【摘要】 榆佳高速公路佳县隧道整体下穿佳县县城,洞顶地表有大量房屋、道路等结构物,钻爆法施工可能造成地表建筑开裂、失稳等不利影响。为明确受影响范围及程度大小,确保工程顺利进行而展开专题研究。根据规范拟定爆破最大段装药量为5.0kg,采用数值模拟方法计算地表振速峰值,对地表建筑进行安全评价并提出应对措施,初步分析黄土的振动响应特征。研究结果显示:隧道上方地表房屋和道路最大振速均满足安全允许标准,距隧道拱顶最近的两座房屋最大振速为2.4cm/s,主振频率为56.0Hz,在施工中应加强监控量测和实施加固保护措施;黄土覆盖层可以有效加速震动能量衰减,频率大于70Hz的高频部分基本被过滤,但震动持续时间加长。评价结果可为施工方案和监控设计提供依据,评价方法可为类似工程提供参考和借鉴。更多还原

【Abstract】 Jiaxian tunnel on Yu-Jia Highway is passing-under the whole Jiaxian county,where a large number of houses,roads and other structures are on ground surface.Drilling and blasting construction may cause cracking,instability and other adverse effects on the structures,so the study is carried out to make clear the affected range and extent and ensure the project success.According to the industry code,the maximum charge of millisecond blasting is identified as 5.0kg.Vibration velocity peak value is calculated by numerical simulation,on the basis of which safety evaluation of buildings on ground surface is made and countermeasures are proposed,meanwhile,vibration response characteristics of loess is analyzed preliminary.The results show that vibration velocities of the houses and roads above tunnel meet safety standards,while the maximum vibration velocities of the two nearest houses from the tunnel vault are 2.4cm/s and frequency is 56.0Hz,so strict monitoring measurements and necessary strengthened methods should be taken for safety concern in the construction.Loess cover can accelerate the vibration attenuation effectively,and filter high-frequency vibration with frequency greater than 70Hz,but result in long duration of shaking.The evaluation results provide a scientific basis for construction program and monitoring design and the evaluation method can provide some reference for similar projects.更多还原