基于抛物线型强度准则的巷道煤柱塑性区宽度确定

Width determination of plastic zone for roadway coal pillar based on parabolic intensity criterion

巷道煤柱塑性区宽度的合理留设是采掘工作的重点,亦为采煤设计提供重要参数。为确定该值,以极限平衡理论为基础,选用抛物线型作为煤岩体破坏强度准则,建立了塑性区极限平衡力学模型,同时以煤岩体达到塑性流变强度作为应力求解的条件,推导得出了煤岩抗拉压强度、煤柱高度、侧向压力系数等条件下的塑性区宽度解析解,讨论分析了塑性区宽度影响因素。结果表明:煤岩体强度、拉压比、侧向压力系数对塑性区极限宽高比影响显著。现场塑性区超声探测结果与理论计算值相吻合,这说明煤柱塑性区模型构建科学合理,为类似煤柱宽度合理留设提供了参考依据。

Width determination for plastic zone of roadway coal pillar is one of the key points in mining and tunneling,which also offers key parameters for coal mining design. In order to determine the plastic zone width of roadway coal pillar,a limit equilibrium mechanical model of plastic zone was established,selecting parabola as the strength criterion of coal and rock damage. Meanwhile,through the stress solution,on condition that to achieve plastic flow intensity of coal and rock,the calculation formula of plastic zone width was obtained considering the influence factors such as the tensile strength of coal and rock,pillar height,lateral pressure coefficient,etc. The influence factors of plastic zone width were discussed,the results showed that the influence of coal and rock mass strength parameters,tension- compression ratio,and lateral pressure coefficient s obvious on plastic zone limit width- height ratio. Contrast of the ultrasonic detection results and theoretical calculation in the plastic zone showed the error was small,so the pillar plastic zone model establishment was reasonable,and the parameters were suitable.