Abstract
The Johnson–Holmquist-II(JH-2) model is introduced as the constitutive model for rock materials in tunnel smooth blasting. However, complicated and/or high-cost experiments need to be carried out to obtain the parameters of the JH-2 constitutive model. This study chooses Barre granite as an example to propose a quick and convenient determination method for the parameters of the JH-2 model using a series of computational and extrapolated methods. The validity of the parameters is verified via comparing the results of 3D numerical simulations with laboratory blast-loading experiments. Subsequently, the verified parameter determination method, together with the JH-2 damage constitutive model, is applied in the numerical simulation of smooth blasting in Zigaojian tunnel, Hangzhou–Huangshan high-speed railway. The overbreak/underbreak induced by rock blasting and joints/discontinuities is well estimated through comparing the damage contours resulting from the numerical study with the tunnel profiles measured from the tunnel site. The peak particle velocities (PPVs) of the near field are extracted to estimate the damage scope and damage degree for the surrounding rock mass of the tunnel on the basis of PPV damage criteria. This method can be used in the excavation of rock tunnels subjected to large strains, high strain rates, and high pressures, thereby reducing safety risk and economic losses.
Highlights
The material constitutive relationship is the conclusion of some regulations summarized from experimental data, and plays an important role in numerical simulations
A determination method for the parameters of the JH-2 constitutive model is conducted in detail using Barre granite rock, in which a new extrapolated method for Hugoniot concerned parameters is proposed as well as the parameters determination methods of strength, Equation of State (EOS), and damage based on data from previous quasi-static and dynamic tests, which further improved the availability of the parameters
The JH-2 damage constitutive model is tentatively adopted to simulate the blasting process in the Zigaojian smooth blasting tunnel, which has a bedded rock mass structure, and 3D damage contours are successfully obtained from the numerical simulation
Summary
The material constitutive relationship is the conclusion of some regulations summarized from experimental data, and plays an important role in numerical simulations. Further studies were performed for the high strain rate properties and constitutive modeling of glass [13] and the response of B4 C [4] subjected to severe loading conditions with LHH based on the JH-2 model, and subsequently a variety of impact and penetration problems were illustrated using the methods of Lagrangian finite element and Eulerian finite difference computations. Holmquist and Johnson [18,19] redressed the response of B4 C to high-velocity impact adopting optimized experimental data, and the JHB constitutive model was used to simulate the material behavior under penetration, which illustrated the importance of the material parameters for the accuracy of simulations. Substantial static and dynamic experiments need to be conducted to completely describe one dynamic constitutive overcome the excessive deformation of explosive, the uncertainty of the artificial contact would model,affect which increase and economic costs. The verified method together with the JH-2 model is applied in the simulation of mechanical mechanical behaviors and evolution induced by blasting for tunnel excavation
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