【作者】 魏海霞；

【导师】 陈士海；

【作者基本信息】 山东科技大学 ， 岩土工程， 2010， 博士

【摘要】 在爆破技术广泛应用的同时,随着爆破环境的复杂化和人们环保意识的日益增强,工程爆破所诱发的一系列负面效应尤其是作为爆破公害之首的爆破地震效应问题,受到普遍的关注和重视。研究爆破地震效应的危害机制,尤其是爆破地震波作用下周围建筑物的地震响应机理及安全判据,是爆破地震效应研究领域中的重点和难点课题,同时是爆破安全技术研究的重要内容。本文结合国家自然科学基金“爆破震动特性与爆破震动对结构危害机制研究”(编号：50778107)和高等学校博士学科点专项科研基金“爆破震动特性与结构爆破震动安全控制理论研究”(编号：20060424002),在大量查阅和深入研究国内外相关文献的背景下,在爆炸动力学、结构动力学、数值分析、信号分析技术、动力有限元理论等相关理论和分析方法的有力支撑下,本文采用数值计算、有限元模拟和现场试验为主要研究手段,对爆破地震波传播特性和爆破地震波作用下建筑结构的动力响应及安全判据进行了深入系统的探讨。得出的主要研究成果有：(1)在利用数值计算结果讨论爆破震动影响区域划分的基础上,基于大量的现场监测数据,研究了不同爆破震动区域内爆破地震波幅值、主频随比例距离的衰减规律及不同震动区域爆破地震波信号的频谱与能量特征。(2)采用集中冲量法,通过在一个多自由度弹性结构体系基底施加不同特性参数的爆破地震波速度荷载,并求解出不同情况下的该结构体系的各动力响应,在分析各动力响应幅值变化的基础上来探讨爆破地震波幅值、频率和持续时间对多自由度弹性体系动力响应的具体影响。(3)利用Matlab编写了一套Newmark时程分析法与刚度退化二线型恢复力模型相结合求解多层砌体结构体系弹塑性地震响应的程序。以一具体的四层砌体结构为分析对象,输入荷载采用不同特性参数的实测及人工模拟爆破地震波信号,根据所求出的结构各弹塑性地震响应幅值结果,分别讨论了爆破地震波幅值、主频和持续时间对多层砌体结构弹塑性地震响应幅值的具体影响。(4)通过在隧道爆破开挖过程中下穿的多层钢筋混凝土建筑沿高度和水平方向上布设测点,采集了大量的钢筋混凝土建筑的爆破地震响应信号。采用小波分析和快速傅立叶变换相结合的方法,研究各方向爆破地震波作用下钢筋混凝土建筑沿高度和水平方向的结构响应频谱、能量分布特性及幅值变化规律。(5)本文采用小波包分解和重构的方法,将复杂的实测爆破地震波速度信号转化为多个简谐波的叠加,将爆破速度荷载作用下结构的动力响应问题转化为一系列简谐荷载作用下的动力响应问题。通过提出速度因子的新概念并将其反映在爆破地震效应计算模型中,考虑了结构动力响应中瞬态响应的影响。同时爆破地震效应计算模型中又融入了归一化的能量比例,在考虑爆破荷载频率的影响时仅需考虑占有相当能量比例的优势频率的综合作用。然后,在该计算模型基础上提出了一个新的爆破地震效应安全判据。该判据能反映出爆破激励荷载作用下结构速度响应大小与结构特性、爆破地震波幅值、频率(包括多个优势频率)、持续时间及能量比例等参数的关系。(6)采用动力有限元方法,参照爆区现场的一实际三层砌体房屋结构,建立三维空间实体模型,并将底层的爆破地震波监测信号加载到砌体结构模型的基底,求解出有限元模拟的砌体结构其它各层的爆破震动响应值,并与监测结果进行了比较分析。对常见的2-4层砌体结构房屋,各取一种典型结构在基底节点垂直方向上施加不同主频的爆破地震波进行动力有限元建模并模拟开裂过程,通过定义结构单元的临界失效状态来寻求典型砌体结构房屋的爆破震动安全标准值,并给出了2-4层典型砌体结构房屋在各主频段爆破地震波作用下的爆破震动安全标准。本文取得的研究成果为科学地预测与控制爆区周围建筑物的爆破地震效应危害,改进和完善现有的爆破震动安全判据有着重要的理论价值和现实意义。更多还原

