爆破振动的研究

从爆破地震与天然地震的区别入手，对爆破地震的破坏机制和影响，爆破地震的强度因素及破坏标准进行了研究，对从事爆破振动研究人员具有一定的参考作用。     

边坡稳定性的动力影响因素分析

边坡在地震或爆破振动等动力作用下的稳定性问题是目前研究的较热门问题．本文在总结影响边坡稳定性因素基础上,给出了描述震动效应的参数．地震或爆破振动的动力作用均可引起边坡的失稳,边坡的高度、形状、结构及地形特点也是决定边坡是否在动力作用下破坏的重要因素．此外,震源及质点的振动速度、振幅等也是判定边坡的失稳依据．     

边坡爆破振动传播规律的试验研究

从爆破地震效应分析入手,对实验室内混凝土边坡的爆破振动进行试验研究,探讨爆破振动在边坡中的传播规律,并分析了边坡爆破振动对边坡作用机理和地震强度的影响。结果表明,人工预留的预裂缝作为减震沟有明显的减震效果,且表明可运用于实际的边坡爆破工程。     

新建隧道下穿既有道路爆破施工影响范围

以宝汉高速爆破施工为例,通过现场监测关键质点爆破振动速度,研究爆破振动对临近既有道路的影响范围.研究结果表明,爆破振动波的主频率在10~50 Hz内,不会使周围临近既有道路与其产生共振.从现场测试结果可知,由于垂直振速大于径向振速和切向振速,且垂直振动对建筑物破坏尤为显著,故在类似工况下爆破振动监测应该以监测垂直振速为主.爆破振动波对既有道路的影响范围为30 m,与理论值相符.当浅埋大断面软弱围岩隧道下穿既有道路施工爆破的安全允许质点振动速度小于2.0 cm/s时,可确保既有道路结构和交通安全.研究可为此类隧道工程的施工提供借鉴.     

基于烦恼率模型的爆破振动舒适性评价方法

随着水利、铁路、公路和城市建设等工程越来越多,邻近人群聚居区的爆破作业也越来越多,由爆破作业诱发的爆破地震效应导致的居民的抱怨、投诉和民事纠纷越来越多。爆破作业产生的振动会对临近建筑物的舒适性造成影响,由此引起居民的烦恼效应、惊扰效应和对建筑物破坏的担忧。利用建立在心理物理学方法上的烦恼率计算方法来定量评价爆破振动舒适度问题,针对目前实践中大多是开展爆破质点振动速度历程监测而非加速度监测,给出了一种基于爆破振动速度推求加速度的四点向前差分方法。根据人体对不同方向、不同频率范围和振动持续时间爆破振动的敏感程度不同,对振动加速度按不同方向进行频率计权与时间计权以获得计权均方根加速度,再计算3个方向的折算总计权均方根加速度并应用于烦恼率模型。结合某水电工程基坑爆破开挖工程,获得了39组爆破质点振动速度监测数据和舒适性调查数据。通过对比分析,39次试验中居民没有明显反应的场次有23场,对应最大烦恼率上限约为0.06;居民有反应的场次共有11次,对应烦恼率值范围约为0.077~0.164;居民出现激烈反应的场次共有5次,烦恼率值约为0.17~0.31。综合爆破振动的特点,建议以烦恼率不大于0.07作为设计爆破方案的依据和控制标准,可有效减少居民对爆破振动的抱怨和投诉。     

露天矿高陡边坡采场爆破振动监测与分析

采用TC-4850型爆破监测仪对内蒙某露天矿进行多次爆破振动监测,并通过一元及二元回归得出基于该矿的径向、切向和垂向振动速度预测公式.分析表明,二元回归的采场爆破振速传播公式较一元回归的精度高,这说明爆破振速不是完全由爆心距决定的,其也受到了高程参数一定程度的影响.高程对爆破振动速度的影响垂向最大,切向次之,径向最小.采场爆破振速随着传播距离的增大而衰减,但高程对爆破振速具有一定的放大效应.通常前者占主导地位,因而一般不表现出高程的放大效应;只有在后者占主导地位时,才表现出高程的放大效应,即高程放大效应是振速传播一定范围内局部效应.     

