不同介质地下爆炸的地震耦合效应

对黄土、砂砾石和花岗岩等几种不同介质中的地下爆炸实验进行了地表速度测量,利用实测数据获得爆炸源频谱以及以折合速度势低频稳态值表示的地震耦合强度。实验结果表明,对于相同当量、相当比例埋深下的地下爆炸,地震耦合强度和源区介质特性有着强烈的依赖关系,其中介质强度是影响地震耦合效率的最主要因素,而介质的干孔隙率和水饱和度也是影响地震耦合效率的重要因素。考察了M.D.Denny等提出的经验公式在估算100kg级当量地下爆炸地震耦合强度的适用性和局限性。

Experimental study on seismic coupling effects of underground explosions in different materials

Underground explosion experiments with the explosion equivalent of 100 kg TNT were performed in different geological mediums,such as loess,sand-gravel composite and granite.And the corresponding surface ground motions induced by underground explosions were observed by a series of seismometers.By using these observed data,the source parameters were obtained,as well as the seismic coupling efficiency represented by the steady value of reduced velocity potential at low frequencies.Experimental results display that for the underground explosions with the same scaled depth of burial and same explosion equivalent,the seismic coupling efficiency was strongly dependant on the source medium property in such a way that the medium strength plays the most significant roles in determining the seismic coupling effect and then the porosity and the water saturation.And based on the experimental data,the feasibility of the empirical formula proposed by M.D.Denny,et al was analyzed in estimating the seismic coupling effect of underground explosions with the explosion equivalent of 100 kg TNT.