水平层状岩隧道荷载计算公式修正方法及其应用  

Revised Method and Application of Load Calculation Formula of Horizontal Stratified Rock Tunnel

作　　者：解仁伟 Xie Renwei(The 3rd Engineering Co.,Ltd.of China Railway Construction Bridge Engineering Bureau Group,Tianjin 300300,China)

机构地区：[1]中铁建大桥工程局集团第三工程有限公司,天津300300

出　　处：《吉林大学学报（地球科学版）》2024年第3期943-953,共11页Journal of Jilin University：Earth Science Edition

基　　金：中国国家铁路集团有限公司系统性重大项目(P2018G048)。

摘　　要：为研究适用于水平层状围岩隧道的围岩荷载计算方法,指导实际隧道工程施工,采用理论推导的方式,结合数值模拟荷载-结构法计算模型,对水平层状围岩隧道的开挖工法和初期支护参数进行了优化。结果表明:1)水平层状围岩隧道塌落拱顶形成岩梁结构,基于此提出了针对水平层状岩隧道的围岩竖向荷载计算公式修正方法。2)基于掌子面力学平衡稳定分析模型,考虑塌落拱顶岩梁作用效应,通过计算得到了铜川隧道一号斜井工区水平层状砂岩、泥岩的岩梁极限厚度分别为1.7和2.3 m,当岩层厚度大于极限厚度时,岩梁可代替超前支护起到拱顶加固作用;同时计算表明Ⅲ、Ⅳ级围岩采用全断面法代替原来的台阶法施工,掌子面稳定系数满足规范要求。3)铜川隧道一号斜井工区Ⅲb型、Ⅳa型和Ⅳb型初期支护参数优化后,钢支撑最大间距分别为1.8、1.6、1.6 m,相应的截面最小安全系数分别为1.65、1.63、1.57,均满足规范中的安全系数控制基准要求。In order to study the surrounding rock load calculation method suitable for horizontal layered surrounding rock tunnel and guide the actual tunnel construction,the paper adopts the method of theoretical derivation and the numerical simulation load-structure calculation model to optimize the excavation method and the initial supporting parameters of horizontal layered surrounding rock tunnel.The results show that:1)Rock beam structure will be formed when the vault of horizontal layered rock tunnel collapses.Based on this,a revised method for the calculation formula of vertical load in horizontal layered rock tunnel is proposed.2)Based on the mechanical balance and stability analysis model of the face and taking into account the effect of collapsing vault rock beams,the ultimate thickness of horizontal layered sandstone and mudstone rock beams in the working area of inclined shaft No.1 of Tongchuan tunnel is calculated to be 1.7 and 2.3 m,respectively.When the rock layer thickness is greater than the ultimate thickness,the rock beams can replace the advance support to strengthen the vault;At the same time,the construction method of surrounding rockⅢandⅣis calculated and analyzed,and the results show that the stability coefficient of the face of the whole section method instead of the original step method still meets the standard requirements.3)After optimizing the initial supporting parameters ofⅢb,Ⅳa andⅣb types in the inclined shaft working area of Tongchuan tunnel No.1,the maximum spacing of steel supports is 1.8,1.6 and 1.6 m,respectively,and the corresponding safety factors of the most unfavorable section are 1.65,1.63 and 1.57,which are all greater than the safety factor control standard in the code.

关 键 词：水平层状岩 荷载计算 施工工法 初期支护 参数优化 

分 类 号：U452.11[建筑科学—桥梁与隧道工程]