软岩巷道岩体力学参数反演方法及工程应用

Inversion method of mechanical parameters of rock mass insoft rock roadway and its engineering applicatio

  • 摘要: 为提高地下岩石工程参数的计算效率,采用正交试验方法进行岩体力学参数反演计算,并将弹性模量、黏聚力、内摩擦角和岩体抗拉强度选作试验参数,建立了巷道岩体等效力学参数反演优化模型。以曲江煤矿-850 m水平软岩运输大巷为工程背景,在现场监测数据的基础上,用建立好的巷道围岩计算模型进行数值计算与回归分析,准确地建立了巷道围岩位移与岩体力学参数的函数关系。等效岩体力学参数识别结果表明,东大巷1 500 m处,原支护情况下的安全系数Fs为0.97,巷道围岩处于不稳定状态,必须进行重新加强支护。最后,针对曲江煤矿-850 m水平东运输返修巷道进行了稳定性评价,试验段巷道监测数据表明,东大巷返修后的围岩体力学强度大大提高,安全系数Fs为1.58,巷道围岩处于稳定状态,说明提出的“锚杆、金属网、喷浆、锚索、注浆和底板锚索”修复方案能很好地抑制巷道变形,从而也验证了软岩巷道岩体力学参数反演方法的有效性。

     

    Abstract: In order to improve calculation efficiency of underground rock engineering parameters, displacement inversion calculation of rock mass parameters was carried out by orthogonal experiment. An optimal model of equivalent mechanical parameters of roadway rock mass was established taking elastic modulus, cohesion force, internal friction angle and tensile strength of rock mass as test parameters. Based on field monitoring data of -850 m horizontal soft rock haulage roadway in Qujiang Coal Mine, function relationship between step displacement and rock mass parameters was established accurately using the established numerical model for numerical analysis and regression analysis. The equivalent rock mass parameter identification results show that at the location of 1 500 m of the east roadway, the safety factor Fs is 0.97 under the original supporting condition, which is in unstable state, so it is necessary to re—strengthen the supporting. Finally, stability evaluation of -850 m horizontal east haulage reworking roadway in Qujiang Coal Mine was carried out. The monitoring data of the roadway in the test section shows that the mechanical strength of the surrounding rock mass after the repair of east roadway is greatly improved, and the safety factor Fs is 1.58, which shows the roadway is in a stable state. It is indicated that the repair scheme of "screw, metal mesh, shotcrete, anchor cable, grouting and floor anchor cable" can well inhibit deformation of the roadway, which also verifies effectiveness of the rock mass mechanical parameter inversion method in soft rock roadway.

     

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