条带式Wongawilli开采煤柱系统突变失稳机理及工程稳定性研究

Engineering stability and instability mechanism of strip Wongawilli coal pillar system based on catastrophic theory

对于条带式Wongawilli新型减沉开采技术,煤柱失稳直接导致地表沉陷,影响建（构）筑物的安全,采用突变理论和损伤本构方程,建立了采硐间狭窄煤柱和条带煤柱失稳的尖点突变模型。计算分析了条带式Wongawilli开采煤柱系统工程稳定性及突变影响参数,得出了窄煤柱与条带煤柱的突跳压缩量计算公式,通过工程实例计算与数值模拟验证了结果的合理性。研究结果表明：采硐狭窄煤柱满足突变失稳的必要条件,其所受载荷、屈服刚度和峰值载荷压缩量决定着突变的发生;当采高在2~6 m变化时,采留宽度比需控制在0.16~0.75,才可保证系统不产生突变失稳。条带煤柱保持稳定则要求其核区率大于17%,在弹塑性区宽度比小于0.21的情况下,条带煤柱可能发生突变失稳。

For the new subsidence reduction mining technology of the strip type Wongawilli,the instability of coal pillar directly affects the surface subsidence and the safety of surface structures. The cusp catastrophe models of narrow coal pillar and strip coal pillar instability were established based on the catastrophe theory and damage constitutive equation. The engineering stability and catastrophic parameters of coal pillar with the strip Wongawilli were analyzed. The calculating equation of narrow coal pillar and strip coal pillar compression was obtained,and the rationality of results is verified by numerical simulation and engineering example. The results demonstrate that the catastrophic occurrence is decided by the load,the yield stiffness and the compression of peak load if the pillar between mining caves meets some necessary conditions for catastrophic instability. If the catastrophic instability of coal pillar system does not occur,the ratio of mining width to pillar width should be between 0. 16 and 0. 75 when the mining height changes between 2 m to6 m. The coal pillar remains stable if the rate of its elastic area is more than 17%. And if the ratio of elastic to plastic zone width is less than 0. 21,the catastrophe instability of the strip coal pillar may occur.