充分采动覆岩“类双曲线”破坏移动机理及模拟分析

Mechanical and numerical analysis of “analogous hyperbola” movement of overlying strata after full mining extraction

针对传统地表沉陷预计理论对岩层移动力学机理解释不足,以及岩层内部破断移动规律不明晰的问题,本文结合Hoek-Brown强度准则和最大剪应力准则分别对基岩和表土层的破断移动特征进行力学分析,揭示了覆岩"类双曲线"破坏移动机理,采用分段函数对其表征。分析了覆岩移动"类双曲线"随表土层厚度、基岩摩擦系数等敏感性参数的变化特征。得出地表沉陷范围理论计算公式,并通过实测数据进行验证。运用离散元PFC模拟获得了覆岩位移场呈"类双曲线"形态,一定程度上验证了"类双曲线"模型的合理性。

The traditional subsidence prediction methods can not reveal the mechanism of rock strata movement and the movement laws of overlying strata are not clear. In this paper, the Hoek-Brown strength criterion and the maximum shear stress criterion was utilized to analyze the fracture mechanism of bedrock and reveal analogous hyperbola movement of overlying strata, which was expressed by piecewise functions. It was also analyzed that the variation laws between analogous hyperbola and sen- sitive parameters of overlying strata, including the thickness of top soil, the friction factor of bed rock, et al. Besides, the theoretical subsidence prediction formula was derived, which was verified by field monitoring data. The Particle Flow Code （PFC） was applied to simulate the movement of overlying strata. The analogous hyperbolic movement boundary of overlying strata was obviously founded, which is approximately consistent with the theoretical model.