隧道爆破作用下砌体结构动力反应及控制研究

发布时间：2018-01-05 18:11

本文关键词：隧道爆破作用下砌体结构动力反应及控制研究　出处：《北京交通大学》2015年博士论文　论文类型：学位论文

【摘要】：近年来,近距下穿城区建筑群的隧道工程越来越多,当采用钻爆法施工时,爆破振动经常会对上部建筑物造成局部损伤。本文依托成渝客运专线重庆新红岩隧道工程,针对隧道上部山坡典型二层砌体楼房进行研究,主要成果如下： 1.研究了隧道爆破引起的山坡浅埋侧和深埋侧的爆破振动特征,阐述了基于监测数据分析的爆破振动安全评价方法。隧道爆破引起的山坡浅埋侧和深埋侧的竖向或水平振速的大小取决于爆心距和应力波与竖直方向的夹角2个因素；山坡的深埋侧地表振速较小、频率较低,而浅埋侧地表振速较大、频率较高,需要综合比较两侧的主频和振速评价建筑物的振动安全性。 2.进行了隧道爆破振动激励的典型二层砌体楼房OMA模态试验,采用增强的频域分解法和随机子空间法研究了二层砌体楼房的模态参数(固有频率、振型和阻尼)；根据OMA模态试验结果建立了砌体楼房结构模型,研究了砌体楼房低阶整体模态和高阶局部模态下的动力特性。二层砌体楼房1-5阶固有频率为8.80～24.99Hz,振型表现为整体均匀变形；6-20阶固有频率为26.10～36.34Hz,振型表现为薄弱的局部构件振动较大；薄弱墙体和突出部位2类典型局部构件的1-10阶固有频率为5.09-157.55Hz,局部构件的固有频率显著高于楼房整体,隧道爆破振动引起的是建筑物局部构件较强的动力反应。 3.研究了隧道爆破作用下典型二层砌体楼房结构的动力反应,揭示了隧道爆破作用下楼房的振速特征、位移特征、混凝土和砖墙构件的应力分布及变化规律。砌体楼房局部构件的振速和位移幅值显著大于整体；隧道爆破作用下楼房的动力反应主要受瞬时产生的高应力控制,而不是位移；随着峰值振速增加,结构应力随之增大,随着振动主频增大,结构应力随之降低；当爆破振动主频远离建筑物的低阶整体固有频率时,可以只考虑竖向振动影响,忽略水平振动影响。 4.研究了隧道爆破作用下砌体楼房的损伤机理和开裂部位,提出了爆破振动下砌体楼房的损伤鉴定和评估方法。砌体楼房的局部构件受隧道爆破振动影响较大,当峰值振速较大引起局部构件上应力水平较高时,可能发生损伤导致开裂；此外,角部应力集中部位、砖墙与混凝土接触部位和预制楼板接缝在隧道爆破振动下也容易产生开裂。 5.提出了电子雷管实现单孔间隔起爆的延时计算方法,研究了电子雷管单孔间隔起爆降低峰值振速和提高振动主频的原理。电子雷管实现单孔间隔起爆的延时需要不小于单孔岩石破碎和抛掷位移为10cm的总时间,其峰值振速低于段药量起爆,主频高于段药量起爆,并且分别接近于单孔药量起爆的振速和主频。
[Abstract]:In recent years, there are more and more tunnel projects through urban buildings in short distance, when drilling and blasting method is used. Blasting vibration often causes local damage to the upper building. Based on Chongqing Xinhong Rock Tunnel Project of Chengdu-Chongqing passenger dedicated Line, the typical two-story masonry building on the upper slope of the tunnel is studied in this paper. The main results are as follows: 1. The blasting vibration characteristics of shallow buried side and deep buried side of hillside caused by tunnel blasting are studied. The safety evaluation method of blasting vibration based on monitoring data analysis is expounded. The magnitude of vertical or horizontal vibration velocities of shallow and deep buried hillsides caused by tunnel blasting depends on the distance between the blasting core and the angle between stress wave and vertical direction. Factors; The deep buried side of the hillside has smaller vibration velocity and lower frequency, while the shallow side is larger and has higher frequency, so it is necessary to compare the main frequency and vibration velocity of both sides to evaluate the vibration safety of the building. 2. The OMA modal test of typical two-story masonry building excited by blasting vibration is carried out, and the modal parameters (natural frequency) of two-story masonry building are studied by means of enhanced frequency-domain decomposition method and stochastic subspace method. Mode and damping; Based on the results of OMA modal test, the structural model of masonry building is established. The dynamic characteristics of the masonry building under the low-order integral mode and the high-order local mode are studied. The 1-5 natural frequency of the two-story masonry building is 8.80 ~ 24.99Hz. The natural frequency of 6-20 order is 26.10 ~ 36.34 Hz, and the vibration of the weak local member is larger. The natural frequencies of the two types of typical local members are 5.09-157.55Hz. the natural frequencies of local members are significantly higher than that of the whole building. The blasting vibration of the tunnel causes the strong dynamic response of the local members of the building. 3. The dynamic responses of typical two-story masonry structures under tunnel blasting are studied, and the characteristics of vibration velocity and displacement of buildings under tunnel blasting are revealed. The stress distribution and variation law of concrete and brick wall members. The vibration velocity and displacement amplitude of local members of masonry buildings are significantly larger than that of the whole. The dynamic response of the building under the action of tunnel blasting is mainly controlled by the instantaneous high stress rather than the displacement. With the increase of peak vibration velocity, the stress of the structure increases, and with the increase of the main frequency of vibration, the stress of the structure decreases. When the main frequency of blasting vibration is far from the low order natural frequency of the building, only vertical vibration can be considered, but the influence of horizontal vibration can be ignored. 4. The damage mechanism and cracking position of masonry building under tunnel blasting are studied. The damage assessment and evaluation method of masonry building under blasting vibration is put forward. The local members of masonry building are greatly affected by blasting vibration of tunnel, and when the peak vibration speed is larger, the stress level of local member is higher. Damage may lead to cracking; In addition, the stress concentration in corner, the contact between brick wall and concrete and the joint of precast floor are easy to crack under blasting vibration of tunnel. 5. The delay calculation method of the electronic detonator to realize the one-hole interval detonation is proposed. The principle of reducing peak vibration velocity and increasing main vibration frequency of electronic detonator with single hole interval initiation is studied. The delay of electronic detonator to realize single hole interval detonation need not less than the total time of single hole rock breakage and throwing displacement of 10cm. . The peak vibration velocity is lower than that of the detonation of the section charge, and the main frequency is higher than the detonation rate of the section charge, and it is close to the vibration velocity and the main frequency of the detonation of the single hole explosive quantity respectively.
【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U455.6;TU364

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