Evaluation of underground blast-induced ground motions through nearsurface low-velocity geological layers  

作　　者：Yonggang Gou Xiuzhi Shi Zhi Yu Xiaofeng Huo Xianyang Qiu 

机构地区：[1]College of Civil and Transportation Engineering,Hohai University,Nanjing,210098,China [2]School of Resources and Safety Engineering,Central South University,Changsha,410083,China [3]Oulu Mining School,University of Oulu,Oulu,FI-90014,Finland

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2023年第3期600-617,共18页岩石力学与岩土工程学报（英文版）

基　　金：supported by Natural Science Foundation of Jiangsu Province,China(Grant No.BK20220975);the National Natural Science Foundation of China(Grant Nos.51874350 and 41807259).

摘　　要：Surface ground motion produced by underground blasts is significantly influenced by near-surface geological conditions.However,near-surface low-propagation velocity layers were always ignored in past analyses of ground motions due to their thin thickness.With the rising concern about surface ground motions produced by the ascendant scale and frequentness of underground excavation and mining,close attention is gradually paid to ground blast vibrations.Therefore,systemic experiments were conducted and took seven months in an underground mine to clarify the variation of motion from underground rock to surface ground.The attenuation of surface ground peak particle velocities(PPVs)is compared to that in underground rock,and horizontal amplitudes are compared to vertical amplitudes.Differences between bedrock and surface ground vibrations are analyzed to illustrate the site effect of near-surface lower-propagation velocity layers.One-dimensional site response analysis is employed to quantify the influence of different geological profiles on surface ground vibrations.The experimental data and site response analysis allowed the following conclusions:(1)geological site effects mainly produce decreasing dominant frequency(DF)of surface ground vibrations;(2)the site amplification effect of blast vibration needs to be characterized by peak particle displacement(PPD);(3)shear waves(S-waves)begin to dominate and surface Rayleigh waves(R-waves)develop as blast-induced ground vibrations travel upward through rock and lower-velocity layers to the surface.The comparison of response relative displacement to a critical value is best to assess the potential for cracking on surface structures.

关 键 词：Surface ground motions Underground blasts Geological site condition Amplitude attenuation Site response analysis 

分 类 号：TU435[建筑科学—岩土工程]