爆破近区地质结构特性对震动信号传播的影响研究EFFECT OF GEOLOGICAL STRUCTURE NEAR BLASTING AREA ON VIBRATING SIGNAL
尚晓江,丁桦
SHANG Xiao-jiang,DING Hua (Chinese Academy of Sciences,Beijing 100080,China)
摘要(Abstract)：
基于文献〔1〕提出的“爆破震动弹性区的信号是经过震源邻近区域等效地质结构滤波后传出的”观点,利用LS-DYNA程序对岩土介质中存在软弱夹层时的爆破震动过程进行了一系列数值计算,讨论了存在软弱地质结构面时自由表面震动信号频率特征的变化规律。比如:爆破点和软弱结构面的相对位置以及软弱结构面分布范围和刚度改变时,爆破地震信号频率特征的演化规律。这些规律说明了爆破邻近区域的结构特征对震动信号频率特征有着显著的影响,同时为各种工程地质结构(如地下裂隙、软弱夹层等)的识别提供了一种新的思路。现场爆破实验的结果也定性地验证了这些规律。
Based on the point of view that the vibration signal is filtered by the geological structure near the blasting vibration source proposed by literature((1)),we calculated a series of blasting vibrations generated by explosives placed at different locations with underground weak layers by means of LS-DYNA.From the numerical results,we studied the evolvement laws of frequency characteristics of the ground vibration signals,including the evolvement law of frequency characteristic of the blasting earthquake signals in the case when the location of the weak layers at blasting point and its distribution range and rigidness change.These laws indicate that geological structure near the blasting vibration source has dramatic effect on the vibration signal.The laws offer a new idea of identifying the varied engineering geological structures like underground cracks and weak interlayer,and have been confirmed by qualitative tests conducted in-situ.
关键词(KeyWords)：
爆破近区;地质结构;爆破震动;频率特征
Area near blasting source;Geo-structure;Blasting vibration;Frequency characteristic
基金项目(Foundation):
作者(Author):
尚晓江,丁桦
SHANG Xiao-jiang,DING Hua (Chinese Academy of Sciences,Beijing 100080,China)
参考文献(References)：
- (1)丁桦,郑哲敏,爆破震动等效载荷模型[J].中国科学(E辑,技术科学)2003,33(1):82-90.
- (2)Sharpe J A.The production of elastic waves by explosionpressure:Ⅰ-Theory and empirical field observations[J].Geophysics,1942,7:144-154;Ⅱ-Results of observationnear an exploding charge[J].Geophysics,1942,7:311-321.
- (3)Ding H,Zheng Z M.,Source Model for Blasting Vibrationand Tentative Application to Engineering Geophysics[A].Proceeding of The 9th International Gongress on Sound andVibration[C].Orlando,Florida,USA,8-11 July 2002.
- (4)Ding Hua,Long Lipin,Wu Yanfeng,Zheng Zhemin.De-tection of Cracks Using Blasting Vibration Part1:Numericalresults[A].International Conference on Slope Engineering[C].8-10 December 2003,Hong Kong.
- (5)Ding Hua,Shang Xiaojiang,Bai Jinze.Characteristics ofBlasting Vibration in Presence of Weak Interlayers[A].Proceedings of The 6th World Congress on ComputionalMechanics[C].Sept.5-10,2004,Beijing China.