跨断层简支梁桥在蠕滑断层作用下破坏特征与土压力变化研究

    Study on failure characteristics and soil pressure change of simply supported beam bridge across fault under creep fault

    • 摘要: 断层错动是威胁跨断层桥梁安全的重要灾害之一。相较于突发性的黏滑错动,蠕滑断层错动以低速、持续的方式释放应力,其累积效应可能导致桥梁结构的渐进性破坏。为探究不同类型断层错动对跨断层桥梁的影响,本文基于自主研制的断层模拟试验装置,开展了1:50缩尺简支梁桥模型的系列试验。分别模拟了走滑断层、正断层和逆断层的错动过程,对比分析了桥梁结构在不同断层作用下的破坏特征和失效机理。结果表明:(1)不同类型断层表现出不同的运移特征,对跨断层桥梁的破坏效应各异;(2)断层错动引起的桥墩相对位移和土体变形是导致桥梁结构破坏的主要原因;(3)不同类型断层引起的土压力分布具有显著差异,反映了断层运动对周围土体的复杂影响;(4)桥梁结构自身特点,如支座约束条件和主梁连接状态,对其抵抗断层位错的能力有重要影响。研究结果为跨断层桥梁抗震抗断层设计提供了理论参考。

       

      Abstract: Fault displacement is a major hazard threatening the safety of bridges crossing faults. Compared to sudden stick-slip movements, creep fault displacements release stress at a low speed and continuous manner, potentially leading to progressive damage of bridge structures due to their cumulative effects. To investigate the effects of different types of fault displacements on bridges crossing faults, this study conducted a series of tests on a 1:50 scale model of a simply supported beam bridge using a self-developed fault simulation test device. The displacement processes of strike-slip, normal, and reverse faults were simulated, and the failure characteristics and mechanisms of the bridge structure under different fault actions were comparatively analyzed. The results show that: (1) Different types of faults exhibit distinct movement characteristics, leading to varied destructive effects on bridges crossing faults; (2) The relative displacement of bridge piers and soil deformation caused by fault displacement are the main reasons for bridge structure failure; (3) Different types of faults lead to significantly distinct soil pressure distributions, reflecting the complex effects of fault movements on the surrounding soil; (4) The inherent characteristics of the bridge structure, such as bearing constraint conditions and girder connection states, have important influences on its ability to resist fault displacement. The research results provide theoretical references for the seismic and fault-resistant design of bridges crossing faults.

       

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