连拱隧道初支结构稳定性评价及施工方法探讨  

The Stability Evaluation of Primary Support Structure and Discussion on Construction Method of Multi-arch Tunnel

作　　者：邹建华[1] 谭捍华[1] 张学民[1] 

机构地区：[1]贵州省交通规划勘察设计研究院股份有限公司,贵阳550001

出　　处：《地下空间与工程学报》2013年第6期1362-1367,共6页Chinese Journal of Underground Space and Engineering

基　　金：贵州省交通运输厅科技计划项目(2010122010)

摘　　要：连拱隧道结构形式复杂,开挖与支护工序转换频繁,围岩受多次扰动,施工风险高,直接影响隧道围岩与支护结构体系的安全性。依托某浅埋偏压连拱隧道工程,采用数值分析方法评价了连拱隧道初期支护结构的安全性。结果表明,受地形偏压影响,左、右侧主洞初支结构内力和变形存在明显的不对称性,深埋侧主洞贯通而未施作二衬情况下开挖浅埋侧主洞,初支结构多个典型特征点处的安全系数均小于规范规定限值,是导致连拱隧道发生大型塌方的主要原因。浅埋偏压连拱隧道主洞开挖时应采取"先外后内"的施工工法,并保持合理的安全步距,相关结论可为相关工程提供参考。Structure type of multiarch tunnel is complex and the excavation and support process converts fre quently, then the scope influenced by excavation is very large; there are several repetitious disturbances to the sur rounding rock. The construction risk of multiarch tunnel is higher, and there is a direct impact on the safety of the tunnel surrounding rock and supporting structure system. Based on one shallow multiarch tunnel under unsymmetrical terrain pressure, the stability of the muhiarch tunnel primary support structure was evaluated by the numerical analy sis method in this paper. The results showed that unsymmetrical internal force and deformation would be produced on the left and right cavern primary support structure because of the terrain bias. When the main cavern on shallow bur ied side is excavated before the primary support structure of the main cavern on deep buried side finished without a second lining, the safety coefficient of some typical structure points would be less than the values specified by the standard. This is the main cause of large landslides for the multiarch tunnel. The reasonable construction method should be taken that main cavern on shallow side is firstly excavated and then the cavern on deep buried side is tun neled. And the reasonable safety interval between different working procedures will be maintained. The results can provide references for shallow multiarch tunnels under unsymmetrical terrain pressure.

关 键 词：连拱隧道 浅埋偏压 安全性评价 工序优化 

分 类 号：U458.3[建筑科学—桥梁与隧道工程]