黏土中爆炸成坑地冲击耦合效应实验研究

Experimental study on explosion cratering and coupled ground shock in clay

为获得黏土中爆炸成坑体积与耦合地冲击能量的关系,采用10.5 g TNT厘米级球形炸药球作为爆炸源,在Φ1500 mm×1490 mm分层式爆炸装置中开展了变埋深条件下的爆炸实验,利用3D扫描设备记录不同埋深下弹坑的真实体积,并通过动态土压力传感器测得地冲击传播衰减规律。实验结果表明:随埋深增大,耦合至黏土中的有效地冲击能量急剧增大,装药中心下方的有效弹坑体积与耦合至黏土中的有效地冲击能量基本呈正比关系,当装药比例埋深与封闭爆炸条件下爆炸空腔半径相当时,耦合至黏土中的有效地冲击能量基本达到饱和。结合实验结果给出了黏土中爆炸耦合地冲击能量分配随装药比例埋深的变化规律,建立了地下爆炸等效封闭当量计算方法,为地下工程抗爆设计提供了理论依据。

To study the distribution of the coupled ground impact energy due to underground explosions,the key is to obtain the experimental parameters of the volume of the crater compression zone under the coupling effect between the clay medium and explosion energy.To reveal the relationship between the distribution of the blast coupling ground impact energy in clay and the compression volume of the crater,10.5 g TNT explosive spheres were used as the blast source,and blast experiments under variable burial depths were conducted in a Φ1500 mm×1490 mm layered blast test apparatus.The real volume of the crater under different burial depths was recorded by using a three-dimensional scanning equipment,and the pressure data under different distances from the blast center were measured by earth pressure sensors to obtain the blast wave propagation law.Meanwhile,the law of energy distribution of coupled ground impact was theoretically revealed,which is proportional to the volume of medium damage.Three conversion relations of coupling coefficient were given,and the coupling coefficient curve of clay was drawn using the Boltzmann function.The experimental results show that in the range of−0.056 m/kg1/3≤h≤0.37 m/kg^(1/3),as the burial depth of the charge increases,the attenuation coefficient increases,and the peak pressure of the blast core distance also increases,and the share of the explosion impact coupling medium also increases with the increase of the charging burial depth.This indicates that the increase of the charging proportion burial depth intensifies the effects of the explosion.This finding implies that the change in burial depth has a negligible impact on the energy of the explosion impact coupling medium.The critical depth of ground shock effect of compacted clay is about 0.55 m/kg^(1/3),which is slightly larger than the radius of underground closed explosion cavity.The experimental value of visible diameter is in good agreement with the corresponding ConWep predicted value.The macroscopic failure critical depth is about 1.46 m/kg^(1/3).Combined with the test results,the variation law of the energy distribution of explosion coupling ground impact in clay with the buried depth of the charge ratio is given,and the calculation method of the equivalent closed equivalent of underground explosion is established.This provides a load basis for underground engineering blast resistance research and structural design.