摘要
原位扩挖隧道由于其节约成本且满足车流量要求而得以广泛采用。鉴于目前缺乏针对此类隧道的松动圈范围计算方法,以原位扩挖楼山隧道为例,采用数值模拟方法对楼山隧道的扩挖动态施工进行分析,对比了两种不同的隧道围岩松动范围计算公式。研究结果表明:在后行洞开挖时需要对地表沉降做好监测;左右洞开挖间距尽量保持在2倍单洞跨径以上;传统的荷载计算方法已经不再适用大断面原位扩挖隧道,对比了修正的芬纳公式和卡斯特奈近似公式分别计算围岩的松动圈范围,证明了采用卡斯特奈近似公式能更准确的描述案例所述原位扩挖大断面隧道围岩松动圈的范围。所得结论对今后类似工程施工具有重要的参考和借鉴价值。
In-situ reaming tunnel is widely used because of its cost saving and traffic flow requirements.In view of the lack of calculation methods for the loose zone range of this kind of tunnel, taking in-situ reaming Loushan tunnel as an example, numerical simulation method is used to analyze the dynamic construction of reaming Loushan tunnel, and two different formulas for calculating the loose zone of tunnel surrounding rock are compared.The results show that it is necessary to monitor the surface subsidence during the excavation of rear tunnel.The distance between the left and right holes should be kept at more than twice the span of a single hole.The traditional load calculation method is no longer suitable for large section in-situ reaming tunnel.Compared with the modified Fenner formula and Castella′s approximation formula to calculate the range of surrounding rock loose circle, it is proved that using Castella′s approximation formula can more accurately describe the range of surrounding rock loose circle in the case of large section in situ reaming tunnel.The conclusion has important reference value for similar engineering construction in the future.
作者
刘立宏
LIU Lihong(China Railway First Survey and Design Institute Group Co.,Ltd.,Xi'an 710043,China)
出处
《粉煤灰综合利用》
CAS
2022年第6期28-34,共7页
Fly Ash Comprehensive Utilization
基金
国家自然科学基金项目(项目编号51678499)。
关键词
原位扩建隧道
围岩力学特性
三维数值模拟
松动圈
in-situ expansion of tunnel
mechanical properties
three-dimentional numerical simulation
loose zone