结构鞭梢效应的动力分析

为减轻地震对建筑物顶部突出部分的破坏作用及影响,作者对其进行了动力分析,得出在地震荷载作用下,结构的鞭梢效应使突出部分的振动反应加大,从而引起破坏,说明其产生的原因和条件,并为结构设计提出建议。     

砌体结构受爆破地震波作用破坏特征研究

在建筑物附近进行爆破作业产生的爆破振动,会引起结构一定程度的损伤,对结构的安全性和耐久性产生影响。根据现场工程情况,采用有限元软件ANSYS建立砌体结构的计算模型,对爆破地震波作用下其受力和变形进行数值模拟分析。研究表明,爆破地震波作用时,房屋门、窗户的四角部位和墙角等是易产生应力集中和破坏的关键部位;结构对爆破振动的响应程度随着结构物高度的增加而增大;砌体结构设计施工和在砌体结构附近进行爆破作业时,应采取相应减振措施,以降低爆破振动的危害。     

质点振动速度与主振频率在爆破监测中的应用

通过分析爆破振动对结构的破坏机理,提出了用质点峰值振动速度和主振频率作为爆破振动的监测方法,并探讨了结构的破坏准则和部分国家的振动安全标准,以及影响爆破的因素,进而对爆破采用有效控制。     

砌体房屋的爆破地震破坏机理和模型

在全面分析工程爆破地震波的特性和砌体房屋的受震破坏破坏特征的基础上,分析并得出了砌体房屋受各类爆破地震破坏的机理和模型,为完善仪器测振和建立适合具体结构特征的爆破地震效应的安全评定方法提供了理论依据、分析方法和观测重点。     

Vibration Effect and Damage Evolution Characteristics of Tunnel Surrounding Rock Under Cyclic Blasting Loading

Model test studies based on the similarity theory were conducted to investigate vibration effect and damage evolution characteristics of tunnel surrounding rock under push-type cyclic blasting excavation. The model was constructed with a ratio of 1:15. By simulating the tunnel excavation of push-type cyclic blasting, the influence of the blasting parameter change on vibration effect was explored. The damage degree of tunnel surrounding rock was evaluated by the change of the acoustic wave velocity at the same measuring point after blasting. The relationship between the damage evolution of surrounding rock and blasting times was established. The research results show that:① In the same geological environment, the number of delay initiation is larger, the main vibration frequency of blasting seismic wave is higher, and the attenuation of high frequency signal in the rock and soil is faster. The influence of number of delay initiation on blasting vibration effect cannot be ignored; ② Under push-type cyclic blasting excavation, there were great differences in the decreasing rates of acoustic wave velocity of the measuring points which have the same distance to the blasting region at the same depth, and the blasting damage ranges of surrounding rock were typically anisotropic at both depth and breadth; ③ When blasting parameters were basically kept as the same, the growth trend of the cumulative acoustic wave velocity decreasing rate at the measuring point was nonlinear under different cycle blasting excavations; ④ There were nonlinear evolution characteristics between the blasting cumulative damage (D) of surrounding rock and blasting times (n) under push-type cyclic blasting loading, and different measuring points had corresponding blasting cumulative damage propagation models, respectively. The closer the measuring point was away from the explosion source, the faster the cumulative damage extension. Blasting cumulative damage effect of surrounding rock had typically nonlinear evolution properties and anisotropic characteristics.     

基于S变换的坝体爆破振动信号时频特征分析

近区工程爆破将对周围建（构）筑物产生不利影响,而爆破振动的破坏作用又与振动强度、频率以及结构自身的振动特性等综合因素有关．利用连续s变换对某浆砌块石单曲拱坝的坝基爆破振动速度信号进行分析,提取x、y、z三个方向速度信号的时频分布特征．结果表明s变换对爆破振动信号有较好的时频分辨率．最后采用质点峰值振动速度、瞬时能量谱和持续时间等指标对坝体的安全性进行评价,认为该大坝处于安全状态．     

小水池中水下爆炸地震波测试与分析

水下爆炸引起的振动会波及附近建筑物,是爆破安全必须考虑的问题。采用UBOX-5016型爆破震动记录仪对某一小水池中炸药爆炸产生的振动效应进行了测试和分析,并对所测波形进行频谱分析,得到该水下爆炸地震波的主震频率在12~60Hz,大于建（构）筑物的固有频率（几赫兹至十几赫兹）,当建（构）筑物固有频率同爆破振动频率接近时,将会产生共振效应,较小的振动也会产生较大的破坏,因此,测试过程不会对火工楼造成太大的影响。研究结果对类似的新建实验室及相关工程实践具有较大的参考价值。     

Features of energy distribution for blast vibration signals based on wavelet packet decomposition

Blast vibration analysis constitutes the foundation for studying the control of blasting vibration damage and provides the precondition of controlling blasting vibration. Based on the characteristics of short-time nonstationary random signal, the laws of energy distribution are investigated for blasting vibration signals in different blasting conditions by means of the wavelet packet analysis technique. The characteristics of wavelet transform and wavelet packet analysis are introduced. Then, blasting vibration signals of different blasting conditions are analysed by the wavelet packet analysis technique using MATLAB; energy distribution for different frequency bands is obtained. It is concluded that the energy distribution of blasting vibration signals varies with maximum decking charge,millisecond delay time and distances between explosion and the measuring point. The results show that the wavelet packet analysis method is an effective means for studying blasting seismic effect in its entirety, especially for constituting velocity-frequency criteria.     

