基于多参数表征的遗留煤柱底板巷道围岩力学响应研究

Mechanical Response of Floor Roadway Under Remnant Coal Pillar with Multi-parameter Characterization

  • 摘要: 针对遗留煤柱作用下底板巷道围岩稳定性问题,基于多参数表征方法,系统研究了遗留煤柱对底板岩层及巷道围岩的力学响应特征。首先,结合Mohr-Coulomb屈服准则,对遗留煤柱承载结构进行修正,构建了考虑浅部塑性承载平衡区的应力分布模型;在此基础上,建立了多邻近子煤柱协同作用下底板应力叠加模型,并引入应力集中系数k、应力梯度G及侧压系数λ等多参数,实现底板应力场的定量表征。其次,通过理论分析与FLAC3D数值模拟相结合的方法,揭示了不同深度底板应力演化规律及多参数空间分异特征。进一步,构建巷道数值模型,分析k、G、λ单参数及耦合作用对围岩应力-位移响应的影响机制。最后,结合现场监测数据,对巷道围岩变形规律进行验证。研究表明:遗留煤柱作用下底板应力呈显著非均匀分布,浅部扰动强烈且随深度快速衰减;多参数耦合作用显著放大围岩变形响应,其中位移对参数变化更为敏感;巷道处于k、G低值且λ接近1.0的区域时,为围岩稳定性最优区段。研究成果可为遗留煤柱影响下巷道布置与围岩控制提供理论依据与技术支撑。

     

    Abstract: Aiming at the stability problem of surrounding rock in floor roadways affected by remnant coal pillar, mechanical response characteristics of floor strata and roadway surrounding rock under the action of remnant coal pillar was systematically investigated based on a multi-parameter characterization method. First, the bearing structure of remnant coal pillar was modified in combination with the Mohr-Coulomb yield criterion, and a stress distribution model considering the shallow plastic bearing equilibrium zone was established. On this basis, a superposition model of floor stress under the synergistic effect of multiple adjacent sub-coal pillars was constructed. Multiple parameters including stress concentration coefficient k, stress gradient G and lateral pressure coefficient λ were introduced to realize the quantitative characterization of the floor stress field. Secondly, by combining theoretical analysis with FLAC3D numerical simulation, the evolution law of floor stress at different burial depths and the spatial differentiation characteristics of multi-parameters were revealed. Furthermore, a numerical model of the roadway was established to analyze the influence mechanism of single parameters and coupling effects of k, G and λ on the stress and displacement response of surrounding rock. Finally, the deformation law of roadway surrounding rock was verified with field monitoring data. The research indicates that the floor stress presents an obvious non-uniform distribution under the influence of remnant coal pillar. The shallow part suffers intense stress disturbance which decays rapidly with increasing depth. The coupling effect of multi-parameters significantly amplifies the deformation response of surrounding rock and displacement is more sensitive to parameter variations. Roadways located in areas with low values of k and G as well as λ close to 1.0 possess the optimal surrounding rock stability. The research findings can provide theoretical basis and technical support for roadway layout and surrounding rock control under the influence of remnant coal pillar.

     

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