独塔单索面预应力斜拉桥爆破拆除倒塌解体过程分析  

Analysis of Collapse and Disintegration Process of Prestressed Cable-stayed Bridge with Single Tower and Single Cable Plane by Demolition Blasting

作　　者：黄小武[1,2,3] 谢先启 陈德志 刘昌邦[2,3] 伍岳 周祥磊 HUANG Xiao-wu;XIE Xian-qi;CHEN De-zhi;LIU Chang-bang;WU Yue;ZHOU Xiang-lei(College of Science,Wuhan University of Science and Technology,Wuhan 430065,China;State Key Laboratory of Precision Blasting,Jianghan University,Wuhan 430056,China;Wuhan Explosions&Blasting Co.,Ltd.,Wuhan 430056,China;SINOSTEEL Wuhan Safety&Environmental Protect Research Institute Co.,Ltd.,Wuhan 430081,China)

机构地区：[1]武汉科技大学理学院,武汉430065 [2]江汉大学精细爆破国家重点实验室,武汉430056 [3]武汉爆破有限公司,武汉430056 [4]中钢集团武汉安全环保研究院有限公司,武汉430081

出　　处：《爆破》2021年第4期108-114,共7页Blasting

基　　金：湖北省自科基金重点项目(创新群体2020CFA043);湖北省重点研发计划项目(2020BCA084)。

摘　　要：斜拉桥属于高次超静定结构体系,在爆破拆除失稳倒塌过程中动力响应特征复杂,相关技术及科学问题研究较少。为探索斜拉桥爆破拆除失稳倒塌力学机理,依托某独塔单索面预应力斜拉桥爆破拆除工程案例,借助动力学有限元程序LS-DYNA模拟了斜拉桥整体模型的失稳倒塌运动过程,重点分析了主塔、主梁、斜拉索三种基本构件的动力响应特征。研究结果表明:采用半波余弦函数形式的加载曲线作为重力荷载,有效避免了显式突加荷载对结构产生的震荡效应;主塔定向倒塌是斜拉桥失稳倒塌的核心,塔身运动过程符合爆破设计方案,总体呈现“首次下坐→缓慢偏转→二次下坐→加速偏转”四个阶段;斜拉索在随着主塔定向倒塌的过程中,斜拉索轴向动力响应复杂,应力起伏振荡频繁,应力峰峰值区间为4.81~14.9 MPa;主梁在失稳坍塌过程中整体呈现“中间高、两头低”的姿态,最大位移差为2.62 m,局部剪切破坏作用明显。主塔的可靠倒塌是斜拉桥成功爆破拆除的关键,主墩的短暂支撑作用有利于主梁充分破碎解体。Cable-stayed bridge is a high-order statically indeterminate structure system.Dynamic response characteristics are complex in the instability and collapse process induced by blasting demolition,and there are few studies on related technical and scientific issues.In order to explore the mechanical mechanism of instability and collapse of cable-stayed bridge induced by blasting demolition,based on an actual engineering that prestressed cable-stayed bridge with single tower single cable plane induced by blasting demolition.Dynamic finite element program LS-DYNA is used to simulate the instability and collapse process of the whole cable-stayed bridge model,and the dynamic response characteristics of the main tower,main beam and stay cable were analyzed.Results show that using the loading curve in the form of half-wave cosine function as the gravity load can effectively avoid the shock effect of explicit sudden load on the structure.The directional collapse of the main tower is the core of the instability and collapse of the cable-stayed bridge.Movement process of the tower body conforms to the established blasting design scheme,and it generally presents four stages:first sitting→slow deflection→second sitting→accelerated deflection.In the process of the directional collapse of the main tower,the axial dynamic response of the stay cable is complex,and the stress fluctuation oscillation is frequent.Peak value range of stress is 4.81~14.9 MPa.In the process of instability and collapse,the main beam shows the posture of“high in the middle and low in both ends”.Maximum displacement difference is 2.62 m,and the local shear failure is obvious.Reliable collapse of the main tower is the key to the successful blasting demolition of the cable-stayed bridge.The short-term support of the main pier is conducive to the full crushing and disintegration of the main beam.

关 键 词：预应力斜拉桥 爆破拆除 倒塌解体 数值模拟 

分 类 号：TU746.6[建筑科学—建筑技术科学]