Key Takeaways & Executive Findings
- •• Creep experiments on pre-damaged rock reveal that initial damage significantly influences time-dependent deformation and accelerates creep failure. • A novel elastic-viscoplastic creep damage (EVPCD) model integrates both time-dependent and instantaneous damage, accurately capturing nonlinear creep behavior under stress disturbances. • The EVPCD model was implemented in FLAC3D and validated against experimental data, demonstrating superior predictive capability compared to CVISC and Nishihara models. • Case study of Xutuan Coal Mine roadway shows that the EVPCD-based numerical simulation effectively predicts long-term stability and damage evolution, matching on-site monitoring.
Abstract
In deep coal mining, surrounding rock is subjected to both high in-situ stress and intense mining disturbances, leading to significant time-dependent behavior. Accurately capturing this behavior is essential for predicting long-term roadway stability, necessitating the development of a reliable constitutive creep model and numerical simulation approach. In this study, creep experiments were conducted on pre-damaged rock with varying initial damage levels to investigate the time-dependent mechanical properties. Based on the experimental results, an accelerated-creep criterion was proposed, and an elastic-viscoplastic creep damage model (EVPCD) was established that simultaneously considers the effects of time-dependent damage and instantaneous damage caused by stress disturbances on rock creep behavior. Subsequently, the effectiveness of the proposed creep model was verified using experimental data, and the secondary development of the EVPCD model was completed based on the FLAC3D platform. Following this, a long-term stability analysis method of deep surrounding rock that accounts for excavation-and mining-induced disturbances was proposed. Using the main roadway of Xutuan Coal Mine as a case study, numerical simulations were carried out to investigate the time-dependent deformation and failure characteristics of the surrounding rock following excavation and mining disturbance. Combined with on-site monitoring of the surrounding rock damage areas, the results indicate that the EVPCD outperforms the CVISC and Nishihara models in predicting the time-dependent behavior of deep surrounding rock.
1. Introduction
Coal occupies a dominant position in global energy consumption. With increasing mining activities, shallow coal resources are gradually being exhausted, prompting a transition of underground mining to greater depths [1–4]. In deep mining, two major features distinguish it from shallow operations: high in-situ stress, which induces strong rheological effects of rock masses, and intense disturbances caused by large-scale excavation and mining activities. The coupled effects of high in-situ stress and intense disturbances lead to significant nonlinear creep behavior of roadway surrounding rock, resulting in frequent repairs and a high risk of instability throughout the service life of deep roadway [5].
Creep models are the theoretical foundation for characterizing the time-dependent deformation behavior of rock. Developing theoretical models that are adaptable to engineering application scenarios is crucial for roadway support design and long-term stability evaluation. Against this background, developing a creep model that incorporates excavation- and mining-induced disturbance responses and nonlinear damage accumulation effects is essential. It can not only provide theoretical support for revealing the delayed deformation and damage mechanism of deep surrounding rock, but also provide key technical support for the support parameter design and prediction of service performance of roadway. This is of great significance for ensuring the safe, efficient extraction of deep coal resources.
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Qingzhe Cui, Rongbin Hou, Zhenhua Li, Feng Du, Xu Chen, Boyang Zhang, Lielie Li (2025). Time-dependent behavior of deep roadway surrounding rock considering damage induced by excavation and mining disturbances: Experiments, modeling, and simulation. SinoTechIntel Verified Research. https://doi.org/10.1016/j.ijmst.2025.12.006
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Frequently Asked Questions
What is the EVPCD creep model?
The EVPCD (Elastic-Viscoplastic Creep Damage) model is a constitutive model developed in this study to describe the time-dependent behavior of deep roadway surrounding rock. It simultaneously considers time-dependent damage and instantaneous damage caused by stress disturbances, and has been implemented in FLAC3D for numerical simulation.
How was the EVPCD model validated?
The model was validated using experimental data from creep tests on pre-damaged rock with varying initial damage levels. The predictions of the EVPCD model were compared with experimental results and also with the CVISC and Nishihara models, showing superior accuracy.
What are the key findings of the study?
The study found that initial damage significantly affects rock creep behavior, and the EVPCD model accurately captures nonlinear creep and damage evolution. Numerical simulations of a deep roadway in Xutuan Coal Mine demonstrated the model's effectiveness in predicting long-term stability and matched on-site monitoring data.
Why is time-dependent behavior important in deep mining?
In deep mining, high in-situ stress and intense disturbances cause significant time-dependent deformation of surrounding rock, which can lead to roadway instability over time. Understanding and predicting this behavior is crucial for support design and long-term safety.
What is the significance of the FLAC3D implementation?
The implementation of the EVPCD model in FLAC3D allows for practical engineering applications, enabling engineers to simulate and analyze the long-term stability of deep roadways under excavation and mining disturbances, thus aiding in support design and risk assessment.
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