岩体巷道光面爆破参数比较分析与应用

光面爆破效果主要取决于岩石条件、炸药性质及光爆参数,岩石条件不同,则光面爆破参数应作相应调整.为将光面爆破更合理地应用于不同条件下的岩石,基于爆炸应力波和爆生气体共同作用理论,提出了普通光面爆破及计入损伤光面爆破参数计算公式.实例及分析说明：基于爆炸应力波和爆生气体综合作用理论的光面爆破计算公式是合理的,适用于不同岩石条件光面爆破参数的确定;在孔深、孔径和装药相同的条件下,岩石越完整,稳定程度越高,其光面爆破的周边眼间距越小;计入损伤时,光面爆破的周边眼间距可适当增大;岩石单轴抗压强度较大,则装药不耦合系数可取较小值,以提高炸药爆炸能量利用率,单轴抗拉强度越高,则光面爆破的周边眼间距值越小.     

基于LS-DYNA的减震沟减震效应研究

为了研究减震沟的减震作用,运用大型动力分析软件LS-DYNA,基于具体工况分别对有减震沟和无减震沟的露天矿台阶爆破进行数值模拟.结果表明,减震沟距离爆源越近,减震效果越好,减震率最高可达77%,为减震沟的减震效应研究和类似工况提供了理论支持.     

爆破震动衰减规律的影响因素

爆破震动衰减公式中K和α的取值对爆破震动的准确预报具有重要意义,在理论分析的基础上,根据大量的实测资料,探讨了K和α值的影响因素. 分析结果表明:爆破条件对衰减公式中的 K值影响甚大,在不同的孔径、孔深及装药结构条件下,爆破震动衰减规律会存在很大区别;而岩体及地形条件的改变都会对K和α值造成较大的影响,相对爆源不同方向和距离上的震动衰减规律也是不尽相同的.     

不同爆源形式的爆破地震能量分布特征

爆破地震对建筑物的影响实质上是一种能量的传递与转化过程,这种传递与转化的过程受到爆破地震波能量分布特征的影响.利用基于功率谱的爆破地震能量分析方法,借助大量工程实测数据,针对爆源形式对爆破地震能量分布特征的影响进行了分析,分析结果表明:对于4类钻孔爆破诱发的地震,能量随频率分布比较分散,0～10 Hz的低频段能量比例非常少;不同爆源形式的爆破地震能量分布特征存在差别,随着孔径、孔深的增大,爆破地震主振能量频带趋于集中,也更倾向低频方向;地下工程爆破地震小于40 Hz的能量比例非常小.不同爆源形式爆破地震能量分布特征上的这种差别,对于控制爆破中钻爆方式的选取具有很好的指导意义.     

减震沟减震的数值模拟

减震沟是降低爆破地震效应的重要措施. 通过数值模拟,比较了有无减震沟时的峰值震速分布和开挖面与减震沟距离变化时质点的峰值震速衰减规律,对比分析了不同深度、不同宽度减震沟的减震效果以及减震沟与炮孔相对深度不同时的减震效果. 结果表明:开挖面距离减震沟越近,减震效果越好;在保护区侧,减震沟附近,由于减震沟的屏蔽作用,存在一个震速很小的区域;减震沟的减震效果随减震沟深度的增加而增加,而减震沟的宽度变化对减震意义不大.     

硬岩地层地铁爆破施工诱发环境振动响应研究

硬岩地层中,对地铁基坑爆破施工所诱发的环境振动传播规律及有效振动控制措施的研究是降低地铁爆破施工对周围环境影响的重要基础。文章以济南轨道交通某拟建地铁车站隔振工程为研究对象,通过理论分析建立了爆破施工振动对周边建筑物影响安全距离计算模型,得出了硬岩地层爆破施工安全距离预测公式。同时,采用非线性有限元软件MIDAS(迈达斯)对隔振矩形空沟建立二维数值模型。对比文献实测及模型数据,校核有限元模型的有效性。通过分析不同工况模拟的隔振效果值,研究得出矩形隔振空沟尺寸对隔振效果的影响。结果表明：所推导的“硬岩地层爆破施工振动对周边建筑物影响的安全距离”计算模型,可对施工安全距离进行预测及估算,计算方法较为可靠。在硬岩地层,对爆破基坑工程进行隔振工程设计时,增加隔振沟深的隔振效果比增加沟宽更有效,对于一般构筑物,采用沟宽为0.5 m、沟深为2.5 m的矩形空沟比较经济合理。     

