隔振沟对爆炸塔周边地表振动的影响

Effects of vibration-isolating trench on ground vibration surrounding blast containment chamber

对内径2m、壁厚0.4m的椭球封头爆炸塔进行有、无隔振沟条件下的对比爆炸实验,并监测塔体周边6个测点的地表竖向及水平方向的振动速度。研究结果表明:地表质点的振动持续时间小于0.2s,竖向振动频谱在20～500Hz范围内,水平方向振动频谱则在200～800Hz范围内;隔振沟使水平方向振动幅度衰减至原来的1/10,对竖向振动幅度衰减至原来的1/4～1/3,对地表振动频率无明显影响;爆炸塔隔振沟的深度为1m时,对爆炸地震波无任何衰减作用,仅当深度达到1.5～2.0倍瑞利波波长时(5.6～7.5m)才会产生明显的隔振效果。

A series of blast experiments with and without vibration-isolating trenches were implemented in the blast containment chamber with an elliptic cone which having an inside diameter of 2 m and a wall thickness of 0.4 m.And the vertical and horizontal ground vibration velocities at 6 different points on the surrounding ground of the chamber were measured.The experimental results show that the ground vibration duration is less than 0.2 seconds,the frequency spectra of the vertical and horizontal vibrations are in the 20-500 Hz and 200-800 Hz ranges,respectively.The horizontal velocity amplitudes after attenuation by the trenches are one-tenth of those before attenuation,as well as one-fourth to one-third for the vertical velocity amplitudes.But the trenches have no obvious effect on the frequency spectra of the ground vibration waves.The vibration-isolating trenches with 1m depth have no attenuation effect on the blast seismic waves,but the attenuation effect will be remarkable when the depths of the trenches are 1.5-2.0 times as long as the wavelengths of the Rayleigh waves.