Experimental investigation on rockburst characteristics of highly stressed D-shape tunnel subjected to impact load  

作　　者：Wuxing Wu Fengqiang Gong Zongxian Zhang 

机构地区：[1]School of Civil Engineering,Southeast University,Nanjing 211189,China [2]State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China [3]Oulu Mining School,University of Oulu,Oulu 90570,Finland

出　　处：《Underground Space》2024年第6期153-168,共16页地下空间（英文）

基　　金：supported by the National Natural Science Foundation of China(Grant No.42077244);the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences(Grant No.Z020005)。

摘　　要：Rockburst has always been a challenge for the safe construction of deep underground engineering.This study investigated the rockburst characteristics in highly-stressed D-shape tunnels under impact loads from rock blasting and other mining-related dynamics disturbances.The biaxial Hopkinson pressure bar was utilized to apply varying biaxial prestress and the same impact loads to cube specimens with D-shape hole.High-speed camera and digital image correlation(DIC)were used to capture the failure process and strain field of specimen.The test results demonstrate that the D-shape hole specimen experience rockburst under coupled static stress and impact load.Under this circumstance,the rockburst mechanism of the D-shaped hole specimens involves spalling in sidewall induced by impact load,indicating dynamic tensile failure.The high static prestress provides the initial stress field,while the impact load disrupts the stress equilibrium,result in the stress or strain concentration in the sidewall of the D-shape hole,inducing rockburst.Moreover,the rockburst process can be divided into(1)calm stage,(2)crack initiation,propagation,and coalesce stage,(3)spalling stage and(4)rock fragments ejection stage.Impact load triggers rockburst occurrence,while vertical stress further determines the rockburst characteristics.The influence range and magnitude of strain concentration zone and displacement deformation of the tunnel surrounding rock increases with increasing vertical stress,thus inducing more severe rockburst.

关 键 词：ROCKBURST SPALLING D-shape tunnel Impact load Biaxial prestresses Biaxial Hopkinson pressure bar 

分 类 号：U45[建筑科学—桥梁与隧道工程]