深部直墙半圆拱巷道围岩时效损伤劣化特征与动态补强技术

Characteristics of aging damage and deterioration of surrounding rock of deep straight wall and semi-circular arch roadway and dynamic reinforcement technology

随着煤矿开采向深部逐渐延伸,巷道的大变形和长时间持续流变特性已成为支护中极具挑战的课题之一。为了探究深部巷道围岩损伤劣化的时效特征及动态补强技术,基于实验室试验,并结合理论分析、数值模拟及现场工业试验进行了研究。研究结果表明:(1)基于Laplace逆变换推导出圆形轴对称巷道的变形规律解析解,结合理论分析、非圆形巷道等效变换和现场试验确定塑性区半径为1.5~2.1m,进一步得到直墙半圆拱巷道时效变形解析解;(2)基于弹性与弹塑性巷道模型,采用能量耗散表征了围岩损伤劣化的时效特征与塑性区演化趋势,并提出了一次支护的时机;(3)阐明了围岩在一次支护后的时效性损伤劣化的演化趋势,基于垂直应力峰值比率,提出了二次支护方案与时机,进一步分析围岩剪应力与垂直应力,确定了二次支护锚杆的长度为3.0 m,支护时机为40~70 d。研究结果可为深部煤矿巷道的设计与维护提供理论依据和实践指导。

As coal mining progressively reaches the deeper strata,the substantial deformation and rheological properties of mine roadways have become one of the most challenging issues to supporting systems.In order to investigate the aging characteristics of damage and dete-rioration of the rock surrounding deep mine roadways and develop dynamic reinforcement technologies,a comprehensive study ncorporating laboratory experiments,theoretical analysis,numerical simulation and field testing was conducted.The findings include:(1)An analytical solution for the deformation pattern of circular,axisymmetric roadways was derived using the Laplace inverse transformation.Via a combination of theoretical analysis,equivalent transformation for non-circular roadways and field tests,the radius of the plastic zone was determined to be between 1.5 and 2.1 m,which in turn leads to an analytical solution for the aging deformation of the surrounding rock for straight-wall semicircular arch road-ways.(2)Based on models of elastic and elastoplastic roadways,energy dissipation was employed to characterize the aging properties of surrounding rock damage and deterioration and the evolution trend of the plastic zone,de-termining an optimal timing for the primary support.(3)The evolutionary trend of timeliness damage and deterio-ration of the surrounding rock after primary support was obtained.Based on the peak ratio of vertical stress,a secondary support scheme and its timing have been determined.The shear stress,vertical stress and the range of the plastic zone in the surrounding rock were further analyzed,determining the length of secondary support bolts to be 3.0 m and setting the support timing to be between 40 and 70 days.The research outcomes provide a theoret-ical foundation and practical guidance for the design and maintenance of roadways in deep coal mines.