摘要
以西安地铁临潼线穿越骊山山前断裂为研究背景,采用数值模拟方法,通过建立地铁隧道-断裂-地层三维有限元模型,研究了骊山山前断裂错动作用下隧道结构的变形受力特征,以此揭示了骊山山前断裂错动作用对西安地铁临潼线的影响机制以及重点设防位置,确定了地铁临潼线的设防范围,提出了相应防治建议措施。研究结果表明:断裂错动作用造成地铁隧道沿纵向发生弯曲变形,大致可分为3个变形区域:下盘稳定区、剪切拉张区和整体沉降区。断裂附近地层竖向应力和隧道拱底接触压力均表现为上盘减小而下盘增大,而隧道拱顶接触压力在上盘增大下盘减小。同时,沿纵向隧道顶部结构在上盘受压而下盘受拉,底部结构受力刚好相反,在上盘受拉下盘受压;隧道受剪区范围随断裂位错量变化基本保持不变,且最大值均出现在与断裂相交位置处。最后,综合确定了西安地铁临潼线跨越骊山山前断裂的纵向设防长度至少为80 m,并给出了跨断裂西安地铁临潼线的防治措施。研究结果可为西安地铁临潼线跨越骊山山前断裂带设计及其病害防治提供科学参考。
Based on the metro Lintong line passing through the active fault of Lishan Mountain on Xi'an metro Lintong line,the three-dimensional finite element model of metro tunnel-active fault-stratum was built. Deformation and stress characteristics of metro tunnel crossing the piedmont fault of Lishan Mountain,effect mechanism and key fortification positions of metro tunnel are revealed. The fortification range of the subway Lintong line crossing piedmont fault of Lishan Mountain is determined,and the corresponding measures for prevention and control are put forward. Research result shows that active fault ruptures caused bending deformation along the longitudinal metro tunnel. The tunnel can be divided into three deformation areas: stability section in the footwall,shear tension section in the fault zone and settlement section in the hanging wall. The vertical stratum stress near the fault zone decreases in the hanging wall and increases in the footwall. In addition,the contact pressure at the bottom of the tunnel decreases in the hanging wall and increases in the footwall. Vault contact pressure increases in the hanging wall and decreases in the footwall. And the top of tunnel is in compression at the hanging wall and in tension at the footwall. The bottom of tunnel was in tension at the hanging wall and in compression at the footwall. The shear scope of the tunnel remains unchanged with the variation of fault dislocation. The maximum shear force occurs at the intersection with the fault. Finally,it is confirmed that the fortification length of Lintong line across the fault is at least 80 m. The measures for prevention and control measures are put forward. The conclusions can be presented as the reference for the design and disease control of Xi'an LinTong Line passing through the piedmont active fault of Lishan Mountain.
引文
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