Transfer and dissipation of strain energy in surrounding rock of deep roadway considering strain softening and dilatancy

Abstract

In this study, the transfer and dissipation of strain energy in the surrounding rock of a deep roadway were analyzed, considering the objective strain softening and dilatancy behaviors. The strain energy increment was decomposed, and its variation was analyzed based on the incremental plastic flow theory; then, a numerical simulation was conducted for verification and further analysis. The results were verified by the field monitoring data of a coal mine gateway. The results show that in the elastic stage, the volumetric elastic strain energy density Uev decreases, while the shear elastic strain energy density Ues increases. In the plastic stage, both Uev and Ues decrease. The volumetric plastic strain energy density Upv is negative, and its absolute value increases, leading to strain energy accumulation. In contrast, the shear plastic strain energy density Ups is positive and increases, leading to strain energy dissipation. Considering strain softening, the elastic strain energy decreases, the plastic strain energy increases, and the region of strain energy dissipation expands. Considering dilatancy, the plastic strain energy varies more significantly, and the effect of strain softening is amplified. The strain energy is transferred from the deep part to the shallow part of the elastic zone and then to the plastic zone. The preexisting and input strain energies in the plastic zone are transformed into considerable amounts of plastic strain energy and then dissipated. Thereafter, a significant plastic strain appears, leading to the large deformation of the surrounding rock.

Numerical simulation of roadway deformation and failure under different degrees of dynamic disturbance

“…According to the research of Kuhlemeyer and Lysmer 28 , a reasonable grid size was calculated, and a 3D model of 40 m × 20 m × 40 m was established. The deformation and failure of the roadway surrounding rock belong to the plane strain problem 29 . The A–B line was set in the y direction of the 3D model, and the 2D model was formed by slicing along the A–B line for research.…”

Sequential stress control and delayed support in deep shaft construction

“…Under high-stress condition, shaft excavation often causes stress redistribution and elastic strain energy accumulation in surrounding rock. If the energy accumulated in the rock mass exceeds its storage capacity, instability or rock bursts may occur (Yi et al 2020;Jiang et al 2010). The energy accumulated in the rock mass should be released before the permanent support is installed for stress control.…”

Nonlinear Dissipative System Mathematical Equations in the Multi-regression Model of Information-based Teaching

“…The thesis establishes a dual ecological model of information-based teaching ecology in the form of selforganisation. This article analyses the core elements of informatisation teaching ecology from the target level, element level, variable level and state-level [8]. The information teaching ecology's positive entropy and negative entropy index system is constructed by combining divergence and convergence.…”