折射波法应用于工程勘查的若干问题讨论
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摘要
地震折射波法以其能够确定折射界面的速度而广泛用于工程地质勘察,但因其解释精度受地表条件、地下界面复杂程度及采集参数有关。本文结合实际工作经验,从折射波观测系统、道间距及炮间距的选取原则、互换时间的确定和地表速度的求取、基岩面的起伏改正及穿透波的处理等进行讨论,分析结果表明,采用基于远炮求取互换时间的追逐相遇时距曲线来解释,可提高资料解释的可靠性;同时,解释成果必须基于基岩面的起伏进行改正,才能准确判定地层岩性和断层的位置。
The shallow refraction seismic is widely used in engineering geological exploration,for it may ascertain the velocity of the refraction surface.However,the accuracy of interpretation of refraction data is affected by the earth surface conditions,the complex conformations of interface and acquisition parameters.In this paper,combining with practical experiences,we discussed how to increase accuracy from the refraction observation system,selection principles of channel interval and shot interval,determination of reciprocal time and the calculation of surface velocity,the correction of slope bedrock surface and existing wave of penetrating bedrock.The results show that reciprocal time calculation based on far shots can improve the reliability of data interpretation.Meanwhile,the velocity calculated must be corrected by slope bedrock surface in order to accurately determine the lithology and fault location.
The shallow refraction seismic is widely used in engineering geological exploration,for it may ascertain the velocity of the refraction surface.However,the accuracy of interpretation of refraction data is affected by the earth surface conditions,the complex conformations of interface and acquisition parameters.In this paper,combining with practical experiences,we discussed how to increase accuracy from the refraction observation system,selection principles of channel interval and shot interval,determination of reciprocal time and the calculation of surface velocity,the correction of slope bedrock surface and existing wave of penetrating bedrock.The results show that reciprocal time calculation based on far shots can improve the reliability of data interpretation.Meanwhile,the velocity calculated must be corrected by slope bedrock surface in order to accurately determine the lithology and fault location.
引文
[1]熊章强,方根显.浅层折射波法在隧道工程地质调查中的应用[J].水文地质工程地质,2001,6(1):63～66.
[2]韩永琦,李来喜,昌彦君.地震折射层析法在隧洞围岩松动圈测试中的应用[J].工程地球物理学报,2004,1(5):412～417.
[3]钱玉贵,顾汉明.倾斜断层面上的折射波时距曲线特征及解释方法对比[J].工程地球物理学报,2005,2(6):408～412.
[4]韩永琦.地震折射层析法在青藏铁路路基开裂调查中的应用[J].工程地球物理学报,2009,6(1):1～5.
[5]熊昌盛,顾汉明,陈毅敏,等.提高浅层地震折射波法在隧道勘察效果的举措[J].工程地球物理学报,2004,1(5):452～456.
[2]韩永琦,李来喜,昌彦君.地震折射层析法在隧洞围岩松动圈测试中的应用[J].工程地球物理学报,2004,1(5):412～417.
[3]钱玉贵,顾汉明.倾斜断层面上的折射波时距曲线特征及解释方法对比[J].工程地球物理学报,2005,2(6):408～412.
[4]韩永琦.地震折射层析法在青藏铁路路基开裂调查中的应用[J].工程地球物理学报,2009,6(1):1～5.
[5]熊昌盛,顾汉明,陈毅敏,等.提高浅层地震折射波法在隧道勘察效果的举措[J].工程地球物理学报,2004,1(5):452～456.
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