备施工。现场监测数据验证了该方案能显著提升施工稳定性,同时缩短了循环进尺时间,降低了施工成本。相关研究结论为类似大跨度断面双侧壁导坑施工提供了一定参考。
Aiming at the contradictory problems of limited mechanical working space and construction step pitch in the construction of single-hole four-lane(double-hole eight-lane)tunnels by double sides wall heading method under V-grade surrounding rock conditions,an optimization method of process based on the adaptability of mechanized construction was proposed.Through theoretical calculation and monitoring analysis,it was found that the insufficient length of the pilot pit by traditional construction methods caused a lack of operating space for large equipment(such as excavators and arch support installation trolleys),which is a key factor restricting the construction efficiency and safety.Based on this,the pilot pit length criterion was innovatively established with the control parameters of the minimum turning radius of the machine,and the improved process of"extending the pit length to 25 m non-symmetric excavation of the direction-finding pilot pit+dynamic adjustment of the heading pitch spacing in the main tunnel"was proposed.Taking a double-way tunnel with eight lanes(with the maximum net width of 18.762 m,the maximum net height of 11.542 m,and V-grade tuff)as the engineering carrier,a 3D numerical model was established by Midas.The comparative analysis showed that settlement at the top of of the arch by 24.6%,the convergence displacement of the side wall by 26.3%,and the redistribution effect of the internal force of the support structure was controllable(the fluctuation of axial force was less than 6%,and the peak bending moment decreased by 24.3%),which facilitated the construction by large-scale mechanized construction equipment in the optimized construction scheme.The field monitoring data verified that the scheme can significantly improve the construction stability,while shorten the cycle advance time and reduce the construction cost.The relevant research conclusions can provide some reference for the construction of similar large-span section double sides wall piolt tunnels.
作者
何俊
HE Jun(Shenzhen Henghao Construction Project Management Co.,Ltd.,Shenzhen 518000,China)
出处
《市政技术》
2025年第8期54-62,共9页
Journal of Municipal Technology
关键词
双侧壁施工
导坑法施工
大跨度断面
工法优化
数值仿真分析
实地监控
double sides wall construction
construction by heading method
large span cross-section
optimization of construction methods
numerical simulation analysis
on site monitoring
