Open Access

ARTICLE

Modeling and Simulation of Dynamic Unloading of Prestressed Rockmass

by Liang Wu¹, Xiaorui Xiang¹, Yang Chen¹, Karrech Ali², Junru Zhou¹, Ming Chen³

1 College of Science, Wuhan University of Science and Technology, Wuhan, 430065, China.
2 School of Civil and Resource Engineering, the University of Western Australia, 35 Stirling Hwy, Crawley WA 6009, Australia.
3 Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering Ministry of Education, Wuhan University, Wuhan, 430072, China.

* Corresponding Authors: Karrech Ali. Email: ;
   Junru Zhou. Email: .

Computer Modeling in Engineering & Sciences 2019, 120(2), 421-443. https://doi.org/10.32604/cmes.2019.05218

Abstract

During the excavation of deep rock, a sudden change in boundary conditions will cause the in-situ stress on the excavation surface to release instantaneously. This disturbance propagates in the form of an unloading stress wave, which will enlarge the damage field of surrounding rock. In this paper, the dynamic unloading problem of the in-situ stress in deep rock excavation is studied using theoretical, numerical, and experimental methods. First, the dynamic unloading process of rock is analyzed through adopting the wave equation, and the equivalent viscous damping coefficient of the material is taken into consideration. Calculations show that there is significant tensile strain in the rock bar when the strain rate is above 10^-1 s^-1. With an increase in the length or damping coefficient, the wave state will change from an underdamped to an overdamped state. Second, implicit and explicit solvers of the finite element method are employed to simulate rock unloading processes, which can be used to verify the theoretical results from one-dimensional to three-dimensional stress states. Finally, the dynamic unloading experiment of a one-dimensional bar is used to further verify the validity and accuracy of the theoretical analysis.

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Citations