【Abstract】 At the meantime of widespread application of the blasting technology, a series of negative effects induced by engineering blasting especially blasting vibration effect which is regarded as head of blasting hazards has been commonly focused with the increasing of complication of blasting surroundings and people’s consciousness for environmental protection. To study the damaging mechanism of blasting vibration effect especially to study the mechanism of dynamic response of surrounding buildings induced by blasting vibration waves is the key and difficult subject in research field for blasting vibration effect, which is also the important content for blasting safety technique.Combining National Natural Science Foundation of China named "Study on Characteristics of Blasting Vibration and Structural Damaging Mechanism Induced by Blasting Vibration" (No:50778107)and Research Fund for the Doctoral Program of Higher Education of China named "Study on Characteristics of Blasting Vibration and Safety Control Theory of Structural Blasting Vibration" (No:20060424002), on the background of consulting and lucubrating on a great many domestic and overseas references related and with the support of related theories and analytical methods such as explosion dynamics, structural dynamics, numerical analysis, signal analytical technology, dynamic finite element theory and etc., characteristics of propagation of blasting vibration waves and structural dynamic response induced by blasting vibration waves and its corresponding safety standard were discussed deeply and systematically by the main studying means of numerical calculation, finite element simulation and field tests in this dissertation. The main research findings are as follows:(1) Based on discussing the influence-zone division of blasting vibration by numerical calculation and a large number of data obtained by field monitoring, the attenuation laws of the amplitude and basic frequency of blasting vibration waves versus scaled distance and spectrum and energy characteristics of blasting vibration waves in different vibration zone were studied.(2) Velocity loads of blasting vibration waves of different characteristic parameters were applied to the foundation base of a multi-freedom elastic structural system, and dynamic responses of the structural system under different conditions were calculated in central impulse method. By analyzing changes of peak values of all the structural dynamic responses, effects of the amplitude, frequency and duration of blasting vibration waves on dynamic response of the multi-freedom elastic structure were discussed.(3) A set of programs for solving elastic-plastic seismic response of multi-storey masonry buildings was written by Matlab, which combined Newmark time-history method with two-linear model of stiffness degradation. A four-storey masonry building was taken as the analyzed object, and the actual and artificial-simulated blasting vibration waves of different characteristic parameters were used as the input loads. According to the calculated results of amplitude for all structural elastic-plastic seismic response, effects of the amplitude, basic frequency and duration of blasting vibration waves on elastic-plastic seismic response of multi-storey masonry buildings were discussed respectively.(4) A large number of blasting vibration response signals of a reinforced concrete building were monitored by locating monitoring points on the multi-storey reinforced concrete building along the height and horizontal direction, which was under-drilled through in the course of blasting excavation of a tunnel. Distribution characteristics of the spectrum, energy and amplitude variation laws of structural response of the reinforced concrete building to the blasting vibration waves in all directions along the height and horizontal direction of the building were studied with the method of wavelet analysis combined with FFT.(5) Complex monitoring velocity signals of blasting vibration waves were transformed to superposition of several simple harmonic waves by the means of decomposition and reconstruction of wavelet packet. In this way, the problem of structural dynamic response under the action of blasting velocity loads became the problem of that under a series of simple harmonic loads. By introducing a new concept of velocity factor and bringing it into the calculation model of blasting vibration effect, the contribution of structural transient response was considered into structural dynamic response. At the meantime, normalized energy proportion was added to the calculation model, and only dominant frequencies of relatively large energy proportions could be included when considering the influence of frequencies of blasting loads. Then, a new safety criterion of blasting vibration effect was put forward on the model above, which can reflect the relation among value of structural velocity response under stimulation of blasting loads and parameters of structural characteristics, amplitude, frequencies (including several dominant frequencies), duration and energy proportion of blasting vibration waves.(6) A three-dimensional solid model was built for an actual three-storey masonry building in blasting filed with dynamic finite element method. Monitoring signals of blasting vibration waves at the bottom of the building were loaded onto the foundation base of the masonry model, and values of blasting vibration response of the other masonry storey calculated with dynamic finite element method were compared with the monitoring results. One representative structure was separately selected among common masonry buildings of 2～4 storeys to build finite element model, and blasting vibration waves of different basic frequencies were loaded on its base nodes in vertical direction and cracking course of the model was simulated. Safety standards of blasting vibration for representative masonry buildings of 2-4 storeys under blasting vibration waves of different basic-frequency bands were given, which were obtained by defining critical failure state of structural element.The research findings obtained in this dissertation are of important theoretical values and practical significance for scientifically forecasting and controlling hazards of blasting vibration effect of surrounding buildings and improving and consummating the existing safety criterion of blasting vibration.更多还原