Evaluation for the Loosening Zone of Cave Surrounding Rock Using Sonic Wave Detection
BAO Naili
ZHAO Jixiang
WANG Qingyu
TANG Kexuan
Abstract：There is currently no clear method or standard for evaluating the thickness and degree of relaxation of the loosening zone in surrounding rock.This study analyzed the theoretical basis for determining the size of the loosening zone and calculated the boundary conditions corresponding to the rock mass wave velocity attenuation rate and the integrity of the rock mass.This achieved a unified approach to evaluating the integrity of the rock mass using the wave velocity attenuation rate and the rock mass integrity index.Additionally,a classification of the relaxation levels of the loosening zone was provided based on the range of attenuation rates.Taking the Tingzikou irrigation area water conveyance tunnel as an example,the single-hole sonic method was used to conduct field tests on the tunnel cross-section's surrounding rock.The average value method of single-hole sonic data was applied to determine the thickness of the loosening zone,and the degree of relaxation was evaluated using the rock mass wave velocity attenuation rate.This evaluation method provides a basis for optimizing support parameters and offers valuable reference for similar projects.
Keywords：loosening zonesingle-hole sonic methodattenuation rateintegrity indexsurrounding rock
Publication Date：2025-09-20
Online Publishing Date：2025-10-10(First online date of this platform, not the publication date of the document)
Pages：4( 97-100 )