| 摘要: |
| [目的]针对浅埋黄土隧洞顶覆土薄,自稳能力差,特别是开挖初期变形增长较快,极易产生坍塌的特征,利用有限元方法模拟隧洞不同施工工序的施工过程,通过比较得出较为合理的施工工序,以指导工程施工.[方法]结合某工程输水隧洞具体施工问题,利用有限元分析计算软件ADINA,建立该隧洞的施工过程数值模拟模型,对上行法和下行法2种开挖过程进行数值模拟,分析2种施工过程中硐室周围土体所产生的应力、应变、屈服区以及位移等.[结果]通过对隧洞施工工序的模拟分析,得到上行法开挖时的拱脚压应力是下行法开挖时的1.5倍,对于拱顶位移和塑性区范围,上行法开挖均大于下行法.[结论]虽然该黄土隧洞埋深较浅,断面较大,采用人工分层开挖,下行法和上行法2种工序均是稳定的,但下行法优于上行法. |
| 关键词: 浅埋黄土隧洞 施工工序 数值分析 围岩稳定 |
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| Numerical simulation of excavation of loess shallow-buried tunnel |
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| Abstract: |
| 【Objective】 Loess shallow buried tunnel is characterized with thin soil layer and poor stability,especially the fast developed deformation at the early excavation stage which is subject to collapse.The excavating process of tunnel under different construction working procedures with FEM was simulated,a more reasonable one was obtained by comparing the construction process to guide engineering construction.【Method】 ADINA was adopted to analyze the construction working procedure with upwards and downwards excavating steps based on the geological conditions of a domestic tunnel project,and the stress,strain and yielding areas and displacement,etc.of surrounding rock were analyzed during two construction process.【Result】 Analysis of the construction process showed that arch feet compress stress of upwards was 1.5 times of downwards excavating process,and for vault displacement and yield areas upwards was more than downwards.【Conclusion】 The results show that although the depth of the loess tunnel is relatively shallow,the cross section is relatively larger,it is stable when excavated with the two working procedures. |
| Key words: loess shallow-buried tunnel construction working procedure numerical simulation stability of surrounding rock |
