基于地质力学模型试验的高原大桥落梁破坏机理研究

摘要：汶川地震给交通运输基础设施带来了严重破坏，造成了大量桥梁的破坏甚至倒塌，其中以近断层处的桥梁震损破坏最为严重，给灾后救援和重建带来极大不便。通过对高原大桥进行地质力学相似模型试验，研究了水平荷载作用下近断层处场地变形对简支梁桥破坏的影响。结果表明，近断层处的场地集中变形导致桥梁结构破坏主要集中于桥面系及近断层一侧桥台，与高桥大桥的实际震害非常相似；地震中断层的错动对其附近场地产生较大的影响，造成桥面系与场地之间的变形不协调；断层的存在对附近场地的压缩变形有明显的放大作用；地震中场地变形，特别是近断层处的集中变形是造成简支梁桥落梁破坏的主要原因之一。

Study on the Girder Falling Mechanism of Gao-yuan Bridge Based on the Geomechanical Model Testing

Abstract: Transport system has been severely destroyed during the 2008 Wenchuan Earthquake, and a great lot of bridges, especially those near the faultage, suffered severe damage and even collapsed, which led to inefficient rescue or reconstruction following the earthquake. The geomechnical similarity model test was conducted to investigate the effect of the deformation of the site nearby the fault on the damage of the simple supported girder bridge under the lateral loading. The results show that: the failure mode of the model was highly similar to that of Gaoyuan bridge and deformation of the site was mainly happened near to the fault due to fault movement; the girder falling partly attributed to the centralized deformation of the site nearby the faultand partly attributed to the nonproportional rigid between the upper structure and the ground site; and the deformation of the ground near to the fault was amplified by the fault movement during earthquake.