城市隧道排烟竖井对主隧道结构的影响研究

摘要:

以长阳凤凰山隧道工程为例,借助MIDAS GTS有限元软件对排烟竖井与主隧道结构节点进行三维数值模拟,研究灰岩地层中排烟竖井施工对主隧道结构的影响。计算结果显示,竖井施工前后主隧道与竖井连接处的最大压应力由0.16MPa增至1.42MPa,出现应力集中现象,表明受力模式发生了变化。竖井施工前后,拱顶沉降值由3.05mm增至3.12mm,底部隆起值由2.41mm增至2.95mm,表明竖井对拱顶沉降影响较小而对底部隆起影响稍微大。为确保隧道结构安全,消除排烟竖井对主隧道结构产生的不利影响,提出了加强衬砌支护设计参数及主隧道增加环框梁等措施。

Abstract:

Taking Changyang Fenghuangshan tunnel project as an example, the three-dimensional numerical simulation of the structural joints between the smoke exhaust shaft and the main tunnel is carried out with the help of MIDAS GTS finite element software to study the influence of the construction of smoke exhaust shaft on the main tunnel structure in limestone stratum. The calculation results show that the maximum compressive stress at the connection between the main tunnel and the shaft increases from 0.16mpa to 1.42mpa before and after the shaft construction, and the stress concentration phenomenon appears, indicating that the stress mode has changed. Before and after the construction of the shaft, the vault settlement value increased from 3.05mm to 3.12mm, and the bottom uplift value increased from 2.41mm to 2.95mm, indicating that the shaft has little impact on the vault settlement and slightly greater impact on the bottom uplift. In order to ensure the safety of tunnel structure and eliminate the adverse impact of smoke exhaust shaft on the main tunnel structure, measures such as strengthening the design parameters of lining support and adding ring frame beam to the main tunnel are put forward.