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为研究地震荷载作用下隧道结构的动力响应,以指导隧道修建施工和衬砌支护,提高地铁隧道的整体抗震能力,采用理论分析、数值模拟和室内试验相结合的方法,对地铁隧道地震动力响应进行研究。选取沈阳地铁2号线某段隧道为工程背景,在理论分析地铁隧道地震动力响应的前提下,运用FLAC~(3D)数值软件模拟地铁隧道地震动力响应情况,地铁隧道两帮壁正负45°区域剪应力、主应力和位移最显著,监测点加速度变化趋势与输入地震波加速度时程曲线较为一致。在室内振动台试验中,地基土体表面峰值加速度明显比地基土体深部大,隧道两帮壁正负45°位置附近应变最大,振动停止后应变并未归零。数值模拟与室内试验研究结果较为吻合表明,由于人工波的地震烈度较现场波大,地铁隧道的地震扰动强烈;地铁隧道两帮壁正负45°区域地震动力响应剧烈,极易发生破坏。可根据这一现象有针对性地采取抗震措施,保证地铁隧道的安全、稳定。
In order to study the dynamic response of the tunnel structure under the earthquake load to guide the tunnel construction and lining support and improve the overall seismic capacity of the subway tunnel, the seismic response of the subway tunnel is analyzed using the theoretical analysis, numerical simulation and laboratory tests. research. Taking the tunnel of Shenyang Metro Line 2 as the engineering background, the dynamic response of the subway tunnel is simulated by using FLAC 3D numerical software on the premise of the theoretical analysis of the seismic response of the subway tunnel. The two walls of the subway tunnel are plus or minus 45 ° The regional shear stress, principal stress and displacement are the most significant. The trend of acceleration at monitoring point is consistent with that of input seismic wave acceleration. In the indoor shaking table test, the peak surface acceleration of foundation soil is obviously larger than that of the foundation soil. The strain near the position of 45 ° plus and minus 45 ° of the two walls of the tunnel is the largest, and the strain does not return to zero after the vibration stops. The results of numerical simulation and laboratory test are in good agreement. It shows that the seismic disturbance of metro tunnel is strong due to the seismic intensity of artificial wave is larger than that of on-site wave. The seismic response to the positive and negative 45 ° of two tunnels in metro tunnel is violent and prone to damage. According to this phenomenon can be targeted to take seismic measures to ensure the safety and stability of the subway tunnel.