作　　者： ; ; (胡杰）;

机构地区： 北京科技大学土木与环境工程学院

出　　处： 《应用基础与工程科学学报》 2016年第1期126-138,共13页

摘　　要： 针对浅埋黄土隧道在开挖过程中发生的拱顶过量沉降问题,采用颗粒离散单元法模拟了不同开挖方法和加固措施对围岩稳定和变形的影响,分析了6种工况的围岩压力分布和位移发展情况,讨论了开挖方法和加固措施对隧道围岩稳定的影响.模拟结果显示,隧道拱肩和拱脚应力集中处水平位移较大,拱部和边墙开挖为黄土隧道留核心开挖施工中的关键工序,施工中宜及早支护避免隧道发生过大变形.浅埋黄土隧道拱顶下沉量远大于周边收敛;对于相同的支护形式,留核心土下部全断面开挖法产生的位移总量约为留核心土下半断面分部开挖法的1.2倍;对于相同的开挖方法,无超前注浆支护产生的位移总量约为有超前支护的1.5倍;而有无系统锚杆的隧道围岩变形量基本相同.研究表明,浅埋黄土隧道可采取超前导管注浆减小隧道开挖变形,而系统锚杆由于支护效果不明显可考虑取消. According to the existing problems of large vault settlement for loess shallow-buried tunnel,granular based DEM was adopted to simulate the effects of different excavation and reinforcement method to the stability of tunnel. The stress distribution and displacement development were analyzed for six selected working modes. The effects of different excavation and reinforcement method to the stability of loess tunnel were discussed in details. The numerical results indicate that the vault settlement is usually larger than convergence and large horizontal displacement appear on tunnel’s spandrel and arch foot where stress concentrates.The excavation of loess tunnel’s arch and sidewall is the key procedure in the construction method of leaving core soil. Thus,appropriate support should be done as early as possible to avoid large deformation.For the same reinforcement method,the displacements of the full section excavation method with reservation core soil are 1. 2 times than that of the stepped excavation method. For the same excavation method,the displacements of the non pre-grouting supporting tunnel are1. 5 times than that of pre-grouting. The displacements are almost the same for the loss tunnel with system bolts supporting or none. The pre-grouting supporting are advised to reduce the deformation of the surrounding soil in the excavation of loess shallow-buried tunnel while the system bolts supporting can be canceled due to the limited reinforcement.

关 键 词： 黄土隧道 加固 颗粒流 数值模拟

领　　域： [建筑科学] [交通运输工程]