ABSTRACT As coal mining in China advances to greater depths, deep and steeply inclined layered roadways are increasingly subjected to high‐stress environments, leading to pronounced nonuniform deformation and instability. These failure behaviors pose significant challenges to roadwatability control and engineering safety. To address this problem, this study investigates the −1000 meters (m) steeply inclined roadway of the Qishan Mine in Xuzhou and aims to clarify the deformation evolution mechanism under deep high‐stress conditions and to evaluate the applicability of second‐generation negative Poisson's ratio (2G‐NPR) bolts for large‐deformation control. Building on previously conducted physical model tests, a 3DEC numerical model was established to reproduce the full deformation–failure process of the surrounding rock. A key contribution of this work is the calibration and numerical implementation of the mechanical characteristics of 2G‐NPR bolts, including their high ductility and constant‐resistance plateau behavior, enabling realistic representation of NPR reinforcement in discrete‐element simulations. The calibrated model was then applied to assess the reinforcing effects of NPR bolts in deep layered rock masses. The results reveal a distinct asymmetric deformation pattern, with the roadway roof and right side identified as critical instability zones. Deformation and failure are dominated by slip and separation along the layered structural planes under high stress. Owing to their constant resistance and large elongation capacity, 2G‐NPR bolts substantially suppress large deformations, reducing roadway sidewall displacement by more than 20% compared with traditional bolt support. This study provides new insights into the deformation mechanisms of deep, steeply inclined layered roadways and demonstrates the engineering advantages of 2G‐NPR bolts, offering an effective reinforcement strategy for controlling large deformations in deep mining environments.
Gong et al. (2026) studied this question.