隧道不同收敛模式穿越既有隧道对比分析

Comparison and Analysis of Different Convergence Modes of Tunnel Crossing Existing Tunnels

文章采用位移控制法建立有限元模型,分析4种不同收敛模式下新建隧道上、下穿越既有隧道时对既有隧道应力、位移的影响。结果表明,收敛模式1,放大了上穿施工对既有隧道的影响,对下穿施工对既有隧道的影响估计不足;收敛模式2、3,隧道底位移为0,弱化了上穿施工对既有隧道的影响;收敛模式4,隧道底位移不为0,隧道顶位移大于隧道底位移,与实际情况接近。因此,在新建隧道上穿既有隧道计算中建议选择收敛模式4,在新建隧道下穿既有隧道计算中应避免选用收敛模式1,可选择收敛模式2、3、4。

This paper establishes the finite element model by using displacement method and analyzes the influence of the 4 different convergence patterns of stress and displacement of tunnels under the conditions of new tunnels under-crossing or over-crossing existing tunnels. The results show that the convergence pattern 1, the impact of the construction of over-crossing existing tunnels is exaggerated, while the impact of the tunnel under-crossing construction is belittled. The convergence patterns 2 and 3, the displacement of the tunnel bottom is 0, which impact of the over crossing construction on the existing tunnels is neglected. For the convergence pattern 4, the displacement of the tunnel bottom is not 0.the displacement at the roof is bigger than the displacement of the tunnel bottom and the actual situation is very close to this fact. Therefore, in the new tunnel over-crossing construction calculation, it is suggested to select the convergence pattern 4. The selection in the calculation of the new tunnel under- crossing the existing tunnel should avoid to use convergence pattern 1, it recommends to use the convergence patterns 2, 3, and 4.