| 地下隧道轴向地震动土作用分析 |
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| 引用本文： | 梁建文,朱俊.地下隧道轴向地震动土作用分析[J].西北地震学报,2017,39(2):301-310. |
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| 作者姓名： | 梁建文 朱俊 |
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| 作者单位： | 天津大学水利工程仿真与安全国家重点实验室, 天津 300072;天津大学建筑工程学院土木工程系, 天津 300072,天津大学建筑工程学院土木工程系, 天津 300072 |
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| 基金项目： | 国家自然科学基金项目（51378348） |
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| 摘 要： | 以弹性基岩上覆层状场地中刚性衬砌隧道为模型,采用间接边界元方法求解衬砌隧道所受的沿轴向地震动土作用,通过参数分析揭示轴向动土作用的幅值大小、空间分布等基本规律。研究表明,土-隧道动力相互作用对地震动土作用的空间分布形式影响较小,但对地下隧道所受地震动土作用峰值大小具有显著影响,隧道主要位置点的地震动土作用峰值与隧道相应位置处自由场土层应力相比放大1.7~2.4倍。论文最后提出一个轴向地震动土作用的简化计算方法。
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| 关 键 词： | 地下隧道 土-隧道相互作用 刚体相互作用 惯性相互作用 轴向地震动土作用 |
| 收稿时间： | 2016/1/15 0:00:00 |
Seismic Soil Pressure on an Underground Tunnel in the Axial Direction |
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| LIANG Jian-wen and ZHU Jun.Seismic Soil Pressure on an Underground Tunnel in the Axial Direction[J].Northwestern Seismological Journal,2017,39(2):301-310. |
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| Authors: | LIANG Jian-wen and ZHU Jun |
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| Institution: | Tianjin University State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin 300072, China;Department of Civil Engineering, Tianjin University, Tianjin 300072, China and Department of Civil Engineering, Tianjin University, Tianjin 300072, China |
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| Abstract: | Considering that seismic soil pressure is the key to an efficient seismic design of an underground tunnel, seismic soil pressure on an underground tunnel in the axial direction is studied by indirect boundary element method. First, the time domain problem is transformed to discrete frequency domain problem by Fourier transform. Next, the free-field ground motion is calculated, and the scattered field is simulated by a set of fictitious loads combined with the Green'' s functions of uniformly distributed load acting on an inclined line. The values of these fictitious loads are determined from the displacement boundary conditions of the underground tunnel. Then, the seismic soil pressure in the axial direction is obtained by utilizing these fictitious loads. Finally, the seismic soil pressure is transformed back to time domain by inverse Fourier transform. The proposed method is verified by comparing its results with those of the analytical solution. Based on the model of a rigid underground tunnel soil layers over elastic bedrock, the amplitude and distribution of the seismic soil pressure are analyzed through parametric studies. Several findings are obtained. (1) For the underground tunnel, the kinematic interaction plays a major role while the inertial interaction has little effect. (2) The dynamic soil-tunnel interaction (SSI) only has minimal effect on the distribution of the seismic soil pressure, but it can significantly affect the amplitude of the seismic soil pressure; moreover, the peak of the seismic soil pressure can be significantly amplified compared with the relevant free-field soil stress. (3) The distribution of the seismic soil pressure is similar with that of the free-field soil stress, which is nearly linear distribution. Furthermore, the seismic soil pressures on the top and the bottom of the underground tunnel are in opposite direction, whereas the seismic soil pressure on the bottom of the underground tunnel is large. (4) Finally, the burial depth of the underground tunnel affects the amplitude and the distribution of the seismic soil pressure. Furthermore, the amplitude of the seismic soil pressure increases with the augmentation of the burial depth. A simplified estimation method is proposed for analyzing seismic soil pressure in accordance with its basic law. The simplified method is based on free-field seismic response analysis, which does not require the calculation of the dynamic soil-tunnel interaction. The method can be utilized to estimate the design load for underground tunnel seismic design in the axial direction. |
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| Keywords: | underground tunnel dynamic soil-tunnel interaction kinematic interaction inertial interaction seismic soil pressure in axial direction |
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