浅埋隧道开挖爆破对临近既有坝体安全影响分析

发布时间：2018-01-30 04:03

本文关键词： 浅埋隧道爆破振动衰减规律坝体安全评价　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：浅埋隧道钻眼爆破施工过程中,由于地表建构筑物与爆源距离较近,爆破施工对地表建构筑物的影响复杂。隧道开挖爆破是一个重复而长期的过程,频繁爆破施工将引起地基沉降、结构损伤甚至造成建构筑物垮塌,直接威胁到隧道周围群众的生命财产安全。故对浅埋隧道开挖爆破引起的地震波传播规律及爆破荷载作用下坝体动力响应展开分析,对爆破荷载作用下坝体安全进行评价。以豆子湾隧道近接下穿桥桥湾水库区段为工程背景,对隧道开挖爆破现场试验的地表和坝体振动监测结果展开分析,得到以下结论:隧道开挖爆破的振动波形中主振相清晰,掏槽孔装药并不是最大单段装药量,但掏槽孔爆破的峰值振速是其它炮孔的峰值振速的2倍以上。浅埋隧道开挖爆破引起的峰值振动在垂直于隧道轴线方向上衰减规律符合萨道夫斯基经验公式,三个垂直方向的场地系数分别为:140.5,88.3,109.5;衰减指数分别为:1.7475,1.6254,1.6706。爆破地震波经过地表强风化岩石、库区底部淤泥和水库蓄水对振动频率的过滤作用后,爆破地震波传播到水库坝体位置时振动频率逐渐趋于平稳,主要集中在18Hz～35Hz的低频段。运用LS-DYNA软件对豆子湾隧道开挖爆破施工进行模拟分析,得到:由于爆破地震波到测点的入射角度不同,在X轴方向上随着传播距离的增加峰值振速增加后逐渐减小,其中最大峰值振速出现在与爆源水平距离为15m位置处。在隧道单循环进尺为1.5m开挖爆破施工时,水库坝体三个垂直方向的峰值振速最大值分别为:0.53cm/s,0.31cm/s,0.54cm/s;坝体内峰值振速最大值都出现在坝体顶部位置,坝体内各点的峰值振速都小于水库坝体允许安全峰值振速。
[Abstract]:In the construction process of shallow tunnel drilling blasting, the influence of blasting construction on surface construction is complicated because of the close distance between the surface building structure and the blasting source. The tunnel excavation blasting is a repeated and long-term process. Frequent blasting construction will cause foundation settlement, structural damage and even collapse of building structure. It is a direct threat to the safety of the lives and property of the people around the tunnel, so the propagation law of seismic wave caused by excavation blasting of shallow buried tunnel and the dynamic response of dam body under blasting load are analyzed. The safety of dam body under blasting load was evaluated. Based on the engineering background of Douzi Bay tunnel, the vibration monitoring results of ground surface and dam body of blasting site test were analyzed. The following conclusions are obtained: the main vibration phase in the vibration waveform of tunnel excavation blasting is clear, and the charge for the slot hole is not the maximum single stage charge. But the peak vibration velocity of the cut hole blasting is more than 2 times that of the other holes. The attenuation law of the peak vibration caused by the shallow tunnel excavation blasting in the direction perpendicular to the tunnel axis conforms to the Sadolski's empirical formula. The site coefficients of the three vertical directions are respectively: 1 140.5 / 88. 3 / 109.5; The attenuation exponents are: 1: 1.7475 / 1.6254N / 1.6706.After the blasting seismic waves are filtered by the strongly weathered rocks at the surface, the silt at the bottom of the reservoir area and the reservoir water storage, the vibration frequency is filtered. When the blasting seismic wave propagates to the reservoir dam body the vibration frequency tends to be steady gradually. It is mainly concentrated in the low frequency band of 18Hz ~ 35Hz. The blasting construction of Douzi Bay tunnel is simulated and analyzed by using LS-DYNA software. It is concluded that the incident angle from blasting seismic wave to measuring point is different. In the direction of X axis, the peak vibration velocity decreases gradually with the increase of propagation distance. The maximum peak vibration velocity occurs at the position of 15m horizontal distance from the explosion source, and when the tunnel single cycle advance is 1.5 m excavation blasting. The maximum value of peak vibration velocity in three vertical directions of reservoir dam is: 0.53 cm / s 0.31 cm / s 0.54 cm / s; The maximum value of peak vibration velocity in the dam body appears at the top of the dam body, and the peak vibration velocity of each point in the dam body is less than the allowable peak vibration velocity of the dam body of the reservoir.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.6;TV698.1

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