掌子面前方边墙溶洞的地质雷达探测方法研究

Study on Detection Method of GPR for Karst Cave on Tunnel Side Wall Ahead of Excavation Face

由于电磁衰减和足印的限制,导致掌子面前方5 m范围内的边墙溶洞往往难以被地质雷达所识别,从而影响地质预报的精度和施工安全。针对目前对其探测方法的研究较为少见的特点,为了能实现有效地对其进行探测,以广西六寨至宜州高速公路40座公路隧道为依托,进行了大量的现场探测,总结出探测该范围内边墙溶洞的方法,现场开挖验证表明:该方法能较为准确地探测出边墙溶洞,从而降低施工中的风险。研究成果为提高超前地质预报的探测精度提供了新的方法,对地质雷达现场探测具有一定的参考意义。

Due to the limitation of electromagnetic wave attenuation and foot-print, the karst cave on tunnel wall ahead of the excavation face （ 〈 5 m） is generally difficult to be detected by ground penetrating radar （GPR） and the forecast precision and construction safety is affected accordingly. As the study on the detection method is less at the present, and in order to detect it effectively, on the basis of 40 highway tunnels of Liuzhai--Yizhou expressway in Guangxi Zhuang Autonomous Region, many spot detection experiments were made to find the detection method for karst cave on tunnel wall within this range. The spot excavation indicates that this method can accurately detect the cave and reduce the construction risk. This research provided a new way to increase the geological forecast precision and offered certain reference for GPR spot detection.