鲁坨路路堑边坡爆破应力波传播规律

为了解决边坡岩体内爆破应力波与介质相互作用以及爆破荷载作用下边坡动力稳定性问题,依托鲁坨路路堑边坡爆破工程,在现场爆破振动测试的基础上采用数值模拟的方法对边坡坡面以及岩体内部质点的振动速度、应力场等分布规律进行深入研究.结果表明:1)对于坡面质点,水平爆心距与高程的增加均会使爆破峰值振速总体呈衰减趋势,但台阶边缘"鞭梢效应"明显,且距离爆源越近,峰值振速放大系数越大. 2)边坡台阶坡角处应力集中显著,但峰值应力与峰值振速并非在同一位置出现.因此,不能将台阶外缘峰值振速作为评价边坡稳定性的单一指标. 3)对于岩体内部质点,爆破振动响应也随爆心距的增大逐渐衰减,但坡面和岩层分界面对应力波的反射叠加会造成岩体质点的峰值振速和应力均有所放大.     

爆震弹近地动爆冲击波超压非致命特性研究

为了研究爆震弹近地动爆冲击波特性,运用AUTODYN软件仿真分析了某型64 mm爆震弹在不同运动速度以及不同距地高度下冲击波的衰减规律及非致命特性.研究结果表明:动爆条件对冲击波的增益效果整体上随距离的增加而逐渐减小;随运动速度的增大,超压值整体增益效果有所增加,对人员致伤效果可达严重损伤;随起爆高度增加,冲击波本身到...     

层间隔震框架结构抗震性能分析

阐述了隔震支座的力学性能,推导了隔震系统的动力平衡方程,利用大型有限元软件SAP2000在7度罕遇EL-Centro地震波作用下对隔震层置于底层、三层及八层柱顶的层间隔震框架结构进行动力时程分析,包括楼层位移、剪力和加速度,并对计算结果与传统抗震结构进行比较分析。研究结果表明,层间隔震具有良好的隔震效果,但隔震层位置的高低对层间隔震的减震效果有较大的影响,隔震层位置越低,减震效果越明显。     

高压输电线路覆冰清除爆破参数研究

针对高压输电线路覆冰严重威胁到国家电网稳定正常运行的问题,对高压输电线路覆冰爆破除冰进行了研究.应用LS-DYNA计算最优控爆参数,确定输电线路覆冰最佳装药量、以及装药与输电线路最优间隔值,并通过缩比爆破除冰实验验证了仿真计算结果.结果表明,有效覆冰参数,以及高压输电线与覆冰表面摩擦系数的确定为爆破除冰控爆参数的计算提供了有力保证;通过高速相机全程拍摄可知,缩比爆破除冰实验研究获得了较好的除冰效果,表明高压输电线路覆冰爆破除冰控爆参数具有可靠性及可行性,可为高压输电线路爆破除冰方案设计提供依据.     

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.     

Dynamic Damage Model of Brittle Rock and Its Application

On the basis of shock-induced experiments and the ultrasonic tests of the damaged rocks, the damage evolution relation between the attenuation coefficient of sound wave and the damage dissipated energy is de-scribed. Based on the TCK and RDA models, a damage model which connects the shock compression and tensile damage is established. And then the damage model is implemented in LS-DYNA3D dynamic nonlinear program.Numerical simulation of deep-hole blasting of groove is studied by use of the damage model proposed. The rock damage evolution process and the distributing rules of stress field under the explosion load are described well fair-ly, which provides the theory basis for the engineering blasting design.     

