Research on the radial stress gradient effect of rockburst characteristics in tunnel under true triaxial condition with single-side unloading
SUN Feiyue1，GUO Jiaqi2，ZHANG Xiaobing1，HE Benguo3，TIAN Yongchao2
(1. School of Emergency Management，Henan Polytechnic University，Jiaozuo，Henan 454003，China；2. School of Civil Engineering，Henan Polytechnic University，Jiaozuo，Henan 454003，China；3. Key Laboratory of Ministry of
Education on Safe Mining of Deep Metal Mines，Northeastern University，Shenyang，Liaoning 110819，China)
Abstract：This research investigates the influence of radial stress gradient on the responses of multivariate catastrophic information of catastrophe process，fragment ejection，acoustic emission signals，and energy evolution related to rockburst in tunnel by using the self-designed rockburst test method and stress path. The three-dimensional polycrystalline discrete element numerical analyses are performed to explore the whole process of rockburst with multi-physics response，and to discuss the influence mechanism of radial stress gradient on rockburst. The findings reveal that rock samples exhibit varying degrees of rockburst under radial stress gradient of 20，50，and 80 kPa/mm. The formation mechanism of rockburst can be delineated into three progressive processes：tensile failure，shear failure，and tensile-shear composite failure. As the radial stress gradient increases，both the distribution range and number of RA-AF values of rock samples gradually increase，along with an increase in the distribution range and number of shear cracks. The rockburst fragments primarily consists of coarse，medium，and fine fragments，and macroscopic characteristics of these fragments reflect the degree of rock fragmentation. The fragmentation degree of rockburst fragments escalates with increasing radial stress gradient. The multivariate catastrophic information under varying radial stress gradients follows the hierarchy：total energy conversion rate＞elastic strain energy conversion rate＞dissipation energy conversion rate. A higher conversion rate of elastic strain energy and a lower conversion rate of dissipative energy correspond to a higher intensity level of rockburst. Furthermore，a competitive evolution mechanism between elastic strain energy and dissipation energy is evident throughout the energy evolution process of rockburst. The whole evolution process of rockburst is effectively reproduced through numerical analysis，which also captures its multi-zonal failure characteristics. Based on the observed characteristics，rockburst can be divided into two types：rupture-stripping and burst-ejection.
孙飞跃1，郭佳奇2，张小兵1，何本国3，田永超2. 真三轴单面卸荷条件下隧道岩爆特征的径向应力梯度效应研究[J]. 岩石力学与工程学报, 0, (): 916-916.
SUN Feiyue1，GUO Jiaqi2，ZHANG Xiaobing1，HE Benguo3，TIAN Yongchao2. Research on the radial stress gradient effect of rockburst characteristics in tunnel under true triaxial condition with single-side unloading. , 0, (): 916-916.
