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中文核心期刊

深埋三连拱隧道围岩压力计算方法

CALCULATION METHOD FOR SURROUNDING ROCK PRESSURE OF DEEPLY BURIED TRIPLE-ARCH TUNNEL

  • 摘要: 基于普氏压力拱理论和过程载荷设计方法, 考虑连拱隧道组合成拱作用, 以及施工工序和中隔墙支撑作用, 量化相邻简化导洞间的施工扰动, 提出深埋三连拱隧道不同施工断面及工序下的载荷分布模型, 进而改进了深埋三连拱隧道围岩压力的计算方法, 结合八达岭长城站三连拱隧道工程, 将理论结果与实测数据对比, 验证计算方法的合理性. 最后系统分析施工工序、中隔墙宽度、开挖跨度等因素对围岩压力的影响规律. 结果表明: 深埋三连拱隧道相互间的施工扰动影响无法忽视, 次行洞、后行洞的开挖都会扩大先行洞上方松散破碎围岩区域, 造成较为明显的偏压现象; 当中隔墙岩体抗压强度较小时, 增加中隔墙宽度难以改善围岩压力分布状态, 当中隔墙岩体抗压强度较大时, 增大宽度能够显著减小围岩压力; 围岩条件越差, 三连拱隧道各洞室所受围岩压力越大, 同时偏压现象也更加明显. 本文基于普氏压力拱理论和过程载荷设计方法所得出的计算方法, 增加考虑了连拱隧道相邻洞室间的施工影响, 揭示了三连拱隧道的偏压效应, 填补了有关三连拱隧道围岩压力计算方法的研究空缺, 为相关工程设计提供了重要参考.

     

    Abstract: Based on the Platts pressure arch theory and process load design method, considering the combined arch effect of the continuous arch tunnel, considering the construction process and the supporting role of the middle partition wall, quantifying the construction disturbance between the adjacent simplified guide holes, and proposing the load distribution model under different construction sections and processes of the deep buried three-arch tunnel, and then improving the calculation method of the surrounding rock pressure of the deep-buried three-arch tunnel, combined with the three-arch tunnel project of Badaling Great Wall Station, the theoretical results are compared with the measured data to verify the rationality of the calculation method. Finally, the systematic analysis of the construction process, the width of the diaphragm wall, the span of excavation and other factors on the influence of the surrounding rock pressure law. The results show that: the influence of construction disturbance among deeply buried triple-arch tunnels cannot be ignored, and the excavation of secondary and posterior caverns will expand the loose and broken surrounding rock area above the first cavern causing a more obvious bias pressure phenomenon; when the compressive strength of the rock body of the diaphragm wall is small, it is difficult to improve the surrounding rock pressure distribution by increasing the width of the diaphragm wall. While the compressive strength of the rock body of the diaphragm wall is large, increasing the width can significantly reduce the surrounding rock pressure; the poorer the rock condition, the greater the rock pressure in each chamber of the triple-arch tunnel, and the more obvious the bias pressure phenomenon. Based on the calculation method obtained by Platts pressure arch theory and process load design method, this paper adds the construction influence between adjacent caverns of the continuous arch tunnel, reveals the bias effect of the three-arch tunnel, fills the research gap on the calculation method of surrounding rock pressure of the three-arch tunnel, and provides important reference and guiding significance for the related engineering design.

     

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