深部高应力下数值模拟本构模型差异性探讨

摘要

Wall rock mechanical response under deep high stress differs from that under shallow mining. In order to study the numerical simulation research method for the mechanical characteristics of wall rock under deep high stress environment, taking the deep mining project of a cooper mine with stable wall rocks as a case,FLAC3D is adopted to build the calculating model respectively by Moore-coulomb model and the strain softening model to analyze the stress,displacement and plastic zone of roof wall rock after deep mining. The results show that under the condition of a wide range of excavation in deep high stress stope,some individual stress index in Moore-coulomb model is less than that in the strain softening model,but the wall rock de-formation and the plastic zone indexes in the strain softening model is even larger. The overall results from the Moore-coulomb model approach to be safe. So,the strain softening model can better reflect the strain softening characteristics of wall rock under the high stress environment in the nonlinear phase,and the calculation results are more close to the practice. The results also show that for deep stope mining simulation under high stress,it is difficult to obtain objective conclusion depending on only a single stress or displacement index. A variety of calculation models and a variety of analysis indicators are necessary to make comprehensive analysis and contrast in order to improve the objectivity of the calculation results.%深部高应力环境下,围岩力学响应特性要异于浅部开采.为研究更符合深部高应力环境下的围岩力学特性的数值模拟方法,结合围岩条件较稳固的某铜矿深部开采工程实例,采用FLAC3D软件,分别以摩尔-库伦模型与应变软化模型建立计算模型,对深部采场开采后顶板围岩的应力、位移、塑性区等情况进行分析对比.研究结果表明:在深部高应力采场大范围开挖的情况下,摩尔-库伦模型个别应力指标要小于应变软化模型,但应变软化模型顶板变形及塑性区更大,摩尔-库伦模型的总体计算结果偏向安全.即应变软化模型能够更好地反映高应力环境下,围岩在非线性阶段的应变软化特性,计算结果更接近于工程实际.计算结果也表明了对于深部高应力下采场的开采模拟,仅靠单一应力或位移指标,难以得出客观结论,可通过多种计算模型及多种分析指标来进行综合分析对比,以提高计算结果的客观性.