Numerical Imaging Characterization of Three-Dimensional Velocity Fields for Creep Damage Evolution in Surrounding Rock of Deep Roadways

Abstract

To characterize the three-dimensional evolution of creep damage in deep roadway surrounding rock, this study establishes a COMSOL-based (Multiphysics 6.3) integrated analysis framework coupling creep damage, seismic velocity response and three-dimensional imaging. The framework adopts the Norton–Bailey creep constitutive model, Weibull-distributed material heterogeneity and an elastic damage model to simulate the 210-day creep damage evolution of surrounding rock. The three-dimensional P-wave velocity field is then reconstructed via a regional correlation approach using active-source P-wave first-arrival times. The results show that with progressive damage accumulation, low-velocity zones gradually expand from the intersection of the fault and roadway roof towards both the fault zone and the surrounding roadway. From 90 d to 210 d, these anomalies develop into a large-scale regional low-velocity belt with significantly enhanced spatial connectivity. The fault weak plane exerts a controlling effect on damage localization and the formation of low-velocity zones. Numerical results demonstrate a distinct spatiotemporal correspondence between P-wave low-velocity zones and damage concentration areas. Furthermore, the predicted damage distribution agrees well with the field failure morphology of surrounding rock, verifying that the proposed method can effectively track creep damage evolution in rock masses and provide an analytical basis for dynamic stability evaluation and early warning of deep roadway surrounding rock.