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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. 相似文献
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Precision blasting, regarded as the symbol of a new stage of development in engineering blasting, is different from the traditional controlled blasting. Its definition, connotation, technology system and current situation of application and development were introduced briefly. With regard to the development of precision blasting in the future, the following aspects should be studied in depth: (1) In order to provide the theoretical basis for explosive energy release and quantitative blasting design, research on the multidisciplinary basic theory should be conducted; (2) Taking the digitalization research and its application in blasting objects as the starting point, syncretic studies of precision blasting and information technology should be conducted; (3) Numerical simulation being an important method for the optimization of engineering blasting schemes and the forecast of blasting adverse effect, numerical simulation of precision blasting should be studied in depth; (4) The modernization and standardization in the precision blasting construction should be enhanced. 相似文献
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The application of numerical simulation in demolition blasting was commented. The main methods of numerical simulation in demolition blasting were reviewed. The advantages and disadvantages of the numerical methods mentioned in this paper were also indicated, respectively. Furthermore, the 3D DEM model, which was developed by the author together with his group, was detailed illustrated. The existed problems in the current numerical simulation methods of demolition blasting were presented and the trend of the further development was finally forecasted. 相似文献
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为了研究钢筋混凝土立柱爆破个别飞散物运动特性与水袋防护效果,探讨了个别飞散物的生成机制与防护手段,其次通过开展大尺寸钢筋混凝土立柱爆破模型试验,分析了高速摄像资料获取的个别飞散物运动特性;再基于AUTODYN数值模拟软件,运用SPH方法分别模拟了直径10 mm个别飞散物以10、15、20 m/s初始速度穿越厚度分别为5、10、15 cm防护水袋的减速效果。研究结果表明:钢筋混凝土构件爆破拆除时,爆破生成个别飞散物粒径以碎块(5 mm≤d≤100 mm)为主;爆破碎块飞离母体的初始速度主要范围为10~20 m/s;水袋厚度从5 cm增加至15 cm时,个别飞散物降速效果可从65%提高至95%左右。研究结果可为拆除爆破个别飞散物防护提供参考和借鉴。 相似文献