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     

超近距离爆破振动下铁路隧道铁轨振动特性研究

依托实际铁路隧道工程,结合铁轨爆破振动测试与能量分析,对超近距离邻近隧道爆破施工影响下既有铁路隧道铁轨爆破振动效应及其控制进行研究。利用小波包分解及其保范性在Matlab里对爆破振动信号进行分解,并计算出铁轨爆破振动不同频带能量分布情况,得到不同频率带所占能量百分比,并拟合出能量衰减公式以更进一步量化铁轨地震波能量变化规律。通过对监测数据进行拟合得到适合琅口隧道场地条件的萨道夫斯基公式,分析超近距离下铁路隧道铁轨的爆破地震波的衰减规律,得出琅口隧道场地条件下的安全药量、距离计算公式。     

Present State of Explosion Seismic Wave Research and Primary Investigation on Its Characteristics

The present state and the significance of research on explosion seismic waves are discussed, and meanwhile the main contents and the basic problems to be solved in the study of explosion seismic waves are analyzed. The spectra characteristics of explosion seismic waves, functions of the isolated-seismic grooves and influences of the detonating methods on explosion seismic waves are investigated by experiments. The experimental method is introduced. Some experimental results are presented which are concerned with the influences of topographical conditions, explosive charges, ignition patterns, isolated-seismic grooves and the other related factors on the characteristics of seismic waves.     

冻土爆破性的初步研究

本文分析了影响冻土爆破性的因素，即形变能系数、单位炸药消耗量、单轴抗压强度、抗拉强度和波速。根据相似原理和利文斯顿爆破漏斗理论对冻结粘土、冻结砂土在三个温度（－７℃，－１２℃，－１７℃）下进行了系列爆破漏斗试验，然后进行了单轴抗压强度、抗拉强度和波速试验。从试验结果得出，随着温度下降冻土趋于难爆，且在同一温度下，冻结粘土比冻结砂土难爆，得出的结论对冻土爆破参数设计有一定参考作用。     

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.     

Influence of millisecond time,charge length and detonation velocity on blasting vibration

The law of blasting vibration caused by blasting in rock is very complex.Traditional numerical methods cannot well characterize all the influencing factors in the blasting process.The effects of millisecond time,charge length and detonation velocity on the blasting vibration are discussed by analyzing the characteristics of vibration wave generated by finite length cylindrical charge.It is found that in multi-hole millisecond blasting,blasting vibration superimpositions will occur several times within a certain distance from the explosion source due to the propagation velocity difference of P-wave and S-wave generated by a short column charge.These superimpositions will locally enlarge the peak velocity of blasting vibration particle.The magnitude and scope of the enlargement are closely related to the millisecond time.Meanwhile,the particle vibration displacement characteristics of rock under long cylindrical charge is analyzed.The results show that blasting vibration effect would no longer increase when the charge length increases to a certain extent.This indicates that the traditional simple calculation method using the maximum charge weight per delay interval to predict the effect of blasting vibration is unreasonable.Besides,the effect of detonation velocity on blasting vibration is only limited in a certain velocity range.When detonation velocity is greater than a certain value,the detonation velocity almost makes no impact on blasting vibration.     

掏槽控制爆破动焦散试验研究

运用焦散线法基本原理，建立了性能稳定的爆炸加载测试系统．用普通药包掏槽爆破和切缝药包掏槽控制爆破进行了透明材料模型的透射式动焦散试验对照试验，结果表明，在相同药量的情况下，普通药包掏槽爆破的裂纹在各炮孔周围为随机分布，裂纹数目多且较短，各掏槽炮眼间没有形成贯通裂纹，其焦散斑随裂纹分布；采用切缝药包掏槽控制爆破的裂纹主要沿切缝方向分布且较长，各掏槽炮眼间形成贫通裂纹，焦散斑主要分布在切缝方向上．最后探讨了掏槽控制爆破的机理．