Experimental Study on Detection of the Loosened Zone of Surrounding Rock in Tunnel Crown
WEI Jizu
ZHONG Han
LI Zhuangzhuang
YU Peng
Abstract：In view of the tight construction schedule and heavy tasks of the tunnel project of the Yunxiao Pumped Storage Power Station in Fujian,as well as the technical characteristics of the loosened zone detection in the tunnel crown—namely the use of dry holes,a"one-transmit-two-receive"transducer,and the requirement of water injection coupling—which result in relatively low detection efficiency,this paper carries out an experimental study on shortening the detection time of the loosened zone of surrounding rock in the tunnel crown.By modifying the water injection device and installing pressure gauges,the reasonable water injection pressure under different testing heights and the pressure for water release during probe movement are determined,respectively.Comparative tests are also conducted by adopting measures such as shortening the length of the water injection pipeline.The results show that this technical approach can effectively improve the efficiency of dry-hole acoustic testing in this project.Engineering practice further verifies that the experimental results of water injection pressure parameters at different heights are scientifically sound and can provide effective guidance for subsequent dry-hole acoustic testing operations.
Keywords：tunnel engineeringcrownloosened zone detection
Publication Date：2026-04-20
Online Publishing Date：2026-09-16(First online date of this platform, not the publication date of the document)
Pages：7( 120-125,144 )