Influence law of multipoint vibration load on slope stability in Xiaolongtan open pit mine in Yunnan,China

The purpose of this work was to explore the influence law of vibration load on rock mass structure and slope stability.Based on the type and transmission way of vibration stress wave,the main stress in the horizontal and vertical directions was analyzed and the superposition effect of the stress wave was revealed.After the mechanical analysis of the sliding mass,the calculation formulas of the anti-sliding force and the sliding force were derived and the damage mechanism of blasting vibration to the structural plane was defined.In addition,according to the structure and lithologic parameter of the slope as well as the vibration monitoring data,the west slope stability of Xiaolongtan open pit mine was analyzed.The results show that the time-dependent stability factor is proportional to the vibration speed and the peak values appear at the same time.Vibration load promotes the breakage of the structural plane leading to the drop of the west slope stability factor by 0.23%.Under the multipoint simultaneous blasting,the fluctuating laws of the stability factors are consistent.The more the start-up points are,the higher the weakening degree to the slope stability is.Under the multipoint allochronic blasting,the stability factor depends on the synthetic waveform structure of all vibration waves.The greater the blasting time difference is,the lower the weakening degree to the slope stability is.Selecting the reasonable quantity of start-up points and time difference could fully reduce the adverse influence of vibration load to slope stability.     

Features of energy distribution for blast vibration signals based on wavelet packet decomposition

Blast vibration analysis constitutes the foundation for studying the control of blasting vibration damage and provides the precondition of controlling blasting vibration. Based on the characteristics of short-time non-stationary random signal, the laws of energy distribution are investigated for blasting vibration signals in different blasting conditions by means of the wavelet packet analysis technique. The characteristics of wavelet transform and wavelet packet analysis are introduced. Then, blasting vibration signals of different blasting conditions are analysed by the wavelet packet analysis technique using MATLAB; energy distribution for different frequency bands is obtained. It is concluded that the energy distribution of blasting vibration signals varies with maximum decking charge, millisecond delay time and distances between explosion and the measuring point. The results show that the wavelet packet analysis method is an effective means for studying blasting seismic effect in its entirety, especially for constituting velocity-frequency criteria. Foundation item: Project(50490272) supported by the National Natural Science Foundation of China; project(2004036430) supported by the Postdoctoral Science Foundation of China     

Vibration velocity and frequency of underwater short-hole blasting

Based on the measuring data of underwater blasting vibration and the regression analysis results of these data, two formulae usually used of blasting vibration velocity were compared. Factors that can affect blasting vibration and frequency were summarized and analyzed. It is thought that the effect of the number of freedom face and burden direction on blasting vibration should be considered during blasting design. Based on the relevant research results and the regression results of these data, a formula to calculate under water blasting frequency was put forward.     

爆破振动作用下砌体结构加固前后动力分析

采用等效体积单元法对采用外支脚手架方法加固的砌体结构在加固前、后抵抗地铁开挖过程中产生的爆破振动荷载的动力性能进行分析.通过分别建立加固前、后结构的模型并进行时程分析,对比顶点侧向位移和墙体的应力,得出采用外支脚手架的加固方法分担了墙体等构件的水平荷载,减小了结构的变形,避免了古建筑被损坏.为今后砌体古建筑的数值模拟和加固提供技术支持以及城市建设过程中由于地铁开挖所产生爆破振动对古建筑的影响提供分析实例.     

Structural safety criteria for blasting vibration based on wavelet packet energy spectra

Given multi-resolution decomposition of wavelet packet transforms, wavelet packet frequency band energy has been deduced from different bands of blasting vibration signals. Our deduction reflects the total effect of all three key elements (intensity, frequency and duration of vibration) of blasting vibration.We considered and discuss the dynamic response of structures and the effect of inherent characteristics of controlled structures to blasting vibration. Frequency band response coefficients for controlled structures by blasting vibration have been obtained. We established multi-factor blasting vibration safety criteria, referred to as response energy criteria. These criteria reflect the total effect of intensity,frequency and duration of vibration and the inherent characteristics (natural frequency and damping ratio) of dynamic responses from controlled structures themselves. Feasibility and reliability of the criteria are validated by an example.