Spalling failure of deep hard rock caverns  

作　　者：Guoshao Su Yanxiang Chen Quan Jiang Chongjin Li Wei Cai 

机构地区：[1]Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education,Guangxi University,Nanning,530004,China [2]Guangxi Provincial Engineering Research Center of Water Security Intelligent Control for Karst Region,Guangxi University,Nanning,530004,China [3]Guangxi Key Laboratory of Disaster Prevention and Engineering Safety,Guangxi University,Nanning,530004,China [4]State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,430071,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2023年第8期2083-2104,共22页岩石力学与岩土工程学报（英文版）

基　　金：The authors greatly gratefully acknowledge the financial support from the National Natural Science Foundation of China(Grant Nos.52169021 and 51869003);the Interdisciplinary Scientific Research Foundation of Guangxi University,China(Grant No.2022JCA004).

摘　　要：Spalling is a typical brittle failure phenomenon of hard rock in deep caverns under high geostress.In this study,key issues are systematically studied concerning the spalling failure of deep hard rock caverns.First,the prismatic rock specimens with small thicknesses(i.e.width×thickness×height:20 mm×50 mm×100 mm)are employed in our tests which not only successfully simulate the spalling failure of hard rock in the laboratory but also obtain a reasonable spalling strength similar to that of the rock mass.Then,a series of spalling experiments is carried out to investigate the mechanism of spalling failure of deep hard rock caverns.Our results show that the intermediate principal stress,weak dynamic disturbances,and rock microstructure have significant effects on the spalling failure.The spalling strength is approximately(0.3–0.8)UCS,where UCS is the uniaxial compressive strength of the cylindrical rock sample with a diameter of around 50 mm.The spalling strength increases first and then decreases with increasing intermediate principal stress.Moreover,an empirical spalling strength criterion and a numerical method of spalling failure are proposed.This numerical method can not only simulate the spalling failure zone formed by tangential compressive stress concentration after excavation under different intermediate principal stresses,but also successfully simulate the failure transition from tensile mode to shear mode associated with confinement change in deep hard rock caverns.Furthermore,an acoustic emission-based early warning method using neural network is proposed to predict the spalling failure.Finally,a technical roadmap for preventing and controlling spalling failure of deep hard rock caverns is presented after summarizing the successful experiences in a typical engineering case.

关 键 词：Spalling failure Hard rock CAVERN TUNNEL Rock test Numerical simulation 

分 类 号：TU45[建筑科学—岩土工程]