弹性波法检测大孔径爆破对基岩松驰层厚度影响的探讨

根据大孔径梯段爆破开挖对底部基岩扰动影响的声波检测情况,对检测资料进行了分析研究,给出了大孔径开挖底部基岩预留保护层厚度,供工程参考。     

Measurement and analysis of near-field blast vibration and damage

Summary Blast vibration and its attenuation within the rock mass immediately adjacent to a blast hole (2–15 m) were monitored for a blast hole diameter of 100 mm and a 2.4 m column of an emulsion explosive charge. Peak particle velocities calculated from the measured accelerations were compared with predictions from the charge-weight scaling law using typical site parameters which would be adopted for many far-field vibration predictions. It was found that the vibration amplitudes predicted by the conventional charge-weight scaling law are significantly lower than measured values. Strain and strain rates at different monitoring holes were calculated from experimental data. Using attenuation analysis of different frequency bands of measured acceleration signals, it was found that blast vibration attenuation between 2 m and 4 m depended not only on frequency but also on amplitude. A failure wave was postulated based on observations at the monitoring hole 2 m from the blast. A blast damage zone was evaluated using borehole camera and cross hole seismic studies. The damage zone in the rock was also analysed according to acceleration waveforms measured at different monitoring locations. The use of different techniques to measure blast damage provided an accurate assessment of the blast damage volume.     

工程爆破中径向水不耦合系数效应数值仿真

在实际工程爆破中,水不耦合炮孔是较常见的,其中水不耦合装药系数是影响爆破效果的关键因素之一。该系数取不同的值,将产生不同的应力波传播机理以及介质的损伤破坏程度。以往的研究主要集中于理论解析法和模型试验法。基于大型非线性动力分析软件LS-DYNA,采用著名的混凝土损伤Johnson-Holmquist-Concrete模型,针对无限混凝土介质水不耦合装药爆破中不同径向耦合系数Kd,展开了对比数值计算,综合分析了损伤破坏区分布和孔壁压力、加速度以及速度等与径向不耦合系数间的关系,得出的结论具有一定的参考价值。     

炸药触地爆炸后核电站安全壳基底振动响应分析

现代战争或恐怖活动中,核电站很可能受到精确制导炸弹的攻击。运用有限元软件LS－DYNA3D,以5 000 kg等效TNT当量的装药在安全壳100 m外触地爆炸为例,将装药爆炸、土中传播和结构构成有限元分析体系,对安全壳基底的振动响应进行了分析。结果表明,安全壳基底和壳体的压力呈环状分布,在基底和壳体的连接处有明显的应力集中;等效应力-时程曲线和径向应力-时程曲线显示,壳体的最大等效应力为35 kPa、最大径向应力为32 kPa,均在安全范围。在给定的条件下,基底和壳体的响应值远未超出设计值,核电站的运行安全可靠。     

控制加载爆炸挤淤置换法在工程中应用

阳江核电海工一期东平台防护堤设计和施工采用了控制加载爆炸挤淤置换法。该方法保证了东平台防护堤堤身的落底宽度与深度,成功地解决了水下宽平台的形成问题,并有效地减少了理坡工程量,是爆炸处理软基技术新方法在防波堤的设计和施工中成功应用的范例。     

江苏数字地震台网中心记录波形分析

对江苏数字地震台网的波形资料,从震相、频谱、振幅比3个方面进行对比分析,找出天然地震、人工爆破、塌陷的不同之处,能够在地震定位过程中快速识别,并将此方法在江苏地震台网实际工作中应用。     

Studies of Laser-Driven Radiative Blast Waves

We have performed two sets of experiments looking at laser-driven radiating blast waves. In the first set of experiments the effect of a drive laser’s passage through a background gas on the hydrodynamical evolution of blast waves was examined. The laser’s passage heated a channel in the gas, creating a region where a portion of the blast wave front had an increased velocity, leading to the formation of a bump-like protrusion on the blast wave. The second set of experiments involved the use of regularly spaced wire arrays used to induce perturbations on a blast wave surface. The decay of these perturbations as a function of time was measured for various wave number perturbations and found to be in good agreement with theoretical predictions.     

高地应力条件下爆破开挖诱发围岩损伤的特性研究

高地应力条件下隧道或硐室钻爆开挖需考虑初始地应力动态卸荷效应,同时其最终损伤形态会受多个因素影响。采用三维有限差分软件FLAC3D讨论了爆破荷载与地应力动态卸荷复合作用下隧道围岩损伤分布,并重点研究了侧压力系数、岩体力学性质、卸荷速率对围岩损伤范围的影响,最后通过赣龙铁路梅花山隧道开挖损伤区检测结果进行了验证。研究表明,考虑动态卸荷效应的围岩损伤范围明显大于只考虑爆破荷载作用下的围岩损伤范围,在中高地应力条件下,初始地应力动态卸荷对围岩的损伤破坏作用不可忽视;随着侧压力系数逐渐增大,损伤区形态呈现明显的方向性,当侧压力系数为1时,损伤区沿开挖轮廓面分布较为均匀,侧压力系数不为1时,损伤区主要向小主应力方向集中;岩石力学性质越好,损伤范围越小;卸荷速率越快,围岩损伤范围越大,但影响并不十分显著。结果可为高地应力下隧道开挖稳定性分析和支护设计提供一定参考。