可控震源地震勘探在大坝检测中的应用试验

某电厂大坝为黏土斜墙堆石坝,其黏土防渗层的状态(密实性、一致性等)是极其重要的问题.瞬态瑞利面波探测技术可用来检测堤坝松散层和土坝渗漏水异常区.可控震源激发波形精确可控,可激发高频地震波,以提高地震勘探分辨率,进行浅层薄层地震勘探.本文应用研制的可控震源地震勘探系统对大坝进行了实地测试,对测试数据进行了频散分析,衰减系数与能量分析,波速计算分析.分析结果表明,大坝局部区域存在低速点;研制的可控震源系统可有效地进行浅层地震信号勘探.

The applied test of vibroseis seismic prospecting system in dam

There is a rockfill dam with clay facing in Guangdong, and its earth blanket′s state such as compactness and uniformity is important. Transient Rayleigh wave can be used to inspect the loose layer and leakage anomaly region of the earth dam. The vibroseis source can arouse precise and controllable high frequency seismic wave so as to improve seismic solution for shallow seismic prospecting. Field test is carried out with vibroseis seismic prospecting system developed by our lab in Nanshui dam. Frequency dispersion,attenuation coefficient,energy and wave speed are analyzed as the testing data. It is indicated that the speed of some spots is low,and that the vibroseis system can do shallow seismic prospecting effectively.