严寒条件下岩体开挖爆破振动安全控制特性研究

发布时间：2018-04-09 15:13

本文选题：严寒条件　切入点：爆破　出处：《岩土工程学报》2017年11期

【摘要】：复杂条件下的岩体爆破振动安全控制是开挖关注的焦点问题。严寒条件下地表一定深度被冰冻,岩体的物理力学性质与波阻抗特性发生改变,导致爆破振动衰减特性发生明显变化。首先针对不同岩性的岩体,开展了冰冻条件下的岩体物理力学性能的对比试验,结果表明岩体被冰冻后弹性模量的增量百分比达30%;然后基于丰满水电站重建工程爆破开挖的振动测试,比较了冬夏季岩体爆破振动衰减规律的变化特征,结果表明冬季爆破振动的衰减速度明显低于夏季,二者存在一个明显的比例距离分界点,在该处冬夏季的爆破振动速度大小发生转变;进而基于数值模拟方法,研究了不同冰冻深度对爆破衰减参数的影响,提出了冬季与冰冻深度相关的爆破最大单段药量的数学表达;最后从地震波的频谱特性以及结构的强度极限等角度探讨了严寒条件对爆破振动安全控制标准的影响,结果表明,严寒条件下建筑物的爆破振动安全控制标准相比夏季可略有提高。研究成果可对广大严寒地区爆破施工的安全控制提供参考。
[Abstract]:The safety control of rock blasting vibration under complex conditions is the focus of excavation.The physical and mechanical properties and wave impedance properties of rock mass are changed in a certain depth of freezing, which leads to the obvious change of the attenuation characteristics of blasting vibration.First of all, the physical and mechanical properties of rock mass under freezing condition are compared with those of rock mass with different lithology.The results show that the incremental percentage of elastic modulus of rock mass after freezing is 30%, and then based on the vibration test of blasting excavation of Fengman Hydropower Station, the variation characteristics of vibration attenuation law of rock mass blasting in winter and summer are compared.The results show that the attenuation rate of blasting vibration in winter is obviously lower than that in summer, and there exists an obvious proportional distance between them, where the velocity of blasting vibration changes in winter and summer, and then based on the numerical simulation method,The influence of different freezing depth on blasting attenuation parameters is studied, and the mathematical expression of the maximum single stage explosive quantity of blasting in winter is put forward, which is related to freezing depth.Finally, the influence of severe cold condition on the safety control standard of blasting vibration is discussed from the view of the spectrum characteristics of seismic wave and the strength limit of structure. The results show that,The safety control standard for blasting vibration of buildings under severe cold conditions can be slightly improved compared with that in summer.The research results can provide a reference for the safety control of blasting construction in cold areas.
【作者单位】：长江水利委员会长江科学院;
【基金】：国家自然科学基金青年基金项目(51609017) 湖北省自然科学基金面上项目(2016CFB605) “十三五”国家重点研发计划项目(2016YFC0402008)
【分类号】：TU45;TU751.9

【相